Histology of the muscle

Question 1

what are the 3 types of muscle

Answer 1

skeletal
cardiac
smooth

Question 2

functions of the muscular system

Answer 2

locomotion
posture maintenance
muscle tone
heat generation
joint stability
vasoconstriction and vasodilation
peristalsis
cardiac motion and contractility

Question 3

transverse Tubule

Answer 3

Well developed in skeletal and cardiac muscles to transport calcium (absent in smooth muscle)

Question 4

intercalated disk

Answer 4

Specialized intercellular junction that is only present in cardiac muscle

Question 5

control

Answer 5

Skeletal muscle is under voluntary control‚ smooth and cardiac muscles are under involuntary control

Question 6

types of skeletal muscle

Answer 6

parallel
convergent
pennate
circular

Question 7

label the image

Answer 7

Question 8

types of connective tissue sheaths

Answer 8

epimysium
perimysium and fascicles
endomysium

Question 9

epimysium

Answer 9

overcoat of dense irregular connective tissue that surrounds the whole muscle

Question 10

perimysium and fascicles

Answer 10

within each skeletal muscle the fibers are grouped into fascicles that resemble bundles of sticks
surrounding each fascicle is a layer of dense irregular connective tissue perimysium

Question 11

endomysium

Answer 11

sheath of connective tissue that surrounds each muscle fibre and is connective tissue in nature

Question 12

what is in the image and from which view

Answer 12

cross section of skeletal muscle

Question 13

what is in the image and from which view

Answer 13

cross section of skeletal muscle

Question 14

skeletal muscle in cross section

Answer 14

hexagonal profile with individual cells moulded together
nucleic beneath cell membrane
fibrocollagenous septa contain blood vessels

Question 15

what is in the image and from which view

Answer 15

skeletal muscle in a longitudinal view

Question 16

skeletal muscle in longitudinal view

Answer 16

shows prominent cross striations
dark bands termed A bands and light are termed I bands
correspond to the arrangement of thick and thin filaments in myofibrils
nuclei appear as elongated structures beneath cell membrane, each fibre has many nuclei

Question 17

what is a sarcomere

Answer 17

the region of myofibril between 2 successive Z discs
smallest contractile unit of a muscle fibre

Question 18

what are the two different bands

Answer 18

dark and light
A and I

Question 19

dark band

Answer 19

A bands
has lighter region in midsection called H zone

Question 20

H zone

Answer 20

bisected vertical by dark line called M line
M for middle

Question 21

light band

Answer 21

I band
has a midline interruption called Z disc or Z line

Question 22

where are I bands found

Answer 22

thin filaments

Question 23

where are H zones found

Answer 23

thick filaments only q

Question 24

where is the M line found

Answer 24

thick filaments linked by accessory proteins

Question 25

outer edge of the A bands

Answer 25

thick and thin filaments overlap

Question 26

what is a motor endplate

Answer 26

specialised chemical synapses formed at the sites where the terminal branches of the axon of a motor neuron contact a target muscle cell.

Question 27

action of the motor end plate

Answer 27

activation causes release of acetylcholine from storage granules by exocytosis then diffuses across gap between axon and muscle fibre and interacts with specific membrane receptors to cause depolarisation of muscle fibre initiates contraction activity of secreted acetylcholine is curtailed by activity of acetylcholinesterase bound to basement membrane hydrolyses acetylcholine into acetic acid and choline specialised motor axons innervate fibres in the muscle spindle

Question 28

myasthenia graves

Answer 28

autoimmune disease antibodies bind to acetylcholine receptors prevent acetylcholine from interacting with receptors causing depolarisation develop muscle weakness manifested by fatiguability, unable to lift arms failure to maintain upright posture of head and drooping of eyelids treatment is by administration of anticholinesterases potentiates action of acetylcholine and allows it to bind to receptors not blocked by antibody

Question 29

Duchenne muscular dystrophy

Answer 29

deficiency of dystrophin genetic disorder dystrophin encoded by gene on short arm of X chromosome Xp21 linked to cytoplasmic side of sarcolemma of muscle fibre rapid progression of skeletal muscle degeneration mainly young boys muscle weakness and wasting

Question 30

what is in the image

Answer 30

Duchenne muscular dystrophy lack of dystrophin results in damage to skeletal muscle cell membrane with eventual death of muscle fibers dead muscle cells replaced y fat cells muscle fibres are of various diameters

Question 31

what is in the image

Answer 31

longitudinal section of cardiac muscle cells contain 1 or 2 nucleus extensive eosinophilic cytoplasm gives 3d appearance elongated nuclei central located

Question 32

what is in the image

Answer 32

transverse section of cardiac muscle

Question 33

what is in the image

Answer 33

ID are intercalated disks cross section under polarised light

Question 34

what is in the amigo and what are the red lines

Answer 34

intercalated discs longitudinal section of cardiac muscle

Question 35

what is in the image

Answer 35

transverse section of cardiac muscle

Question 36

what is in the image

Answer 36

longitudinal section of smooth muscle can see serosa and elongated nuclei but there's no striations

Question 37

what is in the image

Answer 37

cross section of smooth muscle

Question 38

skeletal muscle summary

Answer 38

Striations Long cylindrical unbranched fibres Multinucleated peripheral nuclei No cell junctions Highly developed sarcoplasmic reticulum with termina cisterns Regeneration with satellite cells

Question 39

cardiac muscle summary

Answer 39

Striations Short branch anastomosing fibres Uninucleated, central Intercalated discs cell junctions Small cisterns and less well developed sarcoplasmic reticulum Not able to regenerate

Question 40

smooth muscle summary

Answer 40

No striations Short spindle shaped fibres Uninucleated, central Gap junctions and adherents junctions Poorly developed sarcoplasmic reticulum Regeneration by mitosis

Question 41

what are satellite cells

Answer 41

are adult myogenic stem cells that repair damaged muscle. - produce myoblasts that can replace damaged fibers - undergo self-reneweal