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Connective Tissue

Terms in this set (25)

major functions of connective tissue
- form basis of skeleton (bone/cartilage)
- store and carry nutrients (fat tissue, blood)
- surround all blood vessels and nerves of the body (connective tissue proper)
- fight against infection
- connect other tissues to each other
common characteristics of connective tissues
- relatively few cells and lots of EC Matrix (contrast to epithelium which was almost 100% cellular)
- EC Matrix composed of ground substance + fibers ( 3 types of protein fibers: collagen, reticular, elastic)
- embryonic origin: all originate from embryonic tissue - mesenchyme
3 basic components of connective tissue
- cells: fibroblasts make protein subunits of fibers and secrete molecules that form ground substance of matrix (other cells too)
- fibers: 1) collagen: strong and flexible 2) reticular: type of collagen in basement membrane, supports organs 3) elastic: stretch and recoil
- ground substance: gel-like material among cells and fibers; large sugar-protein molecules; electrical charges attract water fluid cushions body and resists compression
fibroblast/fibrocyte
- most abundant cell type
- "fiber former"
- secrete fibers to form ground substance
- a fibrocyte is not secreting new matrix
adipocyte
- store nutrients
- insulation/temp regulation
- protection/cushioning
- have a giant lipid droplet that dominates the cytoplasm
macrophages
- phagocytosis
- eat foreign crap during an infection or tissue debris after physical damage
mast cells
- secrete during infections and allergic rxns
- heparin: inhibits clotting
- histamine: increases permeability of capillaries and constricts bronchial smooth muscle; mediates inflammation and promotes healing
white blood cells
- respond to infection
- lymphocytes: recognize and help destroy bacteria and viruses in tissue
- neurtophils: phagocytose and destroy bacteria
- distributed in connective tissues
collagen fibers
- most abundant
- flexible but strong
- resist tension
- add strength
reticular fibers
- bundles of collagen
- in basement membrane
- form scaffold for support organs
elastic fibers
- stretch and recoil
composition/function of ground substance
Composition
- gel-like material among cells and fibers
- large sugar and sugar-protein molecules that soak up fluid
Function
- electrical charges attract water
- cushions and protects body (connective tissue proper)
- resists compression (cartilage)
- hold tissue fluid that bathes all cells in body (aerolar connective tissue)
Connective Tissue Proper
Loose
1. areolar
2. adipose
3. reticular
Dense
1. irregular
2. regular
3. elastic
Specialized Connective Tissue
Cartilage
1. hyaline
2. elastic
3. fibrocartilage
Bone
Blood
areolar connective tissue
Connective tissue proper > loose
- gel-like matrix w/ all 3 fiber types
- cells and fibroblasts, machrophages, mast cells, WBC
- wraps/cushions organs
- macrophages eat bacteria
- role w/ inflammation
- holds/conveys tissue fluid
- found under epithelia, forms lamina propria of mucus membrane and packages organs and surrounds capillaries
adipose connective tissue
Connective tissue proper > loose
- matrix like areolar - but very sparse
- closely packed adipocytes have nucleus pushed to side by fat droplet
- reserves food, insulates/supports/protects organs
- found under skin - hypodermis
- found in kidneys, eyeballs, w/in abdomen, breasts
reticular connective tissue
Connective Tissue proper > loose
- network of reticular fibers in loose ground substance
- reticular cells lie on network
- forms soft internal skeleton (stoma) that supports other cells (WBC, mast cells, macrophages)
- found in lymphoid organs (lymph nodes, bone marrow, spleen)
irregular connective tissue
Connective tissue proper > dense
- irregular arrangement of collagen fibers, some elastic fibers
- fibroblast = major cell
- defense and fat cells too
- can withstand tension in many directions - structural strength
- found in fibrous capsules in organs/joints
- found in dermis (skin) and submucosa of digestive tract
regular connective tissue
Connective tissue proper > dense
- parallel collagen fibers, few elastic fibers, major cell type = fibroblast
- attaches muscles to bones/muscles; withstand stress of pull from 1 direction
- found in tendons, most ligaments and aponeuroses
elastic connective tissue
Connective tissue proper - dense
- dense regular connective tissue with lots of elastic fibers
- allows recoil of tissue after stretching
- maintains pulsatile blood flow through arteries
- helps passive recoil of lungs after inspiration
- found in walls of large arteries and w/in certain ligaments (vertebrae) and walls of bronchial tubes
hyaline cartilage
Specialized connective tissue > Cartilage
- amorphous but firm matrix
- collagen-imperceptible network, chondroblasts produce matrix
- supports/reinforces
-resilient, cushion, resists compressive stress
- found in embryonic skeleton
- covers ends of long bones - joint cavities, costal cartilage (ribs), cartilage of nose, trachea, larynx
elastic cartilage
Specialized connective tissue > Cartilage
- like hyaline, but w/ more elastic fibers
- maintains shape while allowing flexibility
- supports inner ear (pinna) and epiglottis
fibrocartilage
Specialized connective tissue > cartilage
- like hyaline, less firm - thick collagen fibers
- tensile strength, can absorb compressive shock
- found in intervertebral disks, pubic symphysis, discs of knee joints
bone
specialized connective tissue
- hard, calcified matrix w/ many collagen fibers
- osteocytes lie in lacunae
- very vascularized
- supports and protects
- levers for muscles to act on
- stores calcium/other minerals/fat
- marrow in bones - blood cell formation
- found in bones
blood
Specialized connective tissue
- red and WBC in a fluid matrix (plasma)
- transport respiratory gases, nutrients, waste
- contained w/in blood vessels
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