ET, CT (bone cartilage, loose + dense) Flashcards
what is ET
sheet of cells that cover the body’s surface/ lines body cavity
what does covering and lining epithelium do
covers walls of organs
forms outer layer of skin
lines open cavities of the digestive and respiratory systems
what does glandular epithelium do
surrounds glands within the body
characteristics and types of ET
C: closely packed cell
minimal matrix
basement membrane
T: simple- single layer
stratified- multiple layer
name types of simple epithelium
squamous
cuboidal
columnar
squamous epithelium
LOCATION: air sacs of lungs
lining of heart, blood easels and lymphatic vessels
FUNCTION: allow material to pass thru diffusions and filtration
secretes lubricating material
cuboidal epithelium
LOCATION: ducts
kidney tubules
glands
FUNCTION: absorbs
secretes enzymes and mucus
columnar epithelium
LOCATION: cilliated- in bronchi, uterine tubes
smooth- in digestive tract and bladder
FUNCTION: secretes and absorbs
what is stratified epithelium
several layers of cells
can be cuboidal/ squamous or columnar
stratified epithelium
LOCATION: lines oesophagus, mouth and vagina
sweat+ salivary glands
outmost layer of skin
FUNCTION: secretes
protects e.g. against abrasion
keratinised SE
LOCATION: most skin
esp areas with no hair e.g. palms
FUNCTION: protects
waterproof
transitional epithelium SE
LOCATION: lines bladder, urethra and ureters
FUNCTION: allows urinary organs to stretch and expand
what is connective tissue
most abundant tissue type in human body
characteristics are: widely separated cells
larger amounts of matrix material (ECM)
basement membrane- specialised form of matrix
what is the ECM in the CT made of
ground substance + fibres
what are the ground substances in ECM
maybe be fluid, semi fluid, gelatinous or calcified
supports cell+ binds together
stores water
provides a medium for exchanges of material
contains large organic molecules e.g. glycosaminoglycans associated with proteoglycans
what are the fibres in ECM
strengthen and support connective tissues
collagen- strong but not stiff- allow for tissue flexibility
elastic- strong but stretchy- forms a branched network
reticular- fine bundles of collagen with a coating of glycoproteins- provide strength and support
examples of cell types in CT
fibroblasts- produce collagen and elastic fibres
adipocytes (fat cells)- occur singly and in groups
wbc- engulf foreign materials and pathogens
loose connective tissue
loose arrangement of fibres in a moderately viscous fluid matrix
AREOLAR: most widely distributed
around nearly every body structure
give strength and elasticity and support
ADIPOSE: cells derive from fibroblasts
co-located in areolar tissue
supports and protects
RETICULAR: formed of reticular fibres
provides supporting framework
acts as a filter
dense connective tissue
dense woven network of collagenous and some elastic fibres in a viscous matrix
dense reg: strong/ poor blood supply e.g ligaments and tendons
dense irreg: high tensile strength/ allow organ to resist excessive stretching and distension e.g. dermis of skin
elastic: allows for stretching and recoil e.g. lung tissue + walls of elastic arteries
types of connective tissue
loose
dense (reg, irreg, elastic)
bone (cortical and trabecular)
cartilage
bone CT
widely spaced cells
large amount of matrix material- 15% water, 55% crystallised mineral salts, 30% collagen
collagen= provide flexibility
min salts= provide hardness
blood supply of bone
requires good supply
calcified matrix doesnt allow diffusion
bone structure
trabecular- spongy, inner bone and porous
all ways located in interior
cortical- compact, outer bone and rigid
protects trabecular, covers
cortical bone
concentric units (ostens) made up of concentric lamellae= strength
arranged in osteons
central canals connected to each other by perforating canals (haversian system)
in an osteon, collagen fibres run in opposite directions
resists twisting forces
multiple layers prevent cracks spreading
