Stimuli and Responses Flashcards
1
Q
what are semi-lunar valves?
A
- one way valves
- open when pressure greater in ventricles than blood vessels
2
Q
what are purkyne fibres?
A
electrical impulses that cause ventricles to contract from base up
3
Q
what are atrioventricular valves?
A
- one way valves
- open when pressure higher in atria than ventricles
4
Q
what does non-conducting tissue do?
A
stops electrical impulse from SAN reaching ventricles
5
Q
define tropism?
A
response of plant to directional stimulus
6
Q
how do plants repond to stimuli?
A
using growth factors/hormones
(INDOLEACETIC ACID)
7
Q
where is IAA found and what does it promote?
A
- growing regions (shoot tips)
- cell ELONGATION
8
Q
how do auxins move long and short distances?
A
- short distances - diffusion and AT
- long distances - via phloem
9
Q
phototropism in shoots?
A
- IAA accumulates in shaded side of shoot
- IAA causes cell elongation in shaded side
- shoot grows towards light
10
Q
phototropism in roots?
A
- IAA accumulates in shaded side
- IAA inhibits cell growth on shaded side
- root grows away from light
11
Q
gravitropism in shoots?
A
- IAA moves to underside
- IAA causes cell elongation on lower side
- shoot moves away from gravity
12
Q
gravitropism in roots?
A
- IAA moves to underside
- IAA inhibits cell growth on lower side
- root grows towards gravity
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
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
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
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
17
Q
what is the pascinian corpuscle?
A
a receptor that detects pressure, touch and vibrations in skin
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
19
Q
what is depolarisation of neurone?
A
generator potential
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
21
Q
left ventricle?
A
- highest blood pressure
- most cardiac muscle - contracts with greatest force
- pumps blood to whole body
22
Q
atrial systole?
A
- atria contract
- ventricles relax
- AV valves open
- SL valves close
23
Q
ventricular systole?
A
- atria relax
- ventricles contract
- AV valves close
- SL open
24
Q
diastole?
A
- atria and ventricles relax
- AV valves open
- SL valves open
25
what are taxes and kinesis?
simple responses that keep organisms in favourable enviro
26
define taxes?
mobile organism moves towards or away from directional stimulus
e.g. light
27
define kinesis?
mobile organisms change movement in response to non-directional stimulus
e.g. humidity
28
advantages of taxes and kinesis?
- reduce water loss
- safe from pred
29
choice chamber?
- put 100 woodlice in centre of choice chamber
- observe for 10 mins
- record number of turns
- rate of movement
- final position
30
what do organisms do in unfavourable conditions?
- move more / faster
- turn more
SO MOVE TO NEW AREA
31
what do organisms do in favourable enviro?
- move less / slower
- turn less
REMAIN IN FAVOURABLE AREA
32
light is focused onto retina by what?
lens
33
detection of light?
- 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
describe rods?
- monochromatic vision
- more sensitive to light
- low visual acuity
- because many rods join ONE neurone
35
where are rods found?
peripheral parts of retina
36
describe cones?
- colour vision (blue,red and green cone)
- less sensitive to low light
- higher visual acuity
- because each cone attached to own neurone
37
what is a blind spot?
- no photoreceptors
38
what is at the fovea?
- lots of photoreceptors
- mainly cones
39
what is reflex?
rapid response to stimulus without conscious control
40
object approaching eye?
- stimulus = object approaching eye
- receptor detects stimulus
- imp sent along sensory neurone
- relay neurone in CNS
- motor neurone
- effectors (muscle/gland)
- response = blink
41
advtange of reflexes?
- help avoid damage to tissue
- very fast - dont think about it
- protection
42
slow twitch fibres
- contract slowly
- relax slowly
- low force of contraction
- resistant to fatigue
- respire **aerobically**
- lots of mitochondria, blood vessels, myoglobin (red)
- little anaerobic resp
43
where slow twitch fibres used
- low intensity
- long duration
e. g. marathon
44
fast twitch fibres
- contract quickly
- relax quickly
- high force of contraction
- respire anaerobically
- few mitochondria, blood vessels, myoglobin (white)
- little aerobic resp
45
where fast twitch fibres used
- high intensity
- short duration
e. g. sprint, long jump
46
describe a relaxed muscle in the sliding filament theory
- acting myosin binding site blocked by tropomyosin
- prevents actin myosin crossbridge forming
47
contracted muscle
- Ca2+ causes tropomyosin to move out of binding site
- allows formation of actin myosin crossbridge
- Ca2+ activate ATPase (ADP + Pi ---\> ATP)
48
what is ATP used for in muscle contraction
- 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
what do skeletal/striated muscles have
- lots of mitochondria
- long cylindrical cells = muscle fibres
- muscle fibres = multinucleate
- contain long organelles = myofibrils
- myofibrils contain myofilaments = actin, myosin
50
what does A band contain
- myosin
- dark in electron micrograph
- some actin
51
what does I band contain
- actin only
- light colour
52
where do you find sarcomeres
between z lines
53
what do muscles act in
antagonistic pairs in incompressible skeleton
54
to move a limb in both directions what do muscles need to work in
antagonistic pairs
55
what can muscles only do
pull (cant push)
56
ligaments attach
bones to bones
57
tendons attach
bones to muscle
58
when sarcomere contracts
- sarcomere shortens
- I band shortens
- H zone shortens
- A band stays same
59
equation for phosphocreatine system
PCr + ADP --\> ATP + Cr
60
phosphocreatine system
FASTEST
- 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
anaerobic resp (glycolysis)
- 2 ATP mady by glycolysis
- pyruvate ---\> lactate
- causes muscle fatigue
- short duration, high intensity
- zoom
62
aerobic resp
SLOWEST
- lots of ATP by oxidative phosphorylation
- slow - many reactions
- no harmful waste prod
- e.g. 10k run
