The regulation of the internal conditions of a cell or organism to maintain optimum conditions for function, in response to internal and external changes.

Why is homeostasis important?

It maintains optimal conditions for enzyme action and all cell functions .

Name three internal conditions controlled by homeostasis in the human body.

Blood glucose concentration Body temperature Water levels

What two types of response can automatic control systems involve?

Nervous responses and chemical (hormonal) responses.

Name the three components of all control systems.

Receptors Coordination centres Effectors

Cells that detect stimuli (changes in the environment).

Muscles or glands that bring about responses to restore optimum levels .

centres, such as the brain and spinal cord, receive and process information from receptors.

Coordination centres, such as the brain and spinal cord, receive and process information from receptors.

A system of glands that secrete hormones directly into the bloodstream .

A chemical messenger secreted by a gland into the blood, which is carried to a target organ where it produces an effect.

True or False? Hormonal responses are faster than nervous responses.

False. Compared with the nervous system, hormonal effects are slower but they act for longer .

Which hormone is produced by each of these glands: pancreas, thyroid, adrenal glands, ovaries and testes?

Pancreas – insulin Thyroid – thyroxine (Higher Tier Only) Adrenal glands – adrenaline (Higher Tier Only) Ovaries – oestrogen Testes – testosterone

Why is the pituitary gland called the 'master gland'?

It secretes several hormones that act on other glands , stimulating them to release further hormones to bring about effects.

Give an example of the pituitary gland controlling another gland. (Higher Tier Only)

The pituitary secretes TSH (thyroid-stimulating hormone) , which stimulates the thyroid to release thyroxine .

Hormones are carried from a gland to their target organ in the .

Hormones are carried from a gland to their target organ in the bloodstream .

A hormone produced by the pancreas when blood glucose is too high ; it causes glucose to move from the blood into cells, lowering blood glucose.

What happens when blood glucose concentration is too high?

The pancreas releases insulin . Glucose moves from the blood into the cells . In the liver and muscle cells , excess glucose is converted into glycogen for storage.

In the liver and muscle cells, excess glucose is converted into for storage.

In the liver and muscle cells, excess glucose is converted into glycogen for storage.

A disorder in which the pancreas fails to produce enough insulin , causing uncontrolled high blood glucose. It is normally treated with insulin injections .

What is Type 2 diabetes and how is it treated?

The body cells no longer respond to insulin produced by the pancreas. It is treated with a carbohydrate-controlled diet and exercise . Obesity is a risk factor.

In a person without diabetes, how does blood glucose change after a carbohydrate meal?

It rises as glucose is absorbed, then falls back to normal as insulin causes glucose to be taken into the cells.

What happens when blood glucose concentration is too low? (Higher Tier Only)

The pancreas releases the hormone glucagon , which causes glycogen to be converted into glucose and released into the blood.

How do insulin and glucagon control blood glucose by negative feedback? (Higher Tier Only)

When blood glucose rises , insulin is released and excess glucose is stored as glycogen , so the level falls. When blood glucose falls , glucagon is released and glycogen is converted back into glucose , so the level rises.

GCSEScienceAQACombined Science: TrilogyBiologyFlashcardsHomeostasis & ResponseHormones: Maintaining Blood Homeostasis

Hormones: Maintaining Blood Homeostasis (AQA GCSE Combined Science: Trilogy: Biology): Flashcards

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Cards in this collection (24)

Homeostasis
The regulation of the internal conditions of a cell or organism to maintain optimum conditions for function, in response to internal and external changes.
Why is homeostasis important?
It maintains optimal conditions for enzyme action and all cell functions.
Name three internal conditions controlled by homeostasis in the human body.
Blood glucose concentration
Body temperature
Water levels
What two types of response can automatic control systems involve?
Nervous responses and chemical (hormonal) responses.
Name the three components of all control systems.
Receptors
Coordination centres
Effectors
Receptors
Cells that detect stimuli (changes in the environment).
Effectors
Muscles or glands that bring about responses to restore optimum levels.
centres, such as the brain and spinal cord, receive and process information from receptors.
Coordination centres, such as the brain and spinal cord, receive and process information from receptors.
Endocrine system
A system of glands that secrete hormones directly into the bloodstream.
Hormone
A chemical messenger secreted by a gland into the blood, which is carried to a target organ where it produces an effect.
True or False?
Hormonal responses are faster than nervous responses.
False.
Compared with the nervous system, hormonal effects are slower but they act for longer.
Which hormone is produced by each of these glands: pancreas, thyroid, adrenal glands, ovaries and testes?
Pancreas – insulin
Thyroid – thyroxine (Higher Tier Only)
Adrenal glands – adrenaline (Higher Tier Only)
Ovaries – oestrogen
Testes – testosterone
Why is the pituitary gland called the 'master gland'?
It secretes several hormones that act on other glands, stimulating them to release further hormones to bring about effects.
Give an example of the pituitary gland controlling another gland.
(Higher Tier Only)
The pituitary secretes TSH (thyroid-stimulating hormone), which stimulates the thyroid to release thyroxine.
Hormones are carried from a gland to their target organ in the .
Hormones are carried from a gland to their target organ in the bloodstream.
Which organ monitors and controls blood glucose concentration?
The pancreas.
Insulin
A hormone produced by the pancreas when blood glucose is too high; it causes glucose to move from the blood into cells, lowering blood glucose.
What happens when blood glucose concentration is too high?
The pancreas releases insulin.
Glucose moves from the blood into the cells.
In the liver and muscle cells, excess glucose is converted into glycogen for storage.
In the liver and muscle cells, excess glucose is converted into for storage.
In the liver and muscle cells, excess glucose is converted into glycogen for storage.
Type 1 diabetes
A disorder in which the pancreas fails to produce enough insulin, causing uncontrolled high blood glucose. It is normally treated with insulin injections.
What is Type 2 diabetes and how is it treated?
The body cells no longer respond to insulin produced by the pancreas.
It is treated with a carbohydrate-controlled diet and exercise. Obesity is a risk factor.
In a person without diabetes, how does blood glucose change after a carbohydrate meal?
It rises as glucose is absorbed, then falls back to normal as insulin causes glucose to be taken into the cells.
What happens when blood glucose concentration is too low? (Higher Tier Only)
The pancreas releases the hormone glucagon, which causes glycogen to be converted into glucose and released into the blood.
How do insulin and glucagon control blood glucose by negative feedback? (Higher Tier Only)
When blood glucose rises, insulin is released and excess glucose is stored as glycogen, so the level falls.
When blood glucose falls, glucagon is released and glycogen is converted back into glucose, so the level rises.

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