Nervous Tissue (5)

Question 1

What does nervous tissue consist of?

Answer 1

It consists of neurons and neuroglia.

Question 2

What is the nervous system consist of?

Answer 2

The nervous system is made up of many millions of special cells called neurons that form a continuous network, extending all over the body. They form the structural units of the nervous system.

Question 3

What do neurons need to function for a life time?

Answer 3

The correct conditions.

Question 4

Neurons cannot undergo ___, so they cannot be ___ if replaced. Stem cells may be used to replace ____ neurons.

Answer 4

Mitosis
Replaced
Damaged

Question 5

Why can neurons not survive for more than a few minutes without oxygen?

Answer 5

Neurons have a very high metabolic rate and need continuous supplies of oxygen and glucose to survive.

Question 6

What do glial cells do?

Answer 6

They are supporting cells which play a critical role in making myelin and supporting and protecting the neurons.

Question 7

What is the structure of neuron? (4)

Answer 7

Neurons are made up of the same basic parts as other animals. 
Membrane 
Cytoplasm 
Cell organelles 
Nucleus

Question 8

What additional structure do neurons have and how are these useful?

Answer 8

They have long, thin processes-fibres of cytoplasm that extend from the cell body. These make it possible for nerve impulses to be carried long distances.

Question 9

What are the two fibres in a typical neuron? (2)

Answer 9

• Dendrites

- Axons

Question 10

What are dendrites?

Answer 10

Dendrites conduct impulses TOWARDS the cell body. They are short, tapering processes that branch extensively to provide a large surface area to receive signals from other neurons.

Question 11

What are axons?

Answer 11

Axons conduct impulses AWAY from the cell body. Each neuron has a single axon although certain axons may give off branches along their length. An axon usually branches extensively at its end to form terminal breaches.

Question 12

What are sensory/unipolar neurons?

Answer 12

These are afferent neurons as they carry impulses from receptors towards the CNS, where the sensation is interpreted.

Question 13

Define unipolar.

Answer 13

One fibre attached to the cell body.

Question 14

What are connector neurons?

Answer 14

These are multipolar neurons found in the CNS and make up 99% of the neurons of the body. They receive impulses from sensory neurons and pass them onto other neurons.

Question 15

Define multipolar.

Answer 15

Many fibres attached to the cell body.

Question 16

What are motor neurons?

Answer 16

These are efferent neurons as they carry impulses away from the CNS to effectors so that the appropriate response can be brought about.

Question 17

Function of dendrite.

Answer 17

Collect information from other cells and pass it on to cell body.

Question 18

Function of the cell body.

Answer 18

Controls the metabolism of cell.

Question 19

Function of the node of Ranvier.

Answer 19

Allows rapid conduction of impulses by forcing them to jump from one node to the next.

Question 20

Function of a Schwann cell.

Answer 20

Secretes the myelin sheath.

Question 21

Function of the axon.

Answer 21

Extended to carry impulses away from the cell body over long distances.

Question 22

Function of myelin sheath.

Answer 22

Forms electrical insulation around the axon preventing impulses being disrupted from activity in neighbouring cells.

Question 23

Function of terminal branches.

Answer 23

Carry impulses to the synaptic knobs/ end plates.

Question 24

Function of the synaptic knob.

Answer 24

Forms a synapse with another neuron, a muscle cell or gland cell.

Question 25

Cell membranes surround _____ just as they do any other cell in the body.

Answer 25

Neurons

Question 26

What are the nissal granules.

Answer 26

Are groups of ribosomes in the neuroplasm that are involved with protein synthesis.

Question 27

What is the neurilemma?

Answer 27

It is collective name for the outer sheath made of Schwann cells.