nervous system - neurons

Question 1

what are neurons?

Answer 1

specialised cells to send and receive nerve impulses

Question 2

what are neuroglia?

Answer 2

cells that have a support function
provide insulation and nutrients
may send and receive impulses

Question 3

how are all the organs in the human body formed?

Answer 3

four types of tissue combine

Question 4

what does nervous tissue do?

Answer 4

allow you to sense and respond to things

Question 5

what do nervous tissue cells do?

Answer 5

they are specialised for receiving and sending information

Question 6

where is the central nervous system?

Answer 6

made up of the brain and spinal cord

Question 7

where is the peripheral nervous system

Answer 7

cranial nerves, spinal nerves, ganglia, peripheral nerves, and neuromuscular junctions

Question 8

what is the function of the cns?

Answer 8

awareness, movement, speech, receiving, processing, responding to sensory information

Question 9

what is the function of the pns?

Answer 9

sending information from different areas of the body back to the brain, and carrying out commands from the brain to various parts of the body.

Question 10

how is the peripheral nervous system further subdivided?

Answer 10

into an afferent sensory division and efferent motor division

Question 11

what are the peripheral organs

Answer 11

nerves and ganglia

Question 12

how does the sensory division of the pns transmit impulses?

Answer 12

from the peripheral organs to the cns

Question 13

how does the motor division of the pns transmit impulses?

Answer 13

from the cns to the peripheral organs

Question 14

how is the motor division further subdivided

Answer 14

into a somatic motor division and an autonomic motor division

Question 15

what does the somatic motor division do?

Answer 15

serves skeletal muscle

Question 16

what does the autonomic motor division do?

Answer 16

serves smooth muscle, cardiac muscle and glands

Question 17

what does the nervous system do?

Answer 17

contains sensory receptors which detect changes in the internal and external environment of the body

Question 18

how does the nervous system send information?

Answer 18

via impulses

Question 19

what are impulses?

Answer 19

a network of cells that use electrical signals

Question 20

what happens when impulses are used?

Answer 20

responses are initiated to changes in the body, allowing the nervous system to maintain homeostasis

Question 21

what does motor function do?

Answer 21

carries out effect

Question 22

what does the integrative function?

Answer 22

decides response

Question 23

what does the sensory function do?

Answer 23

detects stimulus / informs cns

Question 24

what are the effectors of the somatic nervous system?

Answer 24

skeletal muscles

Question 25

what are the effectors of the autonomic nervous system?

Answer 25

cardiac muscles, smooth muscle, glands

Question 26

types of neuroglia

Answer 26

astrocytes ependymal cells microglia oligodendrocytes

Question 27

what is the function of astrocytes

Answer 27

found between neurouns and blood vessels (blood brain barrier) regulate ion concentration in nervous tissue multifunctional

Question 28

what is the function of ependymal cells

Answer 28

cover the choroid plexus line spaces in the brain (ventricles) produce csf

Question 29

what is the function of microglia

Answer 29

function as phagocytes supportive function

Question 30

what is the function of oligodendrocytes

Answer 30

form myelin in central nervous system

Question 31

what is csf

Answer 31

cerebrospinal fluid: flows in and around the hollow spaces of the brain and spinal cord, and between two of the meninges

Question 32

what is the node of ranvier?

Answer 32

exposed area of axon between myelin gaps between neighbourign segments of the myselin sheath

Question 33

what is the myelin sheath

Answer 33

a coating formed by schwann cells wrapped around the axon

Question 34

what is an axon?

Answer 34

thin extension that carries impulse

Question 35

what cells are axons of the peripheral nervous system associated with

Answer 35

neuroglia cells - schwann cells

Question 36

what does the myelin sheath consist of

Answer 36

multiple layers of the cell membrane of neuroglia cells

Question 37

what happens when schwann cells wrap around the axon

Answer 37

cytoplasm becomes the outermost wrapping of the cell

Question 38

what is the neurilemma

Answer 38

the outermost wrapping of the axon containing organelled and nucleus

Question 39

what are myelinated axons

Answer 39

axons with myelin sheaths

Question 40

what are unmyelinated axons

Answer 40

axons without myelin sheaths

Question 41

what is the cell body of a neuron

Answer 41

region that contains the nucleus

Question 42

what is the dendrite of the neuron

Answer 42

branched receptive processes

Question 43

what is the synaptic knob

Answer 43

enlarged structures that store and release neurotransmitters

Question 44

what is myelin

Answer 44

multilayered lipid covering of axon

Question 45

what type of nervous system tissue is formed by bundles of myelinated axons?

Answer 45

white matter

Question 46

what is found within gray matter in the nervous system tissue?

Answer 46

unmyelinated axons, dendrites, neuron cell bodies, and synapses

Question 47

what happens when an action potential arrives at the synaptic terminal

Answer 47

voltage gated calcium channels are opened

Question 48

what neurotransmitter is released from the synaptic vesicles?

Answer 48

acetylcholine

Question 49

When do ligand-gated sodium channels open?

Answer 49

When their ligand (acetylcholine) binds

Question 50

what happens when sodium enters the sodium channels?

Answer 50

the membrane potential becomes more positive.

Question 51

when will an action potential be produced?

Answer 51

if the membrane potential reaches threshold

Question 52

What structure releases neurotransmitter molecules?

Answer 52

synaptic vesicles

Question 53

how do nerve impulses occur?

Answer 53

ions moving through voltage gated ion channels in the plasma membrane

Question 54

The interior of the cell membrane is more__________ than the outside of the cell membrane.

Answer 54

negative

Question 55

What direction does the sodium-potassium pump move ions?

Answer 55

Sodium out of the cell and potassium into the cell

Question 56

Following stimulation, what are the first channels to open?

Answer 56

sodium channels

Question 57

what happens when sodium enters the cell membrane at the location of the sodium channel?

Answer 57

depolarisation

Question 58

When potassium channels open, which way do potassium ions flow?

Answer 58

out of the cell

Question 59

during an action potential what happens when potassium channels are opened?

Answer 59

repolarisation of the cell membrane

Question 60

Following an action potential, activity of the __________ reestablishes the sodium and potassium ion distribution across the cell membrane.

Answer 60

sodium potassium pump

Question 61

what does an action potential involve?

Answer 61

depolarisation repolarisation

Question 62

what is the steps of synaptic transmission?

Answer 62

- nerve impulse at axon terminal - calcium ions enter - exocytosis of neurotransmitter - diffusion through synaptic cleft - binding to receptor on post synaptic membrane

Question 63

what happens during hyperpolarisation?

Answer 63

potassium channels are open membrane potential actually dips lower than -70mV because the potassium channels do not close quickly enough.

Question 64

how can the cell membrane of a resting neuron be described?

Answer 64

polarised

Question 65

what is depolarisation?

Answer 65

the membrane potential becomes less negative than the resting membrane potential

Question 66

when will the action potential only occur?

Answer 66

the membrane potential at the trigger zone reaches threshold level

Question 67

what happens when threshold is reached?

Answer 67

voltage-gated sodium channels of the initial segment open briefly, allowing sodium to diffuse into the cell.

Question 68

what happens when sodium ions enter the cell?

Answer 68

the cell membrane undergoes depolarization, with the membrane potential increasing to a peak of approximately +30mV.

Question 69

what happens when the peak of the action potential is reached?

Answer 69

sodium channels close, and the voltage-gated potassium channels open, allowing these ions to diffuse out of the cell.

Question 70

what happens when potassium ions leave the cell?

Answer 70

the membrane potential at that part of the membrane is reestablishing resting membrane potential. repolarization occurs

Question 71

features of myelinated axon

Answer 71

faster impulse conduction saltatory conduction only nodes depolarise

Question 72

features of unmyelinated axon

Answer 72

slower impulse conduction entire surface depolarises

Question 73

what is an excitatory neurotransmitter?

Answer 73

A neurotransmitter that causes the opening of sodium channels brings the postsynaptic membrane closer to the threshold

Question 74

what is an inhibitory neurotransmitter?

Answer 74

A neurotransmitter that causes the opening of potassium channels causes membrane potential to move away from the threshold

Question 75

What are examples of a neuropeptide?

Answer 75

Enkephalins and substance P

Question 76

what are neuropeptides?

Answer 76

small proteinaceous substances produced and released by neurons through the regulated secretory route and acting on neural substrates.

Question 77

how do neurons communicate chemically with eachother?

Answer 77

using neurotransmitters at a synapse

Question 78

the release of neurotransmitters by the ________ is triggered by nerve impulses

Answer 78

presynaptic neuron

Question 79

what happens when the neurotransmitter binds to the post synaptic neuron?

Answer 79

causes electrical changes in the membrane