Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

biology > Biology Topic 6.1: stimuli and response > Flashcards

Biology Topic 6.1: stimuli and response Flashcards

- survival and response - nervous communication - response in plants - receptors - control of heart rate (61 cards)

Start Studying
1
Q

what do receptors do

A

convert the energy of the stimulus into the electrical energy used by neurones

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

what are types of receptors

A

ex: photoreceptors that connect to nervous system

ex: glucose receptors are proteins found in the cell membrane of pancreatic cells

specific to a stimulus and different types

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

what are the stages of how a receptor works

A
  • resting potential
  • the generating potential
  • the action potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what occurs in the resting potential

A
  • difference in charge between inside and outside of cell (inside = negative)
  • means there is a voltage (potential difference) across the membrane
  • potential difference when is a cell is at rest =. resting potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the resting potential generated by

A

sodium - potassium pumps and potassium ion channels

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

what occurs in generator potential

A
  • stimulus detected

-cell membrane is excited = becomes more permeable

  • more ion movement inside and outside
  • alters potential difference
  • a larger stimulus = larger movement of ions = larger generator potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the generator potential

A

change in potential difference due to a stimulus

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

what is the action potential

A

-big enough generator potential = reached certain threshold = triggers action potential

  • strength of a stimulus measured on frequency of action potential as action potential are all one size
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the action potential

A

an electrical impulse along a neurone

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

what type of stimuli does the pacinian corpuscles detect

A

mechanical stimuli

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

what stimulus does the pacinian corpuscles work on

A

pressure and vibrations

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

where is the pacinian corpuscles found

A

found in the skin

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

what is the structure of the pacinian corpuscles

A

contains end of sensory neurone = sensory nerve ending

sensory nerve ending wrapped in loads of layers of connective tissue = lamellae

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

how does the pacinian corpuscle work

A

lamellae deforms = presses on sensory nerve ending

sensory neurone cell membrane to stretch

deforms stretch-mediated sodium ion channels

channel opened sodium ion diffuses into the cell = creating generator potential

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

what is the structure of the back of the eye

A

retina = contains many photoreceptor cells

fovea = area of retina with lots of photoreceptor cells

optical nerve = carries nerve impulses from retina to brain
optic nerve is a bundle of neurons

blind spot - area where optic nerve leaves the eye= no photoreceptor cells = not sensitive to light

bipolar neurones = connect photoreceptors to optic nerve

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

how does the eye detect light to control the iris?

A
  • light hits the photoreceptors
  • and absorbed by light-sensitive optical pigments
  • light bleaches pigments
  • causes chemical change = alters permeability of membrane
  • generates a generator potential
  • if threshold reached nerve impulse sent a;ong bipolar neurone
  • then sent to brain via the optic nerve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are the types of photoreceptors

A

rods and cones

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

where are the rods found

A

peripherel part of retina

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

where are cones found

A

packed together in the fovea

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

what is the difference between the rods and cones

A
  • contain different optical pigments = sensitive to different wavelengths
  • rods give info. in black and white (monochromatic)

-cones give info. in colour (trichromatic vision)

-rods are sensitive to light

-cones less sensitive to light

-rods give low visual acuity

  • cones have a high visual acuity

rods found on peripheral mainly

cones found in fovea

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

what are the three types of cones

A
  • red sensitive
  • green sensitive
  • blue sensitive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

why do rods work well in dim light

A

rods are sensitive to light as many rods join one bipolar neuron therefore many weak generator potentials combine to reach threshold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

why do cones work better in brighter light

A

less sensitive to light as one cone joints one bipolar neuron so it takes more light to reach threshold

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

why do rods give low visual acuity

A

many rods join one bipolar neurone so light from two points close together can’t be told apart
brain doesn’t get separate info.on two close points

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
why do cones have a high visual acuity
light from two points hits two cones = two action potential go to brain so two separate points can be distinguished
26
what does the somatic nervous system and automatic nervous system control and which main system is it apart of
-the peripheral nervous system -controls conscious activities = somatic - controls unconscious activities = automatic
27
what is the autonomic nervous system split into
sympathetic and parasympathetic
28
what is the sympathetic nervous system
fight or flight mode = gets body ready for action
29
what does the parasympathetic nervous system control
'rest and digest' system = calms the body down
30
what does myogenic mean
means that it contracts and relaxes without receiving signals from nerves (heart muscles)
31
where is the SAN (sinoatrial node) found and what is it
found in wall of the right atrium it is a small mass of tissue
32
what does the SAN do
like a pacemaker sets rhythm of the heartbeat by sending out regular waves of electrical activity to the atrial walls = contraction of right and left at same time
33
what stops the electrical impulse of the SAN causing the ventricles to contract
a band of non-conducting collagen tissue prevents the waves of electrical activity to be passed from atria to ventricles instead passed from SAN to AVN (atrioventricular node) directly
34
what does the AVN do
passes the waves of electrical activity on to the bundle of His
35
why is there a slight delay before the AVN reacts
to make sure the atria have emptied before ventricles contract
36
what is the bundle of His
a group of muscle fibres responsible for conducting the waves of electrical activity between ventricles to the apex (bottom of heart)
37
how does the bundle of His conduct the waves of electrical activity between ventricles to the apex
bundle of His splits into finer fibres in right and left ventricles = Purkyne tissue purkyne tissues carries electrical activity into muscular walls of right and left ventricles = contract simultaneously from bottom up
38
what control the rate at which the SAN fires
the medulla
39
what are internal stimulus detected by
pressure and chemical receptors
40
what are pressure receptors called and where are they found and what are they stimulated by
called baroreceptors in aorta and carotid arteries (major arteries in the neck) stimulated by high and low blood pressure
41
what are chemical receptors called and where are they found and what are they stimulated by
chemoreceptors in the aorta, carotid arteries and in medulla monitor oxygen levels in blood and carbon dioxide and PH
42
what is the process of controlling the heart rate when there is a high blood pressure
baroreceptors detect it send impulses along sensory neurons to medulla which send impulses along parasympathetic neurons these secrete acetylcholine which binds to receptors on SAN this causes heart rate to slow down
43
what is the process of controlling the heart rate when there is a low blood pressure
baroreceptors detect it send impulses along sensory neuron to medulla sends impulse along sympathetic neuron these secrete noradrenaline binds to receptors on SAN causes heart rate to speed up
44
what are acetylcholine and noradrenaline
types of neurotransmitters
45
what is the process of controlling the heart rate when there is a high blood oxygen,low carbon dioxide, high blood PH levels
chemoreceptors detect chemical change in blood send impulses along sensory neurone to medulla send impulse along parasympathetic which secret acetylcholine bind to receptors on SAN causes heart rate to decrease
46
what is the process of controlling the heart rate when there is a low blood oxygen,high carbon dioxide, low blood PH levels
chemoreceptors detect chemical change in blood send impulses along sensory neuron to medulla send impulse along sympathetic which secret noradrenaline bind to receptors on SAN causes heart rate to increase
47
during resting potential what is the movement of the sodium- potassium pump and the potassium channel
- sodium- potassium pump uses active transport - moves 3 sodium ions out and two potassium in -membrane not permeable to sodium ions so sodium ions cannot diffuse back in -creates a electrochemical gradient = a concentration gradient of ions as it is more positive sodium ions outside than inside - potassium ion channels allow facilitated diffusion of potassium ions out of neuron down concentration gradient (more negative inside the cell) - at rest more potassium ion channels open= cell membrane is permeable to potassium ions so some diffuse back out through potassium ion channels -high proportion of ions move out then enter so outside of cell is positive
48
what is the stages of the change in potential difference across a neuron cell membrane during an action potential
stimulus depolarisation repolarisation hyperpolarisation resting potential
49
what is the change in potential difference across a neuron cell membrane during an action potential stimulus stage
- stimulus excites neurons cell membrane = more permeable -sodium ions diffuse into neuron down electrochemical gradient -inside of neuron less negative
50
what is the change in potential difference across a neuron cell membrane during an action potential depolarisation stage
if potential difference = threshold more sodium ion channels open more sodium ions diffuse into neuron
51
what is the change in potential difference across a neuron cell membrane during an action potential repolarisation stage
at P.D of around +30mV the sodium ion channels close otherwise membrane would remain depolarised potassium ions channels open membrane more permeable to potassium so potassium diffuses out of neuron down conc. gradient strats to get back to resting potential
52
what is the change in potential difference across a neuron cell membrane during an action potential hyperpolarisation stage
potassium ion channels slow to close = slight 'overshoot' where too many potassium ions diffuse out of neuron P.D becomes more negative than resting potential
53
what is the change in potential difference across a neuron cell membrane during an action potential resting potential stage
ion channels are reset sodium -potassium pump returns membrane to its resting potential by pumping sodium ions out and potassium ions in maintains resting potential until another stimulus excites membrane
54
what is the refractory period
after action potential neuron cannot be excited again right away ions channels are recovering
55
what is the wave of depolarisation
some of the sodium ions that enter the neuron go sideways triggering the sodium ion channel to open in another part of the neuron creating a wave of depolarisation this wave moves away from the area under the refractory period
56
what is the all or nothing principle
once threshold is reached an action potential will always fire with the same change in voltage no matter how big stimulus is a bigger stimulus will cause the action potential to be fired more frequently and will not cause a bigger action potential
57
what are the factors affecting the speed of conduction of the action potential
myelination axon diameter temperature
58
what is the structure of the neurons in the peripheral nervous system
in peripheral nervous system the myelin sheath is made up of a cell called a Schwann cell between schwann cells = tiny bare patches called nodes of ranvier sodium ion channels concentrated at nodes of ranvier
59
how does myelination affect the speed of conduction of the action potential
saltatory conduction occurs -depolarisation only happens at the nodes of ranvier in a myelinated neuron - neurons cytoplasm conducts enough electrical charge to depolarise the next node - so impulse jumps node to node on non-myelinated neuron impulse travels as wave along the whole length of axon depolarisation occurs through whole length this process is slower than saltatory conduction
60
how does the axon diameter affect the speed of conduction of the action potential
action potential conduction is quicker in axons with larger diameters - less resistance to the flow of ions than in cytoplasm of smaller axon - depolarisation can reach other parts of neuron quicker therefor
61
how does the temperature affect the speed of conduction of the action potential
speed of conduction increases and temperature increases bc ions diffuse faster after around 40 degrees protein begins to denature and speed decreases

biology (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions