Homeostasis and Response Flashcards

1
Q

What is homeostasis?

A

The regulation of the internal condition of a ell or organisms in response to internal and external changes.

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2
Q

What is a receptor?

A

A cell that detects stimuli (changes in the environment).

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3
Q

What are coordination centers?

A

Examples are the brain, spinal cord and pancreas. They receive information from receptors.

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4
Q

What are effectors?

A

Muscles or glands which bring about responses that restore optimum levels.

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5
Q

What is the thermoregulatory center?

A

The body’s temperature control center in the brain- it monitors and controls body temperature.

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6
Q

What is vasodiliation?

A

The widening of blood vessels to direct more blood to the surface in order to lose heat (this happens when the body is too hot).

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7
Q

What is vasocontstriction?

A

The narrowing of the blood vessels in order to direct blood away from the surface to keep heat in (this happens when the body’s temperature is too low).

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8
Q

What is the ideal temperature for the human body?

A

37°C.

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9
Q

Why is it important that the body’s temperature doesn’t become too high?

A

Because the enzymes in the body will denature if the temperature is too high.

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10
Q

Why do humans shiver?

A

To transfer heat to the blood.

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11
Q

What does CNS stand for?

A

Central nervous system.

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12
Q

What does the CNS do?

A

It enables humans to react with their surroundings and coordinates the response of effectors.

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13
Q

What are the gaps between neurones called?

A

Synapses.

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14
Q

What are the three main parts of the brain?

A

Cerebellum, cerebral cortex, medulla.

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15
Q

What part of the eye contains receptor cells that are sensitive to light?

A

Retina.

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16
Q

What is the purpose of the optic nerve?

A

To carry impulses from the retina to the brain.

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17
Q

What is the transparent region at the front of the eye called?

A

Cornea.

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18
Q

What does the iris do?

A

It controls the size of the pupil and the amount of light reaching the retina.

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19
Q

Which parts of the eye can change the shape of the lens to focus light on the retina?

A

The ciliary muscles and the suspensory ligaments.

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20
Q

What is accommodation?

A

The process of changing the shape of the lens to focus on near or distant objects.

21
Q

What is myopia?

A

Short sightedness.

22
Q

What is hyperopia?

A

Long sightedness.

23
Q

What is the endocrine system?

A

A system made up of glands that secrete hormones directly into the bloodstream.

24
Q

What are hormones?

A

Chemical messengers that are carried in the bloodstream to target organ where they produce an effect.

25
Q

What is the pituitary gland?

A

The “master gland” in the brain that secretes several hormones in response to body conditions.

26
Q

Where is adrenaline produced?

A

In the adrenal gland (increases heart rate).

27
Q

Where is thyroxine produced?

A

In the thyroid gland (increases metabolic rate).

28
Q

What is type 1 diabetes caused by?

A

The pancreas failing to produce sufficient insulin.

29
Q

How is type 1 diabetes treated?

A

Insulin injections.

30
Q

What is type 2 diabetes caused by?

A

By the body cells no longer responding to insulin.

31
Q

How is type 2 diabetes treated?

A

With a carbohydrate-controlled diet and regular exercise.

32
Q

What is urea?

A

A waste produced by the liver from the breakdown of proteins and contains nitrogen.

33
Q

Give an example of negative feedback.

A

The control of water level in the body.

34
Q

What is deamination?

A

When excess amino acids from digestion of proteins is converted to ammonia in the liver.

35
Q

How does the kidney produce urine?

A

Filtering the blood, selective reabsorption, and converting the urea and excess water and ions into urine.

36
Q

What hormone controls the water level in the body?

A

ADH.

37
Q

What is the main female sex hormone?

A

Oestrogen.

38
Q

What is the main male sex hormone?

A

Testosterone.

39
Q

What is ovulation?

A

When eggs that have begun to mature at puberty are released.

40
Q

What are the names of the hormones involved in the menstrual cycle?

A

Follicle stimulating hormone (FSH), oestrogen, lutenising hormone (LH), progesterone.

41
Q

Give examples of hormonal contraception.

A

Oral contraceptives (the combined pill) that contain oestrogen and progesterone, an injection, an implant.

42
Q

Give examples of non-hormonal contraception.

A

Barrier methods (condoms, etc.), surgical sterillisation.

43
Q

What is a fertility drug?

A

A drug containing the hormones FSH and LH which stimulate egg maturity if a woman has low fertility.

44
Q

What does IVF stand for?

A

In vitro fertilisation.

45
Q

What is tropism?

A

When part of a plant responds to changes in the external environment by growing in a particular direction.

46
Q

What is gravitropism?

A

When a plant responds to gravity.

47
Q

What is phototropism?

A

When a plant responds to light.

48
Q

What are tropisms controlled by?

A

A group of plant hormones called auxins.

49
Q

What are gibberellins?

A

A group of plant hormones that are important in initiating seed germination.