Physiology

Question 1

Give 4 functions of skeletal muscle?

Answer 1

Maintenance of posture
Heat production
Whole body metabolism
Purposeful movement

Question 2

What is a motor unit?

Answer 2

all of the skeletal muscle fibres a single alpha motor neurone innervates

Question 3

what would more fibres in a motor unit result in?

Answer 3

more power and less precision

Question 4

what would less fibres in a motor unit result in?

Answer 4

less power and more precision, ideal for muscles around the eyes and in the fingers etc

Question 5

what is required for muscle contraction and relaxation?

Answer 5

ATP and Ca2+

Question 6

Where does Ca2+ come from to aid with muscle contraction?

Answer 6

it is actively pumped in and out of the sarcoplasmic reticulum by ATP

Question 7

what is asynchronous motor unit recruitment and what is its purpose?

Answer 7

muscle fibres are recruited at different times when a muscle tenses - they can be swapped about to prevent muscle fatigue

Question 8

when can maximum contraction occur?

Answer 8

when the skeletal muscle is at optimum length (resting)

Question 9

Explain how muscle contraction is produced?

Answer 9

• a single stimulation to a muscle creates a single twitch (contraction) - this isn’t enough to create muscle tension on its own
• repeated stimulation before the muscle has time to relax results in greater tension
• sustained contraction is produced if the muscle is repeatedly stimulated with no chance to relax between stimuli

Question 10

what is the difference between isotonic and isometric contraction?

Answer 10

isotonic = muscle tension stays the same while length changes (body movements)
isometric = muscle length stays the same while muscle tension develops (holding something in the same place)

Question 11

which type of skeletal muscle fibres have high resistance to fatigue and slow contraction, for things like walking?

Answer 11

slow oxidative type I fibres

Question 12

which type of skeletal muscle fibres have medium resistance to fatigue and fast contraction, for things like jogging?

Answer 12

fast oxidative type IIa fibres

Question 13

which type of skeletal muscle fibres have low resistance to fatigue and fast contraction, for things like jumping?

Answer 13

fast glycolytic type Iix fibres

Question 14

what is a stretch reflex?

Answer 14

negative feedback that resists passive change in muscle length so that it maintains its optimum length

Question 15

what is transduction in terms of physiology of pain?

Answer 15

damaging stimulus (e.g. cut in the skin) being converted into electrical signals in the nociceptor

Question 16

what is transmission in terms of physiology of pain?

Answer 16

spreading of the pain signal as the nerve impulses through the nervous system

Question 17

what is modulation in terms of physiology of pain?

Answer 17

modification of the pain transmission in the nervous system (like natural painkillers e.g. indigenous opioids)

Question 18

what is perception in terms of physiology of pain?

Answer 18

conscious experience of pain

Question 19

what are nociceptors?

Answer 19

specific nerve endings that register pain that are activated by painful stimuli (mechanical, thermal or chemical)

Question 20

explain how 1st, 2nd and 3rd order neurones work in the pain pathway?

Answer 20

nociceptors are 1st order neurones that relay info to 2nd order neurones in spinal cord which take the info to the thalamus. 3rd order neurones take the info from the thalamus to the sensory cortex in the brain and provoke a response

Question 21

what is nociceptive pain?

Answer 21

normal response to injury - nociceptors triggered by damaging/painful stimuli in tissues

Question 22

what is inflammatory pain?

Answer 22

pain to stop you doing more damage to an injury/let it repair - activated by mediators released at the site of inflammation

Question 23

what is neuropathic pain?

Answer 23

pain caused by damage to neural tissue e.g. compression neuropathy. Causes burning/shooting pain/pins and needles

Question 24

what is pathological pain?

Answer 24

dysfunctional pain where there is no identifiable cause e.g. fibromyalgia

Question 25

what causes referred pain?

Answer 25

convergence of nociceptive visceral and skin afferents on the same neurones going to the thalamus at the same spinal level

Question 26

what are fibrous joints?

Answer 26

bones united with fibrous tissue with pretty much no movement e.g. bones in the skull

Question 27

what are cartilaginous joints?

Answer 27

bones united by cartilage with limited movement e.g. intervertebral discs

Question 28

what are synovial joints?

Answer 28

bones separated by a synovial fluid-filled cavity and united by a fibrous capsule with a lot of movement

Question 29

what is the difference between and compound and simple synovial joint?

Answer 29

simple = 2 articular surfaces e.g. fingers
compound = more than 2 articular surfaces e.g. elbow joint

Question 30

what is the fibrous capsule in synovial joints lined with and what does this structure do?

Answer 30

lined by synovial membrane - contains fibroblasts which produces the synovial fluid

Question 31

give 4 functions of synovial fluid?

Answer 31

• lubricates joint & facilitates movement
• minimises wear & tear
• aids nutrition of articular cartilage
• supplies chondrocytes (cartilage cells) with oxygen and nutrients and takes away CO2 and waste products

Question 32

what are the 3 main components of hyaline cartilage?

Answer 32

water
type II collagen
proteoglycans

Question 33

what are 2 markers for cartilage degradation?

Answer 33

increased serum/synovial keratin sulphate

type II collagen in synovial fluid

Question 34

why do inflammatory conditions (arthritis and arthropathies) increase the risk of cardiovascular complications?

Answer 34

Inflammation affects vessels - systemic conditions will potentially have an effect

Question 35

Which bone has the most hyaline cartilage in the body?

Answer 35

Patella