Tissues Flashcards
Function of epithelial tissue
covers surfaces and separates compartments
3 types of cell-cell junctions
desmosomes
tight junctions
gap junctions
cell- ECM junction
hemidesmosomes
what do desmosomes do
provide firm anchorage
what do tight/ occluding junctions do
seal intracellular spaces
what do gap junctions do
allow for cell-cell communication
3 types of simple epithelial
squamous - thin for easy diffusion
columnar -when ciliated, move mucus
cuboidal- perform secretion and absorption
where is simple squamous epithelial found
alveoli and capillaries
where is simple cuboidal epithelial found
lining of nephrons
where is simple columnar epithelial found
lining of digestive tract
3 types of stratified epithelium
squamous - thick, and layers can de sloughed off to allow new growth
columnar - protection and secretion
cuboidal -protection
where is stratified squamous epithelial found
epidermis
where is stratified cuboidal epithelial found
ducts of sweat glands
where is stratified columnar epithelial found
pharynx
describe the epithelial componenets of the liver
hepatocytes
arranged in rows between blood vessels
multiple functions including secretion
support epithelial cells line blood vessels and bile ducts
describe the epithelial components of the kidney
epithelial cells arranged into nephrons
multiple functions including filtration of the blood, partial absorption of filtrate
support cells blood vessels and renal pelvis which receives toxic urine
what are the consequences of abnormal function pf covering and lining epithelial
over/under proliferation
over/under secretion
loss of ciliary beat
define the term gland
collections of multi or single cellular secretory epithelial
endocrine glands
secrete into blood, e.g. adrenal cortex
exocrine glands
secrete to the surface e.g. sweat glands
forms of exocrine glands
simple
- tubular
- acinar
compound
-tubuloacinar
consequences of abnormal glandular function
over production- pituitary giantism
under production- pituitary dwarfism
define connective tissue
tissue which provides general structure, mechanical strength, space filling and physical and metabolic support for tissues
4 types of connective
fibres
ground substance
tissue fluid
loose connective tissue
what are fibres
collagen
makes up 30% of body weight
flexible but inelastic with great tensile strength
19types
elastic fibres
stretch to 1.5x length and return to original shape tho can be overstretched
microfibrils and amorphous component
found in sheets
yellow in colour
what is ground substance
proteoglycans
hyaluronic acid
glycoproteins
what is loose connective tissue
fixed cells - fibroblasts, macrophages, adipocytes, mast cells
transient cells- white blood cells
consequences of abnormal connective tissue function
- blood/bone marrow = leukaemia
- loose/dense = loss/abnormal fibres
- cartilage = tare
- bone= osteoporosis