DONE Muscles

Question 1

Striated muscle

Answer 1

Both skeletal + cardiac

Question 2

Non-striated

Answer 2

Smooth muscle

Question 3

Skeletal muscle

Answer 3

Myoglobin
Voluntary
Direct nerve-muscle communication

Question 4

Cardiac muscle

Answer 4

Myoglobin
Involuntary
Indirect nerve-muscle communication

Question 5

Smooth muscle

Answer 5

Myoglobin absent
Involuntary
No direct nerve-muscle communication
No sarcomeres/troponin

Question 6

Myoglobin

Answer 6

Red protein, oxygen storing molecule, no affinity for CO2

Question 7

Sarcolemma

Answer 7

Outer mem. of muscle cell

Question 8

Sarcoplasm

Answer 8

Cytoplasm of muscle cell

Question 9

Sarcosome

Answer 9

Mitochondrion

Question 10

Sarcomere

Answer 10

Contraction unit in striated muscle

Question 11

Sarcoplasmic reticulum

Answer 11

Smooth ER of muscle cell, calcium store

Question 12

Structure + function of skeletal muscle

Answer 12

To contract

3 layers of CT = endomysium (loose, inner CT), perimysium (loose CT, surrounds fascicles), epimysium (outer, dense CT)

Question 13

What colour are slow twitch fibres?

Answer 13

Red = lots of myoglobin, mitochondrion, cytochrome

Question 14

Structure of cardiac muscle

Answer 14

Central nuclei (peripheral in skeletal)
Sarcomere less developed than skeletal 
1 contractile cell type (cardiomyocyte)

Question 15

Smooth muscle structure

Answer 15

Spindle-shaped (fusiform)
Single, large, central nucleus
No sarcomeres
Slower contraction than skeletal

Question 16

How do mature skeletal muscle cells repair?

Answer 16

Cells can’t divide

Regenerate via satellite cells = hyperplasia

Question 17

How do mature cardiac muscle cells regenerate?

Answer 17

Can’t

Fibroblasts invade, lay down scar tissue

Question 18

How do mature smooth muscle cells regenerate?

Answer 18

Retain mitotic activity

Question 19

Tropomyosin

Answer 19

Bonds along actin, prevents myosin binding

Question 20

Troponin-C

Answer 20

Calcium binding unit on troponin

Question 21

Troponin-I

Answer 21

Binds to actin, holds actin-tropomyosin complex in place

Question 22

Troponin-T

Answer 22

Pulls tropomyosin to expose myosin binding site

Question 23

Creatine kinase

Answer 23

Catalyses ATP to ADP and Pi for energy for muscle contraction

Question 24

Myasthenia gravis

Answer 24

Autoimmune disease
Antibodies block ACh receptor
Reduced synaptic transmissions = intermittent mucle weakness

Question 25

Compartment syndrome

Answer 25

Limb divided into compartments by fascia
Trauma in 1 compartment = internal bleeding = pressure on blood vessels + nerves
SYMPTOMS = oedema, prolonged capillary refill time, paresthesia (pins + needles), deep + localised pain

Question 26

Muscle tone

Answer 26

Tension in a muscle @ rest (healthy muscle never fully relaxed)

Question 27

Muscular atrophy

Answer 27

Destruction > replacement (hypertrophy = opposite)

Question 28

Muscular hypertrophy

Answer 28

New muscle fibrils + sarcomeres produced due to overstretching

Question 29

Muscular atrophy

Answer 29

Disuse (bed rest), surgery (denervation of muscle), disease

Question 30

Duchene muscular dystrophy

Answer 30

X-linked recessive
Dystrophin gene mutation
More calcium enters cell, taken up by mitochondria, H2O into mitochondria = burst, muscle cells burst (rhabdomyolysis), creatine kinase + myoglobin levels high in blood
Muscle cells replaced by adipose tissue
SYMPTOMS = stomach sticks out due to weak belly muscles, poor balance, thick lower leg muscles (mainly fat), sway back

Question 31

Botulism toxin

Answer 31

Produced by Clostridium botulinum
Blocks neurotransmitter release @ motor end plate
Cause non-contractile skeletal muscle (flaccid paralysis)
Treat muscle spasms, botox

Question 32

Organophosphate poisoning

Answer 32

Pesticides, inhibit ACh esterase (which stops signalling processes)
MUSCARINIC SYMPTOMS = SLUDGE (salivation, lacrimation, urination, defecation, GI cramp, emesis = vomiting)
NICOTINIC SYMPTOMS = MTWTF (muscle cramps, tachycardia, weakness, twitching, fasciulations)

Question 33

Creatine kinase

Answer 33

Released into blood by damaged skeletal muscle and brain (from Intramuscular injections, a fall, rhabdomyolysis, muscular dystrophy)