3: Muscles and movement

Question 1

What are the three types of muscle?

Answer 1

Cardiac muscle

Skeletal muscle

Smooth muscle

Question 2

Which type(s) of muscle are striated?

What does this mean?

Answer 2

Cardiac muscle

Skeletal muscle

repeated units of muscle (sarcomeres) giving rise to a streaky appearance.

Question 3

Which type(s) of muscle are non-striated?

Answer 3

Smooth muscle

Question 4

Name the units of skeletal muscle from a microscopic to gross level.

Answer 4

Actin & myosin filaments

⇒ Myofibrils

⇒ Myocytes

⇒ Fascicles

⇒ Skeletal muscle

Question 5

Muscle strains result from ___ muscle fibres.

Answer 5

torn

Question 6

Skeletal muscles can only move a joint if they ___ it.

Answer 6

cross

Question 7

Muscles (lengthen / shorten) during contraction.

Answer 7

shorten

Question 8

What structures attach muscle to bone?

Answer 8

Tendons

Question 9

What are tendons?

Can they contract?

Answer 9

Structures which connect muscle to bone

They are non-contractile

Question 10

What is an aponeurosis?

Answer 10

A flattened tendon

Question 11

Aponeuroses (flattened tendons) are usually associated with ___ muscles. They attach muscle to (bone / soft tissue).

Answer 11

flat

soft tissue

Question 12

Skeletal muscles have at least two points of attachment to bone. What are they called?

Answer 12

Origins

Insertions

Question 13

In terms of the origin and insertion, what is the only thing a skeletal muscle can do?

Answer 13

Shorten the distance between the origin and insertion along the long axis

Question 14

During contraction, the origin and insertion move (closer together / further apart).

Answer 14

closer together

Question 15

The biceps brachii has:

_ origin(s)

_ insertion(s)

Answer 15

2 origins

1 insertion

Question 16

The direction of movement produced by a muscle depends on which __ of the joint the muscle spans.

Answer 16

side

Question 17

What is a reflex?

What function do reflexes serve?

Answer 17

A rapid, predictable, involuntary movement made in response to “danger”

Protective function

Question 18

When we touch something potentially damaging, there is sudden __ to withdraw from the danger.

Answer 18

flexion

Question 19

What reflex involves sudden flexion to distance the limb from danger?

Answer 19

Flexion withdrawal reflex

Question 20

Nerve connections involved in reflex responses are found in the (brain / spinal cord).

Answer 20

spinal cord

The brain is not involved in reflex responses.

Question 21

What are the two main reflexes involving skeletal muscles?

Answer 21

Stretch reflex

Flexion withdrawal reflex

Question 22

The normal reflex response to being stretched is to ___.

Answer 22

contract

Question 23

Which reflex involves contraction after the unexpected stretch of a muscle?

Answer 23

Stretch reflex

Question 24

What are some other names for the stretch reflex?

Answer 24

Biceps jerk

Triceps jerk

Knee jerk

Ankle jerk

Question 25

The stretch reflex is **protective** against \_\_\_.

Answer 25

**overstretching**

Question 26

Briefly describe the **reflex arc** response to muscle stretch.

Answer 26

**1.** Overstretching detected by sensory nerve **2.** Sensory nerve sends impulse to synapse in spinal cord **3.** Spinal cord passes message to motor nerve which induces contraction in the muscle

Question 27

What name can be given to the route taken by action potentials following unexpected muscle stretch?

Answer 27

**Reflex arc**

Question 28

A **normal** stretch reflex indicates that **what** is working?

Answer 28

The **muscle** **Sensory nerve fibres** **Motor nerve fibres** Spinal cord connections Neuromuscular junction **"Descending controls"** from the brain

Question 29

What is **paralysis**?

Answer 29

A muscle **without a** **functioning motor supply**

Question 30

A paralysed muscle **(can / cannot****)** contract.

Answer 30

**cannot**

Question 31

On contraction, a paralysed muscle would have **(increased / reduced)** tone.

Answer 31

**reduced**

Question 32

What is **spasticity**?

Answer 32

When a muscle has a functioning motor nerve but **descending controls from the brain don't work** - random contraction

Question 33

On examination, a spastic muscle would have **(increased / reduced)** tone.

Answer 33

**increased**

Question 34

What is **atrophy**? What causes atrophy?

Answer 34

**Muscle wasting** - myocytes become smaller to reduce muscle bulk ## Footnote **Inactivity**

Question 35

What happens to individual myocytes during **hypertrophy**?

Answer 35

Each individual myocyte **enlarges**

Question 36

Skeletal muscle is found **(superficial / deep)** to the deep fascia.

Answer 36

**deep**

Question 37

Within the deep fascia, muscles are held within \_\_\_.

Answer 37

**compartments**

Question 38

What can caused **increased pressure** within muscle compartments?

Answer 38

**Swelling of tissues** **Increase in fluid** (e.g bleeding)

Question 39

Increased pressure in muscle compartments **(positively / negatively)** affects the function of muscles and nerves in the compartments

Answer 39

**negatively**

Question 40

What procedure would be carried out to treat **Compartment Syndrome**?

Answer 40

**Fasciotomy**