connective tissue Flashcards
what do all connective tissues have in common
cells, extracellular fibres and a fluid called ground substance
give 6 functions of connective tissues
provide structural framework for the body, transport substances from one region to another, provide protection for delicate organs, support + surround + interconnect other tissue types, store energy, defend the body from invasion by microorganisms
what is connective tissue proper
loose connective tissue and dense connective tissue (subdivided into dense regular and dense irregular). these are distinguished by the ratio of ground substance to fibrous tissue
give a brief description of the composition of connective tissue proper
contains fibres, viscous ground substance, fixed cells and wandering cells
what are fixed cells
stationary cells that are involved in local maintenance, repair, defense and energy storage
name the 4 types of fixed cells
fibroblasts, fixed macrophages, adipocytes, stem cells
what are fibroblasts
slender/star shaped cells that synthesise and secrete connective tissue fibres + hylauronic acid of ground substance
what are fixed macrophages
are scattered among fibres and phagocytose damaged cells and pathogens
what are adipocytes
these are fat cells consisting of a single enormous fat droplet and the number of them depends on the type of Connective Tissue (CT)
what are stem cells
cells which respond to injury or infection by dividing to produce daughter cells that differentiate into fibroblasts, macrophages or other CT cells
what are wandering cells
include free macrophages which are highly mobile, and mast cells
what are mast cells
found near blood vessels and are packed with histamine and heparin.
what does histamine do
increases blood flow to the area
what does heparin do
prevents blood clotting
what are the three basic types of fibre
collagen, reticular, elastic
what are the features of collagen
long straight unbranched, each fibre is a bundle of fibrils composed of protein collagen. the fibres are strong and stiff
describe the structure of reticular fibres
these contain collagen fibrils interwoven into a tough flexible network
describe the structure of elastic fibres
they contain protein elastin, they are branched and wavy, return to original length after being stretched
write a note on areolar connective tissue
surrounds blood vessels, nerve bundles, muscles and organs. fills spaces between organs and connects skin to muscle
write a note on adipose tissue
lipid rich (from adipocytes) connective tissue. comprises 20-25% of total body weight in healthy people. main function is to store energy as lipids/fat
write a short note on reticular tissue
reticular fibres form a thin reticular network. these are found in diff tissues and support frameworks in the liver, lymphoid organs, capillary endothelia and muscle fibres
write a note on dense regular connective tissue
collagen fibres are densely packed + parallel. found in ligaments and tendons
write a note on dense irregular connective tissue
fibres are not parallel, and consists of mostly collagen fibres. has less ground substance than loose connective tissue
what is the firm gel called that makes up the ground substance in cartilage
chondroitin
what are chondrocytes
they are the only cells found in health cartilage and they are located in pockets called lacunae. they lack nerve fibres. they are avascular (obtain nutrients via diffusion through matrix)
what are three types of cartilage
hyaline, elastic, fibrocartilage
what does avascular mean
that nutrients are obtained through diffusion through matrix
write a note on hyaline cartilage
most abundant, contains a lot of collagen fibres. tough and slightly flexible. located connecting ribs to sternum, embryonic skeleton, covers the end of long bone, nose, trachea, pharynx
write a note on elastic cartilage
contains a lot of elastic fibres, maintains the shape of a structure while allowing great flexibility. located in external ear, epiglottis, vocal chords
write a short note on firbocartilage
has little matrix with a lot of collagen fibres. provides tensile strength with the ability to absorb compressive shock. located in intervertebral disks, bones of pelvis, disks of knee joint
