Sem 1 Exam - Functional Anatomy

Question 1

Structure of a skeletal muscle

Answer 1

Epimysium - surrounds whole muscle belly
Perimysium - surrounds each individual fascicle
Endomysium - surrounds each muscle fibre

Question 2

Fascicle
Muscle fibre
Endomysium

Answer 2

Bundle of muscle fibres
Contain myofibrils
Contain the sarcomeres for muscle contraction

Question 3

Sliding filament theory

Answer 3

1. Calcium is released and enters the sarcomere
2. Actin reveals binding site for myosin head to connect
3. Myosin attaches to actin filaments creating a cross bridge
4. Breakdown of ATP releases energy to stimulate cross bridges
5. Myosin pull on the actin
6. Sarcomere shortens as actin filaments move closer together.
7. Z line is pulled closer together, actin and myosin over lap causing I band and H zone to disappear
8. Myosin detaches from actin and cross bridge is broken.

Question 4

Force velocity

Answer 4

When a force is high - velocity is low

When a velocity is high - force is low.

Question 5

Force length

Answer 5

Extremely lengthened muscle - low force
Optimal length - high force
Fully shortened - low force

Question 6

Types of muscle contractions

Answer 6

Isometric ->
Muscle doesn’t change length, but exerts a force.
Isotonic ->
Concentric - muscle shortens, bicep curl or push up
Eccentric - muscle lengthens. Eg extending arm or going from a sit up position to a laying down one.

Question 7

All or none principal

Answer 7

1. When an action potential reaches the threshold level for the motor unit, all muscle fibres will maximum force at same time, of threshold is not met, no contraction will occur.
2. The number of motor units and muscle fibres recruited determines the force produced by muscles.
3. By sending many action potentials that reach the threshold, many motor units will be recruited. To result in a fast movement.

Question 8

Define: dendrites if sensory neurons

Answer 8

Receive sensory info and pass it onto the cell body of the sensory neuron.

Question 9

Define axons of motor units

Answer 9

Carry motor info away from the cell body towards the muscle fibres in order for them to be stimulated to create movement.

Question 10

Spinal cord

Answer 10

Transmits motor info from the brain to the muscles and sensory info from the muscles to the brain.

Question 11

Motor unit

Answer 11

The motor neuron and the fibres it stimulates

Question 12

Define motor unit

Answer 12

The motor neuron and the fibres it stimulates

Question 13

3 types of neurons

Answer 13

Sensory - conduct impulses from sensory organs eg eyes to the brain.
Motor - conduct impulses from the brain to the muscles.
Interneurons - send messages between the sensory and motor neurons.

Question 14

3 purposes of the nervous system

Answer 14

1. To receive info from the receptors which detect changes in the body and environment
2. To process this information
3. To use effective to carry out the bodies responses

Question 15

Muscle fibre type 1 (slow twitch)

Answer 15

Contraction time - slow
Resistance to fatigue - high
Activity used for - aerobic
Force production - low
Capillary density - high 
Fuel source - triglycerides and glycogen

Question 16

Fast twitch (type IIa)

Answer 16

Contraction time - fast
Resistance to fatigue - medium
Activity used for - long term anaerobic 
Force production - high
Capillary density - medium
Fuel source - creating phosphate and glycogen

Question 17

Fast twitch (type IIb)

Answer 17

Contraction time - very fast
Resistance to fatigue - Los
Activity used for - short term anaerobic
Force production - very high
Capillary density - low
Fuel source - creatine phosphate and glycogen