Chapter 9- The nervous system (1)

Question 1

What is a nervous system?

Answer 1

An organism’s control centre

Question 2

What is the nervous system responsible for?

Answer 2

1- Sensory input- monitoring the internal and external world via millions of receptor cells

2- Integration- processing and interpreting sensory information. Deciding what to do.

3- Motor output- activating effector organs (muscles, glands)

Question 3

What are the two principal divisions of the central nervous system?

Answer 3

1- The central nervous system- Includes the brain and spinal cord

2- The peripheral nervous system- Includes motor nerves and sensory nerves.

Question 4

What nerves form the efferent system?

Answer 4

Motor nerves

Question 5

What nerves form the afferent system?

Answer 5

Sensory nerves

Question 6

What is the efferent system further subdivided into?

Answer 6

Somatic (voluntary) and autonomic (involuntary)

Question 7

What can autonomic pathways be further subdivided into?

Answer 7

Sympathetic and parasympathetic

Question 8

What is sympathetic?

Answer 8

Activates the fight or flight mode response

Question 9

What is parasympathetic?

Answer 9

Initiates the rest and digest response

Question 10

What are the nerve arrangements?

Answer 10

43 pairs of nerves connect the CNS to the rest of the body.

12 cranial nerves exit the brain

3 are sensory nerves

5 are motor nerves

4 are mixed

A further 31 pairs of nerves exit at various levels of the spinal cord. They are all mixed.

Question 11

What is the nervous system primarily composed of?

Answer 11

Nervous tissue- main tissue of the nervous system. It monitors and regulates the function of the body.

Question 12

What is a neuron made up of?

Answer 12

A neuron is made up of a plasma membrane, a nucleus, and various other organelles in the cytoplasm.

Question 13

What is the structure of the neuron?

Answer 13

1- Has a soma (cell body)

2- Has various neurites which can be subdivided into dendrites and one long axon

Question 14

The neuron structure supports a specialised function which is what?

Answer 14

The transmission and processing of information via electrical impulses.

Question 15

What are dendrites?

Answer 15

Dendrites are neurites that receive incoming signals.

Question 16

What do dendrites have to assist with its function?

Answer 16

Lots of branching

Question 17

What does the soma do?

Answer 17

Sums incoming electrical signals from the dendrites.

Question 18

What is situated in the soma?

Answer 18

The nucleus and other organelles are situated, including key organelles that are required for protein synthesis, including:

1- The protein producing rough endoplasmic reticulum

2- The nucleus including a prominent nucleolus

Question 19

Where do most cell bodies like to hide?

Answer 19

In the CNS.

Clusters of cell bodies in the CNS are called nuclei.

Question 20

What is the ganglia?

Answer 20

Clusters of cell bodies lying along the nerves of the PNS

Question 21

What is the axon?

Answer 21

This is a neurite that generates and transmits electrical impulses (action potentials) away from the soma.

They are the conducting region of the neuron

Question 22

Where does the axon join with the soma?

Answer 22

At the axon hillock

Question 23

What does the axon end in?

Answer 23

Axon terminals (synapses) that make contact with other neurons.

Question 24

The axon is coated in between with what?

Answer 24

A myelin sheath- an insulating layer of fat and protein

Question 25

What is the axon surrounded by?

Answer 25

A phospholipid bilayer embedded with proteins.