Coordination & Response Yr10

Question 1

What is a stimulus?

Answer 1

A change in an organism’s internal/external environment

Question 2

What is a receptor?

Answer 2

Detects the stimuli

Question 3

What is an effector?

Answer 3

Cells in muscles/glands that bring about a response to stimuli

Question 4

What is the central nervous system made up of?

Answer 4

Brain
Spinal cord

Question 5

What does the CNS do?

Answer 5

Coordinates a response

Question 6

What is a synapse?

Answer 6

Gap between neurones

Question 7

How do synapses work?

Answer 7

1) nerve signal is transferred by chemicals called neurotransmitters which diffuse across gap
2) chemicals then set off a new electrical signal in the next neurone

Question 8

What is a reflex?

Answer 8

Automatic response to stimuli which keep you safe from harm

Question 9

What is a reflex arc?

Answer 9

Route taken by information in a reflex

Question 10

Reflex arc (hot object)

Answer 10

1) receptor detects stimulus (heat), sends electrical impulse along sensory neurone to CNS
2) in CNS, the relay neurone receives the impulse + sends it down motor neurone
3) impulse will reach an effector (muscle)
4) muscle contracts to pull arm away

Question 11

What is the conjunctiva?

Answer 11

Lubricates + protects surface of eye

Question 12

What is the sclera?

Answer 12

Tough outer layer that protects eye

Question 13

What is the cornea?

Answer 13

Refracts light into eye
Transparent

Question 14

What is the iris?

Answer 14

Controls diameter of pupil
- how much light enters eye

Question 15

What is the lens?

Answer 15

Focuses light onto retina

Question 16

What is the optic nerve?

Answer 16

Carries impulse from receptors to brain

Question 17

What is the retina?

Answer 17

Light-sensitive
Contains light receptors (rods and cones)

Question 18

What are rods and cones?

Answer 18

Rods: more sensitive in dark light
Cones: more sensitive to colours (don’t work in dim light)

Question 19

What happens when ur in bright light?

Answer 19

Circular muscles: CONTRACT
Radial muscle: RELAX
Pupil: SMALL
Light in eye: LITTLE

Question 20

What happens when ur in dim light?

Answer 20

Circular muscles: RELAX
Radial muscle: CONTRACT
Pupil: LARGE
Light in eye: LOTS

Question 21

What is accomodation?

Answer 21

Eye focuses light on retina by changing shape of lens

Question 22

What happens when focusing on near objects?

Answer 22

Ciliary muscle: CONTRACT
Suspensory ligaments: LOOSEN
Lens: FAT
Light refracted: LOTS

Question 23

What happens when focusing on distant objects?

Answer 23

Ciliary muscle: RELAXES
Suspensory ligaments: TIGHTEN
Lens: THIN
Light refracted: LITTLE

Question 24

Short-sighted people:

Answer 24

Can’t focus on distant objects
- cornea/lens refracts too much light or eyeball is too long

Question 25

Long-sighted people:

Answer 25

Can’t focus on near objects - cornea/lens refracts too little light or eyeball is too short

Question 26

What is a hormone?

Answer 26

Chemicals released directly into blood - only affect target cells

Question 27

What hormone does the adrenal gland secrete?

Answer 27

Adrenaline

Question 28

What is the function of adrenaline?

Answer 28

Prepares body for ‘fight or flight’ response - increases heart rate, blood flow + blood sugar level

Question 29

What hormone does the pancreas secrete?

Answer 29

Insulin

Question 30

What is the function of insulin?

Answer 30

Helps control blood sugar level - increases glucose taken up by cells - stimulates liver to turn glucose into glycogen for storage

Question 31

What hormone do the testes secrete?

Answer 31

Testosterone

Question 32

What is the function of testosterone?

Answer 32

Main male sex hormone - promotes male secondary sexual characteristics (facial hair)

Question 33

What hormones do the ovaries secrete?

Answer 33

Oestrogen Progesterone

Question 34

What is the function of oestrogen?

Answer 34

Main female sex hormone - controls menstrual cycle - promotes female secondary sexual characteristics (hips widen)

Question 35

What is the function of progesterone?

Answer 35

Maintains uterus lining

Question 36

Nervous system:

Answer 36

Electrical Nerves Localised Fast Short-term effects

Question 37

Endocrine system:

Answer 37

Chemical Blood Systemic Slow Long-term effects

Question 38

What is homeostasis?

Answer 38

Maintenance of a constant internal environment

Question 39

What are 2 examples of homeostasis?

Answer 39

Water content Body temperature

Question 40

How is water lost in the body?

Answer 40

Through skin as sweat Via lungs in breath Via kidneys as urine

Question 41

Water content on a hot day:

Answer 41

Produce less urine - more concentrated Lose more water through breathing + sweating

Question 42

Water content on a cold day:

Answer 42

Produce more urine - less concentrated Lose less water through sweat

Question 43

What temperature do enzymes in the body work best as?

Answer 43

37C

Question 44

How does the brain act as a thermostat?

Answer 44

Receives messages from temp receptors in skin CNS can activate necessary effectors to regulate body temp

Question 45

What happens when you’re too hot?

Answer 45

VASODILATION: blood vessels dilate so more blood is at surface - more heat energy lost SWEATING: when it evaporates it transfers energy from skin to environment HAIRS: lie flat

Question 46

What happens when you’re too cold?

Answer 46

VASOCONSTRICTION: blood vessels constrict so less blood is at surface - less heat energy lost SHIVERING: increases rate of respiration - transfers more energy to warm body up HAIRS: stand up to trap insulating layer of air Little sweat produced

Question 47

What do smaller organisms have?

Answer 47

Bigger surface area to volume ratio

Question 48

Why do smaller organisms gain/lose heat faster?

Answer 48

They have more area for heat to transfer across - reduces chance of overheating - more vulnerable in cold environments

Question 49

What do bigger organisms have?

Answer 49

Smaller surface area to volume ratio

Question 50

Why do bigger organisms gain/lose heat slower?

Answer 50

They have less area for heat to transfer across

Question 51

Why are animals in cold environments round?

Answer 51

To keep their SA to a minimum - to reduce heat loss

Question 52

What does responses in plants do?

Answer 52

Increase their chance of survival

Question 53

What is auxin?

Answer 53

Plant growth hormone

Question 54

Where is auxin produced?

Answer 54

In tips of shoots + roots

Question 55

What does auxin do in shoots?

Answer 55

Stimulates growth

Question 56

What does auxin do in roots?

Answer 56

Inhibits growth

Question 57

Where does auxin accumulate in shoots?

Answer 57

On shaded side

Question 58

Where does auxin accumulate in roots?

Answer 58

On lower side

Question 59

What are shoots?

Answer 59

Positively phototrophic Negatively geotrophic

Question 60

What are roots?

Answer 60

Negatively phototrophic Positively geotrophic

Question 61

How does positive phototropism work? (SHOOT)

Answer 61

Auxin accumulates on shaded side Cell elongation faster on shaded side - shoot bends TOWARDS light

Question 62

How does negative geotropism work? (SHOOT)

Answer 62

Auxin accumulates on lower side Cell elongates faster on lower side - shoot bends UPWARDS

Question 63

How does negative phototropism work? (ROOT)

Answer 63

Auxin accumulates on shaded side Auxin inhibits cell elongation on shaded side - root bends DOWNWARDS (into ground)

Question 64

How does positive geotropism work? (ROOT)

Answer 64

Auxin accumulates on lower side Auxin inhibits cell elongation of lower side (so top elongates faster) - root bends DOWNWARDS (into ground)

Question 65

What does positively phototrophic mean?

Answer 65

Grows towards light

Question 66

What does negatively geotrophic mean?

Answer 66

Grows away from ground

Question 67

What does negatively phototrophic mean?

Answer 67

Grow away from light

Question 68

What does positively geotrophic mean?

Answer 68

Grows towards ground