Brainscape's Knowledge GenomeTM

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


See full index

Alevel Biology OCR A > 5.1.3 Neuronal Communication COMPLETE > Flashcards

5.1.3 Neuronal Communication COMPLETE Flashcards

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

DEFINITION- Neurone

A

Specialised cells that transmit action potentials from one pat of the body to another

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

DEFINITION- Cell Body

A

Contains the cells nucleus and other organelles

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

DEFINTION- Dendrites

A

Small extensions of cell body, create large SA and carry impulse towards cell body as receive them

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

DEFINITION- Axon

A

Single long fibre that carries nerve impulses away from the cell body

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

DEFINITION- Axon Terminal

A

Release the neurotransmitters into the synapse

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

DEFINITION- Motor Neurone

A

Carries action potential from the CNS to the effector, ie. muscle or gland

Short Dendtrites, Long axon

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

DEFINTION- Sensory Neurone

A

Carries an action potential from sensory receptor to the CNS

Long dendrites, Short Axon

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

DEFINITION- Relay Neurone

A

Connects the sensory and motor neurone

Short axon and dendtrites

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

DEFINITION- Polarised

A

Produce positive and negative charges at opposite ends

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

Depolarisation

A

A reduction in the difference of electrical potential across the plasma membrane. Cell becomes more positively charged as more NA ions flood in, positive feedback. Voltage gated NA channels have opened

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Resting Potential

A

-70V, the potential difference across a membrane when its at rest, maintained by Na and K pumps. Some K channels still open

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

DEFINITION- Threshold Potential

A

Critical level to which a membrane potential must depolarise to, to initiate action potentials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

DEFINITION- Action Potential

A

Change in electrical potential associated with the passage of an impulse along a membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

DEFINITION- Hyperpolarisation

A

K ion gates are slow to shut so too many pass through reducing membrane potential, Na/K pump restores the resting potential.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

DEFINITION- Refractory Period

A

Short period of time where no action potentials are generated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

DEFINITION- Voltage Gated Channels

A

Voltage across a membrane will open/ close the gates

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

DEFINITION- Local Currents

A

Movements of ions along a neurone close to the cell surface membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

DEFINITION- Saltatory Conduction

A

When an action potential only jumps through the Nodes of Ranvier in myelinated neurones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

DEFINITION- Nodes of Ranvier

A

The gaps between the Schwann Cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

DEFINITION- Myelin Sheath

A

Fatty, insulative layers of Schwann cells wrapped around the axon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

DEFINITION- Neurotransmitter

A

A chemical substance which is released at the end of a nerve fibre when a nerve impulse has arrived

22
Q

DEFINITION- Cholinergic Synapse

A

Synapses that use Acetylcholine as their neurotransmitter

23
Q

DEFINITION- Synaptic Knob

A

Where an action potential is converted into a chemical message, interacts with the recipricant neurone

24
Q

DEFINITION- Acetylcholine

A

A neurotransmitter used at the neuromuscular junction

25
Q

DEFINITION- Acetylcholinesterase

A

The enzymes that catalyses the breakdown of acetylcholine

26
Q

DEFINITION- Exocytosis

A

The release of cell contents via a vesicle through diffusion out the exterior membrane

27
Q

DEFINITION- All or nothing

A

Unless the threshold potential (-50V) is reached, no action potential will form

28
Q

DEFINITION- Summation

A

Low level stimuli can be amplified and push multiple neurones into one

29
Q

DEFINITION- Myelinated Neurone

A

Transmits action potentials faster as only travel through the Nodes of Ranvier (100m/s). Has long local currents along with saltatory conduction. Voltage gated NA channels only at the gaps.

30
Q

DEFINITION- Demyelination

A

Damage to the myelin sheath which slows/ stops impulses. Can cause neurological problems

31
Q

DEFINITION- Multiple Sclerosis

A

Progressive disease, causes damage to myelin sheath and affects the CNS

32
Q

DEFINITION- Acclimatisation

A

When the synapse runs out of vesicles due to a prolonged strong stimulus, avoids overstimulation

33
Q

Adaptions of Neurones

A

LONG- transmit over long distance NA/K PUMPS- actively transports 3Na out and 2K in using ATP GATED ION CHANNELS- control the entry and exit of ions ORGANELLES IN CELL BODY- produce the neurotransmitters MYELIN SHEATH- insulates so becomes faster

34
Q

How resting potential is maintained

A

Phospholipid bilayer is impermeable to ions

channel protein pumps 3Na out and 2K in using ATP

second K ion channel so moves faster rate down electrochemical gradient

inside axon is more negative

35
Q

Effect of a stimulus on resting potential

A

triggers the opening of Na channel proteins, casuing a tempory reversal and Na diffuses in

down the electrochemical gradient

36
Q

K Channels opening

A

At 40mV Na channels close but K channels open, both voltage gated

37
Q

Repolarisation

A

K ions diffuse out of the cell down the electrochemical gradient. Inside of the cell becomes negative again so even more K channels open

38
Q

Non Myelinated Neurones

A

Uses local currents and has a refractory period. Action potential moves across as Na gates open as the Na ions moves along the axon away from high conc.

39
Q

Factors Affecting Transmission of action potential

A

MYELIN SHEATH- increases transmission speed due to saltatory conduction, voltage gated Na channels only at nodes of ranvier.

DIAMETER OF AXON- increased diameter means increased speed due to lessened leakage and resistance.

TEMP- increases diffusion rate

REFRACTORY PERIOD- allows recovery, prevents overlap and keeps it to one direction

40
Q

Sensory Receptors

A
  • Specialised cell that detects change in our surroundings
  • Specific to single types of stimuli
  • Energy Transducers convert one form of energy into elecctrical
41
Q

The Pacinian Corpuscle

A
  • Mechanoreceptor in the skin that detects mechanical stimuli
  • The end of the senory neurone is found in the centre of the corpuscle and is surrounded by layers of connective tissue called lamella. seperated by gel
42
Q

How Pacininian corpuscles work

A
  1. When pressure is exerted they change shape
  2. Membrane stretches and Na ion channels open
  3. This depolarises the membrane and forms a generator potential
  4. If large enough it’ll initiate and action potential
  5. This is then transmitted along the CNS
43
Q

Cholinergic Synapses

A
  • Use Acetylcholine as a neurotransmitter
  • Action potentials can’t cross the synpse so they release neurotrasnmitters
44
Q

Transmission across the Synpase

A
  1. Action potential arrives at the synaptic knob
  2. voltage gated Ca ion channels open and they diffuse into the synpatic knob
  3. Causes Synaptic vesicles to move and fuse with presynaptic membrane
  4. Acetylcholine released by exocytosis and they diffuse across the cleft binding to Na+ receptors on post synaptic membrane
  5. Na channels open and Na+ diffuse across postsynaptic membrane into the postsynaptic neurone
  6. A generator potential is created, if there is a sufficent number and it reaches the threshold potential a new action potential is created
45
Q

Acetylcholinesterase

A

Is the enzyme in the synaptic cleft that breaks down the acetylcholine on the postsynaptic membrane.

Breaks down into ethanoic acid and choline

46
Q

Roles of the Synpapse

A
  1. Transmit Information
  2. Unidirectional
  3. Act as junctions
  4. Summation
  5. Acclimatisation
  6. Learning
47
Q

Transmit information

A

Convey impulse from one neurone to the next

48
Q

Unidirectional

A

Postsynpatic membrane has receptors, presynaptic membrane has vesicles. So only moves in one direction

49
Q

Act as junctions

A

DIVERGENCE- allows single stimulus to create many responses

CONVERGENCE- Allows a number of impulses to be combined into a single one e.g. retina

50
Q

Summation

A

TEMPORAL- Low level signals can be amplified, if persistant itll cause the release of many vesicles

SPATIAL- Also casued if several presynaptic neurones ech release acetylcholine into one synapse.

51
Q

Acclimatisation

A

If a stimulus is powerful and prolonged a synapse may run out of vesicles containing neurotransmitter. Said to be fatigued so no longer responds, prevents overstimulation

52
Q

Learning

A

It is believed that synapses have a role in the brain and allow the recall of events.

Alevel Biology OCR A (26 decks)

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