biology EOY 🧑🏽‍🔬 > Nervous Control > Flashcards

Nervous Control Flashcards

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1
Q

What is homeostasis

A

The control of the body’s internal environment to provide constant conditions despite external changes

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2
Q

What does homeostasis control

A

Temperature and pH for correct enzyme activity
Blood glucose for constant energy supply
Water and ion concentrations to control osmosis and chemical reactions

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3
Q

Why are homeostatic control systems important in the body

A

To maintain optimal conditions for enzyme activity and cellular function

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4
Q

What are the three necessary components to an effective control system

A

Receptors to detect the change in conditions , coordination centres to process the information and effectors to bring about the correct response

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5
Q

What is a stimulus

A

Any change in environmental conditions that triggers a response

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6
Q

What are receptors

A

Specialised cells that detect a stimulus and convert it into electrical impulses which are then transmitted to the nervous system to trigger a response

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7
Q

Outline the stages in the negative feedback mechanism when blood pressure becomes too high

A

Receptors detect the increase in blood pressure, the brain processes this info and sends impulses, effectors respond by reducing heart rate and dilating blood vessels, lowering BP back to normal

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8
Q

What part of the nervous system do the brain and spine form

A

Central nervous system

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9
Q

What is the role of the central nervous system

A

To coordinate appropriate response

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10
Q

What is the function of the nervous system in humans

A

Allows detection of changes/ stimuli and coordinates response by communication between tissues

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11
Q

Name the two types of effector and how they respond to nervous impulses

A

Muscle - contract glands - release hormones

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12
Q

Name the two main types or neurones found in humans outside the central nervous system

A

Motor and sensory

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13
Q

What is the nervous system

A

a network of specialised cells called neurones groups together in bundles that we call nerves, it enables the body to respond to hanges in the environment to trigger the appropriate response

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14
Q

Describe how the nervous system coordinates a response to stimuli

A

the receptor detects the stimuli and it sends a nerve impulse along a sensory neurone
This cell takes the impulse towards the central nervous system, made up of the brain and the spinal cord
Once the brain or spinal chord has determined the appropriate response it sends another nerve impulse out along a motor neuron
This takes the impulse to an effector organ to carry out the response
This organ may be a muscle that contracts or relaxes or it may be a gland that is triggered to secrete hormones.

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15
Q

What is the chain reaction of how a body reacts to a stimuli

A

Receptor - sensory neuron - coordinator (CNS) - motor neuron - effector

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16
Q

What is a reflex

A

a reflex is a fast automatic response that occurs without conscious thought

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17
Q

What is a synapse

A

The junction between each two neurons

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18
Q

How do nerve impulses travel along neurons

A

2 neurons are not physically connected so when a nerve impulse arrives at the end of one neuron it releases a chemical into the gap
This chemical diffuses across the gap and binds to receptors on the next neuron triggering the next electrical impulse

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19
Q

What are reflexes used for

A

To control basic body functions such as breathing and digestion and to help you avoid danger or harm

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20
Q

How are reflexed co ordinated

A

The sequence of events is the same as other responses but only one cell is used in the CNS rather than hundreds this cell is called a relay neuron and connects the sensory neuron to the motor neuron through the spinal chord (sometimes in an unconscious part of the brain)

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21
Q

Name the type of cell that makes up most of the brains material

A

Nerve cells (neurons )

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22
Q

Name the region of the brain that controls unconscious activities

A

The brainstem specifically medulla oblongata

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23
Q

What is the chain reaction of a reflex arc

A

Receptor - sensory neuron - relay neuron (CNS) - motor neuron - effector

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24
Q

What are the advantages of the reflex arc

A

As the sequence bypasses the brain it reduces the time between stimulus and response, this is essential in minimising damage caused by a dangerous stimulus- usually the reflex arc will also send another impulse to the conscious brain so that you are aware of what has happened but only after the reflex action has been carried out

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25
Suggest two reasons why it is difficult to investigate and treat brain disorders
Very complex as many regions are responsible for multiple functions Treatments may cause permanent damage and side effects
26
State two ways other than MRI scientists can use to gather information to map the regions of the brain to particular functions
Studying patients with brain damage, linking symptoms to damaged regions Electrically stimulating parts of the brain
27
What is the purpose of the brain in the CNS
Th brain is made of billions of interconnected neurons that receive sensory inputs from your receptors then coordinates the appropriate response through the effectors
28
What does the cerebral cortex control
Consciousness, intelligence, memory and language
29
What does the cerebellum control
Coordinating muscles and balance
30
What does the hypothalamus control
Homeostatic functions eg temperature
31
What does the pituitary gland control
Secretes hormones eg ADH FSH TSH
32
What does the medulla control
Unconscious activities eg heartbeat breathing and digestion
33
Do you know where the cerebral cortex, cerebellum, medulla, hypothalamus, and pituitary gland are located
yes
34
What can magnetic resonance imaging be used for
MRI can show scans of patients brains to see effects of tumours, strokes etc
35
What are the risks with treating the brain
Opening the skull to perform surgery risks damaging the very delicate neurons and synapses, especially since we don't fully understand what each area does MRI scans are completely safe yet only help diagnose the problem not treat it MRI cannot be used on patients with any metal in their bodies from prior surgeries
36
Can drugs be used to treat brain disorders
Drugs can be used to treat brain disorders but many of them struggle to cross the membranes surrounding the brain so do not reach it aswell as this the range of diff chemicals released by synapses can easily be disturbed with serious side effects
37
38
Labelled eye
yes
39
What is the sclera
White outer layer of the eye providing protection
40
What is the cornea
Transparent front section of the sclera to allow light into the eye and refract the light to aid focus
41
What is the iris
Ring of muscle which can contract or relax to change the amount of light passing through to the retina, it constricts in bright light to protect the retina from damage or dilates in low light to allow more to the light sensitive cells
42
What is the lens
a clear disc held in place by suspensory ligaments, ciliary muscles can contract or relax to change its shape to fine tune the focusing of the ligh rays onto the retina for a clear image
43
What is the vitreous humour jelly
Fills the eyeball to help maintain the spherical shape of the eye
44
What is the retina
Layer of light sensitive receptor cells
45
What is the optic nerve
Carries impulse from the retina to the brain to be processed and interpreted as a visual image
46
What is the blind spot
The point where the optic nerve leaves the eye so there is no retina to detect light
47
Which two parts of the eye change the shape of the lens during focussing
Ciliary l,uncles and suspensory ligaments
48
What is the use of the pupil
The pupil allows varying amounts of light to enter the eye and reach the light sensitive cells on the retina
49
What happens to the eye in dim light
Circular muscles relax, radial muscles contract, pupil dilates
50
What happens to the eye in bright light
Circular muscles contract, radial muscles relax, pupil constricts
51
Why is it important for the pupil to change in size in different light levels
Because it controls the amount of light entering the eye preventing damage to the retina in bright light and allows enough light to see in dim light
52
Describe how the process of accommodation in the human eye works to focus on a near object and focus on a distant object Include details of the structures of the eye involved and their functions
Near object - the ciliary muscles (the muscles around the lens that controls its shape) contract, suspensory ligaments relax, the lens becomes thicker and more curved which increases refraction do light rays focus on retina (the light sensitive layer at the back of the eye Distant object - ciliary muscles relax, suspensory ligaments (ligaments that hold the lens in place) tighten, the lens becomes thinner and less curved, decreasing refraction so parallel light rays from distant objects focus on the retina
53
What is another name for short sightedness
Myopia
54
What is another name for long sightedness
Hyperopia
55
What causes short sightedness
If the lens is too curved, or the eyeball is too long the light is reflected too much and is focused in front of the retina, this causes rays that reach the retina from distant objects to be out of focus and blurry
56
How can you treat short sightedness
Glasses or contact lenses which are concave spread out the light before it reaches the eye so the lens then focuses the rays correctly
57
What causes long sightedness
If the lens is too flat and thin or the eyeball is too short the lens cannot refract the light rays enough so they focus behind the retina, this causes close objects to become blurry. It often gets worse with age as the ciliary muscles often become weaker
58
How can you treat long sightedness
Convex glasses or contact lenses refract the light before it reaches the eye so the lens can do the rest
59
Explain how laser eye surgery can be used to correct vision defects
Once an adult's eyes have stopped growing a laser can be used to change the shape of the cornea. To treat myopia the thickness of the cornea is decreased to reduce refraction To treat hyperopia the curvature of the cornea is changed to increase refraction
60
State another new technology apart from laser eye surgery that offers a permanent correction for vision defects
Lens replacement surgery which can replace a faulty lens with an artificial one that refracts the light the correct amount the operation takes under 15 minutes and the patient can go home the same day A permanent contact lenses can be implanted into the eye to aid the natural lense
61
What are the risks of eye surgeries
They are new and carry risks of damage to the retina and infections
62
Explain why the experiment should include a students reaction time without any caffeine
To act as a control so the effect of caffeine can be compared against normal reaction time
63
Where in the body are there cells sensitive to light, sound and changes in position
Retina, cochlea and inner ear
64
Labelled parts of a neuron
yes
65
What are the purpose of sense organs
To detect stimuli using receptor cells
66
What is the main difference between a voluntary action and a reflex action
Reflex actions are automatic and rapid, without conscious thought whereas voluntary actions are controlled continuously
67
Explain the process of phototropism
If onse side of the shoot is in the light, auxin diffuses away from the light The side of the shoot in the shade has more auxin so grows faster causing the shoot to bend towards the light
68
What is the role of auxin in plants
Auxin allows them to selectively grow parts of the plant to gradually move in certain directions to respond to their environment
69
What is gravitotropism
The response to gravity, it ensures that shoots grow up and roots grow down
70
Explain the process of gravitotropism
If the plant is laid on the side, auxin gathers in the lower half of the stem and root Auxin slows growth in the root so the root curves downwards Auxin stimulates growth in the shoot so the stem curves upwards
71
What is phototropism
The response to light, it ensures that the stem bends towards the light to maximise the absorption of light by the leaves for photosynthesis
72
How is auxin used in farming
Rooting powders- the auxin encourages stems to develop roots to grow a new plant from a cutting Weed killers p uses high doses of auxin that encourages uncontrolled growth in broad leaved plants which kills them
73
What is ethene used for in farming
It can rapidly ripen fruit (in combination with warmth) this means that fruit can be transported unripe and stored then ripened to the perfect stage ready for sale
74
What are giberellins used for in farming
Promoting flowering throughout the year for florists Increasing fruit size or triggering fruit development without seeds Speeding up the germination of seeds for brewing
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