Nerve impulses

Question 1

What is the role of synapses and neurotransmitters?

Answer 1

To transfer electrical information from one cell to another

Question 2

What is the kiss and run model? (4)

Answer 2

• Action potential arrives
• calcium channels open and calcium enters
• presysnaptic vesicles exocytose
• straight away endocytosis occurs

Question 3

What is the name for the mechanism that controls neurotransmitter exocytosis?

Answer 3

Fluid phase exocytosis

Question 4

Other than fluid phase exocytosis, what other biological control of neurotransmitter action is there?

Answer 4

Enzymes that break down neurotransmitters like monamine oxidase

Question 5

What is a membrane potential?

Answer 5

An electrical potential difference between the interior and exterior of a cell

Question 6

What is temporal summation

Answer 6

when a neurone releases Its multiple times to cause an action potential

Question 7

What is spatial summation

Answer 7

when multiple neurones release Its to on postsynaptic neurone to cause an action potential

Question 8

How is an action potential formed in an axon? (9)

Answer 8

• Stimulus causes alteration in resting potential
• voltage gated sodium channel open
• influx of sodium
• peak action potential reached
• Sodium channels close potassium channels open
• potassium efflux
• repolarization
• hyperpolarization
• sodium potassium pump returns to normal

Question 9

What are the general function of the nervous system? (3)

Answer 9

• sensory detection
• info processing
• behaviour

Question 10

What is the most exterior layer surrounding a nerve?

Answer 10

epineurium

Question 11

What is bundle of axons called?

Answer 11

fascicule

Question 12

What structure surrounds nerve bundles?

Answer 12

perineurium

Question 13

What layer surrounds each nerve axon?

Answer 13

endoneurium

Question 14

Why is the endoneurium made of loose connective tissue?

Answer 14

So that gaps are left for arterioles

Question 15

Which part of the neurone releases neurotransmitters?

Answer 15

Axon terminal

Question 16

What is the role of the dendrites?

Answer 16

They are the receptive areas for impulse transmission

Question 17

What are Schwann cells?

Answer 17

Cells that wrap around the axons leaving gaps called nodes of Ranvier that allow the action potential to jump via saltatory conduction

Question 18

What are satellite cells?

Answer 18

Cells that control the microenvironment within ganglia via homeostasis

Question 19

What are oligodendrites?

Answer 19

Cells wrap around several axons to form a myelin sheath in the CNS

Question 20

What are astrocytes?

Answer 20

Form the junction between capillaries and neurone. They maintain a proper ionic environment by expressing certain ion channels to buffer any changes in the blood ionic concentration. And therefore are involved in the blood brain barrier.

Question 21

What are microglia?

Answer 21

They phagocytise pathogens and cell debris forming the immune system of the brain and spinal cord. They can multiply during damage

Question 22

What are ependymal cells?

Answer 22

They line the cavities of the CNS and produce CSF by filtering blood. They beat there cilia to help circulate the CSF

Question 23

What are the three types of junction between neurones and excitable tissue

Answer 23

• Synapses
• Neuromuscular junctions
• neuroglandular junctions

Question 24

What are the three structural types of neurones?

Answer 24

• multipolar
• unipolar
• bipolar

Question 25

What are multipolar neurones?

Answer 25

neurone with one axons and multiple dendrites

Question 26

What are unipolar neurones?

Answer 26

neurone with one axon and one dendrite

Question 27

What are bipolar neurones?

Answer 27

neurone with a single process leaving the body which quickly divides into 2. one axon and one dendrite

Question 28

What is an interneurone?

Answer 28

Connect one point in the CNS to another but never leave the CNS.