Homeostasis and Response Flashcards

1
Q

What is homeostasis?

A

The regulation of the internal conditions of a cell or organism in response to internal and external changes.

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2
Q

What does homeostasis control?

A

Blood glucose concentration.
Body temperature.
Water and Ion levels.
Nervous and chemical (hormonal) responses.

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3
Q

What do control systems include?

A

Receptors (detect stimuli).
Coordination centres.
Effectors (responders).

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4
Q

What are examples of coordination centres?

A

Brain, spinal cord, pancreas.

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5
Q

What are examples of effectors?

A

Muscles, glands.

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6
Q

What is negative feedback?

A

A control mechanism where upon a receptor detecting a change in stimulus, the coordinating centre compares the stimulus to a set point, then causes the effector to produce a response to correct any difference from the set point.

Basically, maintains amounts of things in the body. Like blood sugar.

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7
Q

What is the central nervous system (CNS)?

A

The brain and spinal cord.

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8
Q

What is the purpose of the CNS?

A

Coordinates the response of effectors.

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9
Q

Describe a reflex arc.

A
Receptors detect stimuli.
Sensory neurone carries impulse to CNS.
Impulse passes through relay neurone.
Motor neurone carries impulse to receptor.
Effector responds.
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10
Q

In what order, in the reflex arc, do neurones appear?

A

Sensory, relay, motor.

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11
Q

How do neurones communicate?

A

Synapses.

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12
Q

How do electrical impulses travel?

A

Through the neurones: once it reaches the synapse, a chemical is released which diffuses across the gap between the two neurones, which causes the electrical impulse to be generated in the second neurone.

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13
Q

What is the endocrine system?

A

Made up of glands which secrete hormones directly into the blood.

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14
Q

What are hormones?

A

Chemical messengers, carried in the blood, which target an organ where they produce an effect.

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15
Q

What is the pituitary gland?

A

The ‘master gland’ which secrete hormones in response to body conditions.

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16
Q

List some glands.

A
Pituitary gland.
Thyroid gland.
Adrenal gland.
Testis.
Ovaries.
Pancreas.
17
Q

What does adrenaline do?

A

Increases heart rate, so more oxygen and glucose can be supplied to the brain or muscles.

18
Q

What does thyroxine do?

A

Increases the metabolic rate.

19
Q

What does the pancreas do in the endocrine system?

A

Monitor and control blood glucose concentration.

20
Q

What does insulin do?

A

Causes glucose to move from the blood into the cells.

21
Q

What happens if blood glucose concentration is too low?

A

The pancreas produces glucagon, which stimulates glycogen to be converted into glucose and released back into the blood.

22
Q

What is type 1 diabetes caused by?

A

The pancreas fails to produce sufficient insulin.

23
Q

What is type 2 diabetes caused by?

A

The body no longer responds to insulin (usually as a result of an unhealthy diet).

24
Q

What are the four hormones involved in controlling the menstrual cycle?

A

Follicle stimulating hormone (FSH).
Oestrogen.
Luteinising hormone (LH).
Progesterone.

25
Q

Where are follicle stimulating hormones produced?

A

Pituitary gland.

26
Q

Where is oestrogen produced?

A

Ovaries.

27
Q

Where are luteinising hormones produced?

A

Pituitary gland.

28
Q

Where is progesterone produced?

A

Empty follicles in the ovaries.

29
Q

What is the function of FSH in the menstrual cycle?

A

Causes eggs to mature in the ovaries in the first half of the cycle and stimulates ovaries to produce oestrogen.

30
Q

What is the function of oestrogen in the menstrual cycle?

A

Inhibits FSH release and stimulate LH release. It also makes the lining of the uterus grow again after menstruation.

31
Q

What does FSH stand for?

A

Follicle stimulating hormone.

32
Q

What does LH stand for?

A

Luteinising hormone.

33
Q

What is the function of LH in the menstrual cycle?

A

Stimulates ovulation (the release of an egg from the ovaries).

34
Q

What is the function of progesterone in the menstrual cycle?

A

Maintains lining of the uterus in the second half of cycle and inhibits FSH and LH release.

35
Q

Describe vitro fertilisation (IVF).

A

A women is given FSH and LH to stimulate the growth of many eggs.
The eggs are collected from the woman.
The eggs are fertilised with sperm in a laboratory.
A few embryos are inserted into the woman’s uterus.

36
Q

What hormones are in a fertility drug?

A

FSH and LH.

37
Q

What are some disadvantages to fertility treatment?

A

It can be emotionally and physically stressful.
The success rates aren’t high.
It can lead to multiple births, which puts both the mother and the foetuses at risk.