Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Bio year 2 > neuronal communication > Flashcards

neuronal communication Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Nervous pathway

A

Receptor - sensory neurone - CNS (brain, spinal chord + relay neurone) - motor neurone - Effector (gland - hormonal + muscle - nervous)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Internal stimuli

A
  • BGC
  • internal temperature
  • water potential
  • cell pH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

External stimuli

A
  • humidity
  • external temperature
  • light intensity
  • new/sudden sound
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

the need for communication systems in multicellular organisms

A
  • organism needs to respond to in/external changes for survival
  • occurs by electrical impulses/NS in animals
  • chemical/hormones in plants/animals
  • diff cells rely on others for materials/removal of waste(gluc+oxygen)
  • diff organs work together; ensures homeostasis (brain and skin in temp control)
  • cells communicate through cell signalling (cells of pituitary gland secrete ADH acting on cells in kidneys to maintain water balance)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How do cells communicate with one another

A
  • cell releases a chemical

- which has an effect on a target cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Dendron

A

part of neurone that sends impulse to cell body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

cell body

A

releases neurotransmitters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

axon

A

sends impulse away from the cell body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

myelin sheath

A

layers of plasma membranes (lipids)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

sensory neurone

A
  • transmit impulses from receptor cell to RN, MT or the brain
  • dendrite branches
  • have one dendron (carries impulse to the cell body)
  • one axon (impulse away from cell body)
  • cell body in the middle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

motor neurone

A
  • cell body at the start
  • dendrite branches on cell body
  • Axon after cell body
  • Dendrites of the end of axon
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

relay neurone

A
  • only cell body in the middle
  • dendrite receive the signal from SN
  • other branches are axons that send the signal away from cell body to MN.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

function of myelin sheath

A
  • layers of plasma membranes
  • insulating layer
  • speeds up nerve transmission (saltatory conduction) at nodes of Ranvier
  • ## SN + MN have myelin sheath
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what cell produces myelin sheath

A
  • Schwann cells growing around the axon several times
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the nodes of Ranvier + what happens there

A
  • between each adjacent SC there is a small gap = NOR
  • in myelinated neurones the electrical impulse ‘jumps’ from one node to the next (saltatory conduction)
  • impulse transmitted faster compared to unmyelinated
  • in non-myelinated the impulse transmits along the nerve at a slower rate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

features of a SR

A
  • specific to a single type of stimulus

- transducer - covert a stimulus into a nerve impulse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Mechanoreceptor

  • stimulus
  • receptor
  • sense organ
A
  • pressure and movement
  • Pacinian corpuscle (pressure)
  • skin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

chemoreceptor

  • stimulus
  • receptor(detects)
  • sense organ
A
  • chemicals
  • olfactory receptor (smell)
  • nose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

thermoreceptor

  • stimulus
  • receptor(detects)
  • sense organ
A
  • heat
  • end bubs of Krause
  • tongue
20
Q

photoreceptors

  • stimulus
  • receptor (detects)
  • sense organ
A
  • light
  • cone cell (diff wave-lengths)
  • eye
21
Q

role as a transducer

A
  • SR converts stimulus into a nervous impulse

- also called generator potential

22
Q

Pacinian corpuscle

A
  • detect pressure
  • end of SN within the centre of the corpuscle
  • surrounded by layers of connective tissue
  • each layer is separated by a layer of gel
  • neurone ending in PC has stretch mediated Na+ channels
23
Q

how does the PC convert mechanical pressure into a nervous impulse

A
  • at resting state the SM Na+ channels in SN membrane are closed
  • neurone has a resting potential
  • when pressure is applied , PC detects pressure
  • PC changes shape
  • neuronal membrane stretches
  • SM Na+ channels widen
  • Na+ diffuses into the neurone down its ECG
  • membrane becomes depolarised - less negative
  • generator potential formed
  • GP creates an action potential
  • AP transmitted along the SN to the CNS.
24
Q

How is a resting potential created

A
  • sodium potassium pump actively transports Na+/K+ ions (ATP used)
  • 3Na+ moved out
  • 2K+ moved in
  • K+ ions can diffuse out through open K_ ion channels
  • Na+ can’t diffuse in as ‘gated’ Na+ channels closed
  • outside of axon is more positive (more Na+ and K+)
  • axon membrane is polarised
  • creates a resting potential across the membrane of -70mV
25
Q

how is an action potential generated

A
  • neurone has a RP
  • some K+ channels are open
  • VG Na+ closed
  • energy of stimulus triggers some Na+ to open
  • Na+ diffuses into axon down ECG
  • inside of neurone is depolarised
  • more VG Na+ channels opens (change in charge)
  • more Na+ diffuse in (positive feedback)
  • when P.D reaches +40 mV VG Na+ close
  • VG K+ open
  • membrane now permeable to K+
  • K+ diffuses out of axon down ECG
  • charge is reduced
  • inside of axon becomes more negative than the outside
  • Initially lots of K+ diffuse out of axon so inside of axon becomes more negative than RP
  • hyperpolarisation
  • VG K+ close
  • Na+/K+ pump moves Na+ out and K+ in
  • axon returns to RP
  • repolarised.
26
Q

frequency of impulse link to stimulus

A

Higher frequency of impulses means a more intense stimulus

27
Q

saltatory conduction

A
  • AP ‘jumps’ from one node to another as saltatory conduction
  • longer localised circuits
  • less places where channels open and ions move in/out : speeds up AP transmission
  • Repolarisation uses ATP in the pump : reduces repolarisation needed : energy efficient.
28
Q

Factors affecting speed of action potentials

A
  • myelinated
  • axon diameter : bigger the diameter = faster. Less resistance to the flow of ions in the cytoplasm compared to smaller axon
  • temperature : higher temp = faster. ions diffuse faster at high temp . This only occurs up to 40c ; at high temp proteins (pump) can be denatured.
29
Q

All-or-nothing principle

A
  • Power of stimulus isn’t proportional to power of AP
  • If threshold is reached, AP is generated
  • If threshold isn’t reached, AP isn’t generated
  • More intense stimulus = more frequent AP
30
Q

why is the refractory period important

A
  • prevents the propagation of an AP moving backwards along the axon as well as forwards
  • ensures AP are unidirectional
  • ensures AP don’t overlap and occur as discrete impulses.
31
Q

what would happen if a refractory period did not exist

A
  • axon could be immediately depolarised after an AP

- AP could travel backwards/not reach target cell

32
Q

what is the synapse

A

junction between 2 neurones

impulses are transmitted using neurotransmitters

33
Q

synaptic cleft

A

gap that separates the axon of one neurone from the dendrite of the next neurone

34
Q

presynaptic neurone

A

neurone along which the impulse has arrived

35
Q

postsynaptic neurone

A

neurone that receives the neurotransmitter

36
Q

synaptic knob

A
  • swollen end of preS neurone
  • contains mitochondria
  • large amounts of endoplasmic reticulum to enable manufacture of neurotransmitters.
37
Q

synaptic vesicles

A
  • vesicles contain neurotransmitters
  • vesicles fuse with presynaptic membrane
  • release contents into the synaptic cleft.
38
Q

neurotransmitter receptors

A
  • receptor molecules which the neurotransmitter binds to in the postsynaptic membrane.
39
Q

excitatory neurotransmitter

A
  • depolarises the postsynaptic neurone
  • if threshold is reached in the postS membrane - AP is triggered
  • acetylcholine
40
Q

inhibitory neurotransmitter

A
  • hyperpolarisation of the postsynaptic membrane
  • prevents and AP being triggered
  • GABA (gamma-aminobutyric acid) in synapses in the brain
41
Q

transmission across a cholinergic synapse

A
  • arrival of AP at presynaptic end
  • PreS membrane depolarised
  • causes Ca2+ channels to open
  • Ca2+ diffuse into the presynaptic knob
  • synaptic vesicles fuse with presynaptic membrane
  • acetylcholine released into and diffuses across synaptic cleft. (exocytosis)
  • AC binds with receptor sites on Na+ channel in postS membrane
  • Na+ channels open
  • Na+ diffuse in rapidly along CG
  • threshold reached
  • depolarisation triggers an AP
  • effector contracts/secretes
  • Acetylcholinesterase hydrolyses AC into choline+ethanoic acid
  • they diffuse back across synaptic cleft into preS neurone
  • breakdown of AC prevents the continuous generation of a new AP in the postS neurone
  • ATP released by mitochondria is used to recombine choline and ethanoic acid into acetylcholine.
  • stored in synaptic vesicles for future use
  • Na+ channels close in absence of acetylcholine in the receptor sites.
42
Q

role of synapses

A
  • unidirectional transmission
  • cause multiple responses from one stimulus
  • receive multiple stimuli for one response.
  • cell signalling
  • filters low level stimuli
  • prevents over stimulation
43
Q

what is spatial summation

A
  • Several preS neurones connect to one postS neurone.
  • each releases NT
  • which builds up to a high level in the synapse
  • AP triggered in the single postS neurone
44
Q

what is temporal summation

A
  • single preS neurone
  • receives high frequency of AP several times over a short period of time.
  • builds up in synapse until quantity is enough to trigger an AP
45
Q

how do synapses ensure impulses are only transmitted in one direction

A
  • NT receptors only present on the postS membrane

- can only depolarise this membrane to form AP

Bio year 2 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions