Neurons Term 2

Question 1

Describe the structure and function of neurons/nerve cells

Answer 1

Highly specialised NS cells designed to
-rapidly generate electrochemical nerve impulses
-carry info from one part of body to other

Question 2

Define glial cells/tissue

Answer 2

Support, protect and provide nutrition’s to neurons and insulate them from each other

Question 3

Define cell body structure and function

Answer 3

part of neuron containing nucleus
-granular cytoplasm (ribosome clusters)
-abundant organelles
-responsible for controlling the functioning of the cell

Question 4

Define dendrites structure and function

Answer 4

short extensions of the cytoplasm of the cell body
-highly branched
-carry messages/nerve impulses into cell body
-synapse/joins with other neurons or receptors

Question 5

Define axon structure and function

Answer 5

Single, long nerve fibres/extension of the cytoplasm
-connect with muscles (neuromuscular junction), glands (neuroglandular), and other neurons (complex neurons
-carry nerve impulses away from cell body
-axon divides into many small branches that terminate at axon terminals

Question 6

Recall that a nerve consists/Define what a nerve is

Answer 6

bundle of nerve fibres held by connective tissue outside brain and spinal cord

Question 7

Define nerve fibre

Answer 7

long projection/extension of cytoplasm of a nerve cell body (also known as axon)

Question 8

Define neurilemma

Answer 8

sheath surrounding nerve fibre
-protective function for peripheral nerve fibers

Question 9

Describe and give the function of the myelin sheath

Answer 9

fatty sheath made by Schwann cells that wrap around the axon of most neurons
-speeds up nerve transmission along axon
-acts as insulator
-protects nerve fibres/axon from damage

Question 10

Define node of Ranvier and function

Answer 10

microscopic gaps found in myelin sheath-speed up nerve impulses

Question 11

Define synapses structure and function

Answer 11

junction between axon terminal of one neuron with dendrite of another neurons cell body
-neurons do not physically touch at synapse=small gap

Question 12

How are messages carried across synapse gap?

Answer 12

Messages are carried across gap by the movement of chemicals called neurotransmitters

Question 13

Define neurotransmitter

Answer 13

molecule that carries a nerve impulse across the small gap between branches of adjacent nerve cells/neurons

Question 14

Define neuromuscular junction

Answer 14

Synapse where an axon meets a skeletal muscle cell
-jucntion between branches of a motor nerve cell and the muscle fibre=motor end plate

Question 15

Name the three functional types of neurons

Answer 15

Sensory/afferent, Motor/efferent, Interneuron

Question 16

identify and give the function of the sensory neurons

Answer 16

afferent, carry messages form receptors in the sense organs, or skin, to the CNS (brain and spinal cord)

Question 17

identify and give the function of the motor neuron

Answer 17

efferent, carry messages form CNS to the effectors, muscles and glands

Question 18

identify and give the function of interneurons

Answer 18

association neurons, located in CNS and are the link between sensory and motor neurons

Question 19

Name the four structural types of neurons

Answer 19

multipolar, bipolar, unipolar, pseudounipolar

Question 20

Define multipolar neurons and examples

Answer 20

one axon and several dendrites extending from cell body
includes: most of the interneurons in brain/spinal cord, and the somatic motor neurons

Question 21

Define bipolar neurons and examples

Answer 21

one axon and one dendrite extending from cell body
-occur in the eye, ear and nose where they take impulses from the receptor cells to other neurons

Question 22

Define unipolar neurons and examples

Answer 22

one axon extending from cell body
-not found in humans but insects

Question 23

Define pseudounipolar neurons and examples

Answer 23

properties of uni/bipolar
-one axon separating into two extensions
-one connects to dendrites other to axon terminals
-includes most sensory neurons carrying messages to spinal cord

Question 24

Distinguish between a neuron, a nerve, and a nerve fibre

Answer 24

neuron=nerve cell
nerve=bundle of nerve fibres held together by connective tissue
nerve fibre=projection from a nerve cell body (usually axon)