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biology year 2 > Stimuli and Responses > Flashcards

Stimuli and Responses Flashcards

1
Q

what are semi-lunar valves?

A
  • one way valves
  • open when pressure greater in ventricles than blood vessels
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2
Q

what are purkyne fibres?

A

electrical impulses that cause ventricles to contract from base up

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3
Q

what are atrioventricular valves?

A
  • one way valves
  • open when pressure higher in atria than ventricles
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4
Q

what does non-conducting tissue do?

A

stops electrical impulse from SAN reaching ventricles

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5
Q

define tropism?

A

response of plant to directional stimulus

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6
Q

how do plants repond to stimuli?

A

using growth factors/hormones

(INDOLEACETIC ACID)

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7
Q

where is IAA found and what does it promote?

A
  • growing regions (shoot tips)
  • cell ELONGATION
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8
Q

how do auxins move long and short distances?

A
  • short distances - diffusion and AT
  • long distances - via phloem
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9
Q

phototropism in shoots?

A
  • IAA accumulates in shaded side of shoot
  • IAA causes cell elongation in shaded side
  • shoot grows towards light
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10
Q

phototropism in roots?

A
  • IAA accumulates in shaded side
  • IAA inhibits cell growth on shaded side
  • root grows away from light
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11
Q

gravitropism in shoots?

A
  • IAA moves to underside
  • IAA causes cell elongation on lower side
  • shoot moves away from gravity
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12
Q

gravitropism in roots?

A
  • IAA moves to underside
  • IAA inhibits cell growth on lower side
  • root grows towards gravity
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13
Q

high blood o2, low CO2, high pH?

A
  • chemoreceptors detect high blood pressure, low CO2, high pH
  • receptors send nerve imp to medulla oblongata
  • medulla sends imp along parasympathetic neurones
  • parasympathetic neurones secrete ACh
  • heart rate slows down
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14
Q

high blood pressure?

A
  • baroreceptors detect high blood pressure
  • receptors send imp to medulla
  • medulla sends imp along parasympathetic neurones
  • parasympathetic neurones secrete ACh
  • heart rate slows down
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15
Q

low blood o2, high blood co2, low pH?

A
  • chemoreceptors detect low blood o2, high blood CO2, low pH
  • receptors send nerve imp to medulla
  • medulla sends imp along sympathetic neurones
  • sympathetic neurones secrete noradrenaline
  • heart rate speeds up
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16
Q

low blood pressure?

A
  • baroreceptors detect low blood pressure
  • receptors send nerve imp to medulla
  • medulla sends imp along sympathetic neurones
  • sympathetic neurones secrete noradrenaline
  • heart rate speeds up
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17
Q

what is the pascinian corpuscle?

A

a receptor that detects pressure, touch and vibrations in skin

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18
Q

stimulation of pascinian corpuscle?

A
  • pressure causes lamellae to stretch and deform
  • stretch mediated sodium ion channels open
  • sodium ions diffuse into memb
  • greater stimulus, more sodium ion channels open
  • depolarisation
  • if threshold reached - AP initiated
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19
Q

what is depolarisation of neurone?

A

generator potential

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20
Q

control of heart rate?

A
  • SAN initiates heart beat
  • sends electrical imp across atria
  • atria contract
  • non-conducting tissue prevent electrical imp reaching ventricles
  • AVN delays electrical imp
  • allows atria contract and empty before ventricles contract
  • AVN sends imp along bundle of his and purkyne fibres
  • ventricles contract from base up
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21
Q

left ventricle?

A
  • highest blood pressure
  • most cardiac muscle - contracts with greatest force
  • pumps blood to whole body
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22
Q

atrial systole?

A
  • atria contract
  • ventricles relax
  • AV valves open
  • SL valves close
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23
Q

ventricular systole?

A
  • atria relax
  • ventricles contract
  • AV valves close
  • SL open
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24
Q

diastole?

A
  • atria and ventricles relax
  • AV valves open
  • SL valves open
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25
Q

what are taxes and kinesis?

A

simple responses that keep organisms in favourable enviro

26
Q

define taxes?

A

mobile organism moves towards or away from directional stimulus

e.g. light

27
Q

define kinesis?

A

mobile organisms change movement in response to non-directional stimulus

e.g. humidity

28
Q

advantages of taxes and kinesis?

A
  • reduce water loss
  • safe from pred
29
Q

choice chamber?

A
  • put 100 woodlice in centre of choice chamber
  • observe for 10 mins
  • record number of turns
  • rate of movement
  • final position
30
Q

what do organisms do in unfavourable conditions?

A
  • move more / faster
  • turn more

SO MOVE TO NEW AREA

31
Q

what do organisms do in favourable enviro?

A
  • move less / slower
  • turn less

REMAIN IN FAVOURABLE AREA

32
Q

light is focused onto retina by what?

A

lens

33
Q

detection of light?

A
  • light absorbed by pigments in photoreceptors
  • causes sodium ion channels to open (GP)
  • if threshold reached - AP fired
  • along bipolari neurone and optic nerve
  • to CNS (brain)
34
Q

describe rods?

A
  • monochromatic vision
  • more sensitive to light
  • low visual acuity
  • because many rods join ONE neurone
35
Q

where are rods found?

A

peripheral parts of retina

36
Q

describe cones?

A
  • colour vision (blue,red and green cone)
  • less sensitive to low light
  • higher visual acuity
  • because each cone attached to own neurone
37
Q

what is a blind spot?

A
  • no photoreceptors
38
Q

what is at the fovea?

A
  • lots of photoreceptors
  • mainly cones
39
Q

what is reflex?

A

rapid response to stimulus without conscious control

40
Q

object approaching eye?

A
  • stimulus = object approaching eye
  • receptor detects stimulus
  • imp sent along sensory neurone
  • relay neurone in CNS
  • motor neurone
  • effectors (muscle/gland)
  • response = blink
41
Q

advtange of reflexes?

A
  • help avoid damage to tissue
  • very fast - dont think about it
  • protection
42
Q

slow twitch fibres

A
  • contract slowly
  • relax slowly
  • low force of contraction
  • resistant to fatigue
  • respire aerobically
  • lots of mitochondria, blood vessels, myoglobin (red)
  • little anaerobic resp
43
Q

where slow twitch fibres used

A
  • low intensity
  • long duration
    e. g. marathon
44
Q

fast twitch fibres

A
  • contract quickly
  • relax quickly
  • high force of contraction
  • respire anaerobically
  • few mitochondria, blood vessels, myoglobin (white)
  • little aerobic resp
45
Q

where fast twitch fibres used

A
  • high intensity
  • short duration
    e. g. sprint, long jump
46
Q

describe a relaxed muscle in the sliding filament theory

A
  • acting myosin binding site blocked by tropomyosin
  • prevents actin myosin crossbridge forming
47
Q

contracted muscle

A
  • Ca2+ causes tropomyosin to move out of binding site
  • allows formation of actin myosin crossbridge
  • Ca2+ activate ATPase (ADP + Pi —> ATP)
48
Q

what is ATP used for in muscle contraction

A
  • changing shape of myosin head (power stroke)
  • continues as long as binding site exposed (Ca2+ = AP)
  • detach myosin head
  • return myosin head to recovery stroke (resting position)
  • reabsorb Ca2+ into sarcoplasmic reticulum by AT
49
Q

what do skeletal/striated muscles have

A
  • lots of mitochondria
  • long cylindrical cells = muscle fibres
  • muscle fibres = multinucleate
  • contain long organelles = myofibrils
  • myofibrils contain myofilaments = actin, myosin
50
Q

what does A band contain

A
  • myosin
  • dark in electron micrograph
  • some actin
51
Q

what does I band contain

A
  • actin only
  • light colour
52
Q

where do you find sarcomeres

A

between z lines

53
Q

what do muscles act in

A

antagonistic pairs in incompressible skeleton

54
Q

to move a limb in both directions what do muscles need to work in

A

antagonistic pairs

55
Q

what can muscles only do

A

pull (cant push)

56
Q

ligaments attach

A

bones to bones

57
Q

tendons attach

A

bones to muscle

58
Q

when sarcomere contracts

A
  • sarcomere shortens
  • I band shortens
  • H zone shortens
  • A band stays same
59
Q

equation for phosphocreatine system

A

PCr + ADP –> ATP + Cr

60
Q

phosphocreatine system

FASTEST

A
  • phosphate group added to ADP = ATP
  • cells store PCr/CP
  • short and simple - fastest way make ATP
  • PCr store used up quickly - used for high intensity, short duration (power lifting)
  • anaerobic
  • alactic
61
Q

anaerobic resp (glycolysis)

A
  • 2 ATP mady by glycolysis
  • pyruvate —> lactate
  • causes muscle fatigue
  • short duration, high intensity
  • zoom
62
Q

aerobic resp

SLOWEST

A
  • lots of ATP by oxidative phosphorylation
  • slow - many reactions
  • no harmful waste prod
  • e.g. 10k run

biology year 2 (29 decks)

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