Coordination and response

Question 1

What does responding to the environment help organisms do?

Answer 1

Survive

Question 2

What’s a stimulus?

Answer 2

Change in environment

Question 3

What do receptors do?

Answer 3

Detect stimuli

Question 4

What’s an effector?

Answer 4

cells which bring a response to stimuli

Question 5

How do receptors and effectors communicate?

Answer 5

Via the central nervous system or hormonal system

Question 6

What’s in the CNS?

Answer 6

Brain and spine

Question 7

What does the CNS do?

Answer 7

Coordinates electrical impulses to the effectors, very fast responses

Question 8

What’s a reflex?

Answer 8

An automatic response to prevent injury

Question 9

What’s the reflex arc?

Answer 9

Stimulus occurs
receptor creates impulses down the sensory neuron
Impulses are passed along a relay neurone, via a synapse
Impulses travel along a motor neurone, via a synapse
When impulses reach effector the change occurs

Question 10

Structure of the eye?

Answer 10

P45

Question 11

Function of the conjunctiva?

Answer 11

lubricates and protects surface of the eye

Question 12

Function of the cornea?

Answer 12

Refracts light into the eye, transparent and no blood vessels so oxygen diffuses in

Question 13

Function of the iris?

Answer 13

Controls how much light enters the eye

Question 14

Function of the lens?

Answer 14

Focuses the light on the retina

Question 15

Function of the optic nerve?

Answer 15

carries impulses from receptor to the brain

Question 16

What’s the iris reflex?

Answer 16

Bright light= pupil smaller so less light in to damage the retina

Dim light= pupil increases to let more light in to see

Question 17

What happens when the eye focuses on a distant object?

Answer 17

Ciliary muscles relax, suspensory ligaments tighten

Making eyeball thinner, so light reflects onto retina

Question 18

What happens when the eye focuses on a close object?

Answer 18

Ciliary muscles contract, suspensory ligaments slacken

Making eyeball fatter, so light reflects onto retina

Question 19

What does it mean if your long sighted?

Answer 19

Can’t focus on near objects, due to light not being bent enough

Question 20

What does it mean if yourshort sited?

Answer 20

Can’t focus on far objects, since light is bent too much

Question 21

What are hormones?

Answer 21

Chemical messages sent in the blood

Question 22

ADH source Role and effect?

Answer 22

Pituitary gland
Controls water content
Increases the permeability of the kidney

Question 23

Adrenaline source Role and effect?

Answer 23

Adrenal glands
Readies body for fight or flight
Increases blood flow to muscles

Question 24

Insulin source Role and effect?

Answer 24

Pancreas
Helps control blood sugar level
Stimulates the liver to turn glucose into the glycogen for storage

Question 25

Testosterone source Role and effect?

Answer 25

Testes Main male sex hormone Promotes male secondary sexual characteristics

Question 26

Progesterone source Role and effect?

Answer 26

Ovaries Support pregnancy Maintains the lining of the uterus

Question 27

Oestrogen source role and effect?

Answer 27

Ovaries Main female sex hormone Controls menstrual cycle and promotes female secondary characteristics

Question 28

Characteristics of nerves?

Answer 28

Very fast message Act for a short time Act on a precise area

Question 29

Characteristics of hormones?

Answer 29

Slower message Act for a long time Act in a general way

Question 30

What's homeostasis

Answer 30

The maintenance of a constant internal environment

Question 31

How is water lost in the body?

Answer 31

The skin as sweat Lungs as breath Kidneys as urine

Question 32

Why is the body temp 37 degrees?

Answer 32

Optimal for enzymes, CNS triggers effectors to maintain this

Question 33

What happens to the skin when your too hot?

Answer 33

Lots of sweat produced to evaporate and remove heat from the body Vasodilation- blood vessels go closer to skin, so more heat is radiated away Hairs lay flat

Question 34

What happens to the skin you too cold?

Answer 34

Little sweat produced Vasoconstriction, blood vessels move away from skin surface Shiver to create heat Hairs stand up

Question 35

Why do smaller organisms cool down quicker?

Answer 35

Bigger surface area to volume ratio

Question 36

How do plants respond o changes in environment?

Answer 36

Grow towards light to maximise photosynthesis Sense gravity, so their roots grow in the right direction Climbing plants have a sense of touch

Question 37

How do plants respond to predators?

Answer 37

Produce toxins

Question 38

How do plants respond the abiotic stress?

Answer 38

Produce antifreeze

Question 39

What does auxin do?

Answer 39

Plant growth hormone which prevents growth in shoots, but causes growth in roots

Question 40

How are shoots positively phototropic?

Answer 40

Auxin goes to the side of shoot in shade, causing it to grow towards the light, they also grow away from gravity

Question 41

How are roots positively geotropic?

Answer 41

More auxin in lower side, causing it to grow downwards