B1 2 Coordination and Control Flashcards

0
Q

What is a stimulus?

A

A change in the environment.

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1
Q

What does the nervous system do?

A

It coordinates and controls your body so that you react to your surroundings in the appropriate way.

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2
Q

How are stimuli detected?

A

By receptors found in the sense organs.

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3
Q

What does the receptor cell contain?

A

A cell membrane, nucleus and cytoplasm; just like an animal cell.

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4
Q

State the receptors and the stimuli detected in each of the 5 different sense organs.

A

Eye - eye receptors - light

Nose - nose receptors - chemicals in air

Tongue - taste receptors - chemicals in food

Ear - ear receptors - sound and balance

Skin - touch and temperature receptors - heat, coldness and pressure

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5
Q

What does the central nervous system (CNS) contain?

A

Brain and spinal cord; is linked to sense organs by neurones.

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6
Q

What are the 2 types of responses?

A

Voluntary and reflex

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7
Q

What is the difference between a voluntary response and a reflex response?

A

A voluntary response requires involvement of the brain and conscious thought whereas reflex responses don’t. This means reflex responses help survival and are quick and automatic.

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8
Q

What happens during a voluntary response?

A

The stimulation of receptors in the sense organs sends electrical impulses along sensory neurones to the conscious part of the brain which coordinates the response; electrical impulses are sent through motor neurones to the effectors (muscles or glands) resulting in a response.

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9
Q

What is the brain also known as?

A

The coordinator

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10
Q

What is the reflex pathway called?

A

Reflex arc

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11
Q

What are the jobs of the three neurones in a reflex response?

A

Sensory neurones - carry electrical impulses from the receptors in the sense organs to the coordinator which can be the unconscious area of the brain but is often the spinal cord. Relay neurones (found only in CNS) - carry electrical impulses from the sensory neurone to the motor neurone. Motor neurones - carry electrical impulses from the relay neurone to the effector,

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12
Q

What are the effectors? How do each of them respond?

A

Muscles and glands Muscles respond by contracting. Glands redoing by secreting chemical substances.

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13
Q

How do neurones connect with each other?

A

Via a synapse; which is a gap.

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14
Q

How does communication happen across a synapse?

A

By the release of a chemical which diffuses across the gap; electric impulses turn into chemicals and back into electrical impulses.

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15
Q

What is the function of the hormonal system?

A

It controls and coordinates the body just like the nervous system.

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16
Q

What are hormones? What is their function?

A

They are chemicals. They get secreted by glands straight into the bloodstream to target organs.

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17
Q

What are the effects of hormones like compared with the effects of reflex actions?

A

Reflexes are rapid and last for a shorter period of time whereas the effect of hormones is slow and long lasting.

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18
Q

Give an example of a process controlled by hormones.

A

The menstrual cycle

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19
Q

What are the hormones involved in the menstrual cycle? Give their functions.

A

FSH (Follicle Stimulating Hormone) - secreted by pituitary; matures eggs in ovaries and stimulates the secretion of oestrogen from ovaries. LH (Luteinising Hormone) - secreted by pituitary; makes egg ovulate from ovary. (ovulation) Oestrogen - secreted by ovaries; inhibits FSH, stimulates LH and thickens endometrium. Progesterone - secreted by ovary; helps maintain the thickness of the endometrium.

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20
Q

What happens in the menstrual cycle in brief?

A

The menstrual cycle produces a new egg each month and thickens the uterus lining each month in case pregnancy happens. It lasts for 28 days and day 1 is he first day of a period. If the egg is not fertilised by the end of 28 days, oestrogen levels drop and the uterus lining is lost. This brings about a period or menstruation. The cycle repeats.

21
Q

What happens if an egg is fertilised?

A

It gets fertilised in the Fallopian tube, the embryo buries itself in womb lining. Here the embryo is supplied with food and oxygen from the mother’s blood.

22
Q

What can hormones also be used for?

A

To control fertility.

23
Q

What did the first contraceptive pills contain and how did it work?

A

It contained high levels of oestrogen which inhibited FSH production which then stopped eggs maturing in the ovary.

24
Q

What was the problem with the early contraceptive pills? Therefore, what do the modern contraceptive pills contain?

A

They caused serious side effects such as high blood pressure and headaches. Nowadays pills contain lower doses of oestrogen along with done progesterone.

25
Q

What hormones do fertility drugs contain and how do they work?

A

FSH and LH FSH matures the eggs in the ovary and LH makes them ovulate.

26
Q

What does IVF stand for and when is it used?

A

In-Vitro fertilisation It is used when a woman has blocked Fallopian tubes.

27
Q

What happens in IVF treatments?

A

In a laboratory, a sperm is allowed to fertilise an egg in a Petri dish. Some eggs are collected from the mother and a sample of semen from the father. 1 or 2 embryos are put back into the woman’s womb.

28
Q

What are the advantages of using hormones to control fertility?

A

The women can plan when to have babies and can get help when having problems conceiving.

29
Q

What are the disadvantages of using fertility drugs?

A

• They can have some health risks for the mother. • They can be expensive for society and parents, • Can raise ethical issues for society and individuals.

30
Q

What is homeostasis?

A

The maintenance of a constant internal environment.

31
Q

What needs to be maintained in the body?

A

Water, sugar, salt and temperature levels.

32
Q

How is water gained and lost? What happens when there’s too much or too little of it?

A

It is gained from good and drink and is lost by sweating, breathing and in urine. If too much: • Kidneys make more urine • You urinate more frequently • You urinate a greater volume of urine • Your urine is pale in colour If too little: • Your kidneys make less urine • You urinate less frequently • You urinate a smaller volume of urine • Your urine is dark yellow in colour

33
Q

How is salt gained and lost? What happens when there’s too much or too little of it?

A

Salt is gained from food and drink and is lost by sweating and in urine. If too much: • Your kidneys put more salt into the urine. If too little: • Your kidneys put less salt into the urine.

34
Q

How is sugar gained and lost? What happens when there’s too much or too little of it?

A

Sugar is gained from food and drink and is lost when exercising or dieting/fasting; sugar is needed for respiration in cells so that they can release energy. If too much: • Your pancreas detects the increase in sugar. • The pancreas releases the hormone insulin into the blood. • Insulin reduces the level of sugar in your blood by storing excess sugar in the liver. If too little: • Your pancreas detects the decrease in sugar. • Sugar stored in the liver is released into the blood.

35
Q

How is body temperature kept at 37*C? What happens when there’s too much or too little of it?

A

Body temperature is controlled by the brain (a thermostat) and the nervous system; body temperature needs to be at the optimum temperature for enzymes. If too high: • Your brain detects the increase in temperature. • You sweat to cool down. If too low: • Your brain detects the decrease in temperature. • You stop sweating.

36
Q

What are plant hormones called; what are their functions?

A

They are called auxins; they control and coordinate growth by controlling the amount of water that enters the vacuole; the distribution of auxin will cause different parts of the plant to grow at different rates.

37
Q

How do plant cells make auxin?

A

By dividing

38
Q

What are plants sensitive too? How do they respond to these; what are the responses called?

A

Light, moisture and gravity. They respond by growing in different directions; these are called tropisms.

39
Q

What do shoots grow towards and away from? What is each described as?

A

They grow towards light - positively phototropic. They grow away from the force of gravity - negatively gravitropic (geotropic)

40
Q

What do roots grow towards and away from? What is each described as?

A

They grow towards the force of gravity - positively gravitropic. They grow towards moisture - positively hydrotropic. They grow away from light - negatively phototropic.

41
Q

What role does auxin play in phototropism and gravitropism (geotropism) in shoots?

A

• If a shoot is lit from one side, auxin moves to the shady side of shoot and stimulates cells to elongate. • Great elongation of cells on the shaded side compared to the cells on the lit side means that the shoot bends towards the light.

42
Q

What role does auxin play in phototropism and gravitropism (geotropism) in roots?

A

• If a root is lit from one side, auxin moves to the shady side of roots and inhibits growth in cells. • Inhibition in growth of cells on the shaded side compared to the cells on the lit side means that the root bends towards the force of gravity or moisture.

43
Q

What benefits to plants get when the shoot grows upwards?

A

• They can photosynthesise. • They can grow.

44
Q

What benefits to plants get when the root grows downwards?

A

• They can obtain water and dissolved minerals. • To anchor the plant.

45
Q

What is a synthetic chemical auxin used in and as what?

A

It is used in agriculture or horticulture as a weed killer.

46
Q

How does a weed killer work?

A

It only affects broad-leaved plants such as weeds making then grow really quickly so the weeds die. The weed killer does not affect narrow-leaved plants such as grass.

47
Q

Auxin is used as a rooting hormone; what is it’s function as a rooting hormone?

A

To encourage the stems of cuttings to produce roots.

48
Q

Ethene (ethylene) is a plant hormone which is produced by fruits as they ripen; how does it make the fruit taste sweet?

A

It converts starch to sugar in the fruit.

49
Q

What can synthetic plant hormone weed killers cause to the environment?

A

Damage