Chapter 3 And 4: The Nervous System

Question 1

Identify the main divisions of the nervous system.

Answer 1

Flowchart

Question 2

Differentiate between the CNS and the PNS.

Answer 2

The CNS consists of the brain and spinal chord whereas the PNS includes ALL nervous tissue and transmits impulses(and therefore information) to and from the CNS

Question 3

Sensory neurons

Answer 3

Carry messages from receptors in the sense organs or skin, to the CNS(brain and spinal chord).

Question 4

Motor neurons

Answer 4

Carry messages from the central nervous system to the muscles and glands — the effectors.

Question 5

Interneurons(association neurons)

Answer 5

Located in the CNS and are the link between the sensory and motor neurons. Also known as relay neurons

Question 6

Some components of the PNS

Answer 6

• Nerve fibres which carry information to and from the CNS.
• Groups of nerve cell bodies called ganglia which lie outside the brain and spinal chord.
• 12 pairs of cranial nerves and 31 pairs of spinal nerves which contain fibres carrying impulses to and from all parts of the body.

Question 7

Cranial nerves

Answer 7

12 pairs of nerves that arise from the brain

Question 8

Afferent division

Answer 8

the sensory division of the PNS; consists of fibres that carry impulses INTO the CNS.

These impulses are carried to the CNS by the sensory nerve cells from receptors in the skin and around the muscles and joints.
These nerve cells from the body are called somatic sensory neurons.

Question 9

Efferent division

Answer 9

Has fibres that carry impulses AWAY from the CNS.

Question 10

Sensory fibres

Answer 10

Fibres that carry impulses INTO the CNS

Question 11

Motor fibres

Answer 11

Fibres that carry impulses AWAY from the CNS

Question 12

Ventral root

Answer 12

Contains the axons of motor neurons that have their cell bodies in the grey matter of the spinal chord.

Question 13

What are the effectors of the autonomic division?

Answer 13

Heart muscle, involuntary muscle, glands

Question 14

What are the effectors of the somatic division of the peripheral nervous system?

Answer 14

Skeletal muscles(voluntary)

Question 15

What is the general function of the autonomic division of the PNS?

Answer 15

Adjustment of the internal environment(homeostasis).

Question 16

What is the general function of the somatic division of the PNS?

Answer 16

Response to the external environment

Question 17

What is the efferent pathway of the autonomic division?

Answer 17

Two nerve fibres from the CNS to the effector with a synapse in a ganglion.

Question 18

What is the efferent pathway to the somatic division?

Answer 18

One nerve fibre from the CNS to the effector; no synapse, no ganglion

Question 19

What is the neurotransmitter of the autonomic division at the effector?

Answer 19

Acetylcholine or noradrenaline

Question 20

What is the neurotransmitter of the somatic division at the effectors?

Answer 20

Acetylcholine

Question 21

Is the autonomic division voluntary or involuntary?

Answer 21

Usually involuntary

Question 22

Is the somatic division voluntary or involuntary?

Answer 22

Usually voluntary

Question 23

How many sets of nerves to the target organs of the autonomic division?

Answer 23

2 sets — Sympathetic and Parasympathetic

Question 24

How many sets of nerves to the target organs of the somatic division?

Answer 24

One set

Question 25

What effect does the autonomic division have on the organ?

Answer 25

Excitation or inhibition

Question 26

What effect does the somatic division have on the organ?

Answer 26

Always excitation

Question 27

Name 10 structures of the sympathetic and parasympathetic nervous system

Answer 27

Heart
Lungs
Stomach — Intestines 
Liver 
Iris of the eye 
Sweat glands 
Salivary glands
Blood vessels of: skin, skeletal muscle and internal organs
Urinary bladder 
Adrenal medulla

Question 28

Name 10 functions of the sympathetic nervous system (of the structures).

Answer 28

1. Increased heart rate and strength of contraction
2. Dilates bronchioles in the lungs
3. Decreased movement in the stomach; intestines
4. Increase the breakdown of glycogen and release of glucose in the liver.
5. Dilates pupils of the iris of the eye
6. Increases sweat secretion in the sweat glands.
7. Decreases secretion of saliva from the salivary glands.
8. Constricts blood vessels in the skin and internal organs, dilates blood vessels in the skeletal muscle.
9. Relaxes muscles of the wall of the urinary bladder
10. Stimulates hormone secretion in the adrenal medulla.

Question 29

Name 10 functions of the parasympathetic nervous system.

Answer 29

1. Decreased heart rate and strength of contraction
2. Constricts bronchioles in the lungs
3. Increases movement in the stomach; intestines
4. Increases uptake of glucose and synthesis of glycogen.
5. Constricts pupils of the iris of the eye
6. Has no effect on sweat secretion in the sweat glands.
7. Increases secretion of saliva from the salivary glands.
8. Little effect on the p blood vessels in the skin and internal organs, no effect on the blood vessels in the skeletal muscle.
9. Constricts muscles of the wall of the urinary bladder
10. No effect in the adrenal medulla.

Question 30

What are the subdivisions of the efferent nervous system?

Answer 30

Somatic sensory neurons from skin and muscles.

Visceral sensory neurons from internal organs.