B9 Coordination and response

Question 1

describe nerve impulse

Answer 1

electrical signal that passes along nerve cells (neurones)

Question 2

describe the human nervous system (3)

Answer 2

1. central nervous system (CNS)
2. peripheral nervous system
3. coordination and regulation of body functions

Question 3

CNS consists of…

Answer 3

brain and spinal cord

Question 4

peripheral nervous system consists of..

Answer 4

motor neurones and sensory neurones

Question 5

define voluntary action

Answer 5

conscious decisions, it takes longer time and produces different responses everytime

Question 6

define involuntary action

Answer 6

do not involve conscious decisions, takes short time and produces same responses everytime

Question 7

explain reflex arc

Answer 7

a neutral pathway that controls reflex

stimuli - receptor - sensory neurone - relay neurone - motor neurone - effector - response

Question 8

effector example

Answer 8

muscle or gland

Question 9

identify the structures of the eye (9)

Answer 9

1. cornea
2. iris
3. pupil
4. lens
5. ciliary muscle
6. retina
7. optic nerve
8. suspensory ligament
9. blind spot

Question 10

function of cornea

Answer 10

refracts light

Question 11

function of iris

Answer 11

controls the amount of light entering the pupil

Question 12

function of lens

Answer 12

focuses light into retina

Question 13

function of retina

Answer 13

contains light receptors, some sensitive to light of different colors

Question 14

function of optic nerve

Answer 14

carries impulses to the brain

Question 15

rods are located in … and they are sensitive to …..

Answer 15

peripheral parts of the retina

light - black and white

work well in dim lights

Question 16

cons are located in … and they are sensitive to …..

Answer 16

fovea

color

works well in bright light

Question 17

pupil reflex
high light intensity

Answer 17

circular muscle contract
radial muscle relax
pupil size decrease

Question 18

pupil reflex
low light intensity

Answer 18

circular muscle relax
radial muscle contract
pupil size increase

Question 19

accommodation
near objects

Answer 19

ciliary muscle contract
suspensory ligament loosen
refraction large
lens shape fat and short

Question 20

accommodation
far objects

Answer 20

ciliary muscle relax
suspensory ligament tighten
refraction less
lens shape thin and long

Question 21

define hormones

Answer 21

chemical substance, produces by gland carried by blood, which alters the activity of one of more specific target organs

Question 22

describe adrenaline in terms of the secretion organ, effects, and when it is secreted

Answer 22

secreted from adrenal gland

increases breathing rate to provide more o2 and glucose to the muscles
widens pupil to detect more light
increases pulse rate

secreted in dangerous situation - ‘fight or flight’
eg. intense exercise, dangerous situation

Question 23

describe the role of adrenaline

Answer 23

• increase blood glucose concentration
• increase pulse rate

Question 24

compare nervous system and hormonal control system in terms of speed and longevity of action

Answer 24

nervous system
- fast
- short lasting
hormonal system
- slow
- long lasting

Question 25

define homeostasis

Answer 25

maintenance of a constant internal environment within a set limit

Question 26

describe negative feedback

Answer 26

cancels the change made if its excess of deficient of set limit

eg. excess
detected by receptor
effectors stimulated and initiate corrective mechanisms
restoration of set point

Question 27

describe the control of the glucose content of the blood
excess and deficiency

Answer 27

excess
- blood with too much glucose
- pancreas detect it and release insulin
- blood moves to liver and insulin makes glucose intro glycogen and stores in liver
- blood glucose decreased

deficiency
- blood with too little glucose
- pancreas detects it and release glucagon
- glucagon makes the liver turn stored glycogen into glucose and release to blood
- blood glucose increased

Question 28

describe the mechanism to reduce body temperature (3)

Answer 28

1. hair lie flat
   less air is trapped for insulation
2. sweating
   water evaporated and cooling effect
3. vasodilation
   arterioles near the surface of the skin dilate and makes more blood flow through the capillaries in the surface of the skin, to release more heat

Question 29

describe the mechanism to increase body temperature (3)

Answer 29

1. hair stands up
   more air trapped for insulation
2. shivering
   muscle contracts and more heat is produced from increased respiration rate
3. vasocontraction
   arterioles contract, release less blood for less heat loss

Question 30

define gravitropism

Answer 30

plant growing towards or away from gravity

Question 31

define phototropism

Answer 31

plant growing towards or away from the direction from which light is coming

Question 32

shoots are …….. ……….

Answer 32

negative gravitropism
positive phototropism

Question 33

roots are …….. ………

Answer 33

positive gravitropism
negative phototropism

Question 34

explain the role of auxin of controlling shoot growth (4)

Answer 34

1. made in shoot tips
2. spreads through the plant from shoot ip
3. unequally distributed in response to light and gravity
4. stimulated cell elongation