Brainscape's Knowledge GenomeTM

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


See full index

OCR A-Level Biology > Chap 13 - Neural Communication > Flashcards

Chap 13 - Neural Communication Flashcards

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

What are examples of internal changes

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

What are examples of external changes

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

How do animals respond to internal/external changes?

A
  • electrical responses (neurones)
  • chemical responses (hormones)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How do plants respond to changes?

A
  • number of chemical communication systems (including hormones)
  • communication systems must be coordinated to produce required response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does MRS GREN stand for?

A

Movement, Respiration, Sensitivity, Growth, Reproductivity, Excretion, Nutrition

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

Why do organisms need to coordinate?

A
  • as organisms have evolved, they have become specialised to perform specific functions.
  • coordination enables effective operation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is an example of a body system that can work in isolation?

A

the heart can continue to beat if placed in correct bathing solution

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

What is an example of body systems working in coordination? (RBC)

A

red blood cells - transport oxygen effectively but have. no nucleus - so can’t replicate. constant supply of RBC is maintained by haematopoietic stem cells

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

What is an example of body systems working in coordination? (muscle)

A

for muscles to contract, they must constantly respire, requiring constant oxygen supply - cannot transport oxygen so from RBC

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

What is an example of body systems working in coordination (in plants)

A

flowering plants need to coordinate with the seasons, pollinators coordinate with plants - light-sensitive chemicals in plants enables them to coordinate development of flower buds with longer/shorter days

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

Define homeostasis

A

maintaining a constant internal environment - the functions of organs need to be coordinated

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

Give an example of homeostasis

A

digestive organs (eg. exocrine pancreas), duodenum, ileum, endocrine pancreas and liver work to maintain constant blood glucose concentration

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

What systems coordinate activities of organisms

A

nervous and hormonal systems

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

Give 3 other examples of homeostasis

A
  • temperature
  • blood glucose
  • water
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does the coordination rely on

A

cell signalling on a cellular level

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

How does cell signalling work?

A

one cell releases a chemical that effects another cell (known as a target cell)

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

What 2 things can cells do through the process of cell signalling

A
  • transfer signals locally (eg. between neurones and synapses - signal is used as a neurotransmitter)
  • transfer signals across large distances using hormones (eg. cells of pituitary gland secret antidiuretic hormone (ADH) - acts on cells in kidneys to maintain water balance)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Give an example of how plants respond to changes in internal/external environment

A
  • plant stems grow towards a light source to maximise rate of photosynthesis - achieved through hormones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Define stimulus

A

a detectable change in environment

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

What are neurones?

A

specialised cells that transmit impulses in the form of action potentials

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

What is the role of neurones

A

transmit electrical impulses rapidly around the body so that the organism can respond to changes in its internal and external environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the 3 key features of neurones

A
  • cell body
  • axon
  • dendrons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Describe the structure of the cell body of a neuron

A
  • contains nucleus surrounded by cytoplasm
  • cytoplasm has endoplasmic reticulum and mitochondria involved in neurotransmitter production
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Describe the structure of dendrons in a neuron

A
  • short extensions from the cell body
  • divide into smaller brances = dendrites
  • transmit electrical impulses towards the cell body
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Describe the structure of axons in a neuron

A
  • singular, elongated nerve fibres
  • transmit impulses away from the cell body
  • can be long (eg. transmit impulse from tip of toes to spinal cord)
  • cylindrical shape with narrow regin of cytoplasm surrounded by plasma membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the 3 types of neurones?

A
  • sensory neurones
  • motor neurones
  • relay neurones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Describe sensory neurones and their function

A
  • transmit impulses from sensory receptor cell to relay & motor neurones or the brain
  • one dendron - carries impulse to cell body
  • one axon - carries impulse away from cell body
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Describe motor neurones and their function

A
  • transmit impulses from relay neuron or sensory neuron to an effector
  • one long axon and many short dendrites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Name 2 types of effectors

A
  • muscles
  • glands
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the myelin sheath made of?

A

layers of plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How are the layers of plasma membrane made?

A
  • schwann cells grow around the axon many times
  • each time they grow around the axon, a dounle layer of phospholipid bilayer is laid down
  • when it stops, there will be >20 layers of membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What does the myelin sheath do?

A
  • acts as an insulating layer
  • allows myelinated neurones to conduct electrical impulse at faster speed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How fast can myelinated neurones transmit impulses

A

100 metres per second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

How fast can non-myelinated neurones transmit impulses

A

1 metre per second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

How big is the gap between schwann cells (node of Ranvier)

A

2-3 micrometers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is saltatory conduction?

A

where the electrical impulse jumps from one node to the next in myelinated neurones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What does the central nervous system include?

A

the brain and the spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What does the peripheral nervous system include?

A

all neurones that connect the CNS to the rest of the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is the somatic nervous system?

A

when you voluntarily decide to do something under conscious control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is an example of the somatic nervous system

A

when you decide to move a muscle in your arm - impulses are carried to the muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is the autonomic nervous system

A

when the body does something automatically under sub-conscious control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is an example of the autonomic nervous system

A
  • heart beat
  • carrying nerve impulses to glands, smooth muscle and cardiac muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What happens in the parasympathetic nervous system

A

outcomes decrease activity (eg. decrease in heart rate after exercise)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What happens in the sympathetic nervous system

A

outcome increases activity (eg. fight-or-flight response)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

How many neurones does the human brain contain?

A

approx. 86 billion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is the brain responsible for?

A

processing information collected by receptor cells
- receives info from hormonal system through molecules in the blood - then produces coordinated response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What is a benefit of having one central control centre?

A

communication between neurones is faster than if multiple were placed around the body (exludes reflex actions)

47
Q

Where are all nervous reactions processed?

A

in the brain - excluding reflex actions

47
Q

What is the brain surrounded by

A

the skull and protective membranes - meninges

47
Q

What are the 5 main areas of the brain?

A
  • cerebrum
  • cerebellum
  • medulla oblongata
  • hypothalamus
  • pituitary gland
48
Q

What does the cerebrum do?

A

receives sensory information, interprets it and sends impulses along motor neurones to effectors - produces effective response

49
Q

The cerebrum is highly convoluted, why is this important?

A

it increases surface area and therefore space for complex activity

50
Q

How thick is the outer layer of the cerebrum

A

2-4mm thick

51
Q

Where do sophisticated processes (eg. reasoning + decision making) occur?

A

in the frontal/prefrontal lobe

52
Q

What are the two halves of the cerebrum called and what do they control

A

cerebral hemispheres - each controls one half of the body (mirrored)

53
Q

The size of the sensory area is proportional to…

A

the number of receptor cells present in the body part

54
Q

What happens to info in the cerebrum?

A
  • each sensory area receives info from receptors in sense organs
  • info passed on to other areas (association areas) to be analysed and acted upon.
  • impulses move into motor areas where motor neurones send impulse (eg. to move skeletal muscles)
55
Q

The size of the motor area is proportional to…

A

the number of motor endings in it

55
Q

What is the primary region that controls movement

A

primary motor cortex in the back of the frontal lobe

56
Q

How do impulses cross?

A

left hemisphere receives impulses from the right side of the body (vice versa)
- eyes help with the collection of the information - helps judge balance and perspective

57
Q

What does the cerebullum control?

A

muscular movement, body posture, balance
- does not initiate movement but coordinates it

58
Q

What happens if the cerebellum becomes damaged?

A

causes jerky and uncoordinated movement

59
Q

How does the cerebellum work

A
  • receives info from organs of balance (in ears) and about tone of muscles and tendons
  • info is relayed to areas of cerebral cortex involved in motor control
60
Q

What does the medulla oblongata contain?

A

important regulatory centres of the ANS

61
Q

How is the body able to detect changes in environment?

A

sensory receptors

62
Q

Where are sensory organs located?

A

eyes and ears

63
Q

What are the 2 features of sensory receptors

A
  • specific to single type of stimulus
  • act as a transducer - convert stimulus into nerve impulses
64
Q

What types of stimuli do sensory receptors detect?

A

light, heat, sound, pressure

65
Q

Describe mechanoreceptors

A

stimulus: pressure and movement
example of receptor: Pacinian corpuscle
detects: pressure
sense organ: skin

66
Q

Describe chemoreceptor

A

stimulus: chemicals
receptor: olfactor receptor
detects: smell
sense organ: nose

67
Q

Describe thermoreceptors

A

stimulus: heat
receptor: end-bulbs of Krause
sense organ: tongue

68
Q

Describe photoreceptors

A

stimulus: light
receptor: cone cell
detects: different light wavelengths
sense organ: eye

69
Q

What is a generator potential?

A

the nerve impulse that has been converted from the stimulus

70
Q

What is an example of generator potential

A

a rod cell (in the eye) responds to light and produces a generator potential

71
Q

What is a transducer?

A

converts stimulus into a nerve impulse

72
Q

What are Pacinian corpuscles?

A

specific sensory receptors that detect mechanical pressure

73
Q

Where are Pacinian corpuscles located? Where are they most abundant?

A
  • deep in the skin
  • most abundant in fingers and soles of feet
  • also in joints - enables you to know which joints are changing direction
74
Q

What is resting potential

A

when a neurone is not transmitting an impulse, the potential difference is known as resting potential

75
Q

What is potential difference?

A

the difference in charge between the inside and outside of the axon

76
Q

What are the charges of a neurone in resting potential

A

outside of the membrane is more positive than the inside (slightly negative)

77
Q

Why is the membrane considered polarised?

A

because it has a potential difference across it

78
Q

Whaty is the sodium channel called

A

stretch-mediated sodium ion channel

79
Q

How does the Pacinian corpuscle convert mechanical pressure into a nervous impulse

A
  1. in resting state, stretch-mediated sodium channel are too narrow to allow sodium ions to pass through - the neuron has a resting potential
  2. when pressure is applied, corpuscle changes shape - membrane surrounding neurone stretches
  3. when membrane stretches, sodium ion channels widen. sodium can diffuse into neurone now
  4. influx of Na+ changes potential of membrane - becomes depolarised - results in generator potential
  5. generator potential creates action potential that passes along sensory neurone
80
Q

what is a synapse

A

gaps between axon end of one neuron and dendrite of an adjacent neurone

81
Q

how are synapses involved in action potentials?

A

the action potential is transmitted as a neurotransmitter which diffuses across a synapse

82
Q

what does axon terminal button contain?

A
  • vesicles containing neurotransmitters
  • neurotransmitter reuptake pump
  • gated Ca2+ channels
83
Q

why are impulses at synapses unidirectional

A
  • neurotransmitters are only released from presynaptic neurones
  • receptors for neurotransmitters are only on post synaptic neurones
  • so neurotransmitters can only activate action potentials in the post synaptic neurone
84
Q

what is a neuromuscular junction

A

the synapse between a motor nerve and a muscle

85
Q

what is a sarcolemma

A

plasma membrane which surrounds a muscle cell

86
Q

what is the motor end plate

A

the part of the sarcolemma which faces the synapse

87
Q

how does transmission work at a neuromuscular junction

A
  • action potential reaches neuromuscular junction
  • vesicles of acetylcholine fuse with presynaptic membrane
  • acetylcholine diffuses across synapse and binds with receptors of post synaptic neurone
  • allows Na+ to enter muscle which brings about contraction
88
Q

what is divergence

A

one neurone releases neurotransmitter to many neurones

89
Q

what is convergence

A

many neurones release neurotransmitters to one neurone

90
Q

what is an excitatory post synaptic potential?

A
  • action potential passes down axon to synapse
  • causes a few vesicles to move and fuse with pre synaptic membrane
  • small number of acetylcholine molecules produces small depolarisation
  • alone not sufficient enough to cause action potential
91
Q

what is summation

A

the combined effect of several EPSPs to increase membrane depolarisation to reach threshold and cause action potential

92
Q

what is spatial summation

A

when two or more presynaptic neurones converge and release neurotransmitters at the same time onto the same post synaptic neurone
- small amount released from each can be enough altogether to reach threshold and trigger action potential

93
Q

what is temporal summation

A

when two or more nerve impulses arrive in quick succession from same presynaptic neurone
- action potential is more likely because more NT is released into synapse

94
Q

how is the potential difference across a membrane achieved?

A

distribution of ions (Na+, K+)

95
Q

what is the role of the sodium potassium ion pump

A

uses ATP to pump 3 sodium ions out of the cell and 2 potassium ions into the cell
- net movement of one cation outwards

96
Q

…… potassium ion channels allow K+ out by facilitated diffusion
…… sodium ion channels allow Na+ in by facilitated diffusion

A

many
fewer

97
Q

how do metabolic poisons work

A

blocks respiratory pathways and prevent formation of ATP so K+/Na+ pump cannot function

98
Q

describe how the resting potential of a neurone is maintained

A
  • active transport of Na+ out and K+ in
  • membrane less permeable to Na+
  • less Na+ come in and more K+ leave
99
Q

what are voltage gated channels

A

open and close depending on potential differences across membrane

100
Q

during action potential, the voltage gated Na+ channels open which changes ………

A

permeability of membrane so Na+ ions rush into axon

101
Q

what happens when the sodium channels open

A
  • depolarisation
  • Na+ enter and membrane becomes more positive
102
Q

what is the change in voltage of depolarisation

A

-70 to +40mV

103
Q

describe depolarisation

A
  • Na+ channels open
  • increased Na+ ions diffuse in
  • triggers more channels to open and more Na+ to enter
104
Q

what is meant by an action potential

A

when the neurones voltage increases beyond a set point from the resting potential, generating a nervous impulse

105
Q

when will an action potential be generated

A

if a threshold is reached
-55mV

106
Q

describe repolarisation

A
  • Na+ channels close
  • no more Na+ entering but K+ still leaving so voltage decreases
107
Q

describe hyperpolarisation

A
  • more K+ channels are open
  • voltage becomes more negative than resting potential
108
Q

why is there no stimulation in the refractory period

A
  • ensures discrete impulses are produced separately
  • ensure action potential travels in one direction
  • limits number of impulse transmission which prevents overreaction
109
Q

what is the status of the K+ and Na+ channels at resting potential

A

closed

110
Q

when do Na+ channels open

A

depolarisation

111
Q

when do K+ channels open

A

repolarisation

112
Q

what is meant by the all or nothing principle

A

a stimulus only causes voltage gated ion channels to open if it exceeds the threshold level
- all Na+ channels open if threshold reaches
- all action potentials are always same size (level of depolarisation is always +40mV) no matter the stimulus intensity

113
Q

what is the difference between intense and weak stimuli

A

intense stimuli cause many frequent action potentials

OCR A-Level Biology (16 decks)

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