coordination and response

Question 1

what are the parts of the nervous system

Answer 1

• central nervous system

- peripheral nervous system

Question 2

what is the central nervous system

Answer 2

Central nervous system (CNS) consisting of the brain and spinal cord, which are the areas of coordination

Question 3

what is the peripheral nervous system

Answer 3

Peripheral nervous system (PNS) made up of nerves and neurones, which coordinate and regulate bodily functions.

Question 4

what are involuntary actions

Answer 4

not under conscious control e.g. reflex action

Question 5

what are voluntary actions

Answer 5

are done if we decide to carry them out

Question 6

what are nerve impulses

Answer 6

an electrical signal that passes along nerve cells called neurones

Question 7

types of neurones

Answer 7

• motor neurone
• sensory neurone
• relay (connector) neurone

Question 8

what is a reflex action

Answer 8

A reflex action is an involuntary, quick action to respond to a stimulus, in order to protect the body from danger
means of automatically and rapidly integrating and coordinating stimuli with the responses of effectors (muscles and glands)

E.g. quickly removing your hand from hot metal surface

They involve three neurones: a sensory neurone, relay neurone and motor neurone.

Question 9

what is a synapse

Answer 9

The gap between neurones is called a synapse. a junction between two neurones, consisting of a gap across which impulses pass by diffusion of a neurotransmitter

Question 10

how the reflex arc works

Answer 10

A stimulus affects a receptor (cell or organ that converts a stimulus into an electrical impulse)

A sensory neurone carries impulse from the receptor to the CNS

Connector/relay neurone carries impulse slowly (because it has no myelin sheath) across the spinal chord

Motor neurone carries impulse from the CNS to the effector

Effector (either a muscle or a gland) carries out the response

Question 11

what is a synaptic cleft

Answer 11

small gap between each pair of neurones

Question 12

describe diffusion of a neurotransmitter (synapses)

Answer 12

Inside the neurones axom, there are 100s of tiny vacuoles (vessicles each contain a chemical called neurotransmitter)

When an impulse arrives, the vessicles move to the cell membrane and empty their content into the synaptic cleft

The neurotransmitter quickly diffuses across the tiny gap and attaches to receptor molecules in the cell membrane of the relay neurone

This can happen because the shape of the neurotransmitter molecules is complimentary to the shape of the receptor molecule

Many drugs e.g. heroin act upon synapses

Question 13

what are antagonistic muscles

Answer 13

A muscle that opposes the action of another; e.g. biceps and triceps are antagonistic muscles or circular and radial muscles in the eye

Question 14

what is an agonist muscle

Answer 14

a muscle that contracts while another relaxes; e.g. when bending the elbow, the biceps are the agonist

Question 15

what is an antagonist mucsle

Answer 15

a muscle that relaxes while another contracts; e.g. when bending the elbow, the triceps are the antagonist

Question 16

what are sense organs

Answer 16

groups of receptor cells responding to specific stimuli: light, sound, touch, temperature and chemicals.

Question 17

what is the eye

Answer 17

The sense organ responsible for sight

Question 18

parts of the eye

Answer 18

Cornea: refracts light

Iris: controls how much light enters pupil

Lens: focuses light onto retina

Retina: contains light receptors, some sensitive to light of different colours

Optic nerve: carries impulses to the brain

Question 19

what is (sensory) accomodation

Answer 19

• adjusting for near and distant objects
• light rays from distance objects are parallel so do not need much refraction to focus properly
• light rays from closer objects diverged and need much refraction to focus properly

Question 20

what happens to the eye when viewing a near object

Answer 20

• ciliary muscles contract
• ligaments relax
• lens becomes short nd fat

Question 21

what happens to the eye when viewing a distant object

Answer 21

• ciliary muscles relax
• ligaments are tight
• lens becomes long and thin

Question 22

what is pupil reflex

Answer 22

-adjusting for high and low light intensity

Question 23

pupil reflex in low light intensity

Answer 23

Radial muscles (straight lines) contract and become shorter to pull the pupil (black dot) making it wider, to let more light enter, to form a clear image on retina

Question 24

pupil reflex in high light intensity

Answer 24

Circular muscles (circular lines) contract and become shorter to reduce the size of the pupil to protect retina from bleaching.

Question 25

what are rods

Answer 25

- Provide low detail, black & white images, good for seeing in low intensity light (at night). - Packed most tightly around edge of retina so you can see things most clearly when not looking directly at them.

Question 26

what are cones

Answer 26

- Provide detailed, coloured images; they work in high light intensity. - Most tightly packed at centre of retina, so objects are seen most clearly when being directly looked at.

Question 27

what is the fovea

Answer 27

Part of the retina where the receptor cells are pushed most closley together Where light is focused when you look straight at an object has the highest concentration of light sensitive cells and gives the most detailed image

Question 28

what are hormones

Answer 28

A chemical substance, produced by a gland, carried by the blood, which alters the activity of one or more specific target organs and is then destroyed by the liver.

Question 29

what is adrenaline

Answer 29

A hormone secreted by the adrenal gland. It increases pulse rate, makes the glycogen in muscles get converted to glucose, and released into blood, makes you breath deeper and more rapidly, airways become wider, and makes skin become pale as blood is diverted away. Increases conc. of glucose in the blood for respiration. Adrenaline is secreted for example: while bungee jumping or riding a rollercoaster

Question 30

function of adrenal gland

Answer 30

- secretes adrenaline | - Prepares body for vigorous action

Question 31

function of pancreas

Answer 31

- secretes insulin | - Reduces conc. of glucose in blood

Question 32

function of testis

Answer 32

- secretes testosterone | - Causes development of male sexual characteristics

Question 33

function of ovary

Answer 33

- secretes oestrogen | - Causes development of female sexual characteristics

Question 34

comparison of nervous and hormonal system speed of action

Answer 34

- nervous: rapid | - endocrine: can be slow

Question 35

comparison of nervous and hormonal system nature of message

Answer 35

- nervous: Electrical impulses, travelling along nerves | - endocrine: Chemical messenger (hormones) travelling in bloodstream

Question 36

comparison of nervous and hormonal system duration of response

Answer 36

- nervous: Usually within seconds | - endocrine: May take years (puberty)

Question 37

comparison of nervous and hormonal system area of response

Answer 37

- nervous: Localized response (only one area usually) | - endocrine: Widespread response (in many organs)

Question 38

comparison of nervous and hormonal system example of process controlled

Answer 38

- nervous: Reflexes such as blinking | - endocrine: Reflexes such as blinking

Question 39

use of hormones in food production advantages and disadvantages

Answer 39

Hormones are used in food production, for example oestrogen is used to boost growth rate of chickens. Advantage: chickens grow quickly meaning more profit. Disadvantages: this may cause human males to develop feminine characteristics, and it is unnatural.

Question 40

what is homeostasis

Answer 40

The maintenance of a constant internal environment. Homeostasis is the control of internal conditions within set limits

Question 41

what is negative feedback

Answer 41

Feedback controls the production of hormones – the hormones regulate their own production. A negative feedback control is when the change in hormone level acts as a signal to cancel out that change, so when blood hormone level is low, hormone production is stimulated, when it is high, it is inhibited.

Question 42

what is glucoregulation

Answer 42

Blood glucose levels are monitored and controlled by the pancreas The pancreas produces and releases different hormones depending on the blood glucose level Insulin is released when blood glucose levels are high – the liver stores excess glucose as glycogen Glucagon is released when blood glucose levels are low – the liver converts stored glycogen into glucose and releases it into the blood

Question 43

what is type 1 diabetes

Answer 43

When the control of blood glucose does not work, a person is said to have diabetes Type 1 diabetes is caused by the death of the cells that secrete insulin

Question 44

symptoms of type 1 diabetes

Answer 44

hyperglycaemia (feel unwell, dry mouth, blurred vision and feel thirsty) or hypoglycaemia (tired, show confusion and irrational behaviour)

Question 45

treatment of type 1 diabetes

Answer 45

eating little and often and avoiding large amount of carbohydrates, injecting insulin to reduce blood glucose concentration

Question 46

thermoregulation of insulation

Answer 46

provided by fatty tissue retains heat. Hairs become erect to trap warm air by contracting erector muscles and vice versa.

Question 47

thermoregulation of vasodilation

Answer 47

when it is hot, arterioles, which supply blood to the skin-surface capillaries, dilate (become wider) to allow more blood near to skin surface to increase heat loss (face redder)

Question 48

thermoregulation of sweating

Answer 48

the water evaporates giving a cooling effect

Question 49

thermoregulation of skin receptors

Answer 49

sense heat and sensory neurons send impulses to the hypothalamus

Question 50

thermoregulation of shivering

Answer 50

muscular activity generates heat

Question 51

thermoregulation of thermoregulatory centre

Answer 51

in the hypothalamus, it controls the use of corrective mechanisms (e.g. sweating and shivering).

Question 52

homeostasis of cells

Answer 52

change composition of blood as they remove nutrients and O2 and add wastes and CO2

Question 53

homeostasis of heart

Answer 53

keeps blood pressure constant to deliver oxygen and nutrients around body

Question 54

homeostasis of skin

Answer 54

to maintain heat exchange with external environment

Question 55

homeostasis of kidneys

Answer 55

regulate water and salt levels (osmoregulation) and the removal of wastes like urea (excretion)

Question 56

homeostasis of lungs

Answer 56

regulate gas exchange

Question 57

homeostasis of intestines

Answer 57

Intestines: supply soluble nutrients and water to blood

Question 58

homeostasis of liver

Answer 58

regulates blood solutes and removes toxins

Question 59

homeostatic organs

Answer 59

- cells - heart - skin - kidneys - lungs - liver

Question 60

what is auxin

Answer 60

Plant hormones or growth substances Controls tropisms It is produced by cells at the tip of roots and shoots of plants

Question 61

what is gravitropism

Answer 61

a response in which a plant grows towards (positive) or away (negative) from gravity.

Question 62

auxins role in gravitropism

Answer 62

Tend to settle at the bottom end of the root. However, this does not make the cells of the tip of the root grow longer; auxins prevent cells at bottom tip of root from growing, making cells at top of root grow faster. When cells of top of the root grow faster, they push root deeper into soil and root gets longer. The root grows in direction of the gravitational pull.

Question 63

what is phototropism

Answer 63

a response in which a plant grows towards (positive) or away (negative) from the direction from which light is coming.

Question 64

auxins role in phototropism

Answer 64

If sun shines on right side of a plant’s shoot, auxins will accumulate on dark opposite left side. Auxins accumulating makes cells on left side grow faster than cells on right side. When left side of shoot starts growing faster than right side, shoot will start to bend to right side towards sunlight.

Question 65

use of hormones as weed killers

Answer 65

Hormones can be used as weed killers: spraying with high concentrations of hormone (2,4-D) upsets normal growth patterns. It affects different species differently so might only kill one species not the other (this is good). 2,4-D is a weedkiller / AW ; sprayed on crops / applied to leaves ; specific to broadleaved weeds ; does not affect, cereals / narrow-leaved crop plants ; causes uncontrolled growth

Question 66

structure of neurones

Answer 66

Neurones have a long fibre (axon) This means that less time is wasted transferring the impulse from one cell to another The axon is insulated by a fatty sheath with small uninsulated sections along it (called nodes) This means that the electrical impulse does not travel down the whole axon, but jumps from one node to the next Their cell body contains many extensions called dendrites This means they can connect to many other neurones and receive impulses from them, forming a network for easy communication

Question 67

advantages of coordinating endocrine and nervous system

Answer 67

4(d) nervous system, responds quickly / immediately ; ora idea that (nerve) impulses travel to, (specific) muscles / (adrenal) glands / effector(s) ; effects of endocrine system are long lasting ; ora hormones / adrenaline, travels throughout the body / allows multiple (target) organs to respond (to same signal) ; idea that less energy required than to have nerves going to every, cell / tissue ; stimulate both voluntary and involuntary responses (simultaneously) ; more effective / enhanced, response (than using one system alone) ;