coordination and respone

Question 1

what is a stimulus

Answer 1

any change in the internal or external environment

Question 2

what are receptors

Answer 2

receptors detect stimuli, receptors in the sense organs are a group of cells that detect external stimuli

Question 3

what are effectors

Answer 3

effectors are cells that bring about a response to a stimuli, include muscle cells and cells found in glands

Question 4

how do receptors communicate with effectors

Answer 4

via the nervous system or hormonal system

Question 5

3 type sof neurone

Answer 5

sensory
relay
motor

Question 6

what happens when receptors detect a stimulus

Answer 6

they send electrical impulses along sensory neurones to the CNS, the CNS then sends electrical impulses to an effector along a motor neurone, the effector then responds accordingly

Question 7

why is the CNS able to bring about very rapid responses

Answer 7

neurones transit information using high speed electrical impulses

Question 8

what is the connection between 2 neurones called

Answer 8

synapse

Question 9

how is the nerve signal transferred across a synapse

Answer 9

neurotransmitters diffuse across the gap, setting off a new electrical signal in the next neurone

Question 10

what is the purpose of reflexes

Answer 10

to prevent injury

Question 11

what is a reflex arc

Answer 11

the route taken by the information in a reflex from receptor to effector

Question 12

explain the reflex arc of touching a hot object

Answer 12

stimulus (hot object) is detected by receptors, sending an impulse along a sensory neurone to the CNS
the sensory neurone passes on the message to a relay neurone which relays the impulse to a motor neurone
impulse travels along the motor neurone to the effector (muscle)
the muscle (effector) then contracts and moves your hand away from the object

Question 13

block diagram for reflex arc

Answer 13

stimulus
receptor
sensory neurone
CNS
motor neurone
effector
response

Question 14

what is the conjunctiva

Answer 14

lubricates and protects the surface of the eye

Question 15

what is the sclera

Answer 15

tough outer layer that protects the eye

Question 16

what is the cornea

Answer 16

refracts light into the eye

Question 17

what is the iris

Answer 17

controls the diameter of the pupil

Question 18

what is the lens

Answer 18

focuses light onto the retina

Question 19

what is the retina

Answer 19

light-sensitive part, covered in light receptors called cones and rods

Question 20

what do rods receive

Answer 20

light

Question 21

what do cones receive

Answer 21

colour

Question 22

what is the optic nerve

Answer 22

carries impulses from the receptors to the brain

Question 23

what happens to the iris in bright light

Answer 23

circular muscle contracts to make the pupil smaller

Question 24

what happens to the iris in dim light

Answer 24

radial muscles contract making the pupil bigger

Question 25

what is accommodation

Answer 25

focusing light onto the retina by changing the shape of the lens

Question 26

what happens when the eye looks at distant objects

Answer 26

ciliary muscles relax suspensory ligaments contract lens goes thin light is refracted by a smaller amount

Question 27

what happens when the eye looks at distant objects

Answer 27

ciliary muscles contract suspensory ligaments slacken lens goes more curved light is refracted by a greater amount

Question 28

what are hormones

Answer 28

chemical messengers sent in the blood

Question 29

hormone properties

Answer 29

travel slowly and have long lasting effects

Question 30

source of adrenaline

Answer 30

adrenal glands

Question 31

source of insulin

Answer 31

pancreas

Question 32

source of testosterone

Answer 32

testes

Question 33

source of progesterone

Answer 33

ovaries

Question 34

source of oestrogen

Answer 34

ovaries

Question 35

source of ADH

Answer 35

pituitary gland

Question 36

source of FSH

Answer 36

pituitary gland

Question 37

source of LH

Answer 37

pituitary gland

Question 38

roles of adrenaline

Answer 38

readies body for fight or flight response

Question 39

role of insulin

Answer 39

helps control the blood sugar level

Question 40

role of testosterone

Answer 40

main male sex hormone

Question 41

role of progesterone

Answer 41

supports pregnancy

Question 42

role of oestrogen

Answer 42

man female sex hormone

Question 43

role of ADH

Answer 43

controls water content

Question 44

role of FSH

Answer 44

female sex hormone

Question 45

role of LH

Answer 45

female sex hormone

Question 46

effects of adrenaline

Answer 46

increases heart rate, blood flow to muscles and blood sugar level

Question 47

effects of insulin

Answer 47

stimulates the liver to turn glucose into glycogen for storage

Question 48

effects of testosterone

Answer 48

promotes male secondary sexual characteristics

Question 49

effects of progesterone

Answer 49

maintains lining of the uterus

Question 50

effects of oestrogen

Answer 50

controls menstrual cycle and promotes female secondary sexual characteristics

Question 51

effects of ADH

Answer 51

increases permeability of collecting duct in nephrons

Question 52

effects of FSH

Answer 52

causes an egg to mature in an ovary, stimulates ovaries to produce oestrogen

Question 53

effects of LH

Answer 53

stimulates the release of an egg from an ovary

Question 54

differences between nerves and hormones

Answer 54

nerves = fast, short time, precise area hormones = slow, long time, general way

Question 55

what is homeostasis

Answer 55

maintenance of a constant internal environment

Question 56

what conditions does homeostasis keep balanced

Answer 56

water content body temperature

Question 57

what is the ideal body temperature

Answer 57

37 degrees

Question 58

why do you sweat when hot

Answer 58

sweat evaporates from the skin's surface transfers energy from your skin to the environment

Question 59

what is vasodilation

Answer 59

blood vessels close to the surface widen, allowing more blood to flow near to the surface transferring energy to the surroundings

Question 60

what happens to hairs when your hot

Answer 60

hairs lie flat

Question 61

what is vasoconstriction

Answer 61

blood vessels near to the surface of the skin constrict meaning less blood flows near the surface so less energy is transferred to the surroundings

Question 62

why do you shiver when cold

Answer 62

increases rate of respiration, transferring more energy to warm the body

Question 63

what happens to hairs when you are cold

Answer 63

hairs stand on end to trap an insulating layer of air helping to keep you warm

Question 64

why do smaller organisms lose or gain body heart easily

Answer 64

they ahem a bigger surface area to volume ratio

Question 65

what is auxin

Answer 65

plant hormones which control growth at the tips of shoots and roots

Question 66

what is the difference between auxin in shoots and in roots

Answer 66

auxin promotes growth in shoots and inhibits growth in the roots

Question 67

shoot phototropism

Answer 67

positively phototrophic (grow towards the light)

Question 68

how does auxin make shoots grow towards the light

Answer 68

shoot tip accumulates more auxin on the shaded side, making the cells grow faster on the shaded side causing it to bend towards the light

Question 69

shoot geotropism

Answer 69

negatively geotropic (grow away from gravity)

Question 70

how does auxin make a shoot grow away from gravity

Answer 70

when a shoot is growing sideways, gravity produces an unequal distribution of auxin in the tip with more auxin on the lower side. this causes the lower side to grow faster bending the shoot upwards

Question 71

roots geotropism

Answer 71

positively geotropic, grow towards gravity

Question 72

why does auxin make roots grow towards gravity

Answer 72

more auxin on the lower side, it inhibits growth, meaning the cells on top elongate faster bending the root downwards

Question 73

roots phototropism

Answer 73

negatively phototrophic, grow away from light

Question 74

why does auxin make roots grow away from light

Answer 74

more auxin on the shaded side, inhibiting cell elongation and bending the root downwards.

Question 75

why do underground roots grow downwards

Answer 75

positive geotropism, as they are not exposed to the light