Synapse stuff

Question 1

Dendrite

Answer 1

branched nerve fibres which receive nerve impulses and pass them towards a cell body.

Question 2

Cell body

Answer 2

where organelles such as the nucleus are found.

Question 3

Axon

Answer 3

a single nerve fibre that carries nerve impulses away from a cell body which is insulated by a fatty sheath

Question 4

Myelin Sheath

Answer 4

The role of the myelin sheath is to insulate the axon and speed up the transmission of nerve impulses along the neuron. This surrounds axons.

Question 5

Gial Cells

Answer 5

produce the myelin sheath and support neurons.

Question 6

Myelin and Myelination

Answer 6

Myelination continues from birth to adolescence.
Certain diseases destroy the myelin sheath causing a loss of co-ordination.
Responses to stimuli in the first two years of life are not as rapid or co-ordinated as those of an older child or adult.

Question 7

Check topic pitctures

Answer 7

Good

Question 8

Re-uptake

Answer 8

• Re-uptake – the neurotransmitter is reabsorbed back into the presynaptic neuron and restored inside a vesicle ready to be used again. For example, noradrenaline.

Question 9

Enzyme degradation

Answer 9

Enzyme degradation – neurotransmitter is broken down by an enzyme into smaller inactive product which are then reabsorbed by the presynaptic neuron and resynthesised into active neurotransmitter.

Question 10

Neurotransmitter at synapse basic

Answer 10

Neurons connect with other neurons or muscle fibres at a synaptic cleft. Neurotransmitters relay impulses across the synaptic cleft.

Question 11

Neurotransmitter journey

Answer 11

Neurotransmitters are stored in vesicles in the axon endings of the presynaptic neuron. They are released into the cleft on arrival of an impulse. They diffuse across the cleft and bind to receptors on the membrane of the postsynaptic neuron.

Question 12

What can receptors determine?

Answer 12

Receptors determine whether the signal is excitatory or inhibitory.

Question 13

The need for removal of neurotransmitter by enzyme or re uptake

Answer 13

The need for removal of neurotransmitters by enzymes or reuptake to prevent continuous stimulation of postsynaptic neurons.

Question 14

Weak stimuli

Answer 14

Synapses can filter out weak stimuli arising from insufficient secretion of neurotransmitterS

Question 15

Threshold

Answer 15

A minimum number of neurotransmitter molecules must attach to receptors in order to reach the threshold on the postsynaptic membrane to transmit the impulse

Question 16

Summation

Answer 16

Synapses can filter out weak stimuli arising from insufficient secretion of neurotransmitters.

Convergent neural pathways can release enough neurotransmitter molecules to reach threshold and trigger an impulses

Question 17

Reward pathway activated when

Answer 17

The reward pathway is activated when an individual engages in a behaviour that is beneficial to them, for example eating when hungry

Question 18

Reward pathway

Answer 18

The reward pathway involves neurons which secrete or respond to dopamine.

Question 19

Endorphins function

Answer 19

Endorphins are neurotransmitters that stimulate neurons involved in reducing the intensity of pain.

Question 20

Endorphins produced increases in response to

Answer 20

Endorphin production increases in response to severe injury, prolonged and continuous exercise, stress and certain foods.

Question 21

Dopamine

Answer 21

Dopamine is a neurotransmitter that induces feelings of pleasure and reinforces particular behaviour by activated the reward pathway in brain

Question 22

Increased level of endorphins linked to pleasure

Answer 22

Increased levels of endorphins are also linked to the feelings of pleasure obtained from activities such as eating, sex and prolonged exercise.

Question 23

A and A use

Answer 23

Many drugs used to treat neurotransmitter- related disorders are agonists or antagonists

Question 24

Agonist

Answer 24

Agonists are chemicals that bind to and stimulate specific receptors mimicking the action of a neurotransmitter at a synapse

Question 25

Antagonist

Answer 25

Antagonists are chemicals that bind to specific receptors blocking the action of a neurotransmitter at a synapse.

Question 26

D. What do other drugs do

Answer 26

Other drugs act by inhibiting the enzymes that degrade neurotransmitters (I think this is like competitive inhibition) or by inhibiting reuptake of the neurotransmitter at the synapse causing an enhanced effect.

Question 27

Recreational Drugs

Answer 27

Recreational drugs can also act as agonists or antagonists.
Recreational drugs affect neurotransmission at synapses in the brain altering an individual’s mood, cognition, perception and behaviOur

Question 28

R Drugs Reward Pathway

Answer 28

any recreational drugs affect neurotransmission in the reward pathway of the brain.

Question 29

Drug addiction is caused by repeated use of drugs that act as antagonists.

Answer 29

SAN Lewis acronym Antagonists block specific receptors causing the nervous system to increase both the number and sensitivity of these receptors. This sensitisation leads to addiction where the individual craves more of the drug.

Question 30

Drug tolerance is caused by repeated use of drugs that act as agonists.

Answer 30

Agonists stimulate specific receptors causing the nervous system to decrease both the number and sensitivity of these receptors. This desensitisation leads to drug tolerance where the individual must take more of the drug to get an effect.