B10.1 - B10.6 - Human Nervous System✔️ Flashcards

1
Q

Define homeostasis?

A

The bodys balancing of internal conditions to maintain optimum conditions for functioning, in response to internal and external changes

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2
Q

Example of three internal conditions controlled by the body?

A

-body temperature
-water contents of the body
-blood glucose concentration

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3
Q

What are receptors?

A

Cells that detect changes in the internal or external enviorment - changes known as stimuli - receptor cells part of nervous or hormonal control systems

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4
Q

what are stimuli?

A

Changes in the internal or external enviorment and are detected by receptor cells

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5
Q

What are coordination centres?

A

Areas that recieve and process the information from the receptors they send out signals and coordinate the response examples are the brain,spinal cord and some organs like the pancrease

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6
Q

What are effectors?

A

Muslces or glands that bring about response to the stimulus - response restores conditions in the body to optimun levels

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7
Q

What are neurones?

A

Special cells where information is passed along as electrical impulses - found in bundles of hundreds or even thousands which are known as nerves

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8
Q

What is the central nervous system?

A

central nervous system (CNS) is made up of the brain and spinal cord

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9
Q

What are sensory neurones?

A

The cells that carry impulses from your sense organs to your CNS

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10
Q

What are motor neurones?

A

Cells that carry informtion from the CNS to the rest of your body - carry impulses to the correct effectors

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11
Q

How might an effector respond to an impulse?

A

-muscles will respond by contractiing
-glands respond by secreting chemical substances

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12
Q

Order in which the nervous system detects a stimulus and acts?

A

Stimulus - receptor - coordinator(CNS) - effector

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13
Q

Step 1 - nervous sytems response to a stimulus?

A

Receptor sends an impulse along a sensory neurone carrying information about a change in the enviorment to the coordinator (CNS)

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14
Q

Step 2 - nervous sytems response to a stimulus?

A

Once the incoming information has been processed the coordinator (CNS) sends impulses down motor neurones

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15
Q

Step 3 - nervous sytems response to a stimulus?

A

The motor impulses stimulate the effectors to bring about the response needed in any particular situation

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16
Q

What are reflexes?

A

Our bodys automatic, rapid and sub-conscious reaction to harm or incoming danger they do not involve the conscious part of your brain example of some of the functions are breathing and moving food through your digestive system

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17
Q

Describe the process of the reflex ark ?

A

Electrical impulse passes from the receptor along the sensory neurone then passes along a relay neurone (found in the CNS) and straight back to the motor neurone from there it arrives at the effector (muscle or gland)

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18
Q

Why is the reflex arc so rapid and takes place so quick?

A

The impulse bypass the conscious areas of your brain so the time between stimulus and reflex action is as short as possible because it does not require us to think

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19
Q

What are relay neurones?

A

Involved in the reflex ark and connect sensory neurones an motor neurones and are found in the CNS (usually in the spinal cord)

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20
Q

What are synapses?

A

Physical gaps between the neurones - electrical impulses are carried to neighbouring neurones by chemicals called neurotransmitters which are released by the nerve cell and taken up by another cell on the other side

21
Q

Reflex ark main stages ordered?

A

Stimulus - receptor - sensory neurone - relay neurone - motor neurone - effector - response

22
Q

Function of the cerebral cortex?

A

Concerned with consciousness,intelligence,memory and language

23
Q

Function of the cerebellum?

A

Concerned mainly with coordinating muscular activity and balance

24
Q

Function of the medulla?

A

Concerned with unconscious activities such as controlling the heartbeat, the movment of the gut and breathing

25
Q

Function of the hypothalamus?

A

Involved in controlling body tempertaure

26
Q

function of the pituitary gland?

A

Involed in producing many different chemicals (hormones) which play a large part in coordinating and controlling body systems

27
Q

How has studying people with brain damage or head injurys helped us learn about the brain? Refer to phineas gage and his accident and what we have learnt from it ?

A

Matching changes in behaviour or memory with the damaged area - for example in 1848 an explosion blew and iron rod through the skull of Phineas Gage he survived but his behaviour changed from the polite, hardworking man he was to being rude and wild - modern scans show that the accident removed part of his cerebral cortex which controls social inhbitions

28
Q

How does electrically stimulating the brain help us learn more about the brain?

A

Scientists expose the brain by removing the top of the skull and stimulate different areas (no sensory nerve endings so brain surgery is usually done on conscious patients) patients can experince hunger, anger or thirst just from a certain part being stimulated

29
Q

How does MRI scans on the brain help us learn more about the brain?

A

Scanning a patient with a tumour in the brain or a stroke with an MRI scan allows scientists to link loss of a certain function such as speech or movement with the exact part of the damaged brain

30
Q

Why is it hard to study the brain?

A

-The brain is easily damaged or destroyed and very easy to cause unitended damaged as the function of all areas are not understood

-drugs do not always reach the brain due to the membrane which surrounds it

31
Q

Structure and function of the sclera in the eye?

A

The sclera is the white outer layer of the eye - it is relativly tough and strong so the eyeball is not easily damaged - has a transparent area at the front of the eyeball called the cornea

32
Q

Structure and function of the cornea in the eye? Significance of its structure?

A

Transparent area at the front of the eyeball which lets light into the eye - the cured surface of the cornea is important for changing the direction of the light rays coming into the eye to make sure they are focused on the retina

33
Q

What is the pupil?

A

The hole through which light enters the eye - the size of the pupil is controlled by the muscular iris - in bright light the iris makes the pupil small reducing amount of light entering to stop the light damaging the light sensetive cells - in dim light the pupil is enlarged so as much light can enter

34
Q

How does the iris control the pupil?

A

Iris is a muscle which can contract or relax to change the size of the pupil

35
Q

What holds the lens?what is the lens function?

A

Held in place by suspensory ligaments and ciliary muscles - lens ‘fine tunes’ the focusing of the light rays - changing the rays direction to produce a clear image on the retina

36
Q

What happens when light rays hit the retina?

A

Light sensetive cells are stimulated - send impulses to the brain along sensory neurone in the optic nerve - brain interprets them as visual images

37
Q

How is the light focused in our eyes?what process is it? What are involved?

A

Light gets focused by the process of refraction - the cornea changes the direction of the light rays onto the retina - the shape of the lens is important for seeing both close and distant objects (because the shape of the lens changes how the light is refracted)

38
Q

What is accomodation in refrence to eyes and the lens?

A

Is the process of changing the shape of the lens to focus on near or distant onjects

39
Q

How does the eye focus on distant objects?

A

Ciliary muscles relax so the suspensory ligaments are pulled tight and the lens is pulled flat and thin - only refracts light rays slightly so they are focused on the retina

40
Q

How does the eye focus on distant objects?

A

The ciliary msucles contract so the suspensory ligaments loosen - the lens is then thicker and more curved - it refracts light rays strongly so they are focused on the retina

41
Q

What is myopia? what does it cause?

A

Myopia (short sightedness) distant objects look blurred because the light is focused on the front of the retina and may be a result of lens being to curved or a particularly long eyeball

42
Q

How to treat myopia?

A

Wear glasses with concave lens that spread out the light from distant object before it reaches the retina so the thicker lens can bring it into focus on the retina

43
Q

What is hyperopia? what does it cause?

A

Hyperopia (long sightedness) meaning close object appear blurred and may be a result of a lens that is too flat and thin or a particularly short eyeball - as a result the lens cannot refract the rays of light strongly enough so it is focused behind the retina with the images that lands on the retina being out of focus

44
Q

How to treat hyperopia?

A

Wear glasses with convex lens which bring the light rays together before they reach the eye itself and the thinner lens can bring the rays of light into perfect focus on the retina

45
Q

What are contact lenses? How do they work?

A

Lenses that are placed on the surface of the eye they work the same as normal glasses but can be worn for sports and are harder notice however they have to be removed overnight and kept sterile

46
Q

How does laser eye surgery work?

A

Only available to adults once there eyes have stopped growing - lasers are used to treat myopia by reducing the thickness of the cornea (which now focuses the light on the retina instead of infront) to treat hyperopia the laser are used to change the curve so the cornea refracts light from close objects more effectivley

47
Q

How do replacment lenses work?

A

Add another lens inside the eye itself to correct visual defect permanently - permanent contact lens is implanted into the eye and the natural lens is left in place or the other option is to the have the faulty lens replaced by an artifical lens

48
Q

Reflex ark ordered step by step?

A

Stimulus - receptor - sensory neurone - relay neurone - motor neurone - effector - response