Lecture 3: Connective Tissue Flashcards
What the connective tissue does?
- binds, supports, strengthens other body tissues
- transport system of body (blood is a CT)
- stored energy reserves (fat/adipose tissue is a CT)
Differences between Epithelium and CT
CT not on body surface
CT highly vascular (except cartilage and tendons)
Similarity between epithelium and CT
CT supplied by nerves (except cartilage)
What CT is composed of
- Extracellular matrix (ECM)
- Cells
CT equation
CT = ECM + Cells
ECM components
- ground substance (GS)
- Protein fibres
ECM equation
ECM = GS + Fibres
What is secreted in cells of ECM
protein fibres
what dictates the qualities of connective tissue?
structure of ECM
Components of the GS
- water
- proteins
- polysaccharides (sugars)
GS equation
GS = H2O + Proteins + polysaccharides
Function of the GS
support + bind cells together
store H2O
medium for exchange of substances between blood + cells
Type of polysaccharides (sugars) in GS?
glycosaminoglycans (GAGS or mucopolysaccharides)
What is formed when GAGS join with core proteins?
proteoglycans
features of GAGS
- long unbranched polysaccharides
- repeating disaccharide unit
what are these examples of
- amino sugar (eg. N acetylglucosamine)
- uronic sugar (eg. glucuronic acid)
- highly polar and attract H2O
disaccharide units that are repeated to form GAGS
sulphated GAG examples
- derma tan sulphate
- heparin sulphate
- keratan sulphate
- chondroitin sulphate
what bind to proteins to form proteoglycans (PGs)
sulphated GAGS (glycosaminoglycans)
non-sulphated GAG examples
- hyaluronic acid
_____ acid is not directly bound to protein backbone but joined to various _____
(hyaluronic) acid is not directly bound to protein backbone but joined to various (proteoglycans)
are glycosaminoglycan hyaluronic acid sulphated or covalently bound to a core protein
NO, glycosaminoglycan hyaluronic acid IS NOT sulphated nor covalently bound to a core protein
What makes the GS more jelly-like
glycosaminoglycans (GAGS) trapping H2O
Function of the hyaluronic acid
- slippery substance binds cells
- lubricates joints
- maintains shape of eyeball
enzyme that breaks apart hyaluronic acid causing hyaluronic acid in GS to become more liquid
hyaluronidase
what accounts for rapid spread of bacteria in CT
more liquid GS… makes it easier to move around in substance
what produces hyaluronidase?
- white blood cells
- sperm
- bacteria
function of chondroitin sulphate and what function acts in
support + adhesive features
- in cartilage, bone, skin, blood vessels
where is keratin sulphate found
- bone
- cartilage
- cornea of eye
where is Dermatan Sulphate found?
- skin
- tendons
- blood vessels
- heart valves
What is exophthalmos?
Abnormal Periorbital ECM deposition and thyroid disease
exophthalmos symptoms
- Goitre (swollen thyroid gland)
- autoimmune over-activation of thyroid
- autoimmune action on fibroblasts in ECM of eye
Name the 3 type of CT protein fibres in ECM
- Collagen fibres
- Reticular fibres
- Elastic fibres
Function of thick collagen fibres
strong + flexible resist pull forces
- parallel bundles
Locations of collagen
bone, cartilages, tendons, ligaments
what reticular fibres are composed of
collagen with glycoprotein coating
what are reticular fibres made by
fibroblasts
function of reticular fibres
- strength + support
What CT fibre forms…
- part of basement membrane
- networks in vessels in tissues (adipose, nerve, smooth muscle)
reticular fibres
Fibre found in skin, blood vessels, lung
Elastic fibres
what are elastic fibres made of?
protein elastin surrounded by glycoprotein fibrillin
function of elastic fibres
- fibrous network
- strength + stability
what is Marfan syndrome
hereditary defect in elastic fibres
what glycoprotein contributes to structural scaffold for elastin
fibrillin
Symptoms of Marfan syndrome
- tall
- long limbed
- chest deformity
mutation in gene ___ codes for fibrillin results in Marfan syndrome
chromosome 15
consequences of Marfan syndrome
- weakened heart valves
- weakened arterial walls
x2 Cell types in the CT
- fibroblasts
- adipocytes (fat cells)
function of fibroblasts
secrete components of matrix
- fibres and GS
location of fibroblasts
connective tissues; migratory
function of adipocytes
store fat (triglycerides)
location of adipocytes
under skin + around organs
Cells found in solid CT
- macrophages (histiocytes)
- plasma cells
- mast cells
- leucocytes
function of fixed macrophages
- lung = “Dust cells”
- liver = kupffer cells
- skin = langerhand’s cells
Function of wandering macrophages
look for sites of infection/injury/ inflammation
function of plasma cells
- From B-lymphocyte
- produce antibodies
function of mast cells
- produce histamine that dilates vessels
location of leucocytes
white blood cells
- migrate out of blood to respond to infection
classification of CT
- embryonic
- mature
x2 types of embryonic CT
- mesenchyme (embryonic)
- mucous
mesenchyme embryonic CT structure/function/location
- gives rise to all other CT
- consists of mesenchymal cells
- located in semi-fluid GS containing reticular fibres
mucous embryonic CT function/location/structure
- scattered fibroblasts embedded in GS
- supports umbilical cord of foetus
x3 classes of mature CT
- connective tissue proper
- fluid connective tissues
- supporting connective tissues
loose mature CT sub-types
areolar
adipose
fibres present in loose areolar CT
- collagen
- reticular
- elastic
location loose areolar CT
almost every structure
- packing material
function of loose areolar CT
- strength + elasticity + support
function of loose adipose CT
insulation
energy source
temp control
structure of loose adipose CT
- adipocytes dominant
- central triglyceride droplet
location of loose adipose CT
with areolar CT (fibroblasts)
x2 types of loose adipose CT
- white adipose (energy storage)
- brown adipose (heat production)
structure of reticular CT
interlacing network or reticular fibres + reticular cells
location of reticular CT
- stroma of liver
- spleen
- lymph nodes
- red bone marrow
- reticular lamina (basement membrane)
- around blood vessels + muscles
function of reticular CT
- form storma of organs
- binds smooth muscle tissue cells
- filter/remove worn-out blood cells
location of dense regular CT
- tendons
- ligaments
- aponeuroses
function of dense regular CT
- strong attachment
- withstand pull forces
- slow healing to damaged tendons
structure of dense regular CT
collagen fibres regularly arranged in bundles with fibroblasts
structure of dense irregular CT
collagen fibres irregularly arranged; few fibroblasts
function of dense irregular CT
- Tensile strength
function of dense elastic CT
- stretching of organs
- recoil back to original shape
structure of dense elastic CT
elastic fibres with fibroblasts between
location of dense elastic CT
- lung tissue
- walls of elastic arteries
- trachea
- bronchial tubes
- vocal cords
function of hyaline cartilage CT
flexibility + movement
location of hyaline cartilage CT
- nasal septum
- ends of long bones
structure of hyaline cartilage CT
Dense network of collagen + elastic fibres
- resilient gel = fibres present not obvious
structure of fibrocartilage CT
thick bundles of collagen fibres
- chondrocytes among
location of fibrocartilage CT
- portion of tendons
- menisci of knee
- intervertebral discs
- pubic symphysis
function of fibrocartilage CT
support + joining of structures
strength + rigidity
structure of elastic cartilage CT
chondrocytes in threadlike network of elastic fibres in ECM
location of elastic cartilage CT
- larynx
- external ear
- auditory tubes
function of elastic cartilage CT
strength + elasticity
maintain shape of certain structures
x2 types of bone tissue
- compact bone
- spongy bone
what bone tissue is the outer layer and forms shaft of long bones
compact bone
another name for compact bone
cortical bone
what is compact bone composed of?
- rod-shape units
(osteons or Haversian systems)
another name for spongy bone
cancellous bone
porous inner bone tissue that lies underneath compact bone
spongy bone
function of compact bone
- contains osteons
- stores Ca and P
- protection + support
function of spongy bone
- lacks osteons
- store triglycerides (yellow marrow)
- produce blood cells (red marrow)
x4 cell types found in bone
- Osteogenic cells
- osteoblasts
- osteocytes
- osteoclasts
function of osteogenic cells
mesenchymal stem cells develop
> lay down collagen > become trapped = become osteoblasts
function of osteoblasts
bone forming cells
> lay down more collagen > mineralisation process begins
function of Osteocytes
mature bone cells derived from osteoblasts trapped in ECM
> maintain bone tissue > exchange nutrients/wastes
GAP JUNCTIONS
function of osteoclasts
- large, multinucleate cells
- formed from fusion of blood monocytes
- break down bone
composition of osteon x4 parts
- lamellae
- lacunae
- canaliculi
- central (Haversian) canal
lamelle structure
concentric rings of mineral salts = hardness
lacunae structure
small spaces between lamellae contain mature bone cells (osteocytes)
canaliculi structure
“minute canals”
radiate from lacunae + provide routes for O2, nutrients and waste
central canal (Haversian) structure
blood, lymph, nerves
osteoclasts function
reabsorb dead bone
chondroblasts function
lay down byline cartilage cllus
osteoblasts function
lay down new bone
osteoclasts function
remodel new bone
structure of liquid blood CT
consists of blood plasma + formed elements
in blood ___ transport O2 and CO2
erythrocytes
formed elements of blood
- red blood cell (erythrocytes)
- platelets (thrombocytes)
- eosinophil
- basophil
- neutrophil
- monocyte > macrophage
- T lymphocyte (T cell)
- B lymphocyte (B cell) > Plasma cell
formed element for clotting
platelets
- megakaryocytes in red marrow
formed element involved in immune response
lymphocytes
formed element effective against certain parasitic worms and in acute allergic response
eosinophils
formed elements that release substances that intensify inflammatory reaction
basophils (mobile)
mast cells (immature circulate; mature fixed in tissues)
formed elements phagocytic = engulf bacteria
neutrophils
monocytes (macrophages)
