Nervous Tissue and the Central Nervous System (Nervous System I)

Question 1

What is the function of the nervous system?

Answer 1

• Maintains homeostasis
• Responsible for perceptions, behaviour, memories
• Initiates all voluntary & involuntary functions

Question 2

What are the 2 types of cells that nervous tissue consists of?

Answer 2

1) Neurons - basic info processing, nerve impulse conduction
2) Neuroglia - support, nourish & protect the neurons. Maintains homeostasis in the interstitial fluid that bathes the neurons

Question 3

What are the 3 basic parts of the neuron

Answer 3

1) Cell body
2) Dendrites
3) Axon or nerve fibre

Question 4

What is the function of the cell body?

Answer 4

1) Contains nucleus & many organelles involved in the metabolic processes
2) Maintains metabolism of the neuron
3) Growth & repair of the neuron

Question 5

What are dendrites

Answer 5

Dendrites are where neurons receive input from other cells

Question 6

What is an axon?

Answer 6

A single process extending from the cell body that splits off into axon terminals which are responsible for transmitting signals from the neuron to connected cells. (aka output channel)

Question 7

What are the 3 functional classes that neurons are divided into?

Answer 7

1) Sensory neurons - carry info from receptors into the brain
2) Motor neurons - transmit info from the CNS out to effector organs
3) Inter-neurons - originate & terminate within CNS (99%)

Question 8

How are cells under resting conditions charged?

Answer 8

The inside of the cell is negatively charged due to the membrane potential.
- This is due to a diffusion potential caused by the movement of K+ out of the cell

Question 9

What are Action potentials

Answer 9

Voltage changes used by nerve & muscle cells as signals in receiving, integrating & transmitting information

Question 10

What is the membrane potential and what is the value of a typical nerve cell

Answer 10

-70mV ; the difference in electrical charge between the inside and the outside of the neuron. Changes in membrane potential from its resting value can convey meaningful information to a cell

Question 11

What is the body controlled by

Answer 11

Electrical impulses, of which repetition frequency changes but amplitude stays constant

Question 12

How do neurons communicate with one another and with other effector organs?

Answer 12

Across a synapse.

Question 13

Where do most synapses occur

Answer 13

Most synapses occur between the axon terminal of one neuron and the cell body or dendrite of another

Question 14

What are pre-synaptic neurons

Answer 14

Neurons that conduct info TOWARDS a synapse

Question 15

What are post-synaptic neurons

Answer 15

Neurons that conduct information AWAY from a synapse

Question 16

What are the 2 types of synapse

Answer 16

1) Electrical
Local currents that arise from action potentials in the pre-synaptic neuron flow across the synapse to the post-synaptic neuron
2) Chemical
Much more common in the mammalian nervous system
Information is transmitted across the synapse by means of a chemical neurotransmitter

Question 17

What are the 4 most important neurotransmitters

Answer 17

1)Acetylcholine (Ach)
Neuromuscular transmission
2)Dopamine
Acts on brain neurons (emotions, pleasure, addiction)
3)Endorphins
Painkillers
4)Serotonin
Involved in sensory perception, mood, appetite and sleep

Question 18

What are the effects of drugs on neurotransmission and what are agonist and antagonist drugs

Answer 18

• Synaptic mechanisms are altered
  1) Agonists - drugs that bind to receptors & produce a similar response to the neurotransmitter
  2) Antagonist - drugs that bind to receptors & block their transmission

Question 19

What consists of the central nervous system

Answer 19

Brain and spinal cord

Question 20

What consists of the Peripheral nervous system

Answer 20

12 pairs of cranial nerves & branches
31 pairs of spinal nerves & branches

Question 21

What is the purpose of the peripheral nervous system

Answer 21

Provides input from sensory receptors to the central nervous system (afferent division)
Provides output from the central nervous system to effectors such as muscles or glands (efferent division)
- Somatic nervous system
- Autonomic nervous system

Question 22

How is the nervous system supported

Answer 22

• outer layer is bony
• 3 membranes between bone and nervous tissue (dura, arachnoid, pia)

Question 23

What are the 4 main parts of the brain

Answer 23

1) Brain stem (continuous with spinal cord)
2) Diencephalon
3) Cerebrum (bulk)
4) Cerebellum

Question 24

What are the 5 main lobes of the cerebral hemisphere

Answer 24

1) Parietal
2)Occipital
3) Frontal
4) Temporal
5) Limbic

Question 25

What functions is the frontal lobe responsible for

Answer 25

Personality, motor, emotions, problem solving, reasoning

Question 26

What function is the Parietal lobe responsible for

Answer 26

Sensory

Question 27

What functions is the Temporal lobe responsible for

Answer 27

Speech, language, hearing

Question 28

What function is the Occipital lobe responsible for

Answer 28

vision

Question 29

What is the function of the cerebellum

Answer 29

Control of balance & coordination

Question 30

What are the functions of the spinal cord?

Answer 30

1) White matter serves as a highway for nerve impulse conduction
2) Grey matter integrates both the incoming & outgoing information and is a site for integrating reflex e.g. spinal reflex