Homeostasis Flashcards

1
Q

What do control systems include

A

Cells called receptors
Coordination centres
Effectors

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2
Q

What do receptors do

A

They detect stimuli (changes in the environment)

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3
Q

What do effectors do

A

They bring about responses

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4
Q

What are examples of organs that receptors are found in

A

The eyes , ears, tongue and nose, skin, brain and pancreas

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5
Q

What are the eyes sensitive to

A

Light

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6
Q

What are the ears sensitive to

A

Sound, and to changes in position (which enables us to keep our balance)

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7
Q

What is the tongue and the nose sensitive to

A

Sensitive to chemicals (enable us to taste and smell)

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8
Q

What is the skin sensitive to

A

Sensitive to touch, pressure, pain and to temperature changes

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9
Q

What is the brain sensitive to

A

The brain is sensitive to blood temperature and to the concentration of water in the blood

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10
Q

What is the pancreas sensitive to

A

Sensitive to the concentration of glucose in the blood

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11
Q

What do coordination centres include

A

The brain, the spinal cord and the pancreas

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12
Q

What are many processes coordinated by and what happens to them

A

Many processes are coordinated by chemical substances called hormones. Hormones are secreted by glands and are usually transported to their target organs by the bloodstream

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13
Q

What are examples of internal conditions that are controlled

A

Temperature, the water content of the body , the ion content of the body, blood glucose levels

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14
Q

When and how does water leave the body

A

Water leaves he body via the lungs when we breathe out and the skin when we sweat

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15
Q

How is excess water removed

A

Excess water is removed via the kidneys in the urine

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16
Q

How are urea and ions lost

A

Urea and ions are lost via the skin when we sweat.

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17
Q

What happens to excess ions

A

Excess ions are removed via the kidneys in the urine

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18
Q

What happens in the liver

A
  • excess amino acids are deaminated to form ammonia, which is converted into urea for excretion
  • poisonous substances are detoxified, and the breakdown products are excreted in the urine via the kidneys.
  • old blood cells are broken down and the iron is stored
19
Q

What happens in a healthy Kidney

A
  • the blood is filtered
  • all the glucose is reabsorbed
  • the dissolved ions needed by the body are reabsorbed
  • as much water as the body needs is reabsorbed
  • urea, excess ions and excess water are released as urine
20
Q

What happens if the water content of the blood is too low

A

If the water content of the blood is too low, the pituitary gland releases a hormone called ADH into the blood. This causes the kidneys to reabsorbed more water and results in a more concentrated urine

21
Q

What happens if the water content of the blood is too high

A

If the water content of the blood is too high, less ADH is released into the blood. Less water is reabsorbed in the kidneys resulting in a more dilute urine

22
Q

What is the body temperature monitored and controlled by

A

Body temperature is monitored and controlled by the thermoregulatory centre in the brain. This centre has receptors sensitive to the temperature of the blood flowing through the brain

23
Q

What do temperature receptors in the skin do

A

Temperature receptors in he skin send impulses to he thermoregulatory centre, giving in informations about skin temperature

24
Q

What happens if the core body temperature is too high

A
  • blood vessels supplying the skin capillaries dilate so that more blood flows through the capillaries and more heat is lost
  • sweat glands release more sweat, which cools the body as it evaporates
25
Q

How does sweating help to cool the body

A

Sweat increases heat loss by evaporation

More water is lost when it is hot , and more fluid has to be taken through a drink or food to balance this loss

26
Q

What happens if the core body temperature is too low

A
  • blood vessels supplying the skin capillaries construct to reduce the flow of blood through the capillaries
  • muscles may ‘shiver’ - their contraction needs respiration , which releases some energy to warm the body
27
Q

What may people suffering from kidney failure be treated by and what does it do

A

People who suffer from kidney failure may be treated by organ transplant or by using kidney dialysis, which restores the concentrations of dissolved substances in the blood to normal levels

28
Q

What happens in dialysis

A

In a dialysis machine a persons blood flows between partially permeable membranes.
The dialysis fluid contains the same concentration of useful substances as the blood of a person without Kinsey disease
This ensures that glucose and useful mineral ions are not lost but that harmful substances such as urea pas out from the blood into dialysis fluid

29
Q

Advantages of treating organ failure by mechanical devices or transplant

A

Artificial organs can replace diseased or damaged organs thereby providing the ailing patient with an opportunity to lead a healthy and normal life

30
Q

Disadvantages of treating organ failure by mechanical devices or transplant

A

There are high chances of organ failure, and the body may take sometime to adapt to the new organ
There are some ethical issues, for example in the case of smoking , people may not take the consequences seriously, and go for artificial organ therapy instead of avoiding nicotine

31
Q

What keeps conditions in the body relatively constant

A

Automatic control systems

32
Q

What is an advantage of dialysis

A

IMMEDIATE TREATMENT
Machines usually available
No problems with tissue matching
No need for surgery

33
Q

Disadvantages of dialysis

A

INCONVENIENT
has to happen at regular intervals at least twice a week
Expensive in long term
Have to watch a very strict diet
Substances build up inbetween sessions - symptoms show again
Risk of blood clots (-> DVT/ heart attack)
Anticoagulant drugs (-> excessive bleeding)

34
Q

Advantages of kidney transplant

A
LONG TERM / permanent solution
No special diet
No sessions of dialysis
Relatively inexpensive after surgery
Kidney works all of the time (no symptoms)
35
Q

Disadvantages of kidney transplant

A
Need donor (often not available)
Need tissue match (risk of rejection)
Have to take immunosuppressant drugs (increased risk of infection)
Risk of surgery
Danger of infection
Surgery every 10 years (risk/cost)
36
Q

What is the blood glucose monitored and controlled by

A

The pancreas

37
Q

Much of the glucose is stored as ……. In ……….

And what happens when these stores are full

A

Much of the glucose is stored as glycogen in the liver and muscles
When these stores are full, excess glucose is stored as lipid

38
Q

What happens if the blood glucose levels are too brig

A

The pancreas produces the hormone insulin, which allowed the glucose to move from the blood into the cells

39
Q

What happens when the blood glucose levels fall

A

The pancreas produces a second hormone, glucagon. This causes the glycogen to be converted into glucose and released into the blood

40
Q

What happens in type 1 diabetes

A

A persons blood glucose level may be too high because the pancreas does not produce enough of the hormone insulin

41
Q

What can type 1 diabetes be controlled by

A

Careful diet , exercise , and by jnjecting insulin

42
Q

What happens in type 2 diabetes

A

Type 2 diabetes develops when the body does not respond to its own insulin. Obesity is a significant factor in the development of type 2 diabetes

43
Q

What can type 2 diabetes be controlled by

A

Careful diet , exercise and by drugs that help the cells to respond to insulin