Physiology

Question 1

Calcium required for contraction of skeletal muscle is found where?

Answer 1

• Sarcoplasmic reticulum

Question 2

Skeletal muscle is under ____ control?

Answer 2

• voluntary control

- neurogenic initiation

Question 3

Describe the motor unit in skeletal muscle

Answer 3

Single alpha motor neurone and all the skeletal muscle fibres it innervates

Question 4

Muscles with fine movements will have __(more/less)___ fibres per motor unit?

Answer 4

• Less

- Precision more important than power

Question 5

Muscle fibre is another term for what?

Answer 5

• Muscle cell

Question 6

What is the name given to the functional unit of skeletal muscles?

Answer 6

• Sarcomere

Question 7

Define functional unit

Answer 7

• The smallest component capable of performing all the functions of that organ

Question 8

Where is the A band found in skeletal muscle?

Answer 8

• Made up of thick filaments along with portions of thin filaments that overlap

Question 9

Where is the H zone?

Answer 9

• The lighter area within the middle of the A band where thin filaments don’t reach

Question 10

Where is the M line?

Answer 10

• Down the middle of A band

Question 11

ATP is dependant for ______ and _____ of skeletal muscle

Answer 11

• contraction

- relaxation

Question 12

Why is ca2+ required for muscle contraction

Answer 12

• pulls tropomyosin out, to allow cross bridges to form

Question 13

What neurotransmitter is required to allow excitation

Answer 13

-Acetylcholine

Question 14

What effects the strength of skeletal muscle tension?

Answer 14

• Number of muscle fibres

- Tension developed

Question 15

How do twitches arise in skeletal muscles?

Answer 15

• repetitive fast stimulation of skeletal muscles

- provides no opportunity for the muscle to relax

Question 16

What is the effect on muscle length during isotonic contraction?

Answer 16

• Length changes

- Muscle tension remains constant

Question 17

What is an example of an isotonic contraction?

Answer 17

• body movements

Question 18

What is an example of an isometric contraction?

Answer 18

• maintaining posture

Question 19

What is the effect on muscle length during isometric contraction?

Answer 19

• No effect on muscle length

- tension develops

Question 20

What is the main source of ATP when O2 is not present?

Answer 20

• Glycolysis

Question 21

What is the main source of ATP when O2 is present?

Answer 21

• Oxidative phosphorylation

Question 22

Define reflexes?

Answer 22

• action is a stereotyped response to a specific stimulus

Question 23

What is the simplest monosynaptic spinal reflex?

Answer 23

• Stretch reflex

Question 24

What are muscle spindles?

Answer 24

• Specialised muscle fibres

- Sensory receptors for stretch reflex

Question 25

What is a intrafusal fibre?

Answer 25

- muscle spindels | - specialised muscle fibre

Question 26

What is the name given to the efferent neutrons that supply muscle spindles?

Answer 26

- Gamma motor neurons

Question 27

What are some examples of causes of muscle diseases?

Answer 27

Genetics Muscular dystrophy Endocrine (Cushings)

Question 28

Symptoms of muscle disease?

Answer 28

- Muscle weakness - Delayed relaxation (myotonia) - Muscle pain

Question 29

Define Myotonia?

Answer 29

- delayed relaxation of muscle

Question 30

Define myalgia?

Answer 30

- muscle pain

Question 31

How are skeletal muscles innervated?

Answer 31

- fast alpha-motor neurone with myelinated axons and cell bodies in the spinal cord

Question 32

Where are nicotinic ACh receptors located?

Answer 32

- at regions of the junctional folds that face active zones

Question 33

Highlight the main steps involved in neuromuscular transmission

Answer 33

- Synthesis of ACh - Uptake of ACh into synaptic vesicles - Ca2+ dependant release of ACh into synaptic cleft - ACh binding to nicotinic ACh receptors

Question 34

Where is ACh synthesised?

Answer 34

- cytoplasm of bouton

Question 35

What enzyme is involved in the synthesis of ACh?

Answer 35

- acetyltransferase

Question 36

How is Ca2+ released?

Answer 36

- action potential arrives at T-tubule | - triggers release of Ca2+ from SR

Question 37

What enzyme causes termination of ACh binding to nicotinic receptors?

Answer 37

- Acetylcholinesterase (AChE) | - Hydrolyses ACh to choline and acetate

Question 38

Issac's disease has reduce ___ conductance

Answer 38

- Reduced K+ conductance

Question 39

LEMS has reduced ___ conductance

Answer 39

- reduced Ca2+ conductance

Question 40

What is the drug treatment for mysthenia gravis

Answer 40

- Anticholinesterases

Question 41

What are the 4 processes of pain?

Answer 41

- Transduction - Transmission - Modulation - Perception

Question 42

What are the names given to the afferent pain primary neurons?

Answer 42

- Nociceptors | - first order neurons

Question 43

Subtypes of nociceptors?

Answer 43

``` alpha gamma (fast) c-fibers (slow - throbing) ```

Question 44

hyperalgesia?

Answer 44

Causes heightened pain sensitivity to noxious

Question 45

allodynia?

Answer 45

Heightened pain sensitivity to innocuous stimuli

Question 46

Dysfunctional (pathological) pain?

Answer 46

No identifiable damage or inflammation