B10 Flashcards

1
Q

Receptors

A

Cells that detect changes/stimuli in internal or external environment

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2
Q

Coordination centre

A

Areas that receive and process information from receptors. Send out signals to start response
Brain coordinates nervous system

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3
Q

Effectors

A

Muscles or glands that respond once stimuli received, restoring conditions to optimum levels

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4
Q

Central Nervous System (CNS)

A

In vertebrates consists of brain and spinal cord. In mammals connected to body by neurones

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5
Q

Sensory Neurones

A

Neurones that carry information as electrical impulses from receptors to CNS

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6
Q

Motor neurones

A

Carry electrical impulses from CNS to effectors

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7
Q

Synapses

A

The connection between two neurones

Nerve signal is transferred by chemicals that diffuse called neurotransmitters

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8
Q

Reflex arc

A

Neurones go through the spinal cord or through unconscious part of brain
Impulses sent along sensory neurone to relay neurone in CNS
Impulses passed along synapse between neurones
Impulse then travels along motor neurone to effector

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9
Q

Why are reflexes faster that normal reactions

A

Don’t involve conscious part of brain so no thought

Eg: pupils dilate in bright light

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10
Q

Reaction time

A

Time taken to respond to a stimulus

Affected by age, gender or drugs

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11
Q

Cerebral cortex

A

Outer wrinkly area

Responsable for consciousness, intelligence, memory and language

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12
Q

Medulla

A

Brain stem attached to spinal cord

Controls unconscious activity - breathing, heartbeat

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13
Q

Cerebellum

A

Lower rear section

Responsible for muscle coordination

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14
Q

Hypothalamus

A

Small region in centre of brain

Regulation centre - temperature

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15
Q

Meninges

A

Membranes underneath skull

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16
Q

Methods to study brain

A

Patients with brain damage - small part of brain damaged, effect on patient can tell what that part of brain does
Electrically stimulating - stimulating brain by pushing tiny electrode into tissue and giving small bit of electricity, then see what happens
MRI scans - Can see what parts of brain active when listening to music or recalling a memory

17
Q

Sclera

A

Tough, supporting wall of eye

18
Q

Cornea

A

Transparent outer layer at front of eye

Refracts light into eye

19
Q

Iris

A

Contains muscles that control diameter of pupil exposed, so how much light enters eye

20
Q

Lens

A

Focuses light onto retina

21
Q

Retina

A

At back of eye

Contains receptor cells sensitive to light intensity and colour

22
Q

Ciliary muscles and Suspensory ligaments

A

Control shape of lens

23
Q

Optic nerve

A

Carries impulses from receptors on retina to brain

24
Q

The Iris reflex - adjusting for bright light

A

Bright light can damage retina
Light receptors detect very bright light
Reflex is triggered that makes circular muscles in iris contract and radial muscles relax. This makes iris bigger, reducing size of pupil

In dim light
Circular muscles relax
Radial muscles contract
Makes pupil wider

25
Q

Accommodation

A

Eye changes shape of lens to focus on retina

26
Q

Near object

A

Ciliary muscles contract
Slackens suspensory ligaments
Lens becomes thicker
Increases amount of refraction

27
Q

Distant objects

A

Ciliary muscles relax
Suspensory ligaments pull tight
Lens becomes thinner
Less refraction

28
Q

Long sightedness (hyperopia)

A

Cannot see near objects
Occurs when lens is wrong shape (too thin) so doesn’t refract enough
So the refracted light focuses behind retina
Use convex lens (curves outwards)

29
Q

Short sighted (myopia)

A

Cannot see distant object as refracts light too much and focuses before retina
Lens may be too thick
Concave lens (curves inwards)

30
Q

Contact lenses

A

Thin lenses on surface of eye, almost invisible
Hard contact lenses last a long time and have to be taken out and sterilised overnight
Soft contact lenses are more comfortable, some can be worn more than once if sterilised overnight, others are one use and then disposed

31
Q

Laser eye surgery

A
Laser used to vaporise tissue to change shape of cornea 
In laser eye surgery for myopia (short sightedness) they use lasers to reduce the thickness of the cornea so it refracts light less strongly.
For hyperopia (long sightedness) they use lasers to change the curve of the lenses to refract light better
32
Q

Replacement lens surgery

A

Natural lens removed and replaced with artificial one