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33.2B: Birlashtiruvchi to'qimalar: bo'shashgan, tolali va xaftaga - biologiya

33.2B: Birlashtiruvchi to'qimalar: bo'shashgan, tolali va xaftaga - biologiya


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Birlashtiruvchi to'qima butun tanada joylashgan bo'lib, to'qimalar va suyaklarni qo'llab -quvvatlaydi.

O'quv maqsadlari

  • Har xil turdagi biriktiruvchi to'qimalarni farqlang

Asosiy fikrlar

  • Fibroblastlar - bu tanaga kerak bo'lgan har qanday biriktiruvchi to'qima hosil qiladigan hujayralar, chunki ular butun tanada harakatlana oladi va yangi to'qimalarni hosil qilish uchun mitozdan o'tishi mumkin.
  • Protein tolalari biriktiruvchi to'qima bo'ylab o'tib, barqarorlik va qo'llab -quvvatlashni ta'minlaydi; Ular kollagen, elastik yoki retikulyar tolalar bo'lishi mumkin.
  • Bo'shashgan biriktiruvchi to'qima ayniqsa qattiq emas, lekin qon tomirlarini o'rab oladi va ichki organlarni qo'llab -quvvatlaydi.
  • Kollagen tolalarining parallel to'plamlaridan tashkil topgan tolali biriktiruvchi to'qima dermis, tendonlar va ligamentlarda joylashgan.
  • Gialin xaftaga embrion suyagiga aylanmasidan oldin uning skeletini hosil qiladi; u kattalar tanasida burun uchida va uzun suyaklarning uchlari atrofida uchraydi, bu erda bo'g'imlarda ishqalanishni oldini oladi.
  • Fibrokartilaj - biriktiruvchi to'qimalarning eng kuchlisi; u katta stressni boshdan kechiradigan va yuqori darajadagi zarbani yutishni talab qiladigan, masalan, umurtqalar orasidagi hududlarda uchraydi.

Asosiy shartlar

  • xondrosit: xaftaga to'qimasini tashkil etuvchi hujayra
  • harakatchan: o'z-o'zidan harakat qilish qobiliyatiga ega bo'lish
  • fibroblast: biriktiruvchi to'qimada joylashgan hujayra, kollagen kabi tolalarni ishlab chiqaradi

Birlashtiruvchi to'qimalar

Biriktiruvchi to'qimalar tirik hujayralar va tuproq moddasi deb ataladigan jonsiz moddadan iborat matritsadan iborat. Tuproq moddasi organik moddadan (odatda oqsil) va noorganik moddadan (odatda mineral yoki suvdan) iborat. Birlashtiruvchi to'qimalarning asosiy hujayrasi - bu hali farqlanmagan, etuk bo'lmagan biriktiruvchi to'qima hujayrasi - fibroblast. Bu hujayra deyarli barcha biriktiruvchi to'qimalarda joylashgan tolalarni hosil qiladi. Fibroblastlar harakatchan, mitoz o'tkazishga qodir va qaysi biriktiruvchi to'qima kerak bo'lsa, sintez qila oladi. Ba'zi to'qimalarda makrofaglar, limfotsitlar va ba'zida leykotsitlar bo'lishi mumkin, boshqalarida esa maxsus hujayralar bo'lishi mumkin. Birlashtiruvchi to'qimalarda matritsa to'qima zichligini beradi. Birlashtiruvchi to'qima hujayralar yoki tolalarning yuqori konsentratsiyasiga ega bo'lsa, u mutanosib ravishda kamroq zich matritsaga ega.

Birlashtiruvchi to'qimalarda joylashgan organik qism yoki oqsil tolalari kollagen, elastik yoki retikulyar tolalardir. Kollagen tolalari to'qimalarga kuch beradi, uni yirtilmasligi yoki atrofdagi to'qimalardan ajralishini oldini oladi. Elastik tolalar elastin oqsilidan tayyorlanadi; bu tolalar uzunligining bir yarmigacha cho'zilib, asl o'lchamiga va shakliga qaytishi mumkin. Elastik tolalar to'qimalarning moslashuvchanligini ta'minlaydi. Retikulyar tolalar, biriktiruvchi to'qimalarda uchraydigan uchinchi turdagi oqsil tolasi, to'qima va u bog'langan boshqa organlarni qo'llab -quvvatlash uchun tolalar tarmog'ini tashkil etuvchi ingichka kollagen iplaridan iborat.

Bo'shashgan (Areolar) biriktiruvchi to'qima

Bo'shashgan biriktiruvchi to'qima, shuningdek, areolyar biriktiruvchi to'qima deb ataladi, biriktiruvchi to'qimaning barcha tarkibiy qismlarining namunasiga ega. Bo'shashgan biriktiruvchi to'qima ba'zi fibroblastlarga ega, garchi makrofaglar ham mavjud. Kollagen tolalari nisbatan keng va och pushti rangga bo'yalgan, elastik tolalar esa ingichka va to'q ko'kdan qora ranggacha bo'yalgan. To'qimalarning hosil bo'lgan elementlari orasidagi bo'shliq matritsa bilan to'ldiriladi. Birlashtiruvchi to`qimadagi material uni yirtilgan paxta tolasiga o`xshash yumshoq mustahkamlik beradi. Bo'shashgan biriktiruvchi to'qima har bir qon tomirlari atrofida joylashgan bo'lib, tomirni joyida ushlab turishga yordam beradi. To'qimalar ko'pchilik tana a'zolari atrofida va orasida ham joylashgan. Xulosa qilib aytganda, areolyar to'qima qattiq, ammo moslashuvchan va membranalardan iborat.

Tolali biriktiruvchi to'qima

Elyafli biriktiruvchi to'qimalarda ko'p miqdorda kollagen tolalari va oz sonli hujayralar yoki matritsa materiallari mavjud. Elyaflar parallel ravishda o'ralgan iplar bilan tartibsiz yoki muntazam joylashtirilishi mumkin. Tartibsiz joylashtirilgan tolali biriktiruvchi to'qimalar har tomondan stress paydo bo'ladigan joylarda, masalan, terining dermisida uchraydi. Muntazam tolali biriktiruvchi to'qima tendonlarda (mushaklarni suyaklarga bog'laydigan) va ligamentlarda (suyaklarni suyaklarga bog'laydigan) joylashgan.

Kıkırdak

Kıkırdak birlashtiruvchi to'qimadir. Xondrositlar (etuk xaftaga hujayralari) deb nomlangan hujayralar to'qima matritsasini va tolalarini hosil qiladi. Xondrositlar "lakuna" deb nomlangan to'qima ichidagi bo'shliqlarda uchraydi. ”

Kollagen va elastik tolalar kam bo'lgan xaftaga gialin xaftaga kiradi. Lakunalar to'qima bo'ylab tasodifiy tarqalib ketgan va matritsa odatdagi dog'lar bilan sutli yoki tozalangan ko'rinishga ega bo'ladi. Akulalarda tug'ilishdan oldingi rivojlanishning ba'zi bosqichlarida deyarli butun inson skeleti kabi xaftaga tushadigan skeletlari bor. Ushbu xaftaga qoldig'i inson burunining tashqi qismida saqlanadi. Gialin xaftaga, shuningdek, uzun suyaklarning uchlarida joylashgan bo'lib, ishqalanishni kamaytiradi va bu suyaklarning bo'g'imlarini yumshatadi.

Elastik xaftaga ko'p miqdorda elastik tolalar mavjud bo'lib, bu unga katta moslashuvchanlikni beradi. Ko'pchilik umurtqali hayvonlarning quloqlarida bu xaftaga, gırtlak qismlari yoki ovozli quti bor. Bundan farqli o'laroq, fibrokartilaj ko'p miqdordagi kollagen tolalarini o'z ichiga oladi, bu to'qimalarga katta kuch beradi. Fibrokartilaj umurtqali hayvonlarning umurtqali disklarini o'z ichiga oladi, ular katta stressga bardosh berishi kerak. Xaftaga ham bir turdan ikkinchisiga o'tishi mumkin. Masalan, tizza va elka kabi harakatlanuvchi bo'g'inlarda joylashgan gialin xaftaga ko'pincha yosh yoki travma natijasida shikastlanadi. Shikastlangan gialin xaftaga tolali xaftaga almashtiriladi, natijada "qattiq" bo'g'inlar paydo bo'ladi.


Birlashtiruvchi to'qima

Birlashtiruvchi to'qima boshqa to'qimalar turlari va organlari o'rtasida joylashgan. U ko'p miqdorda suv, bir necha turdagi hujayralar va tolali hujayradan tashqari matritsani o'z ichiga oladi. Organning biriktiruvchi to'qimasi odatda stroma deb ataladi. Ushbu to'qima turi uning tarkibiy qismlarining nisbatlariga ko'ra juda boshqacha tuzilishga ega bo'lishi mumkin. Ixtisoslashgan shakllarga suyak, xaftaga, yog 'va hatto qon kiradi.


Kıkırdak sinflarining grafik tasviri | Inson | Biologiya

Ushbu maqolada biz inson tanasidagi xaftaga sinflarining diagramma tasvirini muhokama qilamiz.

Gialin xaftaga diagrammasi:

U xaftaga hujayralaridan va hech qanday tolali (bo'shashgan) to'qimalardan butunlay mahrum bo'lgan bir hil tuproqli moddadan iborat. (1.44-rasm)

Gialin shisha degan ma'noni anglatadi va yangi holatda u shaffof mavimsi oq rangli massa ko'rinishida ko'rinadi. Kıkırdak xujayrasi yoki xondrositlar matritsada lakunalar deb ataladigan kichik bo'sh joylarni egallaydi. Bu hujayralar yumaloq burchakli katta va qo'shni hujayralar bosimi tufayli qo'shni yuzalar tekislanadi.

Yadro katta bo'lib, ikki yoki undan ortiq yadro bilan ta'minlangan. Hujayralar ikki, to'rt va boshqalardan tashkil topganida, bitta lakunada u hujayra uyasi deyiladi. Har bir hujayralar guruhi bitta ota -ona xaftaga hujayralarining ko'payishidan kelib chiqadi.

Sitoplazma glikogenga juda boy bo'lib, yog' tomchilari va mitoxondriyalarni o'z ichiga olishi mumkin. Elektron mikrosxop va sitoplazmada sitoplazmada yirik vakuolalarga ega bo'lgan qo'pol sirtli endoplazmatik to'r, Golgi apparati ko'rsatilgan.

Atrofdagi hujayralararo tuproq moddasi, hujayralar konsentrik halqalarda joylashgan va chuqurroq dog 'oladi. Hujayralar atrofidagi chuqur bo'yalgan bu qismga kapsula deyiladi.

Bu xaftaga yoki suyakning qattiq hujayralararo moddasi. Suyak matritsasi xaftaga qaraganda qiyinroq, faqat birinchisida kaltsiy tuzlarining cho'kishi uchun. Gialin xaftaga tushganda, bu hujayralararo modda matritsasi juda ko'p va yangi holatda bir hil bo'lib ko'rinadi, lekin oddiy fiksatsiyada u kollagen tolalari va amorf hujayralararo moddani ko'rsatadi. Ushbu bo'limlarda polarizatsiya qiluvchi mikroskop ostida kollagen tolalari ko'rinadi.

Er osti moddasi xondroitin-4 sulfat va xondroitin-6-sulfat bilan birgalikda muko-oqsilning polimeri bo'lgan xondromukoprotein mavjudligi sababli yuqori bazofildir. Qaynatganda, xaftaga sekin eriydi va xaftaga yopishtiruvchi - xondrin tarkibida jelatin, xondromukoproteinlar va boshqa albuminli moddalar paydo bo'ladi.

Gialin xaftaga zich biriktiruvchi to'qima kapsulasining qattiq qatlami bilan o'ralgan bo'lib, u peri va shixondriyum deb ataladi. U bo'shashmaydigan (tolali) va zich (xondrogenik) qatlamlardan iborat bo'lib, ularni ajratib bo'lmaydigan fibrositlarga ega.

U suyaklarning bo'g'im uchida (bo'g'im xaftaga), o'sib borayotgan uzun suyaklarning epifiz va diafiz o'rtasida (epifiz xaftaga), qovurg'alarning oldingi uchida (kostal xaftaga) joylashgan. Burunning xaftaga, tashqi eshitish go'shti, halqum, traxeya va bronxlar ham shu sinfga kiradi.

Kostikulyar xaftaga perikondriyum bilan qoplangan. U suyaklarning periosteum bilan bir xil maqsadlarga xizmat qiladi. Kıkırdakın oziqlanishi va kislorod perikondriyumun qon tomirlari orqali ta'minlanadi. Qalin xaftaga bu erda va u erda qon tomirlarini tashuvchi mayda kanallar orqali kirib keladi.

Fibrokartilajning diagrammatik ko'rinishi:

Ushbu turdagi xaftaga moslashuvchanlik va qat'iylik bilan katta kuchlanish kuchi talab qilinadigan joylarda mavjud. U kesish kuchlariga bardosh bera oladi. Hujayralar katta bo'lib, guruhlarga bo'linadi va lakunalar ichiga joylashtiriladi. Fibrokartilaj hujayralararo moddasida gialin xaftaga qaraganda ko'proq kollagenni o'z ichiga oladi va perikondri va shyum yo'q. Hujayra guruhlari orasida oq tolali to'qimalarning to'plamlari ko'rinadi. (1.45 -rasm)

U umurtqalararo disklarda, tizza boʻgʻimlari menisklarida, pastki jagʻ boʻgʻimlarida, pubis sim&shifizlarida, suyaklardagi koʻplab tendon yivlarining qoplamalarida, baʼzi tendonlarning biriktirmalarida va boshqalarda uchraydi.

Elastik xaftaga diagrammasi:

U moslashuvchanlik bilan qo'llab-quvvatlash zarur bo'lgan sohada mavjud. U sariq rangga ega va ko'plab elastik tolalarni o'z ichiga oladi. U gialin xaftaga faqat matritsada ulkan elastik tolalari borligidan farq qiladi. Elastik tolalarga qo'shimcha matritsa kollagen tolalarini o'z ichiga oladi. (1.46 -rasm)

U tashqi quloqda (pin va shyna), Eustaki naychasida, epiglottisda va laringeal xaftaga tushadigan qismlarda uchraydi.


Birlashtiruvchi to'qima

Inson tanasi to'rtta asosiy to'qimalardan iborat: asab, mushak, epiteliya va biriktiruvchi to'qima. Birlashtiruvchi to'qima eng ko'p tarqalgan, keng tarqalgan va xilma -xil. Unga tolali to'qimalar, yog ', xaftaga, suyak, suyak iligi va qon kiradi. Nomidan ko'rinib turibdiki, biriktiruvchi to'qimalar ko'pincha boshqa organlarni bir -biriga bog'lab turadi, a'zolarni joyida ushlab turadi, ularni yostiqlaydi va bo'shliqni to'ldiradi.

Biriktiruvchi to‘qimaning boshqa turlardan farqi shundaki, hujayradan tashqari modda (matritsa) odatda hujayralarga qaraganda ko‘proq joy egallaydi va hujayralar bir-biridan nisbatan uzoqroq joylashgan. Yog 'istisno bo'lib, hujayralari bir -biri bilan yaqin aloqada, lekin katta, tirik bo'lmagan, hujayra ichidagi lipid tomchilar, yog'da tirik moddalarga qaraganda ko'proq jonsiz moddalar mavjud.

The matritsa biriktiruvchi to'qima odatda tolalar va xususiyatsiz tuproqli moddadan iborat. Birlashtiruvchi to'qimalarda eng ko'p tolalar qattiqdir oqsil kollagen deb ataladi. Ba'zi go'sht bo'laklarida ko'riladigan tendonlar, ligamentlar va oq ipli to'qima (fastsiya) deyarli teri kollagenidan iborat bo'lib, teri biriktiruvchi to'qima qatlamidan (dermis) iborat. Kollagen suyak va xaftaga ham mustahkamlanadi. Elastik va retikulyar tolalar kamroq taqsimlangan biriktiruvchi to'qima oqsillaridir.

Tuproq moddasi, qonda bo'lgani kabi, jelatinli bo'lishi mumkin areolar to'qima kauchuk, xaftaga yoki kalsifikatsiyalangan va toshli, suyakdagi kabi. U asosan suv va kichik erigan moddalardan iborat ionlari va organik molekulalar, lekin ba'zi to'qimalarning jelatinsimon va kauchuksimon konsistentsiyasi tuproq moddasida juda ko'p protein-uglevod komplekslaridan kelib chiqadi. Suyakning qattiq mustahkamligi asosan erigan moddadagi kaltsiy fosfat tuzlaridan kelib chiqadi.

Birlashtiruvchi to'qima hujayralarining bir qismi fibroblastlar (kollagen tolalarini ishlab chiqaradigan va tendon va ligamentlardagi yagona hujayra turi) adipotsitlar (yog 'hujayralari) leykotsitlar (oq qon hujayralari, shuningdek, qon hujayralaridan tashqarida joylashgan).

Biriktiruvchi to‘qima turi va xususiyatlari Funksiyalar Joylar
Areolar (bo'sh) biriktiruvchi to'qima. Har xil turdagi hujayralarga ega tasodifiy tolalarning bo'sh to'plami Epitelni oziqlantiradi va yostiqlaydi, infektsiyadan immunitet himoyalanish uchun maydon beradi, organlarni bir -biriga bog'laydi, asab va qon tomirlarining boshqa to'qimalar orqali o'tishiga imkon beradi. Qon tomirlari, nervlar, qizilo'ngach va boshqa organlarning barcha epiteliya qoplamalari ostida muskullar plevra va perikard qoplari orasidagi fastsiya.
Yog 'to'qimasi (yog'). Yog 'bilan to'lgan katta adipotsitlar va kam hujayradan tashqari matritsa. Energiyani saqlaydi, tana issiqligini saqlaydi, ko'p a'zolarni yostiq va himoya qiladi, bo'shliqni to'ldiradi, tanani shakllantiradi Buyraklar, yurak va ko'z atrofidagi teri ostidagi ko'krak qorin pardalari (tutqichlar)
Zich tartibsiz biriktiruvchi to'qima. Zich oraliqda, tasodifiy joylashtirilgan tolalar va fibroblastlar. Qattiqlik organlarni shikastlanishdan himoya qiladi, ko'plab organlar atrofini himoya kapsulalari bilan ta'minlaydi Suyak atrofidagi jigar, taloq va boshqa organlar tolali qobig'i atrofidagi teri kapsulalari
Zich muntazam biriktiruvchi to'qima. Zich joylashgan, parallel kollagen tolalar va fibroblastlar. Suyaklarni bir-biriga bog'laydi va mushakni suyakka biriktiradi, kuchni mushakdan suyakka o'tkazadi Tendonlar va ligamentlar
Kıkırdak (to'qmoq). Kichik bo'shliqlarda (lakunalar) kauchuk matritsada keng tarqalgan hujayralar. Bo'g'imlarning harakatini osonlashtiradi, bo'g'inlardagi siqilishga qarshilik ko'rsatadi, havo yo'llarini ochiq shaklda ushlab turadi, tashqi quloqning harakatlanishini ta'minlaydi, homila skeletining oldingi qismidir. Tashqi quloq, halqum, traxeya atrofidagi halqalar, suyaklarning bo'g'im yuzalari va o'sish zonalari, qovurg'alar va to'sh suyagi orasidagi, intervertebral disklar
Suyak (suyak to'qimasi). Matritsaning katta qismi bo'shliqlarda joylashgan bo'lib, konsentrik piyozsimon qatlamlarda qattiq mineralizatsiyalangan matritsada joylashgan. Tanani jismoniy qo'llab-quvvatlaydi, harakatni ta'minlaydi, yumshoq organlarni o'rab oladi va himoya qiladi, kaltsiy va fosforni saqlaydi va chiqaradi.   Skelet
Qon. Eritrotsitlar, leykotsitlar va trombotsitlar Ozuqa moddalari, gazlar, chiqindilar, gormonlar, Yurak-qon tomir tizimida aylanib yuradi

tolali biriktiruvchi to'qimalarda qon oqimi) makrofaglar (ma'lum leykotsitlardan kelib chiqqan yirik fagotsitar hujayralar) eritrotsitlar (qizil qon tanachalari, faqat qon va suyak iligida topilgan) xondrositlar (xaftaga hujayralari) va osteotsitlar (suyak hujayralari).

Yuqoridagi jadvalda biriktiruvchi to'qimalarning asosiy turlarining joylashuvi va funktsiyalari keltirilgan. Birlashtiruvchi to'qima haqida batafsil ma'lumotni darsliklarda topish mumkin gistologiya va inson anatomiyasi.


Umurtqali hayvonlar skeletidagi suyak va biriktiruvchi to'qima

Birlashtiruvchi to'qima

Birlashtiruvchi to'qima tanada juda ko'p: u oz sonli hujayralar, keng hujayralararo mineral va/yoki oqsil va boy qon ta'minoti bilan ajralib turadi. U boshqa hujayralarni qo'llab -quvvatlaydi, himoya qiladi va bog'laydi. Birlashtiruvchi to'qima "biriktiruvchi to'qima", xaftaga, suyak va qonni o'z ichiga oladi.

Birlashtiruvchi to'qima To'g'ri

Tegishli biriktiruvchi to'qima odatda cho'zilgan fibroblast hujayralari va ko'proq yoki kamroq suyuqlik hujayralararo materialga ega. Besh tur mavjud:

(1) bo'shashgan areolyar to'qima organlar atrofida, shilliq pardalar va teri ostida joylashgan gialuron kislotasi ba'zi tolalar va hujayralar bilan hujayralararo matritsada joylashgan.

(2) yog 'to'qimasi yog 'saqlash uchun maxsus hujayralarga ega bo'lgan areolyar to'qimadir: u hayot davomida o'sishi mumkin

(3) zich biriktiruvchi to'qima kollagen tolalari bor: u tendonlarda, ligamentlarda, mushak fastsiyalarida va boshqalarda uchraydi.

(4) elastik biriktiruvchi to'qima shoxlangan elastik tolalarga ega: arterial devorlarda, traxeyada, ovoz paychalarida va boshqalarda uchraydi.

(5) retikulyar biriktiruvchi to'qima tolalar tarmog'iga ega: u jigar, taloq, limfa tugunlari va boshqalarning bo'sh ramkasini hosil qiladi.

Kıkırdaklı xaftaga xondrositlar va kollagen va elastik tolalarni o'z ichiga olgan jel matritsaga ega. U ichkaridan ham, tashqaridan ham o'sadi.

  • Gialin xaftaga suyaklarning uchlarida, burun va nafas yo'llarida topilgan va bardoshli oynali mustahkamlikka ega.
  • Fibrokartilaj juda kuchli. Kollagen bilan mustahkamlanib, suyaklarni bog'laydi (masalan, tos suyagida) va umurtqalararo disklarni (ko'p umurtqali hayvonlarda notoxordning qoldig'i) hosil qiladi.
  • Elastik xaftaga tashqi quloq (pinna) va halqum shakllarini saqlaydi.

Suyak

Suyak skelet tizimining asosiy komponenti hisoblanadi. Suyakning funktsiyalari (xaftaga bilan) quyidagilarni o'z ichiga oladi:

  • qo'llab -quvvatlash (tana tuzilishi)
  • himoya (masalan, bosh suyagi)
  • qo'l (oyoq -qo'llar)
  • minerallarni saqlash (ayniqsa, kaltsiy va fosfor)
  • sintetik qon hujayralarini saqlash (qizil suyak iligi: faqat quruqlikdagi umurtqali hayvonlar uchun)
  • energiyani saqlash (sariq suyak iligidagi yog ': faqat quruqlikdagi umurtqali hayvonlar).

Suyak gistologiyasi

Suyak suyak to'qimalarining hujayralararo matritsasi bilan o'ralgan ko'plab, keng ajratilgan hujayralardan iborat. Suyak hujayralarining to'rtta asosiy turi mavjud.

(1) Osteoprogenitor hujayralar osteoblastlarni keltirib chiqaradigan ildiz hujayralardir: ular suyaklarni o'rab turgan periosteumda va ichki suyak bo'shlig'ini qoplaydigan endosteum membranasida, shuningdek, qon tomirlarini olib o'tuvchi suyak kanallarida joylashgan.

(2) Osteoblastlar (suyak yuzalarida) suyak minerallari va kollagenni ajratadi.

(3) Osteotsitlar suyak matritsasidagi osteoblastlar bo'lib, ular o'z atrofida to'plangan, ular suyakning ishlashini ta'minlaydi.

(4) Osteoklastlar (monotsitlar/makrofaglar seriyasidagi hujayralar) ortiqcha suyak materialini qaytaradi. Suyak matritsasida kollagen tolalari va kristalli mineral (asosan gidroksiapatit, ba'zi karbonat, ftorid, sulfat va magniy tuzlari bilan gidratlangan kaltsiy fosfat) mavjud. Suyakning 33% ni kollagen oqsili tashkil qiladi: minerallar oqsil atrofida kristallanadi. Qarish paytida suyak tarkibidagi protein miqdori kamayadi, bu esa uni mo'rt qiladi. E'tibor bering, suyak tirik to'qima.

Suyak morfologiyasi

Odatda uzun suyak (masalan, femur) metafizlar bilan bog'langan mil (diafiz) va uchlarini (epifizlarni) o'z ichiga oladi. Uzun suyakning silindrsimon tuzilishi materialning ko'p qismini periferiya bo'ylab to'playdi (ko'ndalang kesimda ko'rinib turganidek), bu egilish momentlariga maksimal qarshilik ko'rsatadi. Gialin xaftaga yupqa qatlami epifizlarni yopadi va bo'g'imlarning ishqalanishini kamaytiradi. Suyak periosteum bilan qoplangan: uning tashqi tolali qatlami (nervlar va qon tomirlari bilan) va suyak hosil qiluvchi hujayralar bilan ichki osteogenik qatlam mavjud. O'rtada (yuqori, quruqlikdagi umurtqali hayvonlarda) suyak moddasidan endosteum bilan ajratilgan ilik bo'shlig'i.

Yilni suyak

  • Yilni suyakning ichida bir nechta bo'shliqlar mavjud bo'lib, u gubka suyagini qoplaydi (pastga qarang) va o'qda ayniqsa qalin. U konsentrik halqa tuzilishiga ega.
  • Periosteumdan chiqqan tomirlar va nervlar teshilgan kanallar orqali suyakka kirib, ilik bo'shlig'ining nervlari va tomirlari bilan bog'lanadi. Haversian kanallari ular uzunlamasına suyak orqali o'tadilar.
  • Gavers kanallari atrofida konsentrik lamellar, qattiq "suyak" halqalari. Lamellar orasida kichik bo'shliqlar, lakunalar, tarkibida osteotsitlar mavjud.
  • Lakunalardan nurlanish kanalikuli Osteotsitlar va hujayradan tashqari suyuqliklar, kanallar bir -biri bilan va Haversian kanallari bilan o'zaro bog'liq jarayonlarni o'z ichiga oladi.
  • Haversian kanali va uning atrofidagi lamellar, lakunalar, osteotsitlar va kanalikulalar osteon.

Shimgichli suyak

Shimsimon (kansellu) suyakda haqiqiy osteonlar yo'q, u nozik plitalarning tartibsiz panjarasidan iborat (trabekulalar). Trabekulalar ichida osteotsitlar bo'lgan lakunalar bor. Suyak suyagi qon tomirlariga boy va iligi trabekulalar tarmog'ida joylashgan. Trabekulalar suyakdagi asosiy siqilish va kuchlanish kuchlariga parallel ravishda hizalanadi.

Ossifikatsiya

  • Suyak tomonidan shakllanadi osteogenez (ossifikatsiya)embriondagi mezenximal hujayralar osteoplastlar va osteoklastlarga bo'linadigan osteoprogenitor hujayralarga aylanishi bilan boshlanadi.
  • Membranalararo ossifikatsiya embrion, homila va bolaning tolali membranalarida (masalan, bosh suyagi) paydo bo'ladi. Osteoblastlar klasterlari tolali matritsada to'planib, kaltsiy tuzlarini to'playdi.
  • Endoxondrial ossifikatsiya xaftaga modeli ichida sodir bo'ladi, asosiy ossifikatsiya markazi mildir. Kıkırdakların parchalanishi kavitasyona olib keladi: bo'shliqlar birlashib, ilik bo'shlig'ini hosil qiladi.
  • Osteoblastlar mineral va oqsil biriktiradilar, natijada xaftaga epifiz o'rnini bosadilar, bu erda faqat xaftaga chig'anoqli bo'g'imlarning oxirgi qatlamlari qoladi. epifiz plitalari epifizlar va o'q o'rtasida: ikkinchisi suyak o'sishi uchun joylardir.

Suyak o'sishi

  • Suyaklar cho'zmoq tomonidan apozitsion o'sish gormonal nazorat ostida epifiz plitalarida (masalan, o'sish gormoni). Plastinkaning epifizal tomonida yangi xaftaga hujayralari paydo bo'ladi va eski xaftaga hujayralari vayron qilinadi va uning o'rniga plastinkaning mil tomonidagi suyak qo'yiladi (shu tariqa plastinka doimiy qalinlikka ega, lekin mil uzunligi oshadi).
  • Diametrdagi o'sish Periosteumdagi osteoblastlar suyakning tashqi yuzasiga yangi suyak qo'shganda paydo bo'ladi, osteoklastlar esa mil ichidagi suyak materialini emirib, ilik bo'shlig'ini kengaytiradi.

Modellashtirish

  • Suyak materialining shakllanishi va rezorbsiyasi o'rtasida gomeostatik muvozanat mavjud qayta qurish. Kaltsiy, fosfor va C va D vitaminlari muhim ahamiyatga ega.
  • Suyaklarning umumiy o'sishi qalqonsimon bezdan oldingi gipofiz kalsitoninidan o'sish gormoni tomonidan boshqariladi, osteoklast faolligini inhibe qiladi paratiroid gormoni (paratormon, PTH) osteoklast faolligini oshiradi jinsiy steroidlar balog'at davrida suyak o'sishi va epifizning xaftaga hujayralarini yo'q qilishiga yordam beradi. plitalar va epifizal birlashma, erta balog'at yoshida suyak o'sishi to'xtaydi.
  • Jismoniy mashqlar paytida mexanik stressga duchor bo'lgan suyak osteoblastlarni rag'batlantiradigan piezoelektrik oqimlarning (mineral kristallardan) hosil bo'lishi tufayli kuchini oshirishi mumkin. Qarish jarayonida kaltsiy suyaklardan chiqariladi, bu esa osteoporozga moyilligi kamroq bo'lgan kollagen keksa suyaklarni mo'rtroq qiladi.

Bo'g'inlar

Bo'g'inlar Bu suyaklar (yoki xaftaga va suyak) o'rtasidagi aloqa nuqtalari bo'lib, ular har xil darajadagi harakatni ta'minlaydi, ular yo'qdan erkin harakatlanadigangacha.


Kıkırdak - biriktiruvchi to'qima. Xondrositlar (etuk xaftaga hujayralari) deb ataladigan hujayralar to'qimalarning matritsasini va tolalarini hosil qiladi. Xondrositlar "lakuna" deb nomlangan to'qima ichidagi bo'shliqlarda uchraydi.

Kollagen va elastik tolalar kam bo'lgan xaftaga gialin xaftaga kiradi. Lakunalar to'qimalar bo'ylab tasodifiy tarqalib ketgan va matritsa muntazam dog'lar bilan sutli yoki tozalangan ko'rinishga ega bo'ladi. Akulalarda xaftaga chalingan skeletlari bor, tug'ilishdan oldingi rivojlanishning deyarli barcha bosqichlarida bo'lgani kabi. Ushbu xaftaga qoldig'i inson burunining tashqi qismida saqlanadi. Gialin xaftaga, shuningdek, uzun suyaklarning uchlarida joylashgan bo'lib, ishqalanishni kamaytiradi va bu suyaklarning bo'g'imlarini yumshatadi.


Mushak to'qimasi

Mushak to'qimasi qobiliyatiga ega bo'lgan maxsus hujayralar bilan tananing harakati uchun javobgardir shartnoma. Ajablanarlisi shundaki, u hayvonlar energiyasining ko'p qismini oladi. Mushak to'qimalarining uch turi mavjud: skelet, silliq va yurak.

Skelet mushaklari uchun javobgardir ixtiyoriy harakatlar va u skelet tizimiga tendonlar orqali biriktirilgan. Skelet mushaklarini hosil qiluvchi mushak hujayralari uzun va tolali joylashtirilgan. Silliq mushak bo'lishi mumkin bo'lmagan qisqarishlar uchun javobgardir ixtiyoriy ravishda ovqat hazm qilish tizimi va arteriyalar devorlari kabi nazorat qilinadi. Yurak muskul yurak devorini hosil qiladi va yurakni tanamiz bo'ylab qon quyish uchun shartnoma tuzadi. Uning xususiyatlari skelet mushaklariga o'xshaydi, lekin uning harakatlari ixtiyoriy emas.


Birlashtiruvchi to'qima bo'yicha MCQ

1. To‘g‘ri gapni toping
(a) Areolyar to'qima - bo'shashgan biriktiruvchi to'qima
(b) Tendon - maxsus biriktiruvchi to'qima
v) Kıkırdak bo'shashgan biriktiruvchi to'qimadir
d) Yog 'to'qimasi zich biriktiruvchi to'qimadir

2. Odamning eritrotsitlari bilan solishtirganda, baqaning eritrotsitlari
(a) kichikroq va kamroq
(b) yadroli va gemoglobinsiz
(c) yadroli, lekin gemoglobin bilan
(d) yadroli va gemoglobin bilan

3. Burunning uchi va tashqi quloqlari bor
a) areolyar to’qima
(b) ligament
(c) xaftaga
d) suyak

4. Mast hujayralari o'z ichiga oladi
a) geparin va gistamin
b) geparin va kalsitonin
v) serotonin va melanin
d) vazopressin va relaksin

5. Hujayradan tashqarida mavjud bo'lgan eng katta material
a) qatlamli epiteliy
b) chiziqli mushak
v) miyelinli nerv tolalari
d) Areolyar to'qima

6. Xaftaga tushadigan peptidoglikan
(a) ossein
(b) xondroitin
(c) xaftaga
(d) kazein

7. Antikorlar tomonidan ajratiladi
a) yog 'hujayralari
(b) retikulyar hujayralar
(c) plazma hujayralari
d) mast hujayralari

8. Gistamin tomonidan ajratiladi
a) gistotsitlar
b) limfotsitlar
v) fibroblastlar
d) mast hujayralari

9. Ligament - bu
(a) o'zgartirilgan sariq elastik tolali to'qima
(b) elastik bo'lmagan oq tolali to'qima
(c) o'zgartirilgan oq tolali to'qima
(d) yuqoridagilarning hech biri

10. Kollagen
a) uglevod
(b) lipid
(c) tolali oqsil
d) globulyar oqsil


BIO 140 - Inson biologiyasi I - Darslik

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Birlashtiruvchi to'qima qo'llab -quvvatlaydi va himoya qiladi

  • Birlashtiruvchi to'qimalarning turlarini aniqlang va farqlang: to'g'ri, qo'llab-quvvatlovchi va suyuqlik
  • Birlashtiruvchi to'qimalarning vazifalarini tushuntiring

Nomidan ko'rinib turibdiki, biriktiruvchi to'qimaning asosiy vazifalaridan biri to'qimalar va organlarni bog'lashdir. Epiteliya to'qimasidan farqli o'laroq, ular orasida hujayradan tashqari bo'sh joy bo'lmagan yoki bo'lmagan hujayralardan tashkil topgan, biriktiruvchi to'qima hujayralari matritsada tarqalgan. Matritsa odatda biriktiruvchi to'qima hujayralari tomonidan ishlab chiqarilgan ko'p miqdordagi hujayradan tashqari materialni o'z ichiga oladi. Ushbu to'qimalarning ishlashida matritsa katta rol o'ynaydi. Matritsaning asosiy komponenti ko'pincha oqsil tolalari bilan kesishgan tuproqli moddadir. Bu tuproq moddasi odatda suyuqlikdir, lekin u suyaklarda bo'lgani kabi mineralizatsiyalangan va qattiq bo'lishi ham mumkin. Birlashtiruvchi to'qimalar har xil shakllarda bo'ladi, lekin ular odatda uchta umumiy xususiyatga ega: hujayralar, ko'p miqdordagi amorf tuproq moddasi va oqsil tolalari. Har bir komponentning miqdori va tuzilishi to'qima funktsiyasiga bog'liq, bunda suyak tarkibidagi qattiq moddalar, tanani qo'llab -quvvatlaydi, masalan, fagotsitik hujayralar patogenlarni yutib yuboradi, shuningdek to'qimalarni hujayrali qoldiqlardan tozalaydi.

Birlashtiruvchi to'qimalarning funktsiyalari

Birlashtiruvchi to'qimalar organizmda ko'p funktsiyalarni bajaradi, lekin eng muhimi, ular mushak hujayralarini o'rab turgan biriktiruvchi to'qima qobig'idan, mushaklarni suyaklarga biriktiruvchi tendonlarga va tananing pozitsiyalarini qo'llab-quvvatlovchi skeletga boshqa to'qimalarni qo'llab-quvvatlaydi va bog'laydi. Himoya - biriktiruvchi to'qimaning yana bir asosiy vazifasi, nozik organlarni va, albatta, suyak tizimini himoya qiladigan tolali kapsulalar va suyaklar shaklida. Birlashtiruvchi to'qimadagi maxsus hujayralar tanani tanaga kiradigan mikroorganizmlardan himoya qiladi. Suyuqlik, ozuqa moddalari, chiqindilar va kimyoviy xabarchilarni tashish maxsus biriktiruvchi to'qimalar - qon va limfa bilan ta'minlanadi. Yog 'hujayralari ortiqcha energiyani yog' shaklida saqlaydi va tananing issiqlik izolatsiyasiga hissa qo'shadi.

Embrion biriktiruvchi to'qima

Barcha biriktiruvchi to'qimalar embrionning mezodermal qatlamidan kelib chiqadi (qarang: [havola]). Embrionda rivojlanadigan birinchi biriktiruvchi to'qima mezenximadir, keyinchalik barcha biriktiruvchi to'qimalar kelib chiqqan ildiz hujayralari chizig'i. Mezenxima hujayralari klasterlari kattalar to'qimasida tarqalgan va biriktiruvchi to'qima shikastlangandan keyin almashtirish va ta'mirlash uchun zarur bo'lgan hujayralarni etkazib beradi. Embrion biriktiruvchi to'qima ikkinchi turi kindik ichakchasida hosil bo'ladi, shilliq biriktiruvchi to'qima yoki Wharton & rsquos jeli deb ataladi. Tug'ilgandan keyin bu to'qima endi yo'q bo'lib, butun tanada faqat tarqoq mezenxima hujayralarini qoldiradi.

Birlashtiruvchi to'qimalarning tasnifi

Birlashtiruvchi to'qimalarning uchta keng toifasi ularning tuproq moddasining xususiyatlariga va matritsada joylashgan tolalar turlariga ko'ra tasniflanadi (jadval). Birlashtiruvchi to'qima to'g'ri biriktiruvchi to'qima va zich biriktiruvchi to'qimalarni o'z ichiga oladi. Ikkala to'qimalarda turli xil hujayra turlari va yopishqoq tuproqli moddada to'xtatilgan oqsil tolalari mavjud. Zich biriktiruvchi to'qima kuchlanish, elastiklik va himoyani ta'minlaydigan tolalar to'plamlari bilan mustahkamlanadi. Bo'shashgan biriktiruvchi to'qimalarda tolalar bo'shashgan holda joylashadi, ular orasida katta bo'shliqlar qoladi. Qo'llab -quvvatlovchi biriktiruvchi to'qima va suyak va xaftaga va mdashpadaga tuzilish va kuch beradi va yumshoq to'qimalarni himoya qiladi. Matritsadagi bir nechta alohida hujayralar va zich o'ralgan tolalar bu to'qimalarni tavsiflaydi. Suyakda matritsa qattiq va kaltsiy tuzlari to'planganligi sababli kalsifikatsiyalangan deb ta'riflanadi. Suyuq biriktiruvchi to'qimada, boshqacha aytganda, limfa va qonda turli xil maxsus hujayralar tuzlar, ozuqa moddalari va erigan oqsillarni o'z ichiga olgan suvli suyuqlikda aylanadi.

1-jadval: Birlashtiruvchi to'qimalarga misollar

To'g'ri biriktiruvchi to'qima

Fibroblastlar barcha biriktiruvchi to'qimalarda mavjud (1-rasm). Fibrositlar, adipotsitlar va mezenximal hujayralar sobit hujayralardir, ya'ni ular biriktiruvchi to'qima ichida qoladi. Boshqa hujayralar kimyoviy signallarga javoban biriktiruvchi to'qima ichida va tashqarisida harakatlanadi. Makrofaglar, mast hujayralari, limfotsitlar, plazma hujayralari va fagotsitar hujayralar to'g'ri biriktiruvchi to'qimada joylashgan, ammo aslida tanani himoya qiluvchi immunitet tizimining bir qismidir.

1 -rasm: Fibroblastlar bu tolali to'qimalarni ishlab chiqaradi. To'g'ri biriktiruvchi to'qima fibrotsitlar, adipotsitlar va mezenxima hujayralarini o'z ichiga oladi. LM × 400. (Michigan universiteti tibbiyot fakulteti regentlari tomonidan taqdim etilgan mikrografiya va nusxasi 2012)

Hujayra turlari

Birlashtiruvchi to'qimalarda eng ko'p to'plangan hujayra fibroblastdir. Fibroblastlar chiqaradigan polisaxaridlar va oqsillar hujayradan tashqari suyuqliklar bilan birikib, yopishqoq tuproqli moddalarni hosil qiladi, ular ko'milgan tolali oqsillar bilan hujayradan tashqari matritsani hosil qiladi. Siz kutganingizdek, fibroblastning kamroq faol shakli bo'lgan fibrotsit biriktiruvchi to'qimalarda ikkinchi eng keng tarqalgan hujayra turidir.

Adipotsitlar - lipidlarni sitoplazmaning ko'p qismini to'ldiruvchi tomchilar shaklida saqlaydigan hujayralar. Adipotsitlarning ikkita asosiy turi mavjud: oq va jigarrang. Jigarrang adipotsitlar lipidlarni shuncha tomchi to'playdi va yuqori metabolik faollikka ega. Aksincha, oq yog 'adipotsitlari lipidlarni bitta katta tomchi sifatida saqlaydi va metabolik jihatdan kamroq faoldir. Ularning katta miqdordagi yog'ni saqlash samaradorligi semiz odamlarda guvohlik beradi. Adipotsitlarning soni va turi to'qima va joylashuvga bog'liq bo'lib, populyatsiyadagi shaxslar orasida farq qiladi.

Mezenxima hujayrasi ko'p potentsial kattalar ildiz hujayralaridir. Ushbu hujayralar shikastlangan to'qimalarni tiklash va davolash uchun zarur bo'lgan har qanday turdagi biriktiruvchi to'qima hujayralariga ajralishi mumkin.

Makrofag hujayrasi qon tomirlaridan biriktiruvchi to'qima matritsasiga kiradigan qon hujayralarining bir turi bo'lgan monotsitdan olingan katta hujayradir. Makrofag hujayralari immunitet tizimining muhim tarkibiy qismi bo'lib, u organizmni potentsial patogenlar va buzilgan xost hujayralaridan himoya qiladi. Rag'batlantirilganda, makrofaglar kimyoviy xabarchilar vazifasini bajaradigan kichik oqsillar - sitokinlarni chiqaradi. Sitokinlar immunitet tizimining boshqa hujayralarini zararlangan joylarga jalb qiladi va ularning faoliyatini rag'batlantiradi. Rouming yoki erkin makrofaglar amoeboid harakati bilan tez harakat qilib, yuqumli agentlar va uyali qoldiqlarni o'z ichiga oladi. Bundan farqli o'laroq, sobit makrofaglar o'z to'qimalarining doimiy rezidentlari hisoblanadi.

Birlashtiruvchi to'qimalarda joylashgan mast hujayrasi ko'plab sitoplazmatik granulalarga ega. Ushbu granulalarda gistamin va geparin kimyoviy signallari mavjud. Tirnashgan yoki shikastlanganda mast hujayralar yallig'lanish vositachisi bo'lgan gistaminni chiqaradi, bu esa shikastlanish yoki infektsiya joyida vazodilatatsiyaga va qon oqimining ko'payishiga olib keladi, qichishish, shishish va qizarish bilan birga allergik reaktsiya sifatida tan olasiz. Qon hujayralari singari, mast hujayralari ham gematopoetik ildiz hujayralaridan olingan va immunitet tizimining bir qismidir.

Connective Tissue Fibers and Ground Substance

Three main types of fibers are secreted by fibroblasts: collagen fibers, elastic fibers, and reticular fibers. Collagen fiber is made from fibrous protein subunits linked together to form a long and straight fiber. Collagen fibers, while flexible, have great tensile strength, resist stretching, and give ligaments and tendons their characteristic resilience and strength. These fibers hold connective tissues together, even during the movement of the body.

Elastic fiber contains the protein elastin along with lesser amounts of other proteins and glycoproteins. The main property of elastin is that after being stretched or compressed, it will return to its original shape. Elastic fibers are prominent in elastic tissues found in skin and the elastic ligaments of the vertebral column.

Reticular fiber is also formed from the same protein subunits as collagen fibers however, these fibers remain narrow and are arrayed in a branching network. They are found throughout the body, but are most abundant in the reticular tissue of soft organs, such as liver and spleen, where they anchor and provide structural support to the parenchyma (the functional cells, blood vessels, and nerves of the organ).

All of these fiber types are embedded in ground substance. Secreted by fibroblasts, ground substance is made of polysaccharides, specifically hyaluronic acid, and proteins. These combine to form a proteoglycan with a protein core and polysaccharide branches. The proteoglycan attracts and traps available moisture forming the clear, viscous, colorless matrix you now know as ground substance.

Loose Connective Tissue

Loose connective tissue is found between many organs where it acts both to absorb shock and bind tissues together. It allows water, salts, and various nutrients to diffuse through to adjacent or imbedded cells and tissues.

Adipose tissue consists mostly of fat storage cells, with little extracellular matrix (Figure 2 ). A large number of capillaries allow rapid storage and mobilization of lipid molecules. White adipose tissue is most abundant. It can appear yellow and owes its color to carotene and related pigments from plant food. White fat contributes mostly to lipid storage and can serve as insulation from cold temperatures and mechanical injuries. White adipose tissue can be found protecting the kidneys and cushioning the back of the eye. Brown adipose tissue is more common in infants, hence the term &ldquobaby fat.&rdquo In adults, there is a reduced amount of brown fat and it is found mainly in the neck and clavicular regions of the body. The many mitochondria in the cytoplasm of brown adipose tissue help explain its efficiency at metabolizing stored fat. Brown adipose tissue is thermogenic, meaning that as it breaks down fats, it releases metabolic heat, rather than producing adenosine triphosphate (ATP), a key molecule used in metabolism.

Figure 2: This is a loose connective tissue that consists of fat cells with little extracellular matrix. It stores fat for energy and provides insulation. LM × 800. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)

Areolar tissue shows little specialization. It contains all the cell types and fibers previously described and is distributed in a random, web-like fashion. It fills the spaces between muscle fibers, surrounds blood and lymph vessels, and supports organs in the abdominal cavity. Areolar tissue underlies most epithelia and represents the connective tissue component of epithelial membranes, which are described further in a later section.

Reticular tissue is a mesh-like, supportive framework for soft organs such as lymphatic tissue, the spleen, and the liver (Figure 3). Reticular cells produce the reticular fibers that form the network onto which other cells attach. It derives its name from the Latin reticulus, which means &ldquolittle net.&rdquo

Figure 3: This is a loose connective tissue made up of a network of reticular fibers that provides a supportive framework for soft organs. LM × 1600. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)

Dense Connective Tissue

Dense connective tissue contains more collagen fibers than does loose connective tissue. As a consequence, it displays greater resistance to stretching. There are two major categories of dense connective tissue: regular and irregular. Dense regular connective tissue fibers are parallel to each other, enhancing tensile strength and resistance to stretching in the direction of the fiber orientations. Ligaments and tendons are made of dense regular connective tissue, but in ligaments not all fibers are parallel. Dense regular elastic tissue contains elastin fibers in addition to collagen fibers, which allows the ligament to return to its original length after stretching. The ligaments in the vocal folds and between the vertebrae in the vertebral column are elastic.

In dense irregular connective tissue, the direction of fibers is random. This arrangement gives the tissue greater strength in all directions and less strength in one particular direction. In some tissues, fibers crisscross and form a mesh. In other tissues, stretching in several directions is achieved by alternating layers where fibers run in the same orientation in each layer, and it is the layers themselves that are stacked at an angle. The dermis of the skin is an example of dense irregular connective tissue rich in collagen fibers. Dense irregular elastic tissues give arterial walls the strength and the ability to regain original shape after stretching (Figure 4).

Dense Connective Tissue

Figure 4: (a) Dense regular connective tissue consists of collagenous fibers packed into parallel bundles. (b) Dense irregular connective tissue consists of collagenous fibers interwoven into a mesh-like network. From top, LM × 1000, LM × 200. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)

Disorders of the&hellip

Connective Tissue: Tendinitis

Your opponent stands ready as you prepare to hit the serve, but you are confident that you will smash the ball past your opponent. As you toss the ball high in the air, a burning pain shoots across your wrist and you drop the tennis racket. That dull ache in the wrist that you ignored through the summer is now an unbearable pain. The game is over for now.

After examining your swollen wrist, the doctor in the emergency room announces that you have developed wrist tendinitis. She recommends icing the tender area, taking non-steroidal anti-inflammatory medication to ease the pain and to reduce swelling, and complete rest for a few weeks. She interrupts your protests that you cannot stop playing. She issues a stern warning about the risk of aggravating the condition and the possibility of surgery. She consoles you by mentioning that well known tennis players such as Venus and Serena Williams and Rafael Nadal have also suffered from tendinitis related injuries.

What is tendinitis and how did it happen? Tendinitis is the inflammation of a tendon, the thick band of fibrous connective tissue that attaches a muscle to a bone. The condition causes pain and tenderness in the area around a joint. On rare occasions, a sudden serious injury will cause tendinitis. Most often, the condition results from repetitive motions over time that strain the tendons needed to perform the tasks.

Persons whose jobs and hobbies involve performing the same movements over and over again are often at the greatest risk of tendinitis. You hear of tennis and golfer&rsquos elbow, jumper's knee, and swimmer&rsquos shoulder. In all cases, overuse of the joint causes a microtrauma that initiates the inflammatory response. Tendinitis is routinely diagnosed through a clinical examination. In case of severe pain, X-rays can be examined to rule out the possibility of a bone injury. Severe cases of tendinitis can even tear loose a tendon. Surgical repair of a tendon is painful. Connective tissue in the tendon does not have abundant blood supply and heals slowly.

While older adults are at risk for tendinitis because the elasticity of tendon tissue decreases with age, active people of all ages can develop tendinitis. Young athletes, dancers, and computer operators anyone who performs the same movements constantly is at risk for tendinitis. Although repetitive motions are unavoidable in many activities and may lead to tendinitis, precautions can be taken that can lessen the probability of developing tendinitis. For active individuals, stretches before exercising and cross training or changing exercises are recommended. For the passionate athlete, it may be time to take some lessons to improve technique. All of the preventive measures aim to increase the strength of the tendon and decrease the stress put on it. With proper rest and managed care, you will be back on the court to hit that slice-spin serve over the net.

Supportive Connective Tissues

Two major forms of supportive connective tissue, cartilage and bone, allow the body to maintain its posture and protect internal organs.

Kıkırdak

The distinctive appearance of cartilage is due to polysaccharides called chondroitin sulfates, which bind with ground substance proteins to form proteoglycans. Embedded within the cartilage matrix are chondrocytes , or cartilage cells, and the space they occupy are called lacunae (singular = lacuna). A layer of dense irregular connective tissue, the perichondrium, encapsulates the cartilage. Cartilaginous tissue is avascular, thus all nutrients need to diffuse through the matrix to reach the chondrocytes. This is a factor contributing to the very slow healing of cartilaginous tissues.

The three main types of cartilage tissue are hyaline cartilage, fibrocartilage, and elastic cartilage (Figure 5). Hyaline cartilage , the most common type of cartilage in the body, consists of short and dispersed collagen fibers and contains large amounts of proteoglycans. Under the microscope, tissue samples appear clear. The surface of hyaline cartilage is smooth. Both strong and flexible, it is found in the rib cage and nose and covers bones where they meet to form moveable joints. It makes up a template of the embryonic skeleton before bone formation. A plate of hyaline cartilage at the ends of bone allows continued growth until adulthood. Fibrocartilage is tough because it has thick bundles of collagen fibers dispersed through its matrix. Menisci in the knee joint and the intervertebral discs are examples of fibrocartilage. Elastic cartilage contains elastic fibers as well as collagen and proteoglycans. This tissue gives rigid support as well as elasticity. Tug gently at your ear lobes, and notice that the lobes return to their initial shape. The external ear contains elastic cartilage.

Figure 5: Cartilage is a connective tissue consisting of collagenous fibers embedded in a firm matrix of chondroitin sulfates. (a) Hyaline cartilage provides support with some flexibility. The example is from dog tissue. (b) Fibrocartilage provides some compressibility and can absorb pressure. (c) Elastic cartilage provides firm but elastic support. From top, LM × 300, LM × 1200, LM × 1016. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)

Suyak

Suyak eng qattiq biriktiruvchi to'qimadir. Bu ichki organlarni himoya qiladi va tanani qo'llab -quvvatlaydi. Bone&rsquos rigid extracellular matrix contains mostly collagen fibers embedded in a mineralized ground substance containing hydroxyapatite, a form of calcium phosphate. Both components of the matrix, organic and inorganic, contribute to the unusual properties of bone. Without collagen, bones would be brittle and shatter easily. Without mineral crystals, bones would flex and provide little support. Osteocytes, bone cells like chondrocytes, are located within lacunae. The histology of transverse tissue from long bone shows a typical arrangement of osteocytes in concentric circles around a central canal. Bone is a highly vascularized tissue. Unlike cartilage, bone tissue can recover from injuries in a relatively short time.

Cancellous bone looks like a sponge under the microscope and contains empty spaces between trabeculae, or arches of bone proper. It is lighter than compact bone and found in the interior of some bones and at the end of long bones. Compact bone is solid and has greater structural strength.

Fluid Connective Tissue

Blood and lymph are fluid connective tissues. Hujayralar suyuq hujayradan tashqari matritsada aylanadi. The formed elements circulating in blood are all derived from hematopoietic stem cells located in bone marrow (Figure 6). Erythrocytes, red blood cells, transport oxygen and some carbon dioxide. Leukocytes, white blood cells, are responsible for defending against potentially harmful microorganisms or molecules. Platelets are cell fragments involved in blood clotting. Some white blood cells have the ability to cross the endothelial layer that lines blood vessels and enter adjacent tissues. Nutrients, salts, and wastes are dissolved in the liquid matrix and transported through the body.

Lymph contains a liquid matrix and white blood cells. Lymphatic capillaries are extremely permeable, allowing larger molecules and excess fluid from interstitial spaces to enter the lymphatic vessels. Lymph drains into blood vessels, delivering molecules to the blood that could not otherwise directly enter the bloodstream. In this way, specialized lymphatic capillaries transport absorbed fats away from the intestine and deliver these molecules to the blood.

Figure 6: Blood is a fluid connective tissue containing erythrocytes and various types of leukocytes that circulate in a liquid extracellular matrix. LM × 1600. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)

Bo'limni ko'rib chiqish

Connective tissue is a heterogeneous tissue with many cell shapes and tissue architecture. Structurally, all connective tissues contain cells that are embedded in an extracellular matrix stabilized by proteins. The chemical nature and physical layout of the extracellular matrix and proteins vary enormously among tissues, reflecting the variety of functions that connective tissue fulfills in the body. Connective tissues separate and cushion organs, protecting them from shifting or traumatic injury. Connect tissues provide support and assist movement, store and transport energy molecules, protect against infections, and contribute to temperature homeostasis.

Many different cells contribute to the formation of connective tissues. They originate in the mesodermal germ layer and differentiate from mesenchyme and hematopoietic tissue in the bone marrow. Fibroblasts are the most abundant and secrete many protein fibers, adipocytes specialize in fat storage, hematopoietic cells from the bone marrow give rise to all the blood cells, chondrocytes form cartilage, and osteocytes form bone. The extracellular matrix contains fluid, proteins, polysaccharide derivatives, and, in the case of bone, mineral crystals. Protein fibers fall into three major groups: collagen fibers that are thick, strong, flexible, and resist stretch reticular fibers that are thin and form a supportive mesh and elastin fibers that are thin and elastic.

The major types of connective tissue are connective tissue proper, supportive tissue, and fluid tissue. Loose connective tissue proper includes adipose tissue, areolar tissue, and reticular tissue. These serve to hold organs and other tissues in place and, in the case of adipose tissue, isolate and store energy reserves. The matrix is the most abundant feature for loose tissue although adipose tissue does not have much extracellular matrix. Dense connective tissue proper is richer in fibers and may be regular, with fibers oriented in parallel as in ligaments and tendons, or irregular, with fibers oriented in several directions. Organ capsules (collagenous type) and walls of arteries (elastic type) contain dense irregular connective tissue. Cartilage and bone are supportive tissue. Cartilage contains chondrocytes and is somewhat flexible. Hyaline cartilage is smooth and clear, covers joints, and is found in the growing portion of bones. Fibrocartilage is tough because of extra collagen fibers and forms, among other things, the intervertebral discs. Elastic cartilage can stretch and recoil to its original shape because of its high content of elastic fibers. The matrix contains very few blood vessels. Bones are made of a rigid, mineralized matrix containing calcium salts, crystals, and osteocytes lodged in lacunae. Bone tissue is highly vascularized. Cancellous bone is spongy and less solid than compact bone. Fluid tissue, for example blood and lymph, is characterized by a liquid matrix and no supporting fibers.


Epiteliya to'qimasi

*Some of this content will be reviewed or built-upon in lecture videos, while some of the epithelial tissue content will be covered in the assignment and interactive activity as self-study material.

Epithelial tissues line all surfaces of the body. This includes the surfaces exposed to the outside world, the surface of organs, and the openings within hollow organs. Epithelium also forms much of the glandular tissue of the body.

Funksiyalar

Epithelial tissues have several functions. You will learn about the different functions of specific types of epithelium later in this module. However, you should know these general functions of epithelial tissue.

  • Himoya: Epithelial tissues provide the body’s first line of protection from physical, chemical, and biological wear and tear.
  • Selective permeability: The cells of an epithelium act as gatekeepers of the body controlling permeability and allowing selective transfer of materials across a physical barrier. All substances that enter the body must cross an epithelium. Some epithelia often include structural features that allow the selective transport of molecules and ions across their cell membranes.
    • Diffuziya: selective, simple transport of substances through a thin layer of tissue
    • Absorbtsiya (hujayralararo transport): absorption of substances through the cell, where it is processed to some degree before being released into the blood and/or underlying tissue. This is called transcellular transport because it is going through the cell.

    Characteristics & Features

    All epithelia share some important structural and functional features:

    • This tissue is highly cellular, with little or no extracellular material present between cells.
    • Epithelial tissues are avascular, meaning they do not contain blood vessels. Instead, they receive nutrients by diffusion or absorption from the underlying tissues or occasionally from substances on the surface.
    • Many epithelial tissues are capable of regeneratsiya, or rapidly replacing damaged and dead cells. Sloughing off of damaged or dead cells is a characteristic of surface epithelium and allows our airways and digestive tracts to rapidly replace damaged cells with new cells.
    • The epithelial cells exhibit polarity, with differences in structure and function between the exposed or apikalsirt of the cell, the free surface away from underlying tissue, and the bazalsirt attached to the underlying tissue.

    The bazal membrana sits just below the basal surface of epithelial cells and anchors the cells to the underlying tissue. It is formed of two layers: the basal lamina, which attaches to the basal aspect of the cells, and the reticular lamina, which is attached to the underlying connective tissue.

    Apical Features

    Two microscopic extensions can be found on the apical surface of some cells.

    • Cilia: extensions from the apical surface of the cell that beat in unison to move fluids as well as trapped particles across the surface of the epithelium (surface parallel transport).
    • Microvilli: extensions that serve to increase the surface area of the apical aspect of the cell for absorption. More surface area means more space for substances to contact the apical surface and be absorbed into the cell.

    Hujayralararo birikmalar

    Epithelial cells are closely connected and are not separated by intracellular material. These cells are held together or interact with each other via junctions, or connections between the cells. Three of these junctions hold the cells together, while one allows for cell-to-cell communication.

    Types of Cell Junctions: The three basic types of cell-to-cell junctions are tight junctions, gap junctions, and anchoring junctions.

    • Tight junction: Holds cells together so there is no extracellular space between them. Tight junctions prevent substances from moving between the cells, instead forcing them to go through the cells. This enables the epithelia to act as a selective barrier.
    • Adhering junction (adherens): Acts like a belt holding the epithelial cells together for support and stability of the tissue.
    • Desmosome: Holds cells together like a push button on a jacket to provide support and stability of the tissue.
    • Gap junction: Forms an intercellular passageway between the membranes of adjacent cells to facilitate the movement of small molecules and ions between the cytoplasm of adjacent cells. These junctions allow electrical and metabolic coupling of adjacent cells, which coordinates function in large groups of cells.

    Classification of Epithelial Tissues

    *This information will not be reviewed in videos. Be sure to understand what is written here in the text and the table. Your assignment and the interactive activity on the Canvas page will help you review this material.

    Epithelial tissues are classified according to the shape of the cells and number of the cell layers formed ((Figure)).

    • Shakl:
      • Squamous: Flattened and thin
      • Cuboidal: Like a cube or box, wide as it is tall
      • Columnar: Like a rectangular cube, taller than it is wide.
      • Simple: A single layer of cells, with every cell resting on the basal lamina of the basement membrane
      • Stratified: More than one layer of cells, with only the basal layer resting on the basal lamina of the basement membrane. This can be just a few layers or dozens of layers depending on the location.
      • Pseudostratified: Only one layer of cells, but the height of the cells vary, giving the appearance of more than one layer (pseudo- = false). Only some of the cells have an apical surface that reaches the free surface of the epithelium.

      Cells of Epithelial Tissue: Simple epithelial tissue is organized as a single layer of cells and stratified epithelial tissue is formed by several layers of cells.

      Thinner epithelium allows for faster and easier transport of substances across the surface, so it functions to allow transcellular (through the cell) transport via simple diffusion. The thicker the epithelium is (cuboidal to columnar), the more space there is for intracellular machinery needed to produce substances for secretion or process substances that have been absorbed before releasing it into the underlying tissue. Stratified epithelium has multiple layers, meaning there are more layers to lose before damaging the underlying tissue. Therefore, stratified epithelium always has a protective function.

      There are several different kinds of epithelium based on different combinations of the shape and number of layers of cells. Note that the name of stratified epithelium is determined by the shape of the cell at the most superficial layer, furthest from the underlying connective tissue. You are responsible for knowing the information in the following table:



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