Physiology

Question 1

How do muscles produce movement?

Answer 1

Through contraction

Question 2

Cardiac muscle

Answer 2

Striated

Involuntary - regulated by ANS

Question 3

Smooth muscle

Answer 3

Non-striated

Involuntary - regulated by ANS

Question 4

Skeletal muscle

Answer 4

Striated
Voluntary - regulated by somatic nervous system
Multi-nucleated (nuclei at periphery)
Needs nervous stimulation to initiate contraction
Motor units present

Question 5

What is the transmitter of the neuromuscular junction?

Answer 5

ACh

Question 6

What is a motor unit?

Answer 6

Single alpha motor neurone which innervates many muscle fibres.
The number of muscle fibres per motor unit varies depending on the functions of the muscle

Question 7

Muscles which serve fine movements (facial expression, intrinsic hand muscles) have LOTS/FEW fibres per motor unit?

Answer 7

Few

Question 8

When power (e.g. thigh muscles) is more important than precision, there are LOTS/FEW fibres per motor unit?

Answer 8

Lots

Question 9

Skeletal muscle organisation

Answer 9

Muscle fibres are held together by loose connective tissue.

Each muscle fibre = 1 muscle cell

Question 10

Contractile units within muscle fibres?

Answer 10

Myofibrils 
contain actin (thin, light) and myosin (thick, dark) filaments

Question 11

Functional units of skeletal muscles?

And where are they found?

Answer 11

Sarcomeres

Found between 2 Z-Z lines

Question 12

Z lines

Answer 12

Connect the thin filaments of 2 joining sarcomeres

Question 13

A band

Answer 13

Made up of thick filaments

Question 14

H zone

Answer 14

Lighter area in the middle of A band

Question 15

M line

Answer 15

Extends vertically down the middle of an A band

Question 16

I band

Answer 16

Remaining portion of thin filaments

Question 17

How do muscles contract?

Answer 17

Sliding of actin filaments on myosin filaments.

ATP and calcium are needed

Question 18

Cross bridge formation - muscle contraction

Answer 18

Calcium binds to troponin causing a conformational change.

This exposes the actin and myosin binding site so cross bridging occurs

Question 19

Muscle relaxation

Answer 19

Calcium unbinds from Troponin and cross bridges between actin and myosin break.
ATP is required

Question 20

If the muscle is stimulated continuously, it produces a STRONGER/WEAKER contraction

Answer 20

Stronger

Question 21

Skeletal muscle action potential

Answer 21

The tension increases with increasing frequency of stimulation.
(if a skeletal muscle is stimulated once, a single twitch is produced. but if a skeletal muscle receives a second stimulation before it has time to completely relax, then greater muscle tension is developed.

Question 22

What is tetanus?

Answer 22

A sustained contraction which occurs if a skeletal muscle is stimulated rapidly and it doesn’t have an opportunity to relax

Question 23

Skeletal muscle optimum length

Answer 23

Resting length

Question 24

Isotonic contraction of skeletal muscle

Answer 24

Length of muscle changes
Muscle tension remains constant
eg: body movements

Question 25

Isometric contraction of skeletal muscle

Answer 25

Length of muscle constant Muscle tension changes eg: maintaining body posture

Question 26

ATP production in skeletal muscle fibres

Answer 26

Transfer of high energy phosphate from creatinine phosphate to ADP (immediate source of ATP) Oxidative phosphorylation produces an abundance of ATP (when O2 present) Gycolysis produces ATP (when O2 absent)

Question 27

Slow oxidative skeletal muscle fibres (type 1)

Answer 27

Low myosin ATPase activity, so contraction is slow Lots of mitochondria -> lots of oxidative phosphorylation Used for prolonged relatively low work aerobic activities (e.g.: walking)

Question 28

Fast glycolytic muscle fibres (type IIb)

Answer 28

High myosin ATPase activity, so contraction is fast Few mitochondria -> rely on glycolysis to get ATP Mainly used for short term high intensity activities (jumping)

Question 29

Fast oxidative skeletal muscle fibres (type IIa)

Answer 29

Mixture of type I and type IIb. High myosin ATPase activity, contraction is fast Lots of mitochondria -> lots of oxidative phosphorylation Use aerobic and anaerobic metabolism Mainly used for prolonged activity (e.g. jogging)

Question 30

Function of synovial fluid

Answer 30

Lubricates joint - minimises wear and tear Facilitates joint movement by reducing friction Supplies chondrocytes with oxygen and nutrients

Question 31

Rapid movement causes an INCREASE/DECREASE in synovial fluid viscosity?

Answer 31

Decrease

Question 32

Rapid movement causes an INCREASE/DECREASE in synovial fluid elasticity?

Answer 32

Increase

Question 33

Gross appearance of normal synovial fluid

Answer 33

Clear, colourless

Question 34

Gross appearance of trauma related synovial fluid

Answer 34

Red

Question 35

Gross appearance of mildly synovial inflammation

Answer 35

Slightly yellow

Question 36

Gross appearance of severe synovial inflammation

Answer 36

Opaque, cloudy

Question 37

What is cartilage?

Answer 37

Semi-rigid, deformable, permeable | No blood supply

Question 38

Hyaline (articular) cartilage - where is it found?

Answer 38

Tracheal rings, costal cartilages, epiphyseal growth plate during development

Question 39

Hyaline (articular) cartilage - function?

Answer 39

Covers articular surfaces of bones Prevents wear and tear Distributes pressure

Question 40

Hyaline (articular) cartilage - composition?

Answer 40

Elastic | Sponge-like properties

Question 41

Elastic cartilage - where is it found?

Answer 41

Ears

Question 42

Elastic cartilage - function?

Answer 42

Flexible | Bounces back into shape

Question 43

Cartilage components

Answer 43

Water Collagen - mainly type II Proteoglycans - responsible for compressive properties

Question 44

What is fibrocartilage

Answer 44

Hybrid between hyaline and tendon cartilage Bands of densely packed type I collagen eg: intervertebral discs

Question 45

Catabolic factors of cartilage matrix turnover

Answer 45

Stimulate proteolytic enzymes | Inhibit proteoglycan synthesis

Question 46

Anabolic factors of cartilage matrix turnover

Answer 46

Stimulate proteoglycan synthesis

Question 47

Markers of cartilage degeneration

Answer 47

Increased levels of type II collagen in synovial fluid (e.g. from cartilage erosion) Increased levels of serum & synovial keratin sulphate

Question 48

Bone

Answer 48

Rigid, not permeable, has a blood supply

Question 49

Functions of bone

Answer 49

Support Protection Calcium store

Question 50

Outer layer of bone

Answer 50

Cortical bone | Makes up diaphysis (shaft)

Question 51

Inner layer of bone

Answer 51

Spongey | Fine meshwork of bone (aero bar appearance)

Question 52

What is a reflex?

Answer 52

Stereotyped response to a specific stimulus

Question 53

Stretch reflex

Answer 53

Causes contraction of stretched muscle

Question 54

How to elicit a stretch reflex

Answer 54

Tap the muscle tendon with a rubber hammer. this rapidly stretches the muscle resulting in its contraction

Question 55

Knee jerk - nerve involved - spinal nerve roots involved

Answer 55

Femoral nerve | L3, L4

Question 56

Ankle jerk - nerve involved - spinal nerve roots involved

Answer 56

Tibial nerve | S1, S2

Question 57

Biceps jerk - nerve involved - spinal nerve roots involved

Answer 57

Musculocutaneous nerve | C5, C6

Question 58

Intrafusal fibres

Answer 58

Muscle spindles

Question 59

Extrafusal fibres

Answer 59

Ordinary muscle fibres

Question 60

Nociceptive pain

Answer 60

Serves as an immediate warning that tissues have been damaged and could get damaged further Protective signal Initiates a withdrawal reflex

Question 61

Nociceptors

Answer 61

First order neurones that relay information to second order neurones. The second order neurones ascend the spinal cord via 2 possible tracts to get to the CNS - STT (spinothalmic tract) which transmits fast A-fibre - SRT (spinoreticular tract) which transmits slow C-fibre

Question 62

What are nociceptors activated by?

Answer 62

Intense stimuli

Question 63

Inflammatory pain

Answer 63

Caused by activation of the immune system in injury or infection Assists in healing of a damaged body part

Question 64

Pathological pain

Answer 64

Results from abnormal nervous system function

Question 65

Neuropathic pathological pain

Answer 65

Ongoing abnormal neuronal activity which results in spontaneous pain (eg stroke)

Question 66

Dysfunctional pathological pain

Answer 66

No precipitating cause

Question 67

2 sub-types of nociceptor?

Answer 67

Alpha fibres | C-fibres

Question 68

Nociceptor alpha fibres

Answer 68

mediate fast pain which is localised (stabbing) and very painful

Question 69

Nociceptor C fibres

Answer 69

Mediate slow pain which is generalised (cramping)