msk histology formatives Flashcards
main features of cardiac muscle?
branching fibres
central nuclei
intercalated discs
main features of smooth muscle?
spindled cells
single central nuclei
no striations
main features of skeletal muscle
multinucleated muscle fibres
striated cytoplasm
why is skeletal muscle striated
bc the myofibrils are in register
what is a myofibril
arrangement of contractile proteins within a muscle fibre
which ions are released into the sarcoplasm via t tubules?
calcium ions (play vital role in contraction of muscle)
what is the diff btwn endomysium, perimysium and epimysium?
endomysium = sticks adjacent muscle fibres to each other
perimysium = binds groups of muscle fibres together to form fascicles
epimysium = binds fascicles together to form anatomically defined muscles
what is the sarcolemma
cell membrane of muscle cells
does exercise change the proportion of t1/t2 muscle fibres
no
exercise incr size of muscle fibres
what is diff btwn t1/t2 muscle fibres
t1 = slow twitch t2 = fast twitch
release of ______ at motor end plates stimulates contraction of skeletal muscle
ACh
are skeletal muscles vascular
yes bc contraction is energy dependant
what do muscle spindles sense
stretch n tension in muscle
do skeletal muscles contain pain receptors
no
what are sharpey’s fibres made of
type 1 collagen
what are sharper’s fibres
bundles of strongly minded t1 collagen connecting periosteum to bone, merging w the bone’s collagen fibres
what is a t tubule
invagination of sarcolemma - conduct charge when cell is depolarised
what may protect tendons from frictional injury
they may lie in a fibrocollagenous tendon sheath
what do tendons comprise of
dense reg fibrous connective tissue
ligaments/tendons: which contains elastin
lig. may contain elastin (not normally found in tendons?
ligaments/tendons: which contains fibroblasts
both
ligaments/tendons: which contain myocytes
none
what do osteoblasts secrte
osteoid
what type of collagen is osteoid rich in
1
are osteoclasts mono or multinucleated
multi
are osteocytes dead cells
no - they dormant but living
which has more ER: osteoblasts or cytes
osteoblasts
are osteocytes in contact w 1 another n how
yes: thin cytoplasmic processes running through canaliculi
what are Haversian canals
run in centre of osteons and convey blood vessels through bone
what is sig about urothelium?
water/urine-proof: umbrella cells that are not in contact w basement membrane
where is urothelium found
renal pelvis
ureters
urinary bladder
urethra
how do the diff parts of the colon differ in their histolofy
they don’t - all same
which 2 autonomic nerve plexuses innervate GI tract
meissner’s plexus: submucosa
Auerbach’s plexus: btwn layers of muscular proprietary
what are the 4 main layers of gi tract
(innermost)
- mucosa (epithelium, lamina propria, muscularis mucosa)
- submucosa
- muscularis propria
- adventitia
what is the colon’s muscularis propria like
double-layered: inner circular, outer longitudinal
what is a prominent brush border a feature of
s intestine NOT colon
what is epimysium
thick layer of connective tissue surrounding muscle
what is tropomyosin
long protein that runs along the actin filament, blocking the myosin head binding sites
what is troponin
small protein that binds the tropomyosin to the actin
3 types: I, T, C
what is the diff btwn troponin I/T/C
i - binds to the actin filament.
t - binds to tropomyosin
c - binds to calcium ions.
briefly describe myosin
myosin filaments have many heads that can bind to sites on actin filament
