14 response to stimuli Flashcards
1
Q
what is a stimulus?
A
a detectable change in environment, either external or internal
2
Q
what is an effector?
A
responds to stimulation by the nerve cells
3
Q
give an example of an effector
A
muscle
gland
organ
cell
4
Q
why do organisms respond to changes in their environment?
A
to increase survival and reproduction by:
1. DISPERSING TO FIND NEW MATES
2. avoiding harmful environments
3. stay in favourable environment
5
Q
is instinctive behaviour learned or inherited?
A
inherited
6
Q
what are the types of simple responses to stimuli?
A
kinesis
taxes
reflex action
7
Q
what is kinesis?
A
random movement responding to a change in stimulus by increasing or decreasing activity
change in rate of movement
8
Q
give an example of kinesis
A
woodlice move around more when humidity is dry and the rate of movement is related to the intensity of the stimulus
9
Q
what experiment would you use to investigate kinesis?
A
choice chamber
10
Q
what statistical test would be used for a choice chamber?
A
chi squared
11
Q
how do you calculate degree of freedom and what is the dof for a basic choice chamber?
A
n-1 so 3 for choice chamber
12
Q
what is taxes?
A
directional movement towards or away from a stimulus
13
Q
what are the types of taxes?
A
positive and negative
14
Q
what is positive taxes?
A
movement towards the stimulus
15
Q
what is negative taxes?
A
movement away from the stimulus
16
Q
give an example of negative taxes
A
earthworms move away from light to find food and avoid predators
17
Q
what are the types of tropism?
A
positive and negative
18
Q
what is positive tropism?
A
growth towards a stimulus
19
Q
what is negative tropism?
A
growth away from a stimulus
20
Q
what does the prefix ‘halo’ mean?
A
salt
21
Q
what does the prefix ‘geo’ mean?
A
gravity
22
Q
what does the prefix ‘photo’ mean?
A
light
23
Q
what does the prefix ‘hydro’ mean?
A
water
24
Q
give an example of positive phototropism
A
plant shoots grow towards light
25
give an example of negative phototropism
plant root grow away from llight
26
what is a similarity between tropism and taxes?
both are directional
27
what is a difference between tropism and taxes?
tropism is part of the organism whereas taxes is al of the organism
28
what do plant growth factor do?
regulate growth in response to stimuli
29
give 2 examples of plant growth factors
gibrellins and indole acetic acid
30
what do gibrellins do?
promotes seed germination
31
where does mitosis occur in plants?
tip of shoots
tip of roots
32
what does IAA stand for?
indole acetic acid
33
what does IAA do in the shoots of plants?
promotes cell elongation
34
what des IAA do in the roots?
inhibits cell elongation
35
explain what happens with IAA in the shoots of plants and light
1. IAA synthesised in shoot tips
2. IAA diffuses into elongation region
3. light causes IAA to move to shady side
4. high conc of IAA on shady side
5. causes greater cell elongation on shady side and for shoot to grow faster and bend towards light
36
explain what happens with IAA in the roots of plants and light
1. IAA synthesised in root tips
2. IAA diffused into elongation region
3. light causes IAA to move to shady side
4. high conc of IAA on shady side
5. cell elongation inhibited on shady side so roots grow away from light and towards gravity
37
where is IAA synthesised?
in the root tips and shoot tips
38
what is tropism?
a growth movement of part of a plant in response to a DIRECTIONAL STIMULUS
39
what is a reflex arc?
an example of behaviour that a certain stimulus produces a specific short lived response
40
are reflex arcs learnt?
no
41
explain the advantages of simple reflex arcs
1. rapid
2. protect against damage to body tissue
3. don't have to be learnt
4. help escape from predators
5. enable homeostatic control
42
what is a receptor called that is found deep in the skin?
pacinian corpuscle
43
what is the pacinian corpuscle an example of?
pressure receptor/mechanoreceptor
44
what is a pressure receptor?
a receptor that responds to mechanical stimuli
45
what are 5 places the pacinian corpuscle is found?
1. fingers
2. soles of feet
3. external genitalia
4. joints
5. ligaments
46
describe the structure of a pacinian corpuscle
unmyelinated axon layered with lamellae with a myelinated axon coming from it
47
what is the lamellae in the pacinian corpuscle filled with?
viscus gel/jelly
48
what is the lamellae that surrounds the axon of a pacinian corpuscle sometimes referred to as?
capsule
49
what are pacinian corpuscles only specific to?
pressure
50
what do pacinian corpuscles generate rather than an action potential?
generator potential
51
how do pacinian corpuscles activate a generator potential?
- pressure on skin causes deformation to lamellae
- which deforms and opens the stretch mediated sodium ion channel proteins
- sodium ions diffuse in
- depolarisation leads to generator potential
52
what do you call the sodium ion channel proteins that are embedded in the pacinian corpuscles?
stretch mediated
53
what happens if the generator potential reaches threshold?
an action potential is created causing a nerve impulse
54
what happens when the pressure increases on the skin in relation to pacinian corpuscles?
more stretch mediated sodium ion channel proteins open and more sodium ions enter
larger generator potential
generator potential reaches threshold causing depolarisation
55
what type of organ is the eye?
sense organ
56
how many types of receptor cells does the eye have?
two
57
what do the receptor cells in the eye respond to?
light intensity and wavelength
58
what are the locations for the receptor cells in the eye?
macula
fovea
59
where are the macula and the fovea in the eye located?
retina
60
what type of receptor are the receptors in the eye?
photo-receptor
61
what are the two types of photo-receptors called?
rods and cones
62
where are the rods and cones located in the eye?
rods- macula
cones- fovea
63
how are the rods and cones distributed in the eyes?
rods- evenly distributed in the macula
cones- densley packed in the fovea
64
explain the sensitivity of rods and cones
rods- sensitive to all wavelengths of of light
cones- each type of cone sensitive to a specific wavelength
65
what is rhodopsin and iodopsin?
pigments
rhodopsin: light sensitive
iodopsin: sensitive to three types
66
what does low visual acuity mean?
image being unclear
67
what does high visual acuity mean?
having a sharp and clear image
68
what causes low visual acuity?
retinal convergence due to several rods sharing a single bipolar neuron
69
what causes high visual acuity?
each cone is connected to a single bipolar neuron
70
what are the pigments called in rods and cones?
rods- rhodopsin
cones- iodopsin
71
how do light sensitive pigments produce a generator potential?
photons break the pigments down which alter the chemical structure
72
explain the relationship between bipolar neurons and rod cells
multiple rod cells synapse with one bipolar neuron
73
explain the relationship between bipolar neurons and cone cells
each cone cell synapses with a single bipolar neuron
74
what type of summation do rods and cones have?
rods- spatial summation
cones- temporal summation
75
why do rods have spatial summation?
because of retinal convergence
76
how does spatial summation lead to activating an impulse?
generator potentials combine to reach threshold
77
why do cones have temporal summation?
because each cone cell must release enough neurotransmitter to reach threshold
78
when are cone cells most likely to reach threshold?
in bright light
79
what does myogenic mean?
it can initiate it's own contraction
80
the heart can initiate its own contraction, what do you call this?
myogenic
81
what nodes are there in the heart?
sinoatrial node
atrio-ventricular node
82
what is responsible for the initial stimulus of the heart
sino atrial node
83
describe how the heart controls the regular contractions in the atria and ventricles
1. sinoatrial node sends electrical activity over both atria
2. atria contract
3. layer of non conductive tissue prevents wave reaching ventricles causing 0.1 second delay
4. atrio-ventricular node sends a wave of electrical activity down the bundle of His and up the purkinje fibres
5. ventricles contract from apex upwards
84
why can heart rate be altered?
in response to the changing demands of respiring tissues for oxygen
85
in what situation may respiring tissues demand more oxygen?
exercise
fight or flight response
86
what controls heart rate?
autonomic nervous system
87
what 2 branches does the autonomic nervous system have?
sympathetic
parasympathetic
88
what does the sympathetic branch and the parasympathetic branch do to effectors?
sympathetic: stimulates effectors
parasympathetic: inhibits effectors
89
what is the neurotransmitter involved in the sympathetic branch?
noradrenaline
90
what is the neurotransmitter involved in the parasympathetic branch?
acetylcholine
91
what is the word you would use to compare the sympathetic and the parasympathetic branch?
antagonistic
92
what in the brain controls heart rate?
medulla oblongata
93
what part of the medulla is important in heart rate?
cardio regulatory centre
94
what are the 2 parts of the cardio regulatory center?
acceleratory centre
inhibitory centre
95
which branch is the acceleratory centre associated with?
sympathetic
96
which branch is the inhibitory centre associated with?
parasympathetic
97
where do the para/sympathetic nerves take the inhibitory and acceleratory to?
sinoatrial node
98
what are the 2 receptors important in the control of heart rate?
baro receptors
chemo receptors
99
where are the baro receptors and chemoreceptors located?
in the aorta and carotid arteries
100
what do baro receptors respond to?
blood pressure
101
what do chemo receptors respond to?
pH levels
102
describe the process with receptors if blood pressure increases above normal
1. baro receptors detect this in the aorta and the carotid arteries
2. more frequent impulses sent to medulla oblongata
3. more frequent impulses sent to SA node from the inhibitory centre through the parasympathetic nerve
4. decreases frequency of impulses from SA node across atria
5. heart rate decreases
103
describe the process with receptors if blood pressure decreases below normal
1. baro receptors detect this in the aorta and carotid arteries
2. more frequent impulses sent to the medulla oblongata
3. more frequent impulses sent to to SA node from acceleratory centre through sympathetic nerve
4. increases frequency of impulses from SA node across atria
5. heart rate increases
104
what affects the pH of blood?
changes in CO2 levels
105
how do CO2 levels affect pH levels in the blood?
forms a weak acid in solution and decreases blood pH
(more acidic)
106
describe the process with receptors if CO2 levels rise and pH decreases below normal
1. detected by chemo receptors in the aorta and carotid arteries
2. more frequent impulses sent to medulla oblongata
3. more frequent impulses sent to SA node from acceleratory centre through sy
mpathetic nerve
4. more frequent impulses from SA node across atria
5. heart rate increases
