Human Biology (Nervous System)

Question 1

What are Neurons?

Answer 1

Specialised cells that pass along nerve impulses.

Question 2

What does the Sensory Nervous System do?

Answer 2

Takes information from the body to the brain:

External conditions: e.g. temperature, hearing, touch

Internal conditions: Blood temperature, pressure, blood gas & pH.

Question 3

What does the Central Nervous System do?

Answer 3

Takes information to and from the brain and co-ordinates spinal reflexes.

Question 4

What do motor neurons do?

Answer 4

Takes information from the brain to the body about responses.

• Stimulates movement or glandular secretions
• Has both voluntary and involuntary secretions.

Question 5

Where are synapses present?

Answer 5

At muscles and glands.

Question 6

What is the cell body of a neuron?

Answer 6

Contains a nucleus and carries impulses to the body.

Question 7

What are the dendrites of a neuron?
Describe their structure and function.

Answer 7

Short extensions of the body that are highly branched.
Receive stimulus and carry impulses to all the body.

Question 8

What are axons? Describe their structure and function.

Answer 8

Longer extensions from the cell body.
Carries nerve impulses away from the cell body
Usually covered with a myelin sheath

Question 9

What is the gaps along an axon called?

Answer 9

Nodes of Ranvier

Question 10

What are 3 functions of the myelin sheath?

Answer 10

• Acts as an inuslator for impulses.
  Protects axon from external damage
  Speeds movement of nerve impulses

Question 11

What is the neurilemma?

Answer 11

The outermost layer of schawnn cells and helps to repair injured fibres by guiding regrowth.

Question 12

What is the difference between grey matter and white matter?

Answer 12

Grey:
- Cell bodies
- Unmyelinated fibres

White:
- No cell bodies
- Myelinated fibres

Question 13

What are sensory neurons?

Answer 13

Carries messages from receptors to the CNS.

Question 14

What are interneurons?

Answer 14

The link between sensory and motor neurons.

Question 15

What are motor neurons?

Answer 15

Carries messages from CNS to muscles and glands.

Question 16

What does autonomic and somatic mean?

Answer 16

Somatic: Means under voluntary control
e.g. skeletal muscles movement, eye movement
Autonomic: Means under involuntary control
e.g. Muscle lining in blood vessels, and glands

Question 17

What are the 3 types of neuron structure?

Answer 17

Multipolar, Bipolar, Pseudopolar

Question 18

What are 4 features of multipolar neurons?

Answer 18

• Most common
• One axon, multiple dendrites
• Axon may have multiple terminals
• Interneurons and motor neurons are of this type

Question 19

What are 2 features of bipolar neurons and 2 examples?

Answer 19

• One axon and one dendrite, branching at ends
• Generally, part of special sense organs
  e.g. in eye, ear, nose

Question 20

What is a feature of pseudopolar neurons?

Answer 20

• Cell body to side

Question 21

What is a synapse?

Answer 21

A point where nerve impulses are passed from one neuron to another.

There is no join because of a small gap for chemical messages neurotransmitters to cross.
Also occur at neuromuscular junctions.

Question 22

What are nerves and the 3 types and their directions?

Answer 22

Bundles of neuron fibres extending from the CNS.

3 Broad Types:

Sensory, Motor, Mixed

Sensory take information from the body to the CNS.
Motor takes information to the body from the CNS.

Mixed takes information from both ways.