Nerve Cells, Neurotransmitters And Hormones

Question 1

What do dendrites do?

Answer 1

Receive stimulation from sensory receptors

Question 2

What is the soma?

Answer 2

The cell body, contains the nucleus. Neurotransmitters are formed in the nucleus.

Question 3

What is an axon?

Answer 3

A long extended finer along which the neural impulse travels

Question 4

What is a terminal button?

Answer 4

Swollen bulb-like structures that contain neurotransmitters found at the end of the axon

Question 5

What are the three main classes of neurons?

Answer 5

Sensory - from sense receptors toward the CNS

Motor - from CNS toward muscles and glands

Interneurons - from sensory neurons to other interneurons or to motor neurons

Question 6

How does action potential work?

Answer 6

There is a difference of charge between the inside of the axon and the outside (like a battery). Action potential occurs when there is a rapid change in voltage along the axon. Gates in the membrane open, allowing the flow of sodium ions IN and potassium ions OUT causing a change of electric potential. This change flows down the axon.

Question 7

What is all or none law?

Answer 7

The size of the action potential is unaffected by increases in the intensity of stimulation beyond the threshold level.

Question 8

How does the brain know that some neurons are being more stimulated than others?

Answer 8

The frequency or how many times signals are being sent

Question 9

What is the refractory period?

Answer 9

A period during which further stimulation can not cause another action potential

Question 10

What is the natural resting potential of a neuron? (In volts)

Answer 10

-70 mv

Question 11

What is a synapse? Explain synaptic transmission

Answer 11

The gap between one neuron and the other. This gap is at the terminal button. Synaptic transmission is the relaying of information from one neuron to another across the synaptic gap.

Question 12

What are neurotransmitters?

Answer 12

Chemical messengers of information. They are received at the receptor site

Question 13

What are the bubbles in the terminal button called?

Answer 13

Vesicles. These are released in response to the action potential from the presynaptic membrane

Question 14

Explain how neurotransmitters are received.

Answer 14

When the presynaptic neuron is excited the action potential causes these bubbles to migrate into the synaptic cleft where they burst. Some of these neurotransmitters then bind to the receptor site where it causes a change in the membrane potential of the postsynaptic neuron.

Question 15

What happens when the effect of this binding is excitatory?

Answer 15

The likelyhood of an action potential occurring in the post synaptic cell more likely. An excitatory action depolarises the membrane. If there are enough of these neurotransmitters are binded then the membrane will change from its resting potential to about -60 where action potential occur.

Question 16

Define depolarised and hyperpolarised

Answer 16

Depolarised - cell potential moves towards 0 from -70mv

Hyperpolarised - cell potential moves further away from 0

Question 17

What happens if the effect of this binding is inhibitory?

Answer 17

Inhibitory neurotransmitters hyperpolarise the post synaptic cell, making action potential less likely.

Question 18

Where do neurotransmitters go when they aren’t binded?

Answer 18

They are put back into the terminal buttons into the vesicles and recycled

Question 19

Binding of the neurotransmitters produces a _______ potential?

Answer 19

Graded. This means it either increases or decreases the likelyhood of the action potential.

Question 20

What is acetylcholine? (ACH)

Answer 20

The neurotransmitter in the motor pathway that causes the muscles to contract.

Question 21

What are the two neurotransmitters that regulate and control anxiety?

Answer 21

GABA (gamma-aminobutyric acid) is an inhibitory neurotransmitter that calms and regulates anxiety and an excess of Glutamate (which is normally used for learning and memory) is excitatory and can cause anxiety

Question 22

What is dopamine responsible for?

Answer 22

Commonly found in the limbic system (the pleasure centre of the brain). Dopamine gives the feeling of pleasure.

Question 23

What do endorphins do?

Answer 23

Counteract pain.

Question 24

What is Serotonin?

Answer 24

Hormone to make you feel good/ happy. Those with depression have a lack of serotonin

Question 25

What are norepinephrine/ noradrenaline?

Answer 25

These hormones increase vigilance and excitement. They also cause the secretion of adrenaline.

Question 26

What are the parts of the endocrine system?

Answer 26

Pituitary gland - the master gland; produces hormones that influence the secretions of the thyroid, pancreas, adrenals and gonads; also secretes growth hormones

Question 27

What is a neuron?

Answer 27

A cell in the nervous system specialised to receive, process, and/ or transmit information to other cells