Brainscape's Knowledge GenomeTM

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


See full index

ocr biology > 5.1 communication and homeostasis > Flashcards

5.1 communication and homeostasis Flashcards

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

How does a stimulus travel in the nervous system?

A

stimulus - receptors - central nervous system - effectors - response

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

what are sensory receptors and what do they do

A

convert energy of a stimulus (light or chemical energy) into electrical energy used to send nerve impulses
-act as transducers

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

describe the neurone when is at resting state

A

difference in charge across membrane, there is a voltage
also called potential difference
at rest resting potential

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

how is the difference in charge generated

A

by ion pump and ion channels

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

what does happen to the resting potential when the membrane is excited?

A
  • membrane becomes more permeable
  • more ions movement
  • change in potential difference, GENERATOR PETENTIAL
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what happens with a bigger generator potential?

A
  • membrane more excited
  • more permeable
  • bigger ions movement
  • bigger change
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what happens when generator potential is big enough ?

A

triggers an action potential

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

what is a pacinian corpuscle

A

a mechanic receptor, detects mechanical stimuli (pressure and vibration)

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

structure of pacinian corpuscle

A
  • contain end of sensory neurone, sensory nerve ending

- wrapped in layers of connective tissue; LAMELLAE

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

what happens when the pacinian corpuscle detects a stimulus?

A
  • lamellae deform pressing on sensory nerve ending
  • causing the deformation of stretch-mediated sodium channels (in neurone membrane)
  • sodium channels open
  • sodium ions diffuse into the cell
  • generator potential is created
  • if reaches the threshold potential it will trigger an action potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

three types of neurone

A

sensory, motor, relay

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

describe sensory neurone

A
  • many short dendrites, one long dendron
  • one short axon
  • from receptor cells (cell body) to cns
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

describe motor neurone

A
  • many short dendrites
  • one long axon
  • from cns (cell body) to effector cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

describe relay neurone

A
  • many short dendrites
  • many short axons
  • from sensory neurones (cell body) to motor neurones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how is the membrane said to be when at rest

A

polarised

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

how much is the resting potential

A

-70mV

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

how is the resting potential maintained

A

sodium potassium pump

potassium ion channel

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

how does the sodium potassium pump works

A

3 sodium ions are actively pumped out of the membrane which isn’t permeable to sodium ions, they can’t diffuse back in
-SODIUM ION ELECTROCHEMICAL GRADIENT is more positive inside
2 potassium ions are pumped in membrane which is permeable to potassium ion and they can diffuse out

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

how do potassium ion diffuse out of the membrane?

A

potassium ion channel

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

how is the charge of the membrane during resting potential

A

the outside of the membrane is positively charged compared to the inside

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

which are the 5 stages of an action potential?

A
  1. stimulus
  2. depolarisation
  3. repolarisation
  4. hyperpolarisation
  5. resting state
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what does a stimulus do to the neurones membrane

A
  • excites it
  • sodium ions channels open
  • membrane more permeable to sodium ions
  • diffuse down sodium ion electrochemical gradient
  • diffuse inside the neurone
  • inside of the membrane becomes less negative
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what happens during depolarisation

A

If potential difference reaches the threshold potential
voltage-gated sodium channels open
more sodium ions enter the cell, positive feedback

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

how much is the threshold potential

A

-55mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what happens during repolarisation

A
  • when potential difference is around 33mV sodium channels close
  • potassium channels open
  • membrane becomes more permeable to potassium ions
  • potassium ions diffuse out down the potassium ions concentration gradient
  • membrane starts to enter in resting potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what happens during hyperpolarisation

A
  • potassium ions channels are slow to close
  • for a bit too many potassium ions diffuse out
  • potential difference is more negative than resting potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what happens during the resting state

A
  • membrane is at resting potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is the refractory period

A

when membrane can’t be excited again yet because channels are recovering

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

when are the ions channel in refactory period?

A

sodium ions channels during repolarisation are closed

potassium ions channels are closed during hyperpolariasation

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

how does an action potential move along the neurone?

A

wave of depolarisation

  • sodium ions enter and diffuse side ways
  • causes sodium ions channel in next region to open
  • moves away from parts in refractory
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what does all-or-nothing mean?

A
  • if threshold potential is reached action potential will always fire
  • if not it won’t
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what does a bigger stimulus do to an action potentials

A

action potentials isn’t bigger

will cause to fire action potentials more frequently

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what are myelinated neurones, whats their structure?

A
  • have a myelinated sheath made of Swann cells

- between Swann cells there are nodes of Ranvier (small gaps) where sodium ions channels are concentrated

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

how do action potential travel in myelinated neurones

A
  • depolarisation only happens in nodes
  • neurones cytoplasm conducts enough electrical charge to depolarise next node
  • impulse ‘jumps’ from node to node - SALTATORY CONDUCTION
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what are synapses

A

junctions between neurones or neurone and effector cells

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

what are synapses that use Ach called?

A

cholinergic synapses

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

how is the gap called

A

synaptic clef

38
Q

how is the swelling at the end of presynaptic neurone called

A

synaptic knob

39
Q

how do cholinergic synapses work?

A
  • action potential reaches ent of presynaptic neurone
  • acetylcholine released in synaptic clef
  • bind to cholinergic receptors
  • trigger an action potential in postsynaptic neurone
40
Q

what happens to neurotransmitters that remain in clef?

A
  • go back in presynaptic neurone

- broken down by enzyme

41
Q

how is acetylcholine removed from clef

A

an enzyme (acetylcholinesterase) it down

42
Q

how do synapses work?

A
  1. action potential arrives at the synaptic knob
    - stimulates voltage gated calcium ion channels to open
    - calcium ion diffuse in (pumped out afterwards - active transport)
  2. influx of calcium ions move vesicle
    - fuse with presynaptic membrane - exocytosis
    - neurotransmitters in synaptic clef
  3. bind to specific receptors in post synaptic membrane
    - cause sodium ion channels to open
    - sodium ions influx causes depolarisation
    - action potential generated if threshold is reached
  4. neurotransmitters removed from clef so that response doesn’t keep happening.
43
Q

how do synapses interact together

A
  • convergence
  • divergence
  • summation
44
Q

describe divergence

A

one neurone connects to many neurones

-info is dispersed in different parts of the body

45
Q

describe convergence

A

many neurones connect to one

-information is amplified

46
Q

what is summation?

A

combination of effect of neurotransmitters combined to reach the threshold potential.

47
Q

how can summation be?

A

spatial

temporal

48
Q

describe spatial summation

A

convergence

signals from different stimulus combined

49
Q

describe temporal summation

A

2 or more impulses in quick succession from the same presynaptic neurone

  • more neurotransmitters released in clef
  • action potential is more likely to happen
50
Q

how do synapses ensure that impulse travels in one direction

A

having receptors only in post synaptic membrane.

51
Q

which are the components of the hormonal system?

A

endocrine glands and hormones

52
Q

what are hormones

A

chemical messengers

  • proteines/peptides
  • steroids
53
Q

who are endocrine glands stimulated?

A

change in concentration of a substance

electrical impulses

54
Q

what happens what endocrine glands are stimulated?

A

hormones are secreted directly into the blood
and diffuse out all over the body, bind to specific receptors in target cells
they will give a response

55
Q

what is hormone said to be and why

A

first messenger

carries message from endocrine glands to receptors

56
Q

what happens when an hormone binds to a receptor?

A

activates an enzyme in cell membrane that catalyses the production of a signalling molecule (inside cell)

57
Q

(hormonal communication) what is the signalling molecule said to be?

A

second messenger

58
Q

(hormonal communication) what does the signalling molecule do

A

single mother parts to change how cell works

activates a cascade inside cell

59
Q

adrenal gland, whats the first messenger

A

adrenaline

60
Q

what does adrenaline do once released

A

binds to receptors and activates adenylyl cyclase (enzyme)

61
Q

what does adenylyl cyclase do

A

catalyses the production of the second messenger

62
Q

adrenal gland, what is the second messenger?

A

cyclic AMP from ATP

63
Q

what does cyclic AMP do?

A

activate a cascade to break down glycogen into glucose, more energy

64
Q

where are adrenal gland found?

A

above kidneys

65
Q

structure of adrenal gland

A

2 parts, cortex and medulla

66
Q

what does the cortex of adrenal gland secrete?

A

steroids hormones eg. cortisol / aldosterone

67
Q

steroid hormones secreted by adrenal gland are a response to?

A

short term and long term stress

68
Q

what is the body response to steroid hormones released by adrenal gland?

A
  • stimulate the break down of proteins and fats, more glucose available
  • increase blood volume and pressure by increasing the uptake of sodium ions and water by kidneys
  • suppressing immune system
69
Q

what does the medulla of adrenal gland secrete?

A

catecholamine hormones (adrenaline/ noradrenaline)

70
Q

what does adrenaline cause in the body and how

A

make more energy in short-term

  • increase heart and breathing rate
  • cause break down of glycogen into glucose
  • constricting some blood vessels, blood diverted into brain and muscles
71
Q

what area of the pancreas contains endocrine tissue?

A

islets of Langerhans

72
Q

where are islets of langerhans found?

A

around blood capillaries

73
Q

where do islets of langerhans secrete the hormones

A

directly into the blood

74
Q

what are the 2 type of cells is islets of langerhans &what do they secrete

A

alpha cells secrete glucagon

beta cells secrete insulin

75
Q

disease where blood glucose concentration can’t be controlled

A

diabetes mellitus

76
Q

describe type 1 diabetes

A
  • auto-immune disease, body attack and destroys beta cells
  • insuline isn’t produced
  • if blood glucose concentration increases it will stay high
  • kidneys can’t reabsorb all glucose, some is excreted in urine
  • usually develops in children or young adults, links to family history
77
Q

treatments for type 1 diabetes

A

insuline therapy
islets transplantation
monitor blood glucose concentration

78
Q

describe insuline therapy

A

regular insulin injections during the day

or insuline pump, machine with a tube that releases insulin in body through a tube

79
Q

describe islets transplantation

A

pancreas produces more insulin

80
Q

how do we monitor blood glucose concentration

A

healthy and balanced diet

activity, regular exercise

81
Q

describe type 2 diabetes

A
  • beta cells don’t produce enough insulin or insulin receptors don’t work properly
  • blood glucose concentration is higher than normal
  • develops alter in life and is linked with obesity
  • increased chances if African /asian/family history of disease
82
Q

treatments for type 2 diabetes

A

life style changes
medication
insuline therapy

83
Q

describe medication to treat type 2 diabetes

A

-metformin, acts on livers cells,
reduces the amount of glucose released
increase sensibility of cells to insulin, more glucose is taken up
-sulfonylureas stimulates production of insulin
-thiazolidinediones makes body cells more sensitive to insulin

84
Q

where was insulin taken from for insulin therapy in the past?

A

pig pancreas

85
Q

where is insulin taken from for insulin therapy nowadays ?

A

made by genetically modified bacteria

86
Q

what are the advantages of using genetically modified bacteria for insulin

A

cheaper
larger quantities are produced
allergic responses or rejection are less likely
ethical religious reasons

87
Q

what other therapy is being developed to treat diabetes

A

stem cells

grown into beta cells

88
Q

whats the normal blood glucose concentration?

A

90 mg per 100cm2

89
Q

how does blood glucose concentration rises and fall

A

rises by eating carbohydrates

falls with exercise - more glucose used in respiration

90
Q

which are the two hormones that control blood glucose concentration?

A

glucagon

insuline

ocr biology (5 decks)

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