4: Nervous Communication

Question 1

Axon

Answer 1

Structure extending from a Neurone that conducts action potentials away from the cell body.

Question 2

Central Nervous System (CNS)

Answer 2

The complex of nerve tissues that controls the activities of the body. In vertebrates, it comprises of the brain and spinal cord.

Question 3

Dendrite

Answer 3

A structure, usually branched, extending from the cell body of a Neurone, which conducts impulses towards the cell body.

Question 4

Effector

Answer 4

An organ that responds to stimulation by a nerve impulse resulting in a change or response.

Question 5

Impulse

Answer 5

A series of action potentials. Transmitted by Salvatore conduction in myelinated axons.

Question 6

Motor Neurone.

Answer 6

Neurone that transmits action potentials from the CNS to the effector (e.g. muscle or gland).

Question 7

Myelin

Answer 7

A fatty substance that surrounds the axon and dendrites in certain neurones.

Question 8

Myelin Sheath

Answer 8

Composed of Schwann cells wrapped around the axon of a Neurone.

Question 9

Neurone

Answer 9

A nerve cell, compromising of a cell body, axon and dendrites, which is adapted to conduct action potentials.

Question 10

Node of Ranvier

Answer 10

A gap in the myelin sheath that surrounds the axon in the Neurone.

Question 11

Peripheral Nervous System

Answer 11

The part if the Nervous System that consists of the nerves on the outside of the brain and spinal cord.

Question 12

Receptor

Answer 12

A cell adapted to detect changes in the environment.

Question 13

Relay Neurone

Answer 13

Neurone that transmits impulses between sensory neurones and motor neurones, or between other relay neurones. Normally found in the CNS.

Question 14

Schwann cell

Answer 14

Cell around a Neurone whose cell-surface membrane wraps around the axon to form the myelin sheath.

Question 15

Sensory Neurone

Answer 15

Neurone that transmits an action potential from a sensory receptor to the CNS.

Question 16

Sypnatic knob/ axon terminal

Answer 16

End of the axon that synapses with the dendrites or cell body of another Neurone or with an effector.

Question 17

Action Potential

Answer 17

Change that occurs in the electrical charge across the membrane of an axon when it is stimulated and a nerve impulse passes.

Question 18

Axoplasm

Answer 18

The cytoplasm of a neurone

Question 19

Depolarisation

Answer 19

Temporary reversal of charges on the cell-surface membrane of a neurone that takes place when a nerve impulse is transmitted.

Question 20

Hyperpolarisation

Answer 20

When the membrane potential becomes more negative than the resting potential following an action potential or as a result of an inhibitory impulse.

Question 21

Ion Channel

Answer 21

A passage across a cell-surface membrane made up o a protein that spans the membrane and opens and closes to allow ions to pass in and out of the cell.