Nervous System Review

Question 1

Name the two types of cells that form the nervous tissue of the nervous system.

Answer 1

i) neuron

ii) neuroglia

Question 2

Define the term neuron;

Answer 2

neurons are cells that transmit nerve impulses between parts of the nervous system

Question 3

List the three classifications of neurons according to function.

Answer 3

i)​sensory neuron
​ii)​interneuron
iii) Motor neuron

Question 4

List the two classifications of neurons according to structure.

Answer 4

i) unipolar – sensory neurons are unipolar

ii) multipolar – interneurons and motor neurons are multipolar

Question 5

All neurons have three parts;

Answer 5

dendrites, cell body, axon

Question 6

What is myelin?

Answer 6

Myelin is formed from Schwann cells; it consists of lipid (fatty) layers; it is found around an axon; it makes the cell appear white and glistening and it forms white matter in the CNS.

Question 7

What is a nerve impulse?

Answer 7

A neural impulse is the way in which the nervous system conveys information. It is an electro-chemical change that travels along the neuron.

Question 8

What is an ion? Name the two major ions involved in neural transmission.

Answer 8

An ion is a charged particle. The particle may be charged negatively or positively. Sodium ion and potassium ion

Question 9

What maintains the polarity of the neuron when it is at rest?

Answer 9

The sodium-potassium pump
the inside of the cell membrane is charged negative, and
the outside of the cell membrane is charged positive

Question 10

Why does a nerve impulse only travel in one direction?

Answer 10

A nerve impulse only travels in one direction due to the refractory period. This is a period of time during which the sodium gate in the previous portion of the membrane is unable to open, preventing another impulse from occurring at that spot.

Question 11

How is a nerve impulse transmitted to another neuron or to an effector?

Answer 11

A nerve impulse is transmitted to another neuron or an effector by transmitting the impulse across the synapse. The synapse is the region between these structures that includes the presynaptic membrane of the first neuron, the synaptic cleft (the actual space) and the postsynaptic membrane of the second neuron or effector. Transmission across the synapse occurs with the help of a neurotransmitter.

Question 12

What is the purpose of a neurotransmitter? Give an example of one.

Answer 12

A neurotransmitter is a chemical stored at the ends of the axon which when released helps the nerve impulse travel across the synapse. The most common neurotransmitter in the body is acetylcholine.

Question 13

List the two structures that form the CNS.

Answer 13

Brain

Spinal cord

Question 14

Briefly describe in words the structure of the spinal cord including the location of white and gray matter, central canal and cerebrospinal fluid.

Answer 14

The spinal cord extends from the base of the brain into the vertebral canal. It is formed of a central canal that runs down the centre of the cord and contains cerebrospinal fluid. (Cerebrospinal fluid is also found within the meninges that surround and protect the spinal cord). Gray matter is located in the middle of the spinal cord in the shape of the letter H. It is formed of cell bodies, dendrites and interneurons The white matter surrounds the gray matter and is formed of myelinated axons of both sensory and motor neurons

Question 15

Name the two functions of the spinal cord.

Answer 15

i) ​it is involved in two-way transmission of nerve impulses. Sensory impulses enter the spinal cord by way of the dorsal root. These impulses then travel in the white matter of the spinal cord to the brain. Motor impulses from the brain travel down the white matter of the spinal cord. These impulses exit the spinal cord by way of the anterior root.
ii) ​it is involved in the reflex when nerve impulses bypass the brain and go directly from the sensory neuron to the interneuron in the spinal cord to the motor neuron

Question 16

Name the three neurons involved in a reflex arc.

Answer 16

​i)​sensory neuron
​ii)​interneuron
iii) motor neuron

Question 17

List the three forms of protection of the brain and spinal cord.

Answer 17

i)​bone - in the case of the brain it is the skull and in the case of the spinal cord it is the spine (vertebrae). Bone protects against physical trauma.
​ii)​meninges – three layers of membrane that surround both the brain and spinal cord protecting them against invasion by pathogens (infection)
iii)​cerebrospinal fluid – is found between the layers of meninges and acts to cushion and nourish the nerve tissue of the brain and spinal cord

Question 18

List the four parts of the brain as outlined in the textbook and the ventricles they are associated with.
​

Answer 18

i)​cerebrum; lateral ventricles
ii)​diencephalons; third ventricle
​iii)​cerebellum; fourth ventricle
​1v)​brain stem; fourth ventricle

Question 19

There are four lobes. They are:

Answer 19

frontal, parietal, temporal, occipital

Question 20

The temporal lobe contains :

Answer 20

Temporal lobe - primary auditory area; auditory association area; sensory speech (Wernicke’s area)

Question 21

Occipital lobe contains:

Answer 21

Occipital lobe - primary visual area; association visual area

Question 22

Frontal lobe contains:

Answer 22

Frontal lobe - primary motor area; premotor area; motor speech area (Broca’s area); left prefrontal lobe

Question 23

Parietal lobe contains:

Answer 23

Parietal lobe – primary somatosensory area; somatosensory association area; primary taste area

Question 24

The hypothalamus is responsible for:

Answer 24

maintaining homeostasis by regulating hunger, sleep, thirst, body temperature and water balance. It also controls the pituitary gland.

Question 25

The thalamus is responsible for:

Answer 25

It receives all sensory input and relays it to the correct region of the sensory cortex; higher mental functions such as memory and emotion; arousal of cerebrum

Question 26

The cerebellum is separated from the brain stem by the fourth ventricle. It is responsible for:

Answer 26

It maintains posture and balance; coordinates complex skeletal muscle actions; assists the learning of new motor skills

Question 27

The brain stem contains the following structures:

Answer 27

midbrain; pons; medulla oblongata

Question 28

The midbrain is responsible for;

Answer 28

​relay station between cerebrum and spinal cord or cerebellum; reflex centres for visual, auditory and tactile responses

Question 29

The pons is responsible for:

Answer 29

bridge between the cerebellum and the rest of the CNS; functions with the medulla oblongata

Question 30

The medulla oblongata is responsible for:

Answer 30

Contains reflex centres for regulating heart beat, breathing rate, blood pressure; contains reflex centres for vomiting, sneezing, coughing hiccupping, and swallowing; cross-over of sensory and motor messages from one side of body to opposite side of brain

Question 31

The Reticular Formation contains:

Answer 31

nuclei (gray matter) and nerve fibres.

Question 32

Explain the left brain/right brain hypothesis

Answer 32

The left brain/right brain hypothesis states that the left brain can be contrasted with the right brain as follows: the left hemisphere is responsible for verbal skills, logical, analytical thinking and rational thought processes. The right hemisphere is responsible for nonverbal and visuospatial skills, intuitive thinking and creative skills The left hemisphere is more global, whereas the right hemisphere is more specific.

Question 33

Trace the path of a neural transmission beginning at a receptor site in a sense organ and ending at an effector. Include the neurons involved and the parts of the CNS involved.

Answer 33

The answer for this question should contain the following: receptor cell, sensory neuron, spinal cord, medulla oblongata, thalamus, sensory cortex, motor cortex, motor neuron, medulla oblongata, spinal cord, effector.

Question 34

Sensory neurons and motor neurons of the peripheral nervous system are grouped into two categories:
​

Answer 34

i)​cranial nerves

​ii)​spinal nerves

Question 35

Cranial nerves are classified as either:

Answer 35

i)​sensory nerves because they have sensory fibers only - e.g. optic and ​auditory nerves
​ii)​motor nerves because they have motor fibers only – e.g. oculomotor nerve
​iii)​mixed nerves because they have both sensory and motor fibers – e.g. ​facial nerve

Question 36

All spinal nerves have both…….

Answer 36

All spinal nerves have both sensory fibres and motor fibres and are referred to as being mixed nerves

Question 37

The PNS is divided into two systems:

Answer 37

The PNS is divided into two systems:
​i)​somatic system
​ii)​autonomic system

Question 38

The somatic system serves the skin, skeletal muscles and tendons. It involves two functions. Please describe.

Answer 38

It involves two functions:
​i)​sensory information from receptors in the skin to the CNS, and motor commands from the CNS to the skeletal muscles
​ii)​involuntary reflex actions of skeletal muscles that involve communication with only the spinal cord of the CNS (these are also known as somatic reflexes)

Question 39

The autonomic system regulates the involuntary activity of;

Answer 39

The autonomic system regulates the involuntary activity of;

​cardiac muscle, smooth muscle of the internal organs and glands

Question 40

The autonomic system is further divided into two divisions:

Answer 40

The autonomic system is further divided into two divisions:
​i)​sympathetic division
​ii)​parasympathetic division

Question 41

The two divisions of the autonomic system have three common characteristics:
​

Answer 41

The two divisions have three common characteristics:
​i)​they function in an automatic involuntary manner
​ii)​they innervate all internal organs
​iii)​they utilize two neurons and one ganglion for each impulse

Question 42

The function of the sympathetic division is:

Answer 42

The function of the sympathetic division is to prepare the body for emergencies. It is the division that is dominant when we are under stress
​It does this by affecting physiological responses. They are as follows:
​Increases heart rate
​Increases breathing rate
​Dilates pupils etc.k

Question 43

Describe the type of fibres of the sympathetic division.

Answer 43

​Short pre-ganglionic fibre and a long post-ganglionic fibre with the ganglion situated closer to the spinal cord

Question 44

The function of the parasympathetic system is:

Answer 44

to maintain or return us to homeostasis. It is responsible for keeping our bodies in a state of balance associated with normal, at rest functioning.
​It has the opposite effect from the sympathetic division on physiological responses. They are as follows:
​Decreases heart rate
​Decreases breathing rate
​Constricts pupils

Question 45

Describe the type of fibres of the parasympathetic division

Answer 45

Long pre-ganglionic fibre and a short post-ganglionic fibre with the ganglion situated closer to the organ

Question 46

List the two main divisions of the nervous system.

Answer 46

CNS, PNS