20 Muscle

Question 1

myalgia

Answer 1

muscle pain

Question 2

myasthenia

Answer 2

muscle weaken

Question 3

myocardium

Answer 3

muscular component of hert

Question 4

myopathy

Answer 4

any disease of the msucle

Question 5

myoclonus

Answer 5

sudden muscle spasm

Question 6

striated:

Answer 6

skeletal and cardiac (myoglobin present)

Question 7

non striated

Answer 7

smooth muscle (myoglobin not present)

Question 8

Skeletal muscle structure

Answer 8

striated
sarcolemma (outer membrane), sarcoplasm (cytoplasm), sarcosome (mitochondria), sarcomere (contraction unit), sarcoplasmic reticulum (SER)

Transverse tubule gtransmits messages to nerves

muscle fibres connected by tendons

apart from tongue muscles

strong capillary network around fibres

Question 9

Skeletal muscle function

Answer 9

contraction. movement along that direction of fibre

movement created at the insertion tendon point

Question 10

histology Skeletal muscle

Answer 10

groups of cells together, fasicle surrounds it

Myofibrils in cells: nucleus on edge, myofibrils lined up, mito lined up between, t tubules very closly associated with the mitochondria

Question 11

Each cell (fibre) contain many myofibrils
Myofibril structure

Answer 11

Dark A band: thick myosin filament

Light I band: actin filaments

Question 12

Slow twitch and fast twitch muscle fibres

Answer 12

slow: very red, built up energy, long distance endurance
fast: white, not much myoglobin. good for eyes, sprint

Question 13

Cardiac muscle histology:

Answer 13

cardiomyocytes (communicate between gap junctions)
nucleus in cneter, lots of glycogen around, 1 or 2 nucleuses. very striped. have intercalated discs
has branches

Question 14

Cardiac muscle

Answer 14

endocrine tissue. contains ANP granules.

Question 15

ANP

Answer 15

made in atrium

Question 16

BNP

Answer 16

in ventricles

Question 17

ANP and BNP

Answer 17

released during heart failure, removes water (vasodilation) to lower blood pressure

Question 18

hypertrophy

Answer 18

increase in cell size

Question 19

hyperplasia

Answer 19

cells dividing

Question 20

purkinje fibres

Answer 20

large cells
lots of glycogen
sparse myofibrils
extensive gap junctions
they conduct action potential rapidly
 lie just under the outer of the heart (under endocardium lining)

Question 21

Smooth muscle cells

Answer 21

non-striated
spindle shape, large nucleus
no sarcomeres or t tubules
few mitochondria
can be stretched
actin myson movement for contraction
slow contractions
responds to nerve signals, hormones, drugs...

Question 22

Where is smooth muscle??

Answer 22

vascular structures, gi tract

can cause incontinence,bp problems, asthma.

Question 23

Where do smooth muscle signals come from?

Answer 23

come from varicosities sitting on outside of muscle. they’re full of mitochondria.

Question 24

Can we repare the muscle?

Answer 24

Skeletal: cells cannot divide but can regenerate by mitotic activity of satellite cells (fuse with exsisting cells)

Cardiac: no regeneration, scar tissue forms. can in kids, not in adults

Smooth: can regenerate, retain mitotic activity (eg pregnant uterus wall grows and divides