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Biology Year 10🌿 > Homeostasis > Flashcards

Homeostasis Flashcards

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1
Q

How does homeostasis work?

A

stimulus–>receptors detect change–>info via sensory neuron–>CNS–>effectors–>response

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2
Q

What are the factors that the body needs to keep constant?

A

1) glucose control
2) water control
3) temperature control

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3
Q

What are the two types of waste removal?

A

Egestion and excretion

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4
Q

What is egestion?

A

The removal of waste material that hasn’t been inside cells (involved in cell reactions), eg fibre in faeces

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5
Q

What is excretion?

A

The removal of waste products of cell reactions from the body, eg water, minerals, urea and carbon dioxide

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6
Q

How does carbon dioxide get out of your body?

A

It is a waste product of respiration and it gets out by exhalation (through your mouth).

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7
Q

How does salt get out of your body?

A

It is a product of cell metabolism and food and drink and it gets out by urine and sweat (through your kidneys and skin).

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8
Q

How does urea get out of your body?

A

It is a product of the breakdown of protein/amino acids and it gets out by urine and sweat (through the kidneys and skin).

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9
Q

How does water get our of your body?

A

It is a product of food and drink and cell metabolism and it gets out by exhalation, sweat and urine (through the mouth, skin and kidneys).

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10
Q

What is osmoregulation?

A

Water homeostasis

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11
Q

What happens when water concentration in the blood is too high?

A

Receptors in the hypothalamus detect high water concentration in the blood, so the hypothalamus decides not to secrete ADH. As a result, water is not re absorbed into the blood in the kidneys and water concentration in blood decreases and more urine is produced.

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12
Q

What happens when water concentration in the blood is too low?

A

Receptors in the hypothalamus detect low water concentration in the blood, so the hypothalamus decides to secrete ADH and there is a feeling of thirst. As a result, water is re absorbed into the blood in the kidneys and you drink. Water concentration in blood increases and less urine is produced.

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13
Q

What happens when carbon dioxide concentration in the blood is too high?

A

Receptors in the respiratory control centre of the CNS in medulla sense high carbon dioxide concentration. As a result, the respiratory control centre of the CNS does send nervous impulses to the diaphragm and intercostal muscles. The diaphragm and intercostal muscles contract and breathing rate and oxygen levels increase and carbon dioxide levels decrease.

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14
Q

What happens when carbon dioxide concentration in the blood is too low?

A

Receptors in the respiratory control centre of the CNS in medulla sense low carbon dioxide concentration. As a result, the respiratory control centre of the CNS doesn’t send nervous impulses to the diaphragm and intercostal muscles. The diaphragm and intercostal muscles relax and breathing rate and oxygen levels drop and carbon dioxide levels increase.

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15
Q

What is thermoregulation?

A

The ability of the body to keep its temperature close to 37 degrees Celsius (only for warm blooded organisms).

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16
Q

What is hyperthermia?

A

When the body temperature increases significantly above 37 degrees Celsius

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17
Q

What is hypothermia?

A

When the body temperature decreases significantly below 37 degrees Celsius

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18
Q

What are the mechanisms of thermoregulation?

A

Variable-temperature
Stimulus-when the external temperature changes
Receptor-the receptors are in the skin
Integrator/coordinator-brain (thermoreceptor sensor)
Set point-37 dC for warm blooded organisms
Effector-a muscle
Response-shivering, goose bumps and sweating
Negative feedback- it brings an end to any further response

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19
Q

What is the dermis?

A

It makes new epidermis at the top and contains all of the nerves, blood vessels, sebaceous glands, sweat glands and hair roots

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20
Q

What is the epidermis?

A

The outside of your skin. The top layer is dead and provides protection from dirt, germs and strong sunlight. The middle layer contains living cells and the bottom layer continually divides to provide new cells for the epidermis.

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21
Q

What is the hair?

A

Made from keratin (protein)

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22
Q

What does the hair follicle do?

A

Grows hair

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23
Q

What does the hair erector muscle do?

A

It pulls the hair upright when the muscle contracts

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24
Q

What does the sebaceous gland do?

A

It produces an oily substance called sebum, which makes the skin waterproof and prevents it from during out and acts as a mild antiseptic to destroy fungi and bacteria

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25
Q

What do the sensory nerves do?

A

They help you feel pain, pressure or temperature

26
Q

What is the subcutaneous layer?

A

A fatty tissue that helps you keep warm and protects organs and bones from injury

27
Q

What does the sweat duct do?

A

It transports sweat from the sweat gland to the sweat pore

28
Q

What does the sweat gland do?

A

It produces sweat, which contains 99.5% water, 0.25% urea and 0.25% sodium chloride

29
Q

What does the sweat pore do?

A

It is for sweat to come out. 3x10 (6) of those cover the skin

30
Q

What do the skin blood vessels do?

A

They provide food and oxygen to the skin cells and help regulate body temperature

31
Q

What is homeostasis?

A

The maintenance of a stable internal environment in the body despite changes in the external environment

32
Q

What does your skin do when it’s too hot?

A

Hairs lie flat so that more heat is lost by radiation
Sweat glands open and the sweat evaporates which cools you down
Blood vessels at the skin’s surface widen (vasodilation), which allows more blood to flow to the surface, so more heat is lost by radiation
Changes in behaviour include undressing, moving into shade and resting

33
Q

What does the skin do when it’s too cold?

A

The hair erector muscles contract, pulling the hairs upright. This traps air, which is a poor conductor of heat, so it reduces heat loss
Sweat glands close. No sweat is produced
Blood vessels at the skin’s surface narrow (vasoconstriction), which causes less blood to flow to the surface, so less heat is lost by radiation
Shivering-produces extra heat
General increase in metabolic rate
Changes in behaviour include dressing, moving into sun and increased activity

34
Q

Why does the core temperature of your body have to be maintained?

A

It has to be maintained at a temperature at which the enzymes work best

35
Q

What is the body temperature controlled by?

A

The thermoregulatory centre in the hypothalamus, which has receptors that are sensitive to the temperature of the blood flowing through the brain.
In addition, temperature sensors in the skin send impulses to the thermoregulatory centre to tell it about the change in temperature

36
Q

What happens when you eat a bar of chocolate?

A

HIGH levels of blood glucose
Chocolate is digested, glucose is absorbed into bloodstream
Pancreas detects high levels of glucose and secretes insulin into bloodstream
Insulin is carried in bloodstream and it binds to the receptors on liver and muscle cells
Liver and muscle cells take up the glucose
Glucose is converted into glycogen for storage
Blood glucose levels drop

37
Q

What is hyperglycaemia?

A

You have too much glucose in your blood

38
Q

What happens if you have hyperglycaemia?

A 
Osmosis occurs
Water diffuses out of cells and into the blood
Water is excreted in urine
Dehydration
Coma and death
39
Q

What happens if you run all the way to school?

A

LOW levels of glucose
Rate of respiration increases, glucose is taken out of the bloodstream
Pancreas detects low levels of glucose and it secretes glucagon into the bloodstream
Glucagon binds to the receptors on liver and muscle cells and it is converted into glucose
Muscle cells use glucose for respiration of release it into bloodstream
Blood glucose levels rise

40
Q

What is hypoglycaemia?

A

When you have too little glucose in the blood

41
Q

What happens when you have hypoglycaemia?

A

You don’t have enough glucose for respiration
There is an inadequate energy supply for brain cells
Coma and death

42
Q

Example of something that makes our blood glucose levels rise

A

Eating a meal - carbohydrates are broken down into glucose and absorbed into the blood

43
Q

Example of what makes our blood glucose levels drop

A

Lots of exercise - glucose is broken down in the muscles in respiration in order to release energy

44
Q

Why is hyperglycaemia dangerous?

A

Having too much sugar in the blood increases the solute concentration of the blood, so that too much water is lost from the cells

45
Q

Why is hypoglycaemia dangerous?

A

The body doesn’t have enough glucose for respiration

46
Q

What monitors blood glucose levels?

A

The pancreas

47
Q

What happens when blood glucose levels rise or fall above or below the norm?

A

Norm = about 80mg/dl

Groups of cells in the pancreas called the islets of Langerhans secrete hormones into the blood

48
Q

What hormone is secreted when blood glucose levels are too high?

A

Insulin

49
Q

What hormone is secreted when blood glucose levels are too low?

A

Glucagon

50
Q

What does the insulin do once it is secreted?

A

It travels all over the body via the bloodstream and encourages cells to take up glucose and use it in respiration.
It also signals to the liver and muscle cells to take up glucose and turn it into an insoluble polysaccharide called glycogen for storage.
This then causes blood glucose levels to drop.

51
Q

What does the glucagon do once it is secreted?

A

In response to glucagon being secreted, the liver breaks down glycogen into glucose.
This is released into the bloodstream, thus raising blood glucose levels.

52
Q

What is diabetes?

A

A chronic disease characterised by increased blood sugar levels

53
Q

What causes diabetes?

A

Type 1) cause unknown but is thought to derive from the body’s immune system attacking the cells that produce insulin in the pancreas
Type 2) eating unhealthy foods (carbohydrates) and sweet products

54
Q

What is diabetes?

A

Type 1) the pancreas can’t produce enough insulin

Type 2) your body has too much insulin and can’t be used effectively

55
Q

What age do people get diabetes?

A

Type 1) usually begins in children and young adults although it can start at any age
Type 2) mostly only in adults but quite frequently in children

56
Q

What are the symptoms of diabetes?

A 
Excessive secretion of urine
Thirst
Constant hunger
Weight loss
Vision changes
Fatigue
57
Q

How can diabetes be treated?

A

Type 1) replace the missing insulin with insulin injections

Type 2) patients have to control their blood glucose levels through diet and exercise and avoiding smoking

58
Q

Why does insulin need to be injected and not taken orally?

A

Insulin needs to be injected directly into the muscle tissue

If it were taken orally, it would be broken down in the gut

59
Q

Why are increasing numbers of young people developing type 2 diabetes?

A

Children are eating increasingly unhealthily

With the intake of more carbohydrates and sugars, they are more liable to diabetes

60
Q

How is diabetes diagnosed?

A

Blood sugar levels are tested

Test for glucose in the urine

Biology Year 10🌿 (2 decks)

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