Paper 2: Topic 5 Homeostasis & response - Homeostasis (LV) Flashcards

1
Q

Define the term homeostasis (2)

A

The maintenance of a stable internal environment even when the internal or external environmental conditions change.

Keeping pH, temperature, water balance and glucose levels in the plasma all within acceptable ranges for the body.

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2
Q

Why is homeostasis essential for all humans?

A

To ensure the internal conditions are kept optimal for enzyme controlled reactions

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3
Q

State the two systems that are both involved in homeostasis

A

Nervous system
Endocrine (hormonal) system

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4
Q

What type of response is homeostasis?

A

Automatic and involuntary
This means no conscious thought or decision is required

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5
Q

State 4 internal conditions that are all regulated/controlled by homeostasis

A

pH
temperature
blood glucose level in the plasma
water content of the plasma

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6
Q

State the 3 components of an automatic control system

A

Receptors
Co-ordination centres
Effectors

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7
Q

Describe the role of a receptor in an automatic control system

A

A specialised cell that can detect the stimulus (change in the environment)
AND
produce a nerve impulse

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8
Q

Define the term ‘stimulus’

A

A change in the environment

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9
Q

Describe the role of a co-ordination centre in an automatic control system

A

To receives and process the information received from the receptors.

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10
Q

Describe the role of an effector in an automatic control system

A

Produces a response to return the environmental factor back to its correct level i.e. counteracts the change

This restores the internal condition to its optimal level

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11
Q

State 2 types of effector

A

Muscle
Gland

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12
Q

Explain how the different effectors bring about a response in homeostasis

A

Muscles contract to bring about movement

Glands produces and then secretes hormones into the plasma

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13
Q

State 3 examples of co-ordination centres in humans

A

Brain
Spinal cord
Pancreas

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