Muscles

Question 1

3 types of muscle

Answer 1

Smooth (involuntary)
Striated/skeletal (voluntary)
Myocardium (cardiac muscle)

Question 2

Neuromuscular junction

Answer 2

Where the nerves reach the motor end plate - nerve endings

Question 3

Striated muscle structure

Answer 3

Muscles are made of muscle fibres
Each fibre is made up of myofibrils
Each functional unit of a muscle is a sarcomere

Question 4

2 contractile proteins

Answer 4

Myosin (with myosin heads) and actin (chains of proteins)

Structure: myosin is strung between 2 actin filaments

Question 5

Tropomyosin

Answer 5

Inhibitory protein which holds the troponin complex

Question 6

Troponin complex is made up of…

Answer 6

Troponin I (inhibitory)
Troponin C (calcium binding site)
Troponin T (tail)

Question 7

Muscle contraction

Answer 7

1. Nerve impulse causes cell to depolarise
2. Sodium channels open -> further depolarisation
3. Calcium channels are opened, calcium enters cell
4. Calcium binds to receptor on sarcoplasmic reticulum
5. Massive store of calcium is liberated
6. Calcium binds to troponin C
7. Troponin complex moves, allowing myosin head to bind to actin

Question 8

ATP and relaxation

Answer 8

ATP stops the interaction between actin and myosin

Also actively pumps ions to normalise intracellular concentrations between contractions

Question 9

Tendons

Answer 9

Connect muscle to bone - strong, fibrous tissues

Question 10

Proprioception

Answer 10

Awareness of your physical self allowing conscious and subconscious coordination of the body.
Muscle spindles/proprioceptor in muscle constantly measures stretch
Cerebellum feeds into spinal cord input (feedback from eyes)
Vestibular organs feed into spinal cord input (fluid-filled semi-circular canals in the ear, with hairs to detect fluid movements across x, y and z dimensions)