14.7: Nervous System Worksheet Answers

1. The diagram below is of a nerve cell or neurone.

i. Add the following labels to the diagram.

Axon; Myelin sheath; Cell body; Dendrites; Muscle fibres;

ii. If you like, colour in the diagram as suggested below.

Axon - purple;

Myelin sheath - yellow;

Cell body - blue;

Dendrites - green;

Muscle fibres – red;

iii. Now indicate the direction that the nerve impulse travels.

2. There are three different kinds of neurone or nerve cell. Match each kind with its function.

A. Motor neuron; B. Sensory neuron; C. Relay neuron;

Kind of neurone	Function
B. Sensory neuron	The nerve cell that carries impulses from a sense receptor to the brain or spinal cord.
C. Relay neuron	The nerve cell that connects sensory and motor neurons
A. Motor neuron	The nerve cell that transmits impulses from the brain or spinal cord to a muscle or gland

3. Match the descriptions in the table below with the terms in the list.

Term	Function
B. Axon	1. The long fibre that carries the nerve impulses.
J. Nerve	2. A bundle of axons.
A. Synapse	3. The connection between adjacent neurons.
K. Neurotransmitter	4. The chemical secreted into the gap between neurons at a synapse.
G.Reflex	5. A rapid automatic response to a stimulus.
C. Myelin sheath	6. The covering of fatty material that speeds up the passage of nerve impulses.
L. Axon terminal	7. The structure at the end of an axon that produces neurotransmitters to transmit the nerve impulse across the synapse.
D. Nerve impulse	8. The high speed signals that pass along the axons of nerve cells.
I. Dendrites	9. The branching filaments that conduct nerve impulses towards the cell.
E. Sense receptor	10. The sense organ or cells that receive stimuli from within and outside the body.
F. Response	11. The reaction to a stimulus by a muscle or gland.
H. Cell body	12.The part of the nerve cell containing the nucleus.

4. The diagram below shows a cross-section of the spinal cord. Add the following labels to the diagram.

Central canal; White matter; Dorsal root; Grey matter; Ventral root; Skin;

Muscle; Sensory neuron; Relay neuron; Motor neuron; Pain receptors in skin

5.

a) List in order the 3 different neurons involved in a reflex arc from the stimulus to the response.

Stimulus	sensory neuron	relay neuron	motor neuron	Response

b) Name 3 different reflexes found in animals.

Reflex 1. Blink reflex.

Reflex 2. Paw pinch reflex.

Reflex 3. Swallowing reflex, plus many others.

6. The diagram below shows the nervous system of a horse. Add the following labels.

Brain; Spinal cord; Cranial nerves; Spinal nerves; Sciatic nerve; Nerves of the autonomic nervous system; Vagus nerve; Network of nerves to forelimb.

7. Indicate whether the following parts of the nervous system are part

of the Central Nervous System CNS) or the Peripheral Nervous System (PNS).

Part of nervous system	CNS or PNS?
Brain	CNS
Autonomic nervous system	PNS
Spinal nerves	PNS
Spinal cord	CNS
Cranial nerves	PNS

8. The diagram below shows a section of a dog’s brain. Add the labels

in the list below and, if you like, colour in the diagram as suggested.

Cerebellum - blue;

Spinal cord - green;

Medulla oblongata - orange;

Hypothalamus - purple;

Pituitary gland - red;

Cerebral hemispheres – yellow.

9. Match the descriptions below with the terms in the list. You may need to use some terms more than once.

Term	Description
E. Hypothalamus	1. Controls water balance and body temperature.
D.Medulla oblongata	2. Where the respiratory rate is controlled.
C. Cerebellum	3. Where posture, balance and voluntary muscle movements are controlled.
A. Cerebral hemispheres	4. Contains centres governing mental activity, including intelligence, memory, and learning.
H. Meninges	5. The tough fibrous envelope enclosing the brain and spinal cord.
F. Pituitary	6. The “master” gland of the endocrine system.
Cerebral hemispheres/cortex	7. Responsible for instigating voluntary movements.
J. Cerebrospinal fluid	8. The fluid that surrounds the brain and spinal cord.
G. Grey matter	9. Composed of cell bodies and nuclei.
B. White matter	10. Composed of axons.
Cerebral hemispheres/cortex	11. Where the sensations of sight, sound, taste etc. are interpreted.
I. Ventricles	12. Spaces in the brain filled with cerebral spinal fluid.
K. Sulcus	13. A fold in the cerebral cortex.
L. Carotid artery	14. The artery that supplies the brain with oxygenated blood.

10. Match the descriptions below with the parts of the nervous

system in the list. You may need to use some terms more than once.

Description	Part of the nervous system
1. Part of the nervous system that is composed of the brain and the spinal cord.	B. Central nervous system
2. Part of the nervous system that is composed of the cranial and spinal nerves.	C. Peripheral nervous system
3. The part of the peripheral nervous system that regulates the activity of the heart and smooth muscle.	A. Autonomic nervous system
4. The part of the autonomic nervous system that increases heart and respiratory rates, increases blood flow to the skeletal muscles and dilates the pupils of the eye.	E. Sympathetic nervous system
5. The part of the autonomic nervous system that increases gut activity and decreases heart and respiratory rates.	D. Parasympathetic nervous system

11. Name the nerves described below using the choices in the list.

Nerve	Description
Vestibular nerve	1. The 8th cranial nerve that carries impulses from the organs of balance and hearing to the brain.
Optic nerve	2. The 2nd cranial nerve that carries nervous impulses from the retina of the eye to the brain.
Sciatic nerve	3. The largest nerve in the body serving the muscles of the leg.
Olfactory nerve	4. The 1st cranial nerve that carries impulses from the organ of smell in the nose to the brain.
Vagus nerve	5. The 10th cranial nerve that supplies the pharynx, lungs, heart, stomach and most of the abdominal organs.