Anatomy: Muscles and nerves

Question 1

In basic words, describe what flexion is.

Answer 1

Bend/shorten a joint by pulling bones closer together

Question 2

What is extension?

Answer 2

Unbend/lengthen a joint by pulling bones further apart

Question 3

Give an example of a muscle that causes flexion when it contracts.

Answer 3

Biceps brachii

Question 4

Give an example of a muscle that causes extension when it contracts.

Answer 4

Triceps brachii

Question 5

In anatomical terms, describe the position of the biceps brachii.

Answer 5

Anterior

Question 6

“All skeletal muscles cross at least ___ joint”

Answer 6

One

Question 7

“The bulk of a skeletal muscle lies _____ to the joint crossed”

Answer 7

Proximal

Question 8

All skeletal muscles have at least 2 attachments.

What are their names?

Answer 8

Origin and insertion

Question 9

True or false

Most skeletal muscles pull, but a few exceptions push.

Answer 9

False

Skeletal muscles can only pull, never push

Question 10

What happens when a skeletal muscle contracts?

Based on the relative positions of the origin and insertion

Answer 10

Origin and insertion move closer to each other

Question 11

What is a nerve plexus?

Answer 11

Nerves containing fibres from more than one spinal nerve

Question 12

What supplies the appendicular (limb) muscles, plexuses or segmental nerves?

Answer 12

Plexuses

EG - brachial plexus supplies the arm

Question 13

How are nerve plexuses different from nerves that supply segmentally?

Answer 13

Plexuses - mixed fibres from different spinal nerves

Segmental - separate nerves that have not mixed with each other

Question 14

What is Hilton’s law?

Answer 14

The nerve supplying the muscles, extending across and acting at a joint, also innervates that joint and the overlying skin

Question 15

Appendicular muscles are arranged in compartments. What are these called, and what separates compartments?

Answer 15

Fascial/muscle compartments

Separated by connective tissue septa

Question 16

Skeletal muscle: mononucleate or multinucleate?

Answer 16

Multinucleate

Question 17

“Bundles of muscle fibres are called _____”

Answer 17

Fascicles

Question 18

What organelle is especially abundant in skeletal muscle?

Answer 18

Mitochondria

Question 19

Which muscle types have striations?

Answer 19

Skeletal

Cardiac

Question 20

What are the intercalated discs in cardiac muscle?

Answer 20

Regions where the ends of cells are connected

Question 21

What feature do intercalated discs have, and why is it important?

Answer 21

Gap junctions

Allows the muscle cells to be electrically coupled ∴ contract in synchrony

Question 22

What is the difference between a ligament and a tendon?

Answer 22

Tendon = bind muscle to bone

Ligament = bind bone to bone

Question 23

“Spinal nerves exit the vertebral canal through ______ ______”

Answer 23

Intervertebral foramen

Question 24

Nerve plexuses are formed from which rami?

Answer 24

Ventral rami

Question 25

The nerves coming from one region of the spinal cord do not form plexuses. What region is this?

Answer 25

Thoracic

Question 26

In a spinal nerve, a layer of connective tissue encases individual nerves and their myelin sheath. What is this called?

Answer 26

Endoneurium

Question 27

What is contained in a fasciculus?

Answer 27

Bundle of nerves

Question 28

What encases a fasciculus?

Answer 28

Perineurium

Question 29

A spinal nerve is made of a bundle of fasciculus. What other structure is present in nerve?

Answer 29

Blood vessels

Question 30

What is the name of the layer that encases spinal nerves?

Answer 30

Epineurium

Question 31

What is a synergist?

Answer 31

A muscle that works alongside the agonist to stabilise and assist the movement of a joint

Question 32

Fixator muscles are common around the hips and shoulder joints. What are they?

Answer 32

Stabilising muscles These muscles and their tendons allow mobile joints to move freely without risk of dislocation

Question 33

Other than fixator muscles. what feature is found in and around joints to aid stabilisation?

Answer 33

Ligaments

Question 34

An aponeurosis is a type of tendon found in the abdominal region. Describe it's shape.

Answer 34

Flat, thin, broad

Question 35

What is a dermatome?

Answer 35

An area on the skin that is supplied by nerves from a single nerve root (eg C6)

Question 36

What is the difference between cutaneous nerves, and a dermatome?

Answer 36

``` CN = Nerves at the skin D = Area of skin supplied by single nerve type ``` Ie a dermatome will be supplied by many different cutaneous receptors

Question 37

What cell produces the myelin that surrounds axons?

Answer 37

Schwann cells