Biopsychology- Neurons and synpatic transmission

Question 1

What is the function of dendrites?

Answer 1

Receive signals from other neurons or sensory receptor cells- typically connected to the cell body

Question 2

What is the function of the cell body?

Answer 2

Contains the nucleus (genetic info)

Question 3

What is the function of an axon?

Answer 3

Long slender fibre that carries nerve impulses in the form of electrical signal known as action potential

Question 4

What is the function of the Myelin sheath?

Answer 4

Most axons are surrounded by myelin sheath which insulates the axon so electrical impulses travel faster along the axon

Question 5

What is the function of the axon terminal?

Answer 5

Connects the neuron to another neuron (or directly to organs using synaptic transmission

Question 6

What are the 5 structures of a neuron?

Answer 6

1. Dendrites
2. Cell body
3. Axon
4. Myelin sheath
5. Axon terminal

Question 7

Neurons vary in 1.____ but all share the same basic 2.____

Answer 7

1. Size
2. Structure

Question 8

What are the 3 types of neurons?

Answer 8

-Sensory neuron
-Relay (interconnecting) neurons
-Motor neuron

Question 9

What is the function of sensory neurons?

Answer 9

-Carry nerve impulses to the spinal cord and brain
-Nerve impulses are translated into sensations
-Not all sensory neurons reach the brain as some neurons stop at the spinal cord allowing for quick reflex actions

Question 10

Where are sensory neurons found?

Answer 10

-Found in receptor cells

Question 11

What is the length of the fibre of sensory neurons?

Answer 11

-Long dendrites and short axons

Question 12

Where are relay (interconnecting) neurons found?

Answer 12

-In between sensory and motor neurons
-Found in the brain and spinal cord

Question 13

What is the function of relay neurons?

Answer 13

-Allow sensory and motor neurons to communicate

Question 14

What is the length of the fibres on the relay neuron?

Answer 14

-Short dendrites and short axons

Question 15

Where are motor neurons found?

Answer 15

-Found in the CNS

Question 16

What is the function of motor neurons?

Answer 16

-Control muscle movements
-When motor neurons are stimulated they release neurotransmitters that bind to receptors on muscles to trigger a response

Question 17

What is the length of fibres in a motor neuron?

Answer 17

-Short dendrites and long axons

Question 18

What is synaptic transmission?

Answer 18

-A nerve impulse passes across the synaptic gap from one neuron (pre-synaptic neuron) to another (Post synaptic neuron)

Question 19

What is a synapse?

Answer 19

Each neuron is separated from the next by a tiny gap- a conjunction of the end of the axon of one neuron and the dendrite or cell body of another neuron

Question 20

What is the 1st step of Synaptic transmission?

Answer 20

-Action potential- information passed down the axon of the neuron as an electrical impulse or the contraction of a muscle

Question 21

Define action potential

Answer 21

-The change in electrical potential that propagates along the axon of a neuron during the transmission of a nerve impulse or the contraction of a msucle

Question 22

What is the 2nd step of Synaptic transmission?

Answer 22

Once the action potential reaches the end of the axon it needs to be transferred to another neuron/ tissue by crossing the synaptic gap

Question 23

What is the 3rd step of synaptic transmission?

Answer 23

At the end of the neuronic (in the axon terminal) are the synaptic vesicles which contain neurotransmitters

Question 24

What is the 4th step of synaptic transmission?

Answer 24

The electrical (nerve) impulse (action potential) stimulates the release of neurotransmitters from the synaptic vesicles

Question 25

What is the 5th step of synaptic transmission?

Answer 25

Neurotransmitters then carry the signal across the synaptic gap, they bind to receptor sites on the postsynaptic cell (neuron) which then becomes activated

Question 26

Which neurotransmitters make the postsynaptic cell/ neuron more likely to fire? (eg. noradrenaline)

Answer 26

Excitatory

Question 27

What do inhibitory neurotransmitters do? (eg. GABA)

Answer 27

Make them less likely to fire

Question 28

What is summation?

Answer 28

The net effect of the EPSPS and IPSPS (adding up the positive and negative charges)

Question 29

When does excitation occur?

Answer 29

-When receptor stimulation results in an increase in the positive charge of the postsynaptic neuron and increases the likelihood of the neuron firing and passing on the electrical impulse (EPSP)

Question 30

When does Inhibition occur?

Answer 30

When receptor stimulation results in an increase in the negative charge of the postsynaptic neuron and decreases the likelihood of the neuron firing and passing on the electrical impulse

Question 31

How many neurons (nerve cells) are in the body?

Answer 31

100 billion nerve cells, 80% located in the brain

Question 32

What are neurons?

Answer 32

Cells that conduct nerve impulses, transmit signals electrically and chemically

Question 33

In a reflex arc, like the knee-jerk reflex, a stimulus such as a hammer hitting the knee is defected by sense organs in the 1.____ which conveys a message along a 2.___. The message reaches the 3.___ where it connects with a 4.____, this then transfers the message to a motor neuron which then carries the message to a 5._____ such as a muscle which causes the muscle to contract and the knee to jerk/move,

Answer 33

1. PNS
2. Sensory neuron
3. CNS
4. Relay neuron
5. Effector