Muscles and body position

Question 1

3 types of muscle

Answer 1

Skeletal (attached to bones)
Smooth (walls of organs, blood vessels)
Cardiac (forms bulk of heart)

Question 2

How many types of skeletal muscle?

Answer 2

600

Question 3

Flexor vs extensor

Answer 3

Flexor - bend

Extensor - straighten

Question 4

Muscle fibers

Answer 4

Constitute muscle. Each is a living cell containing several nuclei

Question 5

Muscle fibers

Answer 5

Constitute muscle. Each is a living cell containing several nuclei (in skeletal muscle)

Question 6

Outer membrane of muscle is called?

Answer 6

Sarcolemma

Question 7

Myofibrils

Answer 7

Long cylindrical structures found within muscle.

Question 8

What are myofibrils made of?

Answer 8

Sarcomeres.

Question 9

What are Sarcomeres made of?

Answer 9

Actin (thin filaments) and Myosin (thick filaments)

Question 10

Sarcomere’s two darkened ends are called

Answer 10

Z lines, actin

Question 11

Sarcomere’s lighter middle

Answer 11

H zone, myosin attached to fine M line

Question 12

Sarcomere’s lighter middle

Answer 12

H zone, myosin attached to fine M line

Question 13

EPP - End Plate Potential

Answer 13

Depolarises muscle membrane producing an action potential in the muscle membrane

Question 14

Another term for Proprioception

Answer 14

Kinesthetic Sense

Question 15

What system deals with movement of the head

Answer 15

The Vestibular System

Question 16

Second set of muscles in centre of muscles

Answer 16

The Muscle Spindle System

Question 17

What system possesses both Afference and Efference? How so?

Answer 17

The muscle spindle system
Afference - very fast - 1a sensory fibres
Efference - Gamma motor neurons

Question 18

Two sources of information regarding limb position

Answer 18

Proprioception - Muscle spindles

Efference copy theory - the brain compares the muscle signal with the actual effect

Question 19

Two sources of information regarding limb position

Answer 19

Proprioception - Muscle spindles

Efference copy theory - the brain compares the muscle signal with the actual effect

Question 20

Alpha motor neurons

Answer 20

Among the largest in the body. Each muscle is served by at least one motor neuron, which branches to hundreds of axonal endings.

Question 21

Neuromuscular junctions are between…

Answer 21

The axon endings of the motor neuron and the muscle fibre

Question 22

What is involved in an endplate potential?

Answer 22

• Motor neuron’s endings (synaptic knobs) fit into ‘pits’ located in the motor endplate
• Release acetylcholine.
• This binds to ‘nicotinic acetylcholine receptors’
• Increases permeability of the muscle fibre membrane to sodium and potassium ions

Question 23

Sarcoplasmic Reticulum

Answer 23

network of tubes and sacs found in the cytoplasm of each muscle fibre. As the action potential moves through the muscle fibre, it releases large numbers of Calcium ions. These are what cause actin and myosin to slide over one another.

Question 24

Two sources of information regarding limb position

Answer 24

Proprioception - Muscle spindles

Efference copy theory - the brain compares the muscle signal with the actual effect

Question 25

Alpha motor neurons

Answer 25

Among the largest in the body. Each muscle is served by at least one motor neuron, which branches to hundreds of axonal endings.

Question 26

Neuromuscular junctions are between…

Answer 26

The axon endings of the motor neuron and the muscle fibre

Question 27

What is involved in an endplate potential?

Answer 27

• Motor neuron’s endings (synaptic knobs) fit into ‘pits’ located in the motor endplate
• Release acetylcholine.
• This binds to ‘nicotinic acetylcholine receptors’
• Increases permeability of the muscle fibre membrane to sodium and potassium ions

Question 28

Sarcoplasmic Reticulum

Answer 28

network of tubes and sacs found in the cytoplasm of each muscle fibre. As the action potential moves through the muscle fibre, it releases large numbers of Calcium ions. These are what cause actin and myosin to slide over one another.

Question 29

Ia sensory fibres

Answer 29

Fibres wrapped around the middle of muscle spindles which project into spinal cord (

Question 30

Ia sensory fibres

Answer 30

Fibres wrapped around the middle of muscle spindles which project into spinal cord

Question 31

2 functions of a muscle spindle

Answer 31

Send information to CNS on the state and position of muscles and initiate reflex contraction of the muscle when stretched by a load

Question 32

Best known example of a stretch reflex?

Answer 32

Patella tendon muscle reflex

Question 33

Monosynaptic Reflexes

Answer 33

eg Patella tendon reflex - reflexes that only involve one synaptic gap

Question 34

Golgi tendon organs

Answer 34

Lie at the point of attachment between muscle and tendon. Communicate with the spinal cord regarding the load on muscles by Ib sensory fibres

Question 35

Reciprocal inhibition

Answer 35

simultaneous inhibition of one muscle while exciting another (for example, to withdraw from pain)

Question 36

Two main components of vestibular system?

Answer 36

Semicircular canals and otolith organs

Question 37

Utricle and saccule

Answer 37

two sac-like structures in the inner ear providing info about the position of the head relative to the body, gravity and accelleration

Question 38

Why are the Utricle and Saccule sometimes called “otolith organs?”

Answer 38

because they contain little ‘stones’ that displace and cause sensory hairs to bend

Question 39

Why are the Utricle and Saccule sometimes called “otolith organs?”

Answer 39

because they contain little ‘stones’ that displace and cause sensory hairs to bend