Tissues Flashcards
Tight Junctions
(zonula occludens)
- occluding junctions
- tightly bound at apical regions
- transmembrane proteins; OCCLUDINS & CLAUDINS
- claudin-1 waterproofing of skin
- claudin-16, kidney permeability to Mg2+
Zonula adherens
- anchoring
- strengthens cell attachments at apical region
- links cytoskeletons of cells(actin myofilaments).
- E-CADHERINS
- loss of e-caherins associated with cancer metastisis
Desmosomes
- anchoring
- firmly anchors neighboring cells together
- link cytoskeletons of adjacent cells
conencts to cytokeratin - CADHERINS such as desmoglein
- autoimmune attack on desmoglein-3 resoults in skin sloughing off
Hemidesmosomes
- anchoring
- anchors cell to basement membrane
- modified desmosomes; bind cells to basement membrane.
- bind to cytokeratin
- INTEGRINS
Gap junctions
- communicating
- open channels between cell’s cytoplasm
- CONNEXINS
hyperplasia
increase in size of tissue/organ
caused by increased cell reproduction rate
adaptation
- breast epithelial tissue changes during pregnancy
pathology
- oestrogen-secreting ovarian tumour causing endometrial cell proliferation
Hypertrophy
increase in size of tissue/organ
caused by increase of cell size
adaptation
- breast epithelial tissue changes during pregnancy
tissue/cell atrophy
decrease in size
metaplasia
reversible transition of a mature cell from one cell type to another
pathology
- transitional epithelium —> strat squam due to bladder stones
- cilia colum epi bronchi –> strat squam due to cigarette smoke
- barrett’s oesophagous squamous –> columnar with goblet
dysplasia
presence of abnormal type of cells
pathology
- sunburn
- cervial dysplasia
neoplasia
new, uncontrolled cell growth
cancer
- cervical neoplasm
- cancer
epithelial tumours
benign:
- squamous & transitional cell papilloma
- renal, thyroid, or hepatic adenoma
malignant
- squamous or transitional cell carcinoma
- thyroid, renal or hepatic adenocarcinoma
Connective tissue proper; types
loose;
- areolar(cushioning, lamina propria)
- reticular(supports organs)
- adipose(fat; white or brown)
dense
- regular(parallel fibers)
- irregular(random fibres)
Cartilage types
Hyaline
- smooth, translucent
- little collagen
- eg. end of bones, tracheal rings
Fibrocartilage
- lots of collagen
- eg. cartilaginous joints, menisci
Elastic
- elastin and collagen
- eg. ear
Bone
- collagen in ECM
- calcification
- cancellous or compact.
ECM components
ground substance;
- glycosaminoglycans(GAGs/unbranching polysaccharides, e.g. hyaluronic acid)
- proteogycans - covalently bound to GAGs
fibrillar proteins
- strength(collagen) and elasticity(elastin
Adhesion proteins
- link fibres, ground substanc e and cells(fibronectin & laminin)
Collagen types
I: 90%. ligaments, tendons, bones, skin.
II: cartilage
III: reticular tissue
IV: basement membrane
(muscle) myofilaments(4)
actin; contains binding sites for thick filaments
tropomysin; covers binding sites in relaxed state
troponin; sits on tropomyosin and responds to signals for contraction
myosin; main thick filament protein. elongated with distinct head. ‘walks’
Basement membrane layers
lamina lucida
lamina densa
lamina fibroreticularis
RIgor mortis
Ca2+ leaks from sarcoplasm into muscle fibrea, myosin binds to actin; no ATP to unbind myosin.
Nermaline myopathy
birth defect; muscle weakness.
gene mutation in;
- NEB(thin filament length), or ACTA1(actin substance)
arrythmogenic right ventricular cardiomyopathy
- arhythmia caused by cardiac muscle death and replace meant by adipose
- desmosome dysfunction
Multiple sclerosis
autoimmune disorder, attacks CNS myelin sheaths
- visual disturbances,
- muscle weakness
- difficulty with coordination and balance
GUillan barre
autoimmune attack on the myelin sheath of the PNS
- tingling & weak limbs
- altered heart rate & BP
Myasenthia gravis
autoimmune disease- attacks nicotinic receptor
blocks Ach
- worse eyes, face & swallowing.
Epithelia types in the trachea, oesophagus, and small intestine
Trachea;
- pseudostratified ciliated columnar with goblet cells
Oesophagus:
- stratified squamous
Small intestine:
- simple columnar
