B10 The human nervous system Flashcards

1
Q

What is homeostasis?

A

The process by which your body maintains a constant internal environment

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2
Q

Why is homeostasis important?

A

To maintain optimal conditions for enzyme actions

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3
Q

What does homeostasis rely on?

A

Automatic control systems such as your nervous system, hormones and body organs

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4
Q

What are the internal conditions that are controlled? (3)

A

Water content, body temperature and blood glucose concentration

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5
Q

How does water leave the body? (3)

A

Respiration, sweat and urine

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6
Q

What is the core body temperature?

A

37 degrees celsius

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7
Q

What controls the level of glucose in your blood?

A

The pancreas

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8
Q

What is the energy source for cells?

A

Glucose

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9
Q

What do receptor cells do?

A

Detect stimuli in the external or internal environment

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10
Q

What does the coordination centre include? (3)

A

The brain, spinal cord and pancreas

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11
Q

What are effectors and what do they do?

A

Usually muscles or glands that bring responses to stimulus

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12
Q

Where are receptor cells found?

A

In sense organs

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13
Q

What two things make up the central nervous system?

A

The brain and spinal cord

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14
Q

What are nerve cells called?

A

Neurones

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15
Q

What is a bundle of neurones called?

A

Nerves

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16
Q

What do sensory neurones do?

A

Carry impulses from receptors to the CNS

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17
Q

What do motor neurones do?

A

Carry impulses from CNS to effectors, which then respond to the impulses

18
Q

How do muscles respond to impulses?

A

Contracting

19
Q

How do glands respond to impulses?

A

Secreting chemicals

20
Q

What are the main steps involved in reflexes?

A

A receptor detects a stimulus > a sensory neurone transmits the impulse to the CNS > a relay neurone in the CNS passes the impulse on > a motor neurone is stimulated > motor neurone passes the impulse to an effector > action is taken

21
Q

What is the gap between two neurones called?

A

Synapses

22
Q

What is the sequence from a receptor to an effector called?

A

A reflex arc

23
Q

What does the cerebral cortex control?

A

Consciousness, intelligence, memory and language

24
Q

What does the cerebellum control?

A

Coordination of muscular activity

25
Q

What does the medulla control?

A

Unconscious activities, such as controlling heartbeat and breathing

26
Q

What does the pituitary gland do?

A

Produces hormones

27
Q

How have scientist been able to map out the brain?

A

By studying patients with brain damage, electrically stimulating parts of the brain, using MRI

28
Q

What is the sclera?

A

Tough, white outer layer that prevents damage to the eye

29
Q

What is the cornea?

A

Transparent area in front of sclera that lets light into the eye

30
Q

What do the muscles of the iris do?

A

Contract and relax to control the size of the pupil

31
Q

How do the muscles of the iris respond to bright light?

A

The circular muscles contract, radial muscles relax and pupil constricts, getting smaller

32
Q

How do the muscles of the iris respond to dim light?

A

Circular muscles relax, radial muscles contract and pupil dilates

33
Q

What does the lens do?

A

Clear disc held in place by suspensory ligaments and the ciliary muscles, changes direction of the light so that the image is focused

34
Q

What does the optic nerve do?

A

Carries impulses from the retina to the brain

35
Q

What is accommodation?

A

The process of changing the shape of the lens to focus on objects

36
Q

How do the lens change shape to focus on close objects?

A

The ciliary muscles contract, the suspensory ligaments loosen and the lens becomes thicker so it can refract light rays strongly

37
Q

How do the lens change shape to focus on distant objects?

A

The ciliary muscles relax, the suspensory ligaments are pulled tight and the lens in pulled so it only refracts light rays slightly

38
Q

What is myopia?

A

Short sightedness

39
Q

What is hyperopia?

A

Long sightedness

40
Q

How can slight defects in the eye be treated?

A

Spectacle lenses to refract light rights, laser surgery, lens replacement