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82 Cards in this Set
- Front
- Back
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what are the three classifications of CT |
1. embryonic CT- mesenchyme 2. connective tissue proper- loose CT, reticular CT, adipose CT 3. specialized connective tissue- cartilage, bone, adipose |
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what does pluripotent mean |
giving rise to many different cell types |
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what is mesenchyme derived from |
mesoderm |
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what does mesenchyme differentiate into |
hematopoietic and connective tissue |
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what type of CT is mesenchyme |
loose connective tissue -prominent ground substance with reticular gibers and unspecialized mesenchymal cells capable of developing into all CT cells |
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what are the cellular descendants of mesenchyme? |
fibroblasts chondroblasts osteoblast hematopoietic stem cells |
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what type of CT results from fibroblasts |
CT proper 1. loose connective tissue - areolar, adipose, reticular 2. dense CT- regular, irregular, elastic |
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what type of CT results from chondroblasts |
cartilage 1. hyaline cartilage 2. fibrocartilage 3.elastic cartilage |
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what type of CT results from osteoblasts |
osseous 1.compact bone 2. spongy bone |
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what type of CT results from hematopoietic stem cells |
blood |
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what is embryonic CT - mucous |
type of CT found during fetal development present in umbilical cord -consists of specialized, gelatin like ECM whose GS is referred to as Wharton's jelly |
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what is mucous composed of |
mostly GS (hyaluronic acid and chondroitin sulfare) with a few cells (fibroblasts and macrophages) and fibres |
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what does mucuous do |
protects and insulates umbilical blood vessels |
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what can be done with whartons jelly |
can be extracted, cultured and induced to differentiate into mature cells types (such as neutrons), it's a potential source of adult stem cells |
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what is loose connective tissue / areolar tissue |
has a gel like matrix with all three fiber types, several cell types, and semi-fluid ground substance -loose organization, wide distribution -predominance of fibroblasts and macrophages -variable ground substance -very loosely packed, lots of liuqid |
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whats the function of areolar tissue |
wrap and cushion organs -packing material of the body -attaches skin to muscle -swells during inflammation |
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where is areolar tissue found |
lamina propria of mucous membranes under epithelial tissue |
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what is reticular tissue |
it resembles areolar CT, but the only fibres are reticular fibres -reticular fibres form a delicate stroma along which reticular cells lie scattered -delicate |
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function of reticular tissue |
support |
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location of reticular tissue |
surrounding lymph organs -where structural support is needed but not as strong as collagen fibres -bone marrow |
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whats the largest repository of energy in the body |
adipose tissue in the form of triglycerides |
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what kind of receptors do adipose tissue have |
insulin, GH, NE, glucocorticoids |
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what are the two types of adipose tissue |
unilocular (white) multilocular (brown) |
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how does differentiation of adipocytes work |
-all originate from undifferentiated mesenchymal stem cells -white tissue begins to form midway through fetal development -early lipoblasts look like fibroblast but develop small lipid inclusions and a thin external lamina -midstage lipoblasts become ovoid as lipid accumulation changes cell dimension -mature adipocyte has single, large inclusion surrounded by a thin rim of cytoplasm |
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where is adipose tissue found |
subcutaneous around kidneys abdomen breasts |
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whats the function of white adipose tissue |
insulation, padding, protection |
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what does adipose look like and consist of |
similar to loose CT, but very sparse, closely packed adipocytes, have nucleus pushed to the side by large fat droplet -held together by reticular fibers -90% of tissue is adipocytes |
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what two physiological systems regulate amount of adipose tissue |
1. short term weight regulation -controls appetite and metabolism on a daily basis -ghrelin, an appetite stimulant -peptide YY, appetite suppressant 2. long term weight regulation -controls appetite and metabolism on a continual basis over months and years -2 major hormones: leptin and insulin -others: thyroid hormone, glucocorticoids, pituitary hormones |
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what is brown adipose tissue |
multilocular, contains numerous fat droplet -NE stimulates thermogenesis -newborns have a lot -energy released as heat is transferred to other parts of the body via the blood |
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what % of BW is brown adipose in infants |
in neck and abdomen up to 25% |
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where is most brown adipose found in humans |
lower neck and supraclavicular regions |
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whats the relationship between brown adipose and BMI? |
inverse correlation |
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what allows for sympathetic stimulation to the adipocyte |
numerous unmyelinated nerves in brown adipose tissue
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what is non shivering thermogenesis |
-uncoupling protein 1 (thermogenin) -allows uncoupling of electrons moving down their mitochondrial gradient from the synthesis of ATP ,thus allowing the energy to be dissipated as heat |
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what is dense CT |
has same components as loose CT but fewer cells and dominance of collagen fibers -less flexible and more resistant to stress |
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what are the types of dense CT |
dense regular dense irregular elastic |
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where is dense regular CT found |
ligaments and tendons |
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what is the function of regular dense CT |
-attaches muscles to bones or to muscles -attaches bones to bones -withstands great tensile stress when pulling force is applied in one direction -resist pull and stretching |
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what are tendons |
elongated cylindrical structures attaching striated muscle to bone |
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what type of fibers do tendons have a lot of |
collagen -parallel, closely packed bundles of collagen separated by a small quantity of GS -collagen bundles in tendons (primary) aggregate into larger bundles (secondary) that are enveloped by loose CT containing blood vessels and nerves |
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what is the tendon surrounded by |
Sheath of dense CT with two layer -one attaches to tendon -one lines the neighbouring structure |
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where is dense irregular CT found |
bladder dermis- under the skin, holding the skin in place |
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whats the function of dense irregular CT |
-able to withstand tension exerted in many directions -provides structural strength -helps prevent over expansion of organs such as the urinary bladder |
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what types of fibers does dense irregular CT consist of |
primarily irregularly arranged collagen -some elastic -major cell type is the fibroblast |
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where is elastic CT found |
-arteries (irregular) -vocal cords (regular) -yellow ligaments of vertebral column -suspensory ligament of the penis |
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whats the function of elastic connective tissue |
-flexibility and stability- stretch and rebound quality -accomodates cycles of expansion and contraction |
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what fibres does elastic CT contain |
-elastic fibres out number collagen fibres -usually thick bundles of elastic fibers with a few collagen and flattened fibroblasts in between - can be dense regular or irregular |
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what two types of tissue combine to form membranes |
epithelia and connective tissue
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whats the function of a membrane |
to create a barrier or functional divide (define enclosed spaces) -help maintain chemical/biochemical environment that differs from the outside |
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what are the 4 types of membranes |
1. mucous membranes 2. serous membranes 3. cutaneous membranes 4. synovial membranes |
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where are mucous membranes found |
line cavities that communicate with the exterior including the digestive, respiratory, reproductive and urinary tracts |
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what are the epithelium and CT portions of mucous membranes |
epithelium- provides barrier to infection (tight junction) - kept moist at all time via mucous production by goblet cells or multicellular glands to prevent desiccation, trap particles and determine environment of fluid connective tissue- called lamina propria, thin layer of loose CT -bind epithelium to underlying structures, allows strength with flexibility -houses vessels, nerves, lymphatics, immune tissue, allows flow of nutrients and wastes -protects underlying structures from abrasion and puncture |
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where are serous membranes found |
line the sealed, internal cavities of the body (those that don't get exposed to exterior), cover organ that lie within the cavity -pleura=lungs -pericardium=heart -peritoneum=abdomen |
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what are the two layers of the serous membrane |
lining the cavity wall (parietal) covering an organ (visceral) |
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whats the function of serous membranes |
allow surfaces of organs to glide past each other without adhering or injuring by secreting a lubricating SEROUS FLUID that reduces friction between organs and the walls of the cavities in which they're located |
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what are the epithelium and CT portions of serous membranes made up of |
epithelium- simple, squamous epithelium called mesothelium connective tissue- thin layer of areolar CT |
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where is the cutaneous membrane found |
organ of the integumentary system- covers the entire surface of the body |
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what are the epithelium and CT portions of the cutaneous membrane made up of |
epithelium- stratified squamous epithelium connective tissue- layer of loose CT reinforced by a layer of dense CT |
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where are synovial membranes found |
line the non-cartilaginous surfaces within joints |
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what are the epithelium and CT portions of synovial membranes made up of |
epithelium- squamous or cuboidal cells, not true epithelium because there's no basement membrane and cellular layer incomplete with gaps connective tissue- loose |
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whats the function of cartilage |
specialized CT in which firm consistency of the ECM allows the tissue to bear mechanical stresses without permanent distortion -supports soft tissues -smooth surface/resilient/acts as shock absorber and sliding area for joints -essential for development and growth of long bones before and after birth |
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whats the structure of cartilage |
matrix with many spaces called lacunae, occupied by chondrocytes -chondroblasts- synthetically active -chondrocytes- surrounded by their secretory product |
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what fibres are found in cartilage |
collagen and elastic |
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what is the ground substance of cartilage |
3 GAGS -hyaluronic acid -chondroitin sulfate -keratan sulfate |
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how is the function of cartilage dependent on hormonal balance |
synthesis of GAG is -accelerated: GH, thyroxine, testosterone -slowed: cortisone, hydrocortisone, estradiol |
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what are some types of cartilage |
hyaline elastic fibrocartilage |
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what is chondrocyte viability dependant on |
diffusion of nutrients, wastes, ions, gases through intercellular substance from adjacent capillaries |
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what are the two layers of perichondrium in cartilage |
1.outer fibrous layer - collagen fibers and cells (dense irregular CT) 2. thin internal chondrogenic layer- with cells that have capacity to divide and become chondroblasts to actively secrete new cartilage matrix on the surface of the pre-existing cartilage -contains BV, nerves, lymph -except articular cartilage- all hyaline cartilage covered in perichondrium |
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what are the two mechanisms of cartilage growth |
1. appositional growth - fibroblasts in perichondrium give rise to chondroblasts which lay down cartilage until sealed off into there own lacunae 2. interstitial growth- mitotic division of preexisting chondrocytes -occurs only during early phases of cartilage formation, when it increases tissue mass by expanding the cartilage matrix from within |
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how is cartilage regenerated |
except in young children, damaged cartilage regenerates with difficult and often incompletely - by activity of the perichondrium which invades the injured area and generates new cartilage |
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whats the most common type of cartilage |
hyaline |
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where is hyaline cartilage found |
synovial joints
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whats the function of hyaline cartilage |
supports and reinforces- reduces friction -has cushioning properties- reduces pressure -resists compressive stress -serves as temporary skeleton until gradually replaced by bone |
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what does hyaline cartilage consist of |
-amorphous, firm matrix -collagen fibers- form imperceptible network -few chondrocytes -type II collagen, GAGs, PG -looks glassy -chondronectin |
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how does hyaline cartilage metabolize glucose |
mainly by anaerobic glycolysis to produce lactic acid as the end product |
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how do nutrients from blood get to hyaline cartilage |
-cross the perichondrium -diffusion -transport promoted by pumping action of cartilage- decompression and compression |
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where is elastic cartilage found |
ear epiglottis tip of ear eustation tube |
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whats the function of elastic cartilage |
maintains shape of structure while allowing flexibility |
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whats the difference between hyaline and elastic cartilage |
elastic is similar to hyaline but there's more elastic fibers in the matrix so it appears more fibrous -contains type II collagen as well |
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where is fibrocartilage found |
intervertebral discs pubic symphysis discs of knee joint |
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whats the function of fibrocartilage |
shock absorption supports/has good tensile strength |
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what does fibrocartilage contain |
-matrix similar to (less firm) than hyaline -type I collagen -rows of chondrocytes and collagen fibers |
