unit 14 - coordination and response Flashcards

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1
Q

what is a nerve

A

a bundle of neurons

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2
Q

where are electrical impulses sent through

A

through nerves to quickly send signals around the body

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3
Q

what are nerve electrical impulses used for
examples (5)

A

for rapidly coordinating or regulating the bodies functions
eg pupils dilate, breathing contractions, bladder relaxes, stomach digestion, heart rate.

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4
Q

what does the central nervous system consist of

A

brain and spinal cord

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5
Q

function and look of dendrites

A

receive signals from surrounding neurons . they are branches to allow connections with many neurons

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6
Q

function of axon

A

a long structure off the cell body that electrical signals can rapidly be sent through. its long length allows for signals to be sent rapidly

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7
Q

what is the axon terminal

A

where the signal is passed to the next neuron over the synapse

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8
Q

4 steps of reflex responses / how nerve signals are sent

A
  1. a stimulus is received by a receptor
  2. sensory neurons pass these signals back to the relay neuron in the CNS
  3. relay neuron sends this signal on to the motor neuron
  4. motor neuron sends the signal to an effector organ which is then stimulated to respond.
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9
Q

stimuli examples

A

light, sound, touch, temperature, chemicals.

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10
Q

what is a reflex action

A

a means of automatically and rapidly integrating and coordinating stimuli with the response of effectors

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11
Q

what are effector organs

A

muscle or gland

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12
Q

where is cell body on a sensory neuron

A

half way down axon

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13
Q

defining look of relay neuron

A

short axon

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14
Q

where is cell body on motor neuron

A

at end with dendrites

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15
Q

what is the synapse

A

the junction between 2 neurons

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16
Q

what does the presynaptic cell do

A

releases neurotransmitters into the synaptic cleft, which then bind to receptors on the postsynaptic cell, triggering a response

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17
Q

how electrical impulses trvael from neurone to neurone

A
  • electrical impulses trvael along the first axon
  • this triggers the nerve ending of the presynaptic neurone to release neurotransmitters from vesicles which fuse with the presynaptic membrane
  • neurotransmitters diffuse across the synaptic cleft and bind with the receptor molecules on the postsynaptic membrane
  • thus stimulates 2nd neurone to generate and electrical impulse that trvales down the 2nd axon
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18
Q

why are neurotransmitters destroyed

A

to prevent continued stimulation which would cause repeated impulses to be sent

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19
Q

why do impulses only travel one way

A

neurotransmitters are released from the presynaptic end only and their receptors are present on the postsynaptic end only

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20
Q

function of the optic nerve

A

sends nerve signals from rod and cone cells in the retina to the brain.

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21
Q

function of the retina

A

is where light is focused in the eye. it contains light sensitive rod and cone receptor cells

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22
Q

function of the iris

A

is the coloured part of the eye which affects pupil size

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23
Q

function of the lens

A

is able to change shape to focus light on the retina

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24
Q

function of pupil

A

is the opening in the eye which allows light to enter

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25
Q

function of cornea

A

the curved part of the eye which refracts light as it enters

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26
Q

function of the suspensory ligaments

A

attaches the lens to the ciliary muscles

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27
Q

function of the ciliary muscles

A

they contract or relax to make the suspensory ligaments go slack or tight respectively, therefore changing the shape of the lens.

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28
Q

what happens to eye in low light

A

radial muscles contract in low light so the pupil will appear larger and allow more light in

29
Q

what happens to eye in bright light

A

circular muscles contract in bright light so the pupil will appear smaller and less light enters eye

30
Q

why do pupil size change in light

A

means light sensitive cells of the retina would gave an appropriate amount of light to be able o send impulses to the brain along the optic nerve to form the image you see.

31
Q

about rod cells

A
  • detect differences in light intensity
  • don’t detect colour
  • used extensively in dim light
32
Q

about cone cells

A
  • detect differences in colour
  • red, green, blue cones work together to allow us to perceive a range of colours.
33
Q

where is information carried from the eye

A

sensory neurons to the occipital lobe.

34
Q

what is the fovea

A

in the eye a tiny pit in the retina that provides the clearest vision. the eye lense will focus light onto the fovea
- no rods only cones

35
Q

definition of hormones

A

a chemical substance , produced by a gland and carried by the blood, which alters the activity of one or more specific target organs

36
Q

what does the pituitary release/excrete

A

releases ADH

37
Q

what do the adrenal glands produce

A

adrenaline

38
Q

what does the pancreas produce

A

insulin and glucose

39
Q

what do the testes produce

A

testosterone

40
Q

what do the ovaries produce

A

oestrogen

41
Q

changes when adrenaline is released (5)

A
  1. increased breathing rate + deeper breathes
  2. increased heart rate
  3. increased pupil diameter - can see more
  4. hair stands on end- making animal look larger
  5. glucose is released from the liver
42
Q

short vs long term signal

A

nerve : send signals fast through neurons , effect is short term
hormones: send signals slowly through blood stream.

43
Q

hormones that control glucose levels (3)

A
  1. adrenaline
  2. glucose
    3.insulin
44
Q

how does adrenaline help control blood glucose levels

A

is secreted from adrenal gland, causes liver to break down glycogen and release glucose into the blood stream

45
Q

how does glucagon help control blood glucose levels

A

secreted from pancreas. causes the liver to breakdown glycogen into glucose and release it into the blood stream
its the hormone we use when our blood sugar levels are low but we are not in fight or flight.

46
Q

how does insulin help control blood glucose levels

A

secreted from pancreas causes the liver to absorb glucose from the bloodstream and covert it to glycogen for later use.
used when blood sugar levels are high

47
Q

insulin flow chart

A

eat a large meal

blood sugar levels rise

pancreas releases insulin

insulin travels through blood to liver

this stimulates liver to absorb glucose from blood and convert to glycogen

lowers blood sugars again

48
Q

describe how eyes adjust to focus on something far away (5)

A
  • suspensory ligaments become taut
  • ciliary muscles relax
  • image forms on fovea
  • lens thinner
  • less refraction of light
49
Q

describe how urea is transported in the blood to the kidney

A

soluble in plasma

50
Q

homeostasis defenition

A

the maintenance of a constant internal environment

51
Q

what does insulin do to blood glucose concentration

A

decrease

52
Q

What is the purpose of Homeostasis?

A

keeps a variable in our body at a set point using negative feedback.

53
Q

what triggers homeostasis

A

if a variable changes from the set point it will be detected by a receptor, transmitted by nerves and an effector will be activated to return the variable to its set point.

54
Q

How is temperature sensed in the body and prompted to be regulated

A
  • the thermoregulatory centre in the hypothalamus senses the temperature of the blood flowing through it
  • the hypothalamus also receives information via sensory neurones from heat receptors in the skin.
55
Q

How is vasodilation triggered

A

if body temperature rises

56
Q

steps of vasodilation

A
  1. smooth muscle in wall of arteriole relaxes and arteriole dilates
  2. more blood flows through capillaries close to surface of the skin
  3. less blood flows through shunt vessel
    rate of heat loss from body increases
57
Q

what triggers vasoconstriction

A

when body temperature falls

58
Q

steps of vasoconstriction

A
  1. smooth muscles in wall of arteriole contracts which constricts the lumen
  2. more blood is shunted away from surface of skin
  3. less blood flows close to the skin
    rate of heat loss from body decreases
59
Q

steps of sweating

A
  1. sweat is secreted onto surface of skin
  2. water in sweat absorbs heat from the body as it evaporates
    this increases the rate of heat loss from the body
60
Q

purpose/ setps of goosebumps

A

pili erector muscles contract and hairs stand up straight
still layer of insulating air is trapped by the hairs

61
Q

how does shivering keep you warm

A

when we shiver the muscles contract repeatedly so the rate of respiration in muscles increase. uses lots of energy and more heat energy is generated

62
Q

ways to warm up and cool down

A

warm up
1. shivering
2. goosbumps / pili erection
3. vasoconstriction
cool down
1. vasodilation
2. sweating

63
Q

What is tropism

A

a growth a response of an organism towards or away from a stimulus

64
Q

describe gravitropism

A

a response in which parts of a plant grow towards or away from gravity

65
Q

describe phototropism

A

a response in which parts of a plant grow towards or away from the direction of the light source

66
Q

positive vs negative tropism

A

towards vs away

67
Q

what is auxin

A

a growth regulating hormone. it makes plant shoot cells elongate and inhibits elongation in roots.

68
Q

What does auxin do in shoot tips

A

loosens the cell wall and stimulates cell elongation. in the shoot tip iir diffuses away from light, elongating cells on shaded side so shoot grows towards the light.