Case 9 - Development of skeletal muscle and response to injury

Question 1

what kind of control at skeletal muscles under

Answer 1

voluntary

Question 2

what type of work do skeletal muscles do

Answer 2

high powered work

Question 3

what is skeletal muscles typical activity

Answer 3

usually relaxed

Question 4

where does skeletal muscle originate from

Answer 4

from the somites, you get the bone, connective tissue and muscle fo your limbs (paraxial mesoderm)

skeletal muscle cells originate from dorsal somites

ventral somite makes bone, cartilage and tendons

Question 5

how does skeletal muscle form

Answer 5

forms in waves: doesn’t develop all at once

Question 6

histology slide of skeletal muscle

Answer 6

Question 7

what is the very thick membrane called in striated muscle structure

Answer 7

the epimysium

Question 8

what are the fascicles of groups of muscle fibres separated by

Answer 8

perimysium membranes

Question 9

diagram showing striated muscle structure

Answer 9

Question 10

where are the motor neurones located in the spinal cord

Answer 10

in the anterior horns

Question 11

what is the neurotransmitter involved and where is it contained

Answer 11

acetylcholine and is contained in the synaptic vesicles

Question 12

what is the acetylcholine receptor

Answer 12

a ligand operared sodium channel

Question 13

what is the troponin complex made up of

Answer 13

TnT, TnC, TnL

Question 14

what is an isotonic force

Answer 14

producing a force that moves the muscle

Question 15

what is isometric movement

Answer 15

trying to move muscle against resistance that prevents this movement. does not shorten the muscle but essentially increases the tension

Question 16

what does a motor neurone pool consist of and what do they innervate

Answer 16

consists of many motor neurones, each of which innervates a motor unit with the muscle.

Question 17

what does a motor neurone innervate

Answer 17

one set of muscle fibres

Question 18

what is muscle fibre type X

Answer 18

in between type 2B and 2A

Question 19

what is muscle strain

Answer 19

commonly referred to as a pulled muscle. this injury can happen when the muscle is over stretched, over used or used improperly.

Question 20

what is a muscle tear

Answer 20

larger injury in which a muscle and the blood vessels that supply it are torn. it typically takes a significant amount of force to cause this type of injury

Question 21

what is rhabdomylysis

Answer 21

is a serious condition that occurs when muscle fibres die and their contents are released into the bloodstream. Since the kidneys filter out these muscle byproducts, rhabdomyolysis can result in kidney failure, which may be fatal. Symptoms of rhabdomyolysis include muscle pain, weakness and dark urine. Causes include crash injuries, car accidents, heatstroke, infections, intense exercise, seizures and the use of cocaine

Question 22

what is muscle contusion

Answer 22

also referred to as a muscle bruise. Occurs when a blunt object strikes the body and crushes underlying muscle tissue, but does not break the skin. Contusions typically cause pain, swelling and decreased range of motion.

Question 23

muscle damage regeneration

Answer 23

Question 24

what do M1 macrophages do

Answer 24

stimulate production of satellite cells for proliferation and make new muscle fibres

a satellite cell is a stem cell

Question 25

what is the Duchenne muscular dystrophy

Answer 25

X linked recessive disease caused by mutation of dystrophin gene, the largest known gene (2.4Mb) coding for a 427kD cytoskeletal protein (only males get it)
It is the second most common genetic disorder in man and most common muscular dystrophy of childhood (incidence 1:5000 male live births)
Characterised by degeneration of skeletal muscle due to absence of dystrophin on muscle fibre membrane.
Gastrocnemius muscle inflammation

Question 26

what is dystrophin

Answer 26

connects the sarcomeres to the membrane and through other proteins to the basal lamina. dystrophin protects from stress and doesn’t let muscle get damaged

Question 27

what is Becker

Answer 27

mild form of muscle dystrophy

Question 28

pathophysiology of DMD

Answer 28

Question 29

pathophysiology of DMD

Answer 29