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Biology > Topic 7 Animal Coordination, Control and Hormones > Flashcards

Topic 7 Animal Coordination, Control and Hormones Flashcards

1
Q

What are hormones?

A
  • Chemicals messengers* sent directly into blood via diffusion to target organs to control things in organs and cells that need constant adjustment.
  • Released by endocrine glands.*
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2
Q

Pituitary gland

A

Produces many hormones that regulate body conditions

These hormones can act on other glands to release more hormones.

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3
Q

Thyroid

A

Produces thyroxine which regulates metabolism, heart rate and temperature.

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4
Q

Adrenal gland

A

Produces adrenaline which prepares the body for ‘flight or fight’ response.

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5
Q

Ovaries

A

Produce oestrogen which is involved in menstrual cycle.

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6
Q

Pancreas

A

Produces insulin to regulate blood glucose level.

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7
Q

Properties of nervous system

A

Very fast action.
Act for short time.
Act on precise area.
Electrical signal.

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8
Q

Properties of hormonal system

A

Slower action.
Act for a long time.
Act in a general way.
Chemical signal.

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9
Q

Effect of adrenaline

A

Increases supply of oxygen and glucose to cells.

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10
Q

How does adrenaline increase supply of oxygen and glucose?

A

Adrenaline binds to specific receptors in the heart and causes it to contract more frequently with more force, increasing heart rate and blood pressure.
Increases blood flow to muscles so cells receive oxygen and glucose for increased respiration.
Adrenaline binds to receptors in liver to cause it to break down its glycogen stores to release glucose.
Increases blood glucose level so there’s more glucose in the blood for cells.

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11
Q

When is adrenaline released?

A

In stressful situations nervous impulses are sent to adrenal glands that secrete adrenaline.

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12
Q

What is negative feedback?

A

When the body detects the level of a substance has gone above or below the normal level and triggers a response to bring the level to normal again.

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13
Q

How the body raise thyroxine levels in the blood to a normal level?

A

When it is lower than normal, the hypothalamus (part of brain) releases thyrotropin releasing hormone (TRH) that stimulates the pituitary gland to release thyroid stimulating hormone (TSH) that stimulates the thyroid gland to release thyroxine so the level goes back to normal

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14
Q

How does the body lower thyoxine levels in the blood to a normal level?

A

The release of TRH from the hypothalamus is inhibited (stopped completely) which reduces the production of TSH, so the blood thyroxine level falls.

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15
Q

What does TRH stand for?

A

Thyrotropin releasing hormone

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16
Q

What does TSH stand for?

A

Thyroid stimulating hormone

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17
Q

What does thyroxine do?

A

Regulates metabolic rate.

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18
Q

How many stages does the menstrual cycle have?

A

4

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19
Q

Stage 1 of the menstrual cycle (day 1 - 4)

A

The lining of the uterus is broken down and released.

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20
Q

Stage 2 of the menstrual cycle (day 4 - 14)

A

The uterus lining is repaired. It builds up over the 10 days until it becomes a thick spongy layer full of blood vessels, ready for a fertilised egg.

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21
Q

Stage 3 of the menstrual cycle (day 14)

A

Egg develops and is released from the ovary (ovulation).

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22
Q

Stage 4 of the menstrual cycle (14 - 28)

A

Lining is maintained for 14 days and in no egg has landed on the lining the spongy lining starts to break down again and the cycle repeats.

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23
Q

FSH (Follicle-Stimulating Hormone)

A

Released by pituitary gland and causes follicle (egg and surrounding cells) to mature in one of ovaries.
Stimulates oestrogen production.

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24
Q

Oestrogen

A

Released by ovaries.
Causes lining of uterus to thicken and grow.
High level of oestrogen stimulates LH surge.

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25
Q

LH (luteinising hormone)

A

Released by pituitary gland.
LH surge stimulates ovulation at day 14 - causes follicle to rupture and release the egg.
The remains of follicle is also stimulated by LH to develop into the corpus luteum which secretes progesterone.

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26
Q

Progesterone

A

Released by the corpus luteum after ovulation.
Maintains lining of the uterus.
Inhibits release of FSH and LH.
When the progesterone level drops and there is a low oestrogen level, the uterus lining breaks down.
Low progesterone allows FSH to increase and the cycle to start again.

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27
Q

What happens to the progesterone level if a fertilised egg is implanted?

A

The level of progesterone will stay high to maintain the thick uterus lining during pregnancy.

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28
Q

Clomifene Therapy for infertile women

A

Clomifine is a drug for people who don’t ovulate and it causes more FSH and LH to be released to stimulate egg maturation and ovulation and the couple can try for a baby when they know exactly when the woman is ovulating.

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29
Q

IVF (in vitro fertilisation)

A

Collecting eggs from a woman’s ovaries and fertilising them in a lab and grown into embryos.
The embryo is transferred to the woman’s uterus after they become a ball of cells to improve chance of pregnancy.
FSH and LH are given before egg collection to stimulate egg production to collect more than one egg.

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30
Q

Use of oestrogen as a contraceptive

A

If oestrogen is taken every day to keep the level high permanently then the production of FSH is inhibited and egg development and production stop.

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31
Q

Use of progesterone to reduce fertility

A

Stimulates production of thick cervical mucus and prevents any sperm getting through the cervix.

32
Q

Barrier methods of contraception

A

A barrier stops the sperm from meeting the egg. E.g. condom, diaphragms.

33
Q

Pros of hormonal contraception

A

They are more effective at preventing pregnancy and means the couple do not have to stop and think about contraception each time they have intercourse.

34
Q

Cons of hormonal contraception

A

They have side-effects such as headaches, acne and mood changes and don’t protect against STIs (only condoms do this).

35
Q

Homeostasis definition

A

Maintaining a constant internal environment.

36
Q

Examples of homeostasis in action

A

Blood glucose regulation
Thermoregulation
Osmoregulation

37
Q

What causes a lower blood glucose level

A

Normal metabolism, vigorous exercise

38
Q

What causes a higher glucose level

A

Eating food containing carbohydrates.

39
Q

Where is excess glucose stored?

A

As glycogen in the liver and muscles and if these stores are full then as lipid in the tissues.

40
Q

Where is blood glucose monitored and controlled?

A

Pancreas

41
Q

How is blood glucose concentration reduced?

A

When too much glucose is detected by the pancreas, insulin is secreted into the bloodstream.
This insulin travels to the liver where the liver detects the insulin and removes glucose from the blood and turns it into glycogen to be stored in the liver and muscles.

42
Q

How is blood glucose concentration increased?

A

When too little glucose is detected by the pancreas, glucagon is secreted into the bloodstream.
This glucagon travels to the liver where the liver detects the glucagon and turns its glycogen stores into glucose and it is released into the bloodstream.

43
Q

What is type 1 diabetes?

A

Where the pancreas produces little or no insulin so the person’s blood glucose level can rise to a point where it can kill them.

44
Q

How to treat type 1 diabetes

A

Insulin therapy where the person injects insulin into themselves after meals to make sure the glucose is removed from the blood after digestion quickly so the glucose level in the blood does not become too high.

45
Q

What does the amount of insulin injected in insulin therapy depend on?

A

Diet and how active they are.

46
Q

What do people with type 1 diabetes do other than insulin therapy?

A

Limiting intake of food rich in carbohydrates i.e. sugars so their blood glucose level does not rise rapidly.
Taking regular exercise to remove excess glucose from the blood.

47
Q

What is type 2 diabetes?

A

Condition where the pancreas does not produce enough insulin or when someone becomes resistant to insulin so the blood glucose level rises.

48
Q

What has a correlation with type 2 diabetes?

A

Obesity

49
Q

Formula for BMI

A

mass (kg) / height (m) ^2

50
Q

What BMI indicates that someone is obese?

A

Over 30.

51
Q

What is alternative to BMI to check risk of developing type 2 diabetes and why?

A

Waist-to-hip ratio because storing a lot of fat around the abdomen is associated with an increased risk of developing type 2 diabetes.

52
Q

Formula for waist-to-hip ratio

A

Waist circumference (cm) / hip circumference (cm)

53
Q

What waist-to-hip ratio indicates a risk of developing type 2 diabetes?

A

A ratio above 1.0 for men and a ratio above 0.85 for women.

54
Q

How can type 2 diabetes be controlled?

A

By eating a healthy diet, getting regular exercise and losing weight.
Medication or insulin injections can be had if necessary.

55
Q

What controls body temperature?

A

The hypothalamus through receptors sensitive to blood temperature in the brain and receptors on the skin on the dermis and epidermis.

56
Q

Why is body temperature controlled?

A

Enzymes in the body work best around 37C.

57
Q

What happens when you are too hot?

A

Erector muscles relax so hairs lie flat.
Sweat containing water and salts is produced in sweat glands in the dermis and released on epidermis through sweat pores that transfer heat away to environment through evaporation.
Blood vessels close to skin dilate (widen). This is called vasodilation. This allows more blood to flow near the surface so it can transfer more energy to the surroundings.

58
Q

What happens when you are too cold?

A

Erector muscles contract so hairs stand on end to trap an insulating layer of air near the surface of the skin.
Little sweat produced.
Blood vessels close to skin constrict (vasoconstriction) so less blood flows near the surface so less energy is transferred to the surroundings.
Also, you shiver to increase your rate of respiration to transfer more heat to warm the body.

59
Q

What happens if the concentration of water in the blood is too high?

A

The water will move into the body cells by osmosis and they may burst.

60
Q

What happens if the concentration of water in the blood is too low?

A

The water will move out of the body cells by osmosis and cause them to shrink.

61
Q

Which organ controls water content of the blood?

A

The kidneys

62
Q

3 roles of kidney

A

Removal of urea in the blood.
Adjustment of iron levels in the blood.
Adjustment of water content in the blood.

63
Q

How the kidney filters the blood

A

Blood is pumped at high pressure into the nephron at the glomerulus to filter small molecules such as urea, water, ions and glucose into the nephron tubule.

64
Q

How does the kidney selectively reabsorb useful substances?

A

In the first convoluted tube, glucose and some mineral ions are pumped against the concentration gradient by proteins back into the bloodstream.
At the loop of Henle and collecting duct, water is reabsorbed by osmosis depending on how much the body needs.

65
Q

What happens to the filtered out fluid at the end of the nephron?

A

Urea, excess water and ions continues out of the nephron into the collecting duct where they pass into the ureter and then to the bladder as urine.

66
Q

Which hormone controls the amount of water reabsorbed at the kidney?

A

Anti-diuretic hormone (ADH)

67
Q

Which gland releases ADH?

A

The pituitary gland

68
Q

What specific effect does ADH have on the nephron?

A

It makes the walls of the collecting duct more permeable so more water can be reabsorbed into the blood to stop the body being dehydrated.

69
Q

How does the body absorb less water?

A

Brain detects water gain.
Pituitary gland releases less ADH.
Less ADH so kidney reabsorbs less water.

70
Q

How does the body absorb more water?

A

Brain detects water loss.
Pituitary gland releases more ADH.
More ADH so kidney reabsorbs more water.

71
Q

What does a dialysis machine do?

A

Filters blood for patients who have kidney failure.

72
Q

How does a dialysis machine work?

A

Dialysis fluid with same concentration of salts and glucose as blood plasma is put through the machine along with the blood where waste diffuses out of the blood (ions and urea and water) and the selectively permeable membrane means that cells and proteins stay in the blood.

73
Q

How to cure kidney disease

A

Have a kidney transplant from people who have died suddenly.

74
Q

Risks and how to avoid them of a kidney transplant

A

Donor kidney can be treated as a foreign object and attacked by antibodies.
The donor has to have a similar tissue type as patient and the patient is treated with a drug that suppresses the immune system so it doesn’t attack the kidney.

75
Q

Adaptations of the kidney

A

Lots of contact between nephron and capillaries which increase surface area for exchange.
Cells lining convoluted tubules have tiny folds called microvilli which increase surface area to volume ratio to maximise reabsorption.
Cells have many mitochondria for active transport during selective reabsorption using protein pumps where energy is needed.

Biology (8 decks)

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