Nervous A & P

Question 1

Principle divisions of the nervous system

Answer 1

CNS

PNS

Question 2

What does the CNS consist of?

Answer 2

Brain and Spinal Cord

Question 3

What does the PNS consist of?

Answer 3

PNS=12 pairs of cranial nerves and 31 pairs of spinal nerves

Question 4

What are the 3 PNS sub-devision.

Answer 4

Somatic nervous system (voluntary) i.e. impulses to skeletal muscle.
Autonomic nervous system (involuntary) i.e. impulses to smooth muscle, cardiac muscle and glands.
Enteric nervous system (involuntary) i.e. gastro-intestinal tract.

Question 5

What are sensory nerves know as?

Answer 5

AFFERENT NERVES (AS) they carry information towards the spinal cord and brain.

Question 6

What are Motor Nerves know as?

Answer 6

EFFERENT NERVES (ME) carry information from brain and spinal cord, travel down the spinal cord via descending tracts.

Question 7

What are the 2 types of nervous tissue?

Answer 7

Neuroglia

Neurones

Question 8

Describe Neuroglia

Answer 8

Supports and protects neurones,capable of multiplying and dividing.
Can not generate electrical impulses.
6 types to be found CNS=4(oligondendrocyctes produce myelin), PNS=2(neurolemnocytes) also know as (Schwann cells) produce myelin.

Question 9

What is Myelin?

Answer 9

Myelin a multi layered protein covering sheath, cover Axons only.
Axons covered are called MYELINATED, increase nerve impulse conduction.

Question 10

What rate breaks in myelin sheath along an axon is called?

Answer 10

NODES OF RANVIER

Question 11

Describe neurones.

Answer 11

Responsible for the transmission of impulses, neurones consist of 3 parts.
Dendrite, cell body (contains nucleus and organelles) Axons.

Question 12

What do axons do?

Answer 12

They propagate impulses towards additional neurones, effector i.e. muscles or glands. Axons are long thin cylindrical projection.

Question 13

Name the Nerves impulse conduction

Answer 13

Resting membrane potential.
Polarised.
Action potential.
The absolute refractory period.
Relative refractory period.
All or nothing principal.

Question 14

What is resting membrane potential?

Answer 14

An electrical voltage difference across the membrane in excitable cells.

Question 15

What is it meant by polarised?

Answer 15

Any cell that exhibits a membrane potential.

Question 16

What is an action potential?

Answer 16

Is also known as an impulse, is the decrease and eventual reversal of the membrane potential (depolarisation) and then restoring it to its original state (repolarisation).

Question 17

What is it meant by the absolute refractory period?

Answer 17

When another impulse cannot be generated.

Question 18

What is it meant by the Relative refractory period?

Answer 18

When another impulse can be initiated the stimulus has to be larger than the pervious one.

Question 19

What is it meant by the all or nothing principle?

Answer 19

Where the stimulus is larger enough to change the membrane potential, therefore producing an action potential I.E the domino falls or it doesn’t.

Question 20

What are 5 requires for the Reflex arc?

Answer 20

Sensory receptor i.e. skin
Sensory neurones i.e. nerve transmitting impulses towards the spinal cord and brain.
Integrating centre i.e. control centre (brain).
Motor neurone i.e. nerve transmitting impulses out of CNS to the part of the body that will respond.
Effector i.e. the part of the body that responds to motor nerve impulses (finger).