CHANGES TO environment

Question 1

define taxis

Answer 1

directional response stimulus

Question 2

define kinesis

Answer 2

a non-directional response to stimuli

Question 3

what tropism

Answer 3

the growth part of a plant in response to a directional stimulus.

Question 4

which way do plant shoot grow in negative phototropism

Answer 4

plants grow away from light - down into the soil

Question 5

which direction do plant shoots grow in positive phototropism

Answer 5

plants grow towards the light.

Question 6

which direction do plant roots grow in positive geotropism

Answer 6

down

Question 7

what does IAA control

Answer 7

cell elongation

Question 8

where will IAA move to in the plant

Answer 8

shaded side

Question 9

in which direction will IAA caused the plant shoot to bend towards

Answer 9

shoot tip bends towards the light

Question 10

what does IAA do in the root

Answer 10

inhibits the elongation of root cells

Question 11

what does IAA increase

Answer 11

plasticity - as cells get older they increase in ridgidity and they cannot stretch

Question 12

what is the central nervous system made up of

Answer 12

brain and spinal chord

Question 13

what si the peripheral nervous system made of

Answer 13

pairs of nerves that originate from the brain or spinal chord

Question 14

which kind of impulses do sensory neurones carry

Answer 14

from receptors towards the central nervous system

Question 15

which kind of impulses do motor neurones send

Answer 15

from the CNS to the effectors

Question 16

what is the voluntary nervous system

Answer 16

carries impulses to the body muscles which are all under voluntary control

Question 17

what is the automatic nervous system

Answer 17

carries nerves impulses to the glands, smooth muscles and cardiac muscles which is not under voluntary control

Question 18

briefly describe the reflex arc

Answer 18

stimulus - receptor- sensory neurone- coordinator- motor neurone- effector- response

Question 19

which type of stimulus is the Pacinian corpuscle related to

Answer 19

pressure mediated response

Question 20

how does the Pacinian Corpuscle work

Answer 20

changes in pressure will deform the membrane and the surrounding neurones - they will become stretched.

• this stretching will allow the sodium channels to open and Na+ will diffuse intot he neurone.
• the neurone will become depolarised and will from a generator potential
• the generator potential will act as a transducer and create an action potential, that can be transmitted along other neurones to the CNS

Question 21

what kind of pigment is in a rod cell

Answer 21

rhodopsin

Question 22

what kind of pigment is a cone cell

Answer 22

iodopsin

Question 23

do rods high or low visual acuity

Answer 23

low

Question 24

do cones have high or low visual acuity

Answer 24

high

Question 25

where are the cones centred

Answer 25

concentrated in the fovea ( very central) - not many in the periphery

Question 26

where are the rods centred

Answer 26

at the periphery of the retina

Question 27

is there retinal convergence in the rods

Answer 27

yes - summation to produce an Action potential many rods to one neurone

Question 28

is there summation in cone cells

Answer 28

no - one cone to one neurone.

Question 29

what do rod and cone cells act as

Answer 29

transducers

Question 30

what type of light frewuwncies do cones detect

Answer 30

red blue green

Question 31

which light frequencies do rods detect

Answer 31

black and white

Question 32

what does the sympathetic nervous system do

Answer 32

stimulates effectors to produce a faster response - and prepares the fight or flight response

Question 33

what does the parasympathetic nervous system do

Answer 33

inhibits effectors and slows and response. it controls resting conditions - it is concerned with conserving energy

Question 34

what does myogenic mean

Answer 34

that the contraction of the heart muscle is initiated from itself rather than neurogenic impulses from outside the heart

Question 35

what does the SAN do

Answer 35

the initial stimulus for contraction is created and determines the beat of the heart. it is also known as the pacemaker

Question 36

where is the SAN located

Answer 36

right atrium

Question 37

describe the pathwayof a myogenic impulse

Answer 37

-a wave of electrical excitation spreads from the SAN across both atria causing them to contract. - the atrioventricular septum prevents the wave crossing to the ventricles -the wave of excitation enters the AVN. - after a short delay the AVN will convey a wave along the purkyne tissue, which collectively make the bundle of his. - the bundle of his conducts the wave between the atrioventicular septum to the base of the ventricles, where the bundle branches into smaller fibres of purkyne tissue - thewave of excitation is released from the purkyne tissue causing the vrntricles to contract quickly at the same time from the bottom up

Question 38

what does the medulla oblongata do

Answer 38

an area in the heart which is responsible for changes in heart rate - increasing - the SAN which is sympathetic nervous system and decreasing which is part of the parasympathetic nervous system linked to the SAN

Question 39

will more CO2 in the blood lower or raise blood pH

Answer 39

lower

Question 40

where are chemoreceptors

Answer 40

carotid arteries and aorta

Question 41

where is the AVN

Answer 41

between the atria

Question 42

where is the purkyne tissue located

Answer 42

distributed in the ventricles

Question 43

where is the bundle of his located

Answer 43

atrioventricular septum

Question 44

what is the function of chemoreceptors

Answer 44

to detect changes in pH and send impulses to the medulla oblongata

Question 45

what happens when BP is higher than normal

Answer 45

baroreceptors send more impulses to the medulla oblongata to decrease heart rate - via the PARASYMPATHETIC nervous system to the SAN

Question 46

what happens when BP is lower than normal

Answer 46

baroreceptors send more impulses to the medulla oblongata to increase heart rate - via the SYMPATHETIC nervous system to the SAN