FOM 4/5: Nervous system

Question 1

Direction of afferent neurons

Answer 1

• carry sensory information towards CNS

Question 2

Direction of efferent neurons

Answer 2

• carry motor information away from CNS

Question 3

Where does the spinal cord end?

Answer 3

• level of intervertebral disc between L1/2

Question 4

What is superior of the spinal cord?

Answer 4

• medulla oblongata (part of brainstem)

Question 5

What is inferior of the spinal cord?

Answer 5

• conus medullaris

Question 6

What is the filum terminale?

Answer 6

• fibrous band that extends from conus medullaris to periosteum of coccyx

Question 7

Describe grey matter of spinal cord

Answer 7

• composed primarily of cell bodies of neurons arranged as dorsal and ventral horn

Question 8

Describe white matter of spinal cord

Answer 8

• longitudinally oriented nerve fibres
• colour is resulting from myelinated axons within fibres

Question 9

What is the subarachnoid space?

Answer 9

• space between pia and arachnoid matter
• filled with CSF which cushions and protects your brain and spinal cord
• protects brain from sudden head movement

Question 10

What is the epineurium?

Answer 10

• dense irregular connective tissue which surrounds group of fascicles

Question 11

What is the perineurium?

Answer 11

• surrounds each fascicle of nerve fibres

Question 12

What is the endoneurium?

Answer 12

• delicate loose connective tissue surrounding and embedding the individual nerve fibres and blood vessels

Question 13

What do dorsal roots/rootlets do?

Answer 13

• transmit sensory information towards spinal cord

Question 14

What do ventral roots/rootlets do?

Answer 14

• transmit motor information away from spinal cord

Question 15

Where are the cell bodies of multipolar motor neurons located?

Answer 15

• ventral horn of grey matter

Question 16

Where are the cell bodies of pseudo unipolar sensory neurons located?

Answer 16

• dorsal root ganglia

Question 17

Describe ventral rami distribution

Answer 17

• forms intercostal nerve passing anteriorly in intercostal space between 2 ribs giving branches other than intercostal muscles
• skin also supplied
• lower nerves continue into abdomen and supply abdominal wall muscles and overlying skin

Question 18

Describe dorsal ramus distribution

Answer 18

• supplies the erector spine muscles and area of skin over these muscles

Question 19

What is a myotome?

Answer 19

• region of skeletal muscle innervated by single spinal nerve/ spinal cord segment

Question 20

Which areas does the cervical plexus supply?

Answer 20

• skin and muscles of head, neck and shoulder region

Question 21

Cervical plexus is comprised of which spinal nerves?

Answer 21

• C1- 4

Question 22

Which areas does the brachial plexus supply?

Answer 22

• skin and muscles of upper limb

Question 23

What spinal nerves comprise the brachial plexus?

Answer 23

• C5-8, T1

Question 24

What are the 5 main nerves in the brachial plexus?

Answer 24

• axillary, musculocutaneous, radial, ulnar and median

Question 25

What spinal nerves comprise the lumbar plexus?

Answer 25

- L1-4

Question 26

Which areas does the lumbar plexus supply?

Answer 26

- muscle and skin of anterior and medial aspect of thigh via femoral and obturator nerves

Question 27

Which spinal nerves comprise the sacral plexus?

Answer 27

- L4-5, S1-4

Question 28

Which areas does the sacral plexus supply?

Answer 28

- skin and muscle of posterior aspect of thigh, leg and foot via the sciatic nerve

Question 29

Where does the femoral nerve pass?

Answer 29

- anteriorly to thigh

Question 30

What does the femoral nerve innervate?

Answer 30

- quadriceps femoris muscle compartment

Question 31

Where does the obturator nerve pass?

Answer 31

- medially through pelvis

Question 32

What does the obturator nerve innervate?

Answer 32

- medial muscle compartment of thigh

Question 33

When does limb development take place?

Answer 33

- 4-8th weeks of development - upper limb buds appear at 24 days - lower limb buds appear at 28 days

Question 34

Where is the skin of limbs derived from?

Answer 34

- embryonic ectoderm

Question 35

Where the skeletomuscular system derived from?

Answer 35

- mesoderm

Question 36

Why the apical ectodermal ridge important?

Answer 36

- critical structure for normal limb development, directs proximo-distal growth of limb - promotes proliferation of cells in underlying mesenchyme

Question 37

What occurs in limb development in week 6?

Answer 37

- distal parts of limb buds form hand plates and footplates. - digits formed by apoptosis occurring in sections of AER - separate hand and foot plates into 5 distinct regions that form the digits

Question 38

ANS innervation

Answer 38

- heart and smooth heart muscle of blood vessels, viscera and glands

Question 39

What are the two neurons in the efferent pathway of ANS?

Answer 39

- preganglionic - postganglionic

Question 40

What are the preganglionic neurons?

Answer 40

- axons of first neurons leave spinal cord or brain - travel to sympathetic/parasympathetic - synapse on second neuron (postganglionic)

Question 41

Where are the sympathetic centres found?

Answer 41

- thoracic and lumbar segments of spinal cord - thoracolumbar division

Question 42

Where are the parasympathetic centres found?

Answer 42

- brainstem and sacral parts of spinal cord - craniosacral

Question 43

Where are preganglionic neurons found?

Answer 43

- grey matter of CNS

Question 44

What neurotransmitter do all preganglionic fibres of ANS release?

Answer 44

- acetylcholine

Question 45

Where are paravertebral ganglia found?

Answer 45

- left and right of body, parallel to vertebral column - linked together in a chain to form left and right sympathetic trunk or chain

Question 46

Where are pre vertebral ganglia found?

Answer 46

- anterior to vertebral column, forming several plexuses around major branches of the abdominal aorta - leave spinal cord anteriorly