Exercises 5

Question 1

What is the name of the cylindrical structure enclosed within the vertebral column/

Answer 1

The spinal cord - approx. 42cm long and 1.8cm thick.

Question 2

What serves as a 2 way pathway for sensory & motor activity between the brain & the body?

Answer 2

the spinal cord.

Question 3

What is the space called between the vertebrae and the spinal dura mater?

Answer 3

epidural space

Question 4

What is the name of the tapered, lower end of the spinal cord covered in pia mater?

Answer 4

conus medullaris

Question 5

What extends from the conus to the coccyx where it anchors the spinal cord so as to stabilize the cord & prevent jostling by body movements?

Answer 5

filum terminale - fibrous extension of the conus covered by pia mater.

Question 6

Paired spinal nerves are attached to the spinal cord by what?

Answer 6

nerve roots. each nerve exits from the vertebral column by passing above its corresponding vertebra.

Question 7

What is the name of the bundle of spinal nerves & spinal nerve roots from the L2 nerve to the coccygeal nerve?

Answer 7

cauda equine (horse’s tail) - These nerves supply the pelvic organs & lower limbs

Question 8

Anatomy of the spinal cord - what is the H shaped mass divided into horns called?

Answer 8

grey matter - consisting mainly of neuron cell bodies

Question 9

Anatomy of the spinal cord - entry point for sensory nerves?

Answer 9

dorsal (posterior) horns - primarily relay sensations

Question 10

Anatomy of the spinal cord - exit point for motor nerves?

Answer 10

ventral (anterior) horns - primarily relay voluntary motor & reflex activity.

Question 11

Anatomy of the spinal cord - what surrounds the horns & consists of myelinated nerve fibres or axons grouped in vertical tracts or long ropes?

Answer 11

white matter - all axons in one tract serve one general function such as touch or pain.

Question 12

In addition to carry impulses to & from the brain, the spinal cord regulates what?

Answer 12

reflexes - a reflex is the simplest response to a stimulus.

Question 13

What is the name of the automatic, involuntary reaction to a stimulus e.g. when I doctor taps your knee?

Answer 13

reflex arc - the reaction to the stimulus is involuntary with the CNS being informed but not consciously controlling the response. also e.g. balance, blinking & stretching reflex.

Question 14

The PNS can be divided into two nervous systems which are?

Answer 14

somatic NS & autonomic NS

Question 15

PNS - which nervous system includes all nerves controlling the voluntary muscular syst & external sensory receptors such as smell, taste, hear, seeing & touching?

Answer 15

somatic nervous system (SNS) it consists of cranial nerves & spinal nerves

Question 16

Which nerves in the Somatic NS take impulses to and from the brain?

Answer 16

cranial nerves (CN) there are 12 pairs of CN which emerge from and enter into the skull.

Question 17

Which nerves in the SNS take impulses to and from the spinal cord?

Answer 17

spinal nerves - there are 31 pairs of spinal nerves which emerge from the spinal cord.

Question 18

PNS - which nervous system regulates activities that are automatic or involuntary?

Answer 18

autonomic NS - it maintains homeostasis.

Question 19

The Autonomic NS has two divisions which are ?

Answer 19

sympathetic NS and parasympathetic NS

Question 20

Within the Autonomic NS which NS controls organs in times of stress?

Answer 20

sympathetic NS e.g. the heart rate is speeded up by the SNS and slowed down by the PSN

Question 21

Within the Autonomic NS which NS controls organs when the body is at rest?

Answer 21

parasympathetic NS - the bladder is relaxed by the SNS so that when it is full it can release urine and contracted by the PNS after releasing urine.