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Module 5.5 Flashcards

Plant and animal responses (89 cards)

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1
Q

divisions of the nervous system

A

central nervous system
peripheral nervous system

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2
Q

divisions of the central nervous system

A

brain spinal cord

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3
Q

division of the peripheral nervous system

A

sensory system
motor system

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4
Q

divisions of the motor system

A

somatic nervous system
autonomic nervous system

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5
Q

role of the peripheral nervous system

A

ensures rapid communication between the sensory receptors the CNS and the effectors

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6
Q

what is the PNS composed of

A

sensory and motor neurones

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7
Q

what is the brain composed of

A

mainly relay neurones with multiple connections to allow complex neural pathways
mostly non myelinated (grey matter)

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8
Q

what is the spinal cord composed of

A

non-myelinated neurones make up the central grey matter
myelinated neurones make up an outer region of white matter to carry action potentials up and down the spinal cord for rapid communication over longer distances

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9
Q

what is the sensory nervous system composed of

A

sensory neurones conduct action potential from the sensory receptors to the CNS

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10
Q

what is the motor nervous system composed of

A

motor neurones to conduct action potentials from the CNS to effectors

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11
Q

what is the somatic nervous system composed of

A

motor neurones that conduct action potentials to effectors under conscious control
mostly myelinated and one single neurone connecting CNS to effector

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12
Q

what is the autonomic nervous system composed of

A

motor neurones that conduct action potentials from the CNS to effectors not under voluntary control
unmyelinated and at least 2 neurones involved

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13
Q

divisions of the autonomic nervous system

A

sympathetic nervous system
parasympathetic nervous system

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14
Q

role of the sympathetic nervous system

A

prepares the body for activity

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15
Q

role of the parasympathetic nervous system

A

conserves energy

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16
Q

what are the 4 main parts of the brain

A

cerebrum
cerebellum
hypothalamus and pituitary complex
medulla oblongata

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17
Q

role of the cerebrum

A

controls higher brain functioning
conscious thought and actions
emotional responses
intelligence, reasoning, judgement and decisions making
factual memory

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18
Q

function of the cerebellum

A

coordinates fine control of muscular movements
maintaining body position and balance
judging position of objects and limbs
tensioning muscles
coordination contraction and relaxation of antagonistic muscles

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19
Q

function of the hypothalamus

A

controls homeostatic mechanisms
temperature regulation
osmoregulation
manufactures hormones

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20
Q

function of the pituitary gland

A

posterior lobe linked to hypothalamus by neurosecretory cells
hormones manufactured in hypothalamus released into blood by pituitary gland
anterior lobe produces and releases its own hormones in response to releasing factors from the hypothalamus

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21
Q

function of the medulla oblongata

A

controls non-skeletal muscle
regulates many vital processes
heart rate
circulation and blood pressure
rate and depth of breathing

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22
Q

what is a reflex action

A

a response to changes in the environment that do not involve any processing in the brain to coordinate the movement
the pathway is as short as possible so the reflex is rapid
most consist of 3 neurones

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23
Q

examples of reflexes

A

blinking
corneal reflex
optical reflex
knee jerk reflex

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24
Q

what type of reflex is the knee jerk reflex

A

spinal reflex
passes through the spinal cord rather than through the brain

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25
how does the knee jerk reflex work
when muscles at the front of the thigh are stretched specialised stretch receptors called muscle spindles detect the increase in length of the muscle if the stretching is unexpected a reflex action causes the contraction of the same muscle
26
role of the knee jerk reflex
enables balance e.g. if standing and body is bending or starting to lean forward the muscle contraction straightens the knee or brings the body back above the legs
27
why is the knee jerk reflex unusual
nervous pathway only consists of 2 neurones a sensory and motor neurone
28
why are reflex actions needed
survival value may be used to get out of danger avoid damage to a part of the body or to maintain balance
29
what is the fight or flight response
stimulated by the detection of a threat to survival leads to a range of physiological changes to prepare the animal for activity activity may be running away or a direct challenge to the perceived threat
30
examples of physiological changes associated with the fight or flight response
pupils dilate HR and BP increase arterioles to digestive system constricted while those to the muscles and liver are dilated blood glucose levels increase metabolic rate increases endorphins (natural pain killers) released in the brain
31
examples of receptors to detect threats
external: eyes, ears, nose Internal: decrease in BP, pain
32
how is the fight or flight response coordinated
input from receptors feed into sensory centres in the cerebrum signal passed to association centres if a threat is identified the cerebrum stimulates the hypothalamus which stimulates the nervous and endocrine response
33
what is the nervous system response in fight or flight
sympathetic nervous system activated adrenal medulla activated to release adrenaline into the blood stream glands and smooth muscles activated e.g. HR and BP
34
what is the endocrine response in fight or flight
hypothalamus secretes releasing hormones to stimulate the pituitary gland pituitary gland secretes hormones which stimulate the adrenal cortex and thyroid
35
what releasing hormones does the hypothalamus produce in fight or flight
CRH TRH
36
what hormones does the pituitary gland release in fight or flight
ACTH TSH
37
what does the adrenal cortex release in fight or flight
corticoid hormones e.g. cortisol increases glycogen to glucose conversion
38
what does the thyroid gland secrete in the fight or flight response
thyroxine increases metabolic rate
39
mechanism of adrenaline action
adrenaline (first messenger) binds to adrenaline receptor on plasma membrane receptor is associated with G protein G protein stimulated to activate adenyl cyclase adenyl cyclase converts ATP to cyclic AMP (second messenger) cAMP causes effect inside the cell
40
why does heart rate need to be controlled
heart tissue is myogenic so would beat on its own but atrial muscle has a higher myogenic rate than the ventricular muscle chamber must contract in a coordinate way
41
where is heart rate controlled
cardiovascular centre in the medulla oblongata
42
how is heart rate increased
action potentials sent down the accelerans nerve (sympathetic nerve) cause the release of noradrenaline at the SAN heart rate increases
43
how is heart rate decreased
action potential sent down the vagus nerve (parasympathetic nerve) acetylcholine release at the SAN heart rate decreases
44
what receptors input to the cardiovascular centre
stretch receptors in muscles chemoreceptors in the carotid artery stretch receptors in the walls of the carotid sinus co2 concentration in the blood
45
role of muscle stretch receptors in heart rate
if a lot of muscle movement is detected cardiovascular centre is informed extra oxygen may be needed soon increased HR
46
role of chemoreceptors in heart rate
detect reduction of pH due to increase of CO2 in the blood HR increases
47
role of carotid sinus stretch receptors in heart rate
monitor blood pressure if BP is too high HR will decrease
48
what are the 3 type of muscle
involuntary (smooth) muscle cardiac muscle skeletal muscle
49
structure of involuntary muscle
individual cells tapered at both ends cells contain a nucleus and bundles of action and myosin
50
function of smooth muscle
unvoluntary muscle contraction e.g. blood vessels intestine does not tire quickly
51
structure of cardiac muscle
individual cells form long fibres which branch to form cross bridges cells joined by intercalated discs
52
function of cardiac muscle
makes up the muscular part of the heart cross bridges ensure electrical stimulation spreads evenly over the walls of the chambers intercalated discs produce gap junctions that allow free diffusion of ions between the cells action potentials pass quickly and easily between the fibres
53
structure of skeletal muscle
cells form fibres each fibre is multinucleate and surrounded by a membrane called the sarcolemma
54
divisions of skeletal muscle
muscle fibre myofibril sarcomere
55
what is a neuromuscular junction
junction between the nervous system and the muscle similar to a synapse
56
how is muscle contraction stimulate
action potentials at the end of an axon open calcium channels allowing calcium ions into the end of the axon acetylcholine vesicles fuse with the end membrane the diffuse across the gap to fuse with receptors in the sarcolemma this opens sodium ion channels sarcolemma depolarise wave of depolarisation spreads along the sarcolemma into the muscle fibre
57
elements of myofibrils
I band A band Z line
58
what is the I band
actin filaments tropomyosin wound around troponin attached to tropomyosin
59
what is the A band
myosin filaments with mobile protruding heads
60
how is muscle contraction started
action potential passes along the sarcolemma and down the transverse tubule into the muscle fibres action potential is carried to the sarcoplasmic reticulum which stores calcium ions calcium ions released into the sarcoplasm
61
what happens to the actin in muscle contraction
calcium ions bind to the troponin altering its shape this pulls the tropomyosin aside binding sites on the actin exposed
62
what happens to myosin in muscle contraction
myosin heads bind to the actin forming cross bridges between the filaments myosin heads move pulling the actin filament past the myosin filaments myosin heads detatch and can bind again further up the actin
63
role of ATP in muscle contraction
part of the myosin head can hydrolyse ATP to ADP and Pi to release energy myosin head moving to slide actin requires energy ADP and Pi are released ATP attaches again to break cross bridge myosin head goes to original position as ATP is hydrolysed
64
what is the power stroke
movement of the myosin head to slide the actin filament over itself
65
how is ATP supply maintained in muscles
ATP from aerobic respiration ATP for anaerobic respiration creatine phosphate in the sarcoplasm acts as a reserve store of phosphate groups which can be transferred to ADP molecules to create ATP using creatin phosphotransferase
66
what are the plant responses to herbivory
chemical defences and folding in response to touch
67
what chemical defences are used in response to herbivory
alkaloids (feeding deterrent as they taste bitter) pheromones (can affect the behaviour or physiology of another)
68
what are tropisms
directional growth responses of plants
69
types of tropisms
phototropism (light) geotropism (gravity) chemotropism (chemicals) thigmotropism (touch)
70
what is a positive tropic response
if a plant responds towards a stimulus e.g. growing towards light
71
what is a negative tropic response
if a plant responds away from a stimulus e.g. shoots growing away from the force of gravity
72
what is a nastic response
a non-directional response to external stimuli
73
what plant hormone play a role in leaf loss
cytokinins delay leaf senescence/ageing auxins inhibit leaf abscission/loss
74
what plant hormone plays a role is seed germination
gibberellins promote germination abscisic acid inhibits seed germination
75
what plant hormone plays a role in stomatal closure
abscisic acid causes stomatal closure when the plant is stressed by low water availability
76
role of cytokinins
delays leaf senescence/ageing overcomes apical dominance
77
role of abscisic acid
inhibits seed germination and growth causes stomatal closure when the plant is stressed by low water availability
78
role of auxins
inhibits leaf abscission/fall inhibits growth of side shoots
79
role of gibberellins
promotes seed germination
80
role of ethene
promotes fruit ripening
81
what is apical dominance
inhibition of lateral bud growth further down the shoot by chemical by the apical bud at the tip of the plant shoot
82
effect of auxin concentration on apical dominance
normal auxin level in lateral buds inhibits growth low auxin levels promote growth in lateral buds
83
example of experimental evidence for the role of auxins
when auxin paste is applied to the cut end of a shoot the lateral buds did not grow when auxin transport inhibitor is applied below the apex of the shoot the lateral buds grow
84
effect of gibberellin concentration on stem elongation
stimulates cells division and elongation
85
how do gibberellins promote seed germination
when seeds absorb water the embryo releases gibberellins which enables the production of amylase to break starch into glucose providing the substrate for respiration so the embryo can grow
86
commercial uses of plant hormones
control of ripening rooting powders hormonal weed killers
87
how is fruit ripening controlled
ethene can be sprayed on plants to speed up ripening and make all fruits ripen at the same time fruit can be stored in low temperatures with little oxygen to prevent ethene synthesis to prevent fruit ripening so it can be stored for longer
88
what is rooting powder
contains auxins to encourage root growth from a cutting
89
what are hormonal herbicides
auxins promote shoot growth so much that the stem cannot support itself, buckles and dies

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