9 - Structure & Function of Skeletal Muscle

Question 1

what are the 3 types of muscle?

Answer 1

• skeletal
• cardiac
• smooth

Question 2

where is skeletal muscle located?

Answer 2

connected to bones

Question 3

where is smooth muscle located?

Answer 3

hollow organs

Question 4

what is the morphology of each type of muscle?

Answer 4

skeletal - striated
cardiac - striated
smooth - smooth

Question 5

what is the control of each muscle type?

Answer 5

skeletal - voluntary
cardiac - involuntary
smooth - involuntary

Question 6

what is the power of each muscle type?

Answer 6

skeletal - high power
cardiac - high power
smooth - high power

Question 7

what is the typical activity of each muscle type?

Answer 7

skeletal - usually relaxed
cardiac - pump / cyclic
smooth - usally contracted

Question 8

draw a diagram with the qualities of each different muscle type?
* location
* morphology
* control
* type of work
* activity

Answer 8

Question 9

where does skeletal muscle originate from?

Answer 9

paraxial mesoderm and somites

Question 10

specifically what part of the somite does skeletal muscle originate?

Answer 10

myotome

Question 11

label the somite

Answer 11

1. neural tube
2. notochord
3. aorta
4. dorsal somite
5. ventral somite
6. somitocele

Question 12

how does skeletal muscle form?

Answer 12

in waves

Question 13

label the skeletal muscle

Answer 13

Question 14

what neurotransmitter is present at NMJ?

Answer 14

ACh

Question 15

what is the importance of T tubules at NMJ?

Answer 15

they ensure synchronised depolarisation across all myofibrils

Question 16

what are the elements of the troponin complex?

Answer 16

TnT
TnC
TnI

Question 17

explain striated muscle contraction in 5 stages

Answer 17

1. ATP binds to myosin head and causes dissociation of actin-myosin complex
2. ATP hydrolysed - myosin heads return to resting conformation
3. cross-bridge forms and myosin head binds in new position on actin
4. P is released - myosin heads change formation, power stroke occurs, filaments slide past each other
5. ADP released

Question 18

what are the 2 different types of contraction?

Answer 18

isometric - muscle does not shorten, but tension increases
isotonic - most common, muscle shortens

Question 19

what is a muscle unit?

Answer 19

muscle fibres innervated by a single MN

Question 20

what is a motor unit?

Answer 20

muscle unit plus its motor neuron

Question 21

what is a motor neuron pool?

Answer 21

collection of neurons innervating a single muscle

Question 22

what is the difference between fine motor control and coarse control in terms of muscle fibres?

Answer 22

fine - few muscle fibres per motor unit
coarse - many muscle fibres per motor unit

Question 23

typically a muscle is controlled by how many motor neurons?

Answer 23

100

Question 24

typically each motor neuron controls how many muscle fibres over the muscle?

Answer 24

100-1000

Question 25

what are type 1 muscle fibres?

Answer 25

oxidative
slow
red

Question 26

what are type 2B muscle fibres?

Answer 26

glycolitic
fast
white

Question 27

what are type 2A muscle fibres?

Answer 27

glycolitic
fast
red

Question 28

what muscle fibres may a marathon runner typically have?

Answer 28

type 1

Question 29

what muscle fibres may a sprinter typically have?

Answer 29

type 2A

Question 30

what is a muscle strain?

Answer 30

• pulled muscle
• muscle is overstretched, overused, improperly used

*

Question 31

what is a muscle tear?

Answer 31

• muscle and blood vessels that supply it are torn
• significant force is neede

Question 32

what is rhabdomyolysis

Answer 32

• muscle fibres die and content released into blood stream
• results in kidney failure

Question 33

what is muscle contusion?

Answer 33

• muscle bruise
• blunt object striked body and crushes underlying muscle tissue

Question 34

muscle injury causes what two things?

Answer 34

• inflammation
• proliferation

Question 35

what are 3 types of chronic muscle damage?

Answer 35

• genetic diseases
• chronic inflammatory diseases
• sarcopenia

Question 36

what is sarcopenia?

Answer 36

reduction of muscle mass and strength associated to aging, cachexia, malnutrition

Question 37

what is the gene responsible for muscular dystrophy?

Answer 37

• X-linked recessive disease
• mutuation of dystrophin gene

Question 38

fill in this table of muscle fibres

Answer 38