Topic 7 - Animal Coordination, Control And Homeostasis Flashcards
1
Q
What are hormones?
A
Chemical messengers sent in the blood.
2
Q
What are target organs?
A
The particular organs that the hormones effect.
3
Q
What do hormones do?
A
Control things in organs that need constant adjustment.
4
Q
What are endocrine glands?
A
Hormones are produced in and secreted by various glands called endocrine glands.
5
Q
Where is the pituitary gland located?
A
In the brain just below the hypothalamus.
6
Q
What hormones does the pituitary gland produce?
A
Many hormones that regulate body temperatures.
7
Q
Why is the pituitary gland often called the ‘master gland’?
A
These hormones act on other glands, directing them to release hormones that bring about change.
8
Q
Where is the thyroid gland located?
A
The throat.
9
Q
What hormone does the thyroid gland produce?
A
Thyroxine.
10
Q
What does the thyroxine hormone do?
A
It’s involved in regulating things like the rate of metabolism, heart rate and temperature.
11
Q
What hormone do the ovaries produce?
A
Oestrogen.
12
Q
What does oestrogen do?
A
It’s involved in the menstrual cycle.
13
Q
What hormone do the adrenal glands produce?
A
Adrenaline.
14
Q
What does the hormone adrenaline do?
A
Prepares the body for a ‘fight or flight’ response.
15
Q
Where are the adrenal glands located?
A
Just at the top of each kidney.
16
Q
What hormone do the testes produce?
A
Testosterone.
17
Q
What does the hormone testosterone do?
A
Controls puberty and sperm production in males.
18
Q
What hormone does the pancreas produce?
A
Insulin.
19
Q
What does the hormone insulin do?
A
Used to regulate the blood glucose level.
20
Q
What are the features of neurones compared to hormones?
A
- Very fast action.
- Act for a very short time.
- Act on a very precise area.
21
Q
What are the features of hormones compared to neurones?
A
- Slower reaction.
- Act for a long time.
- Act in a more general way.
22
Q
What does ‘fight or flight’ mean in terms of adrenaline?
A
Standing your ground in the face of threat or running away.
23
Q
How does adrenaline prepare the body for ‘fight or flight’?
A
By activating processes that increase the supply of oxygen and glucose to the cells.
24
Q
What are the 4 steps of adrenaline in action?
A
- Adrenaline binds to specific receptors in the heart. This causes the heart muscle to contract more frequently and with more force so the heart rate and blood pressure increase.
- This increases blood flow to the muscles, so the cells receive more oxygen and glucose for increased respiration.
- Adrenaline also binds to the receptors in the liver. This causes the liver to break down its glycogen stores to release glucose.
- This increases the blood glucose level, so there’s more glucose in the blood to be transported to the cells.
25
How does the body control the levels of hormones?
Negative feedback.
26
What important role does thyroxine play in?
Regulating metabolic rate.
27
What is metabolic rate?
The speed at which chemical reactions in the body occur.
28
What happens when the levels of thyroxine in the blood are low?
The hypothalamus is stimulated to release thyrotropin releasing hormone (TRH). TRH stimulates the pituitary gland to release thyroid stimulating hormone (TSH). TSH stimulates the thyroid gland to release thyroxine so the blood thyroxine levels return to normal.
29
What happens when the levels of thyroxine in the blood are high?
The release of TRH from the hypothalamus is inhibited, which reduces the production of TSH, so the blood thyroxine level falls.
30
What is the menstrual cycle?
A monthly sequence of events in which the female body releases an egg and prepares the uterus (womb) in case the egg is fertilised.
31
What happens in stage 1 of the menstrual cycle?
The menstruation starts at day 1. The lining of the uterus breaks down and is released.
32
What happens in stage 2 of the menstrual cycle?
The uterus lining is repaired from day 4 to day 14 until it becomes a thick spongy layer full of blood vessels ready for the fertilised egg to implant there.
33
What happens in stage 3 of the menstrual cycle?
An egg develops and is released from the ovary (ovulation) at about day 14.
34
What happens in stage 4 of the menstrual cycle?
The lining is then maintained for about 14 days until day 28. If no fertilised egg has landed on the uterus wall by day 28, the spongy lining starts to break down again and the cycle starts over again.
35
What does FSH stand for?
Follicle-stimulating hormone.
36
What is a follicle?
An egg and its surrounding cells.
37
What is FSH released by?
The pituitary gland.
38
What does FSH do?
It causes a follicle to mature in one of the ovaries and stimulates oestrogen production.
39
What is oestrogen released by?
The ovaries.
40
What does oestrogen do?
Causes the lining of the uterus to thicken and grow. A high level stimulates an LH surge (a rapid increase).
41
What does LH stand for?
Luteinising hormone.
42
What is LH released by?
The pituitary gland.
43
What does LH do?
The LH siege stimulates ovulation at day 14 - the follicle ruptures and the egg is released. It also stimulates the remains of the follicle to develop into a structure called a corpus luteum - which secretes progesterone.
44
What is progesterone released by?
The corpus luteum after ovulation.
45
What does progesterone do?
It maintains the lining of the uterus and inhibits the release of FSH and LH.
46
What happens when the level of progesterone falls and there's a low oestrogen level?
The uterus lining breaks down.
47
What happens when there's a low level of progesterone?
It allows FSH to increase and the cycle to start again.
48
If a person is infertile, what does this mean?
It means they can't reproduce naturally.
49
What are the two methods an infertile couple can use to become pregnant?
Clomifene therapy and IVF.
50
What does IVF stand for?
In Vitro Fertilisation.
51
Why would a woman use clomifene therapy?
If she doesn't ovulate or doesn't regularly ovulate.
52
What does the drug clomifene do?
It causes more FSH and LH to be released by the body, which stimulates egg maturation and ovulation.
53
How does IVF work?
It involves collecting eggs from the woman's ovaries and fertilising them in the lab using the man's sperm. These are grown into embryos and when the embryos are tiny balls of cells, one or two of them is transferred into the woman uterus.
54
What is IVF an example of?
ART.
55
What does ART stand for?
Assisted Reproductive Technology.
56
What is ART?
A fertility treatment that involves eggs being handled (and usually fertilised) outside the body.
57
What does homeostasis mean?
Maintaining the right conditions inside your body so that everything works properly.
58
Why is it really important that conditions in your body need to be kept steady?
Your cells need the right conditions in order to function properly.
59
What does your body need to do to maintain a constant internal environment?
Respond to both internal and external changes, whilst balancing inputs (stuff going into your body) and outputs (things leaving your body).
60
What is osmoregulation?
The regulation of the water content you gain and lose.
61
What is thermoregulation?
The regulation of body temperature.
62
What is blood glucose regulation?
The regulation of the amount of glucose in your blood.
63
When the blood glucose concentration is too high, what hormone is added?
Insulin.
64
When the blood glucose concentration is too low, what hormone is added?
Glucagon.
65
How does insulin decrease the amount of glucose in the blood?
It makes the liver turn glucose into glycogen.
66
How does glucagon increase the amount of glucose in the blood?
it makes the liver turn glycogen into glucose.
67
What is type 1 diabetes?
A condition where the pancreas produces little or no insulin.
68
How can a person with type 1 diabetes be treated?
Insulin therapy - this usually involves injecting insulin into the blood and is often done at mealtimes to make sure the glucose is removed from the blood quickly once the food has been digested.
69
How can a person with type 1 diabetes try to reduce the amount of glucose in their blood?
Limiting the intake of foods rich in simple carbohydrates i.e. sugars and taking regular exercise to help remove excess glucose from the blood.
70
What is type 2 diabetes?
A condition where a person becomes resistant to insulin or the pancreas doesn't produce enough insulin.
71
What is the link between obesity and type 2 diabetes?
There is a correlation meaning obese people have an increased risk of developing type 2 diabetes.
72
How do you classify a person as obese?
If they have a BMI of over 30.
73
How do you work out BMI?
Weigh (kg) ÷ (Height (m))²
74
What is the link between where a person stores fat and type 2 diabetes?
Storing fat around the abdomen (stomach) is associated with increased risk of developing type 2 diabetes.
75
How do you work out waist-to-hip ratio?
Waist circumference (cm) ÷ Hip circumference (cm)
76
What ratios for each gender is associated with type 2 diabetes?
A ratio above 1.0 for men and a ratio above 0.85 for women.
77
How do you control type 2 diabetes?
Eating a healthy diet, getting regular exercise and losing weight. Some people also have medications or insulin injections.
78
What is the optimum temperature for enzymes inside the body?
37℃.
79
Where is the thermoregulatory centre?
In the hypothalamus.
80
What does the thermoregulatory centre do.
It contains receptors that are sensitive to the blood temperature in the brain. It also receives impulses from receptors in the skin (nerve endings) that provide information about the external temperature.
81
Where are the receptors in the skin located?
Epidermis and dermis.
82
What is the epidermis?
The outer layer of the skin.
83
What is the dermis?
A deeper layer of skin just below the epidermis.
84
What happens in the skin when you're too hot?
1) Hairs lie flat.
2) You sweat.
3) Blood vessels dilate.
85
What happens to the erector muscles when you're too hot?
The erector muscles relax so hairs lie flat.
86
What happens to the sweat glands when you're too hot?
Lots of sweat is produced in the sweat glands in the dermis. The sweat is released onto the surface of the skin through pores in the epidermis.
87
What happens when your sweat evaporates?
It transfers energy from your skin to the environment, cooling you down.
88
Where are the sweat glands located?
The dermis.
89
What happens to your blood vessels when you're too hot?
Blood vessels close to the surface of the skin dilate to allow more blood to flow near the surface so it can transfer more energy into the surrounding.
90
What happens to your skin when you're cold?
1) Hairs stand up.
2) No sweat.
3) Blood vessels constrict.
4) You shiver.
91
What happens to your erector muscles when you're too cold?
Erector muscles contract. Hairs stand on end.
92
When you're too cold why do hairs stand on end?
To trap an insulating layer of air near the surface of the skin which helps keep you warm.
93
Why do blood vessels constrict when you're cold?
Less blood flows near the surface, so less energy is transferred to your surroundings.
94
What causes you to shiver when you're cold?
Muscles quickly contracting and relaxing.
95
Why do you shiver when you're cold?
It increases the rate of respiration, which transfers more energy to warm the body.
96
What is the name for blood vessels dilating
Vasodilation.
97
What is the name for blood vessels restricting?
Vasoconstriction.
98
What happens if the concentration of water in the blood is too high?
The water will move into the body cells by osmosis. If too much water moves into the cells then the cells may burst.
99
What happens if the concentration of water in the blood is too low?
Water will move out of the cells causing them to shrink.
100
How do the kidneys help to regulate water content?
They control how much water is reabsorbed and how much is lost in urine.
101
Where is the urea produced?
In the liver from the breakdown of excess amino acids.
102
What are the 3 main roles of the kidney?
1) Removal of urea.
2) Adjustment of ion levels in the blood.
3) Adjustment of water content in the blood.
103
How do kidneys complete their roles?
They filter stuff out of the blood under high pressures and then reabsorb the useful things.
104
What is the end product of the kidney functions?
Urine
105
What is a nephron?
The filtration units in the kidney.
106
What does ADH stand for?
Anti-diuretic hormone.
107
What is ADH and what does it do?
It's a hormone that controls the amount of water reabsorbed in the kidney nephron.
108
How does the brain stop the body from becoming dehydrated?
It monitors the water content of the blood and instructs the pituitary gland to release the ADH into the blood according to how much is needed.
109
How does ADH stop the body from becoming dehydrated?
It makes the collecting ducts of the nephrons more permeable so that more water is reabsorbed back into the blood.
110
How is a dialysis machine used for a patient with kidney failure?
A patient with kidney failure can't filter their blood properly but a dialysis machine can be used to filter their blood properly.
111
What safety precautions are taken to help prevent rejection in a kidney transplant?
1) A donor with a tissue type that closely matches the patient chosen.
2) The patient is treated with drugs that suppress the immune system, so that their immune system won't attack the transplanted kidney.
112
What happens in the filtration stage in the nephron
The liquid part of the blood (containing water, urea, ions and glucose) is forced out of the glomerulus and into the Bowman's capsule at high pressure (ultrafiltration). Bigger molecules (e.g. proteins) and blood cells can't pass through the membranes and are not forced out
113
What happens in the reabsorption stage in the nephron?
As the liquid moves along the nephron, useful substances are reabsorbed:
- All the glucose is selectively reabsorbed - it's moved back into the blood
- Sufficient ions are reabsorbed
- Sufficient water is reabsorbed according to the level of ADH
114
What happens to the stuff that isn't reabsorbed?
Whatever isn't reabsorbed (e.g. urea, excess water, excess ions) continues out of the nephron via the collecting duct. It then passes into the ureter and down to the bladder as urine. Urine is released through the urethra.
