coordination and response

Question 1

define stimulus

Answer 1

a change in the external or internal environment

Question 2

CNS

Answer 2

central nervous system: brain and spinal cord

Question 3

sensory neurone

Answer 3

carries impulse from receptor to CNS
-cell body in the middle of axon

Question 4

motor neurone

Answer 4

carries impulse from CNS to effector
-cell body at end of neurone
-long axon

Question 5

relay neurone

Answer 5

carries impulse through the CNS
-lots of dendrite

Question 6

reflex arc

Answer 6

1. receptor detects stimuli
2. sensory neurone carries impulse form receptor to CNS
3. relay neurone carries impulse through the CNS
4. crosses a synapse by neuro transmitters
5. motore neurone carries impulse from CNS to effector
6. effector contracts so muscle cause movement

Question 7

explain a synapse

Answer 7

1. impulse reaches end of a neurone
2. the impulse signals for neuro transmitters to be released into the synapse
3. they bind to receptors on the cell membrane of the next neurone
4. they signal the electrical impulse to be carried out

Question 8

differences between nervous and hormonal

Answer 8

-nervous are fast, hormonal is slow
-in the nervous system the message is electrical impulses, in hormonal the message is chemical hormones
-nervous is short lasting, hormonal has long lasting effects
-nervous system has a more specific target, hormonal has a larger area of affect
-in the nervous system the message is carried by neurone, in hormonal system message is carried in blood stream in plasma

Question 9

role of reflexes

Answer 9

rapid, unconscious, involuntary response to stimuli that could cause you danger or harm, they are protective

Question 10

function of iris

Answer 10

controls diameter of pupil by contractions of circual and radial muscles

Question 11

function of pupil

Answer 11

allows light into the eye

Question 12

function of cornea

Answer 12

reflects light

Question 13

function of lens

Answer 13

retracts light

Question 14

function of fovea

Answer 14

highest conc. of cone cells so colour is best seen here

Question 15

cone cells

Answer 15

colour

Question 16

Rod cells

Answer 16

light

Question 17

function of retina

Answer 17

contains rods and cones, images are made here

Question 18

function of optical nerve

Answer 18

carries electrical impulses to brain

Question 19

function of sclera

Answer 19

protection

Question 20

function of conjunctiva

Answer 20

protection

Question 21

how does lens change because of near objects

Answer 21

suspensory ligaments slacken, ciliary muscles contract, lens gets shorter and thicker so light is refracted more

Question 22

how does lens change because of far away objects

Answer 22

suspensor ligaments tighten, ciliary muscles relax, lens becomes thinner and longer so light is refracted less

Question 23

how does your iris react to bright lights

Answer 23

radial muscles relax, circular muscles contract, diameter of pupil decreases so more light is let in

Question 24

how does your iris react to dim lights

Answer 24

radial muscles contract, circular muscles relax, pupil diameter increases to let more light in to the eye

Question 25

define tropism

Answer 25

directional growth in response to a stimulus

Question 26

name the hormone in plants that allows phototropism and geotropism

Answer 26

auxin, released from tip of shoot

Question 27

phototropism

Answer 27

auxin is released at the tip of the shoot, it accumulates on the shaded side of the shoot and promotes cell elongation so the plant grows toward the light

Question 28

geotropism in roots above the ground

Answer 28

auxin is released in the root, it accumulates of the lowest side of the root and inhibits cell elongation so the root grows towards the ground

Question 29

phloem

Answer 29

-cells are living but need support
-two way movement
-organic molecules

Question 30

xylem

Answer 30

-water and minerals
-no end wall between cells
-one way only
-outer cells are not living