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Biology > Nerves and hormones > Flashcards

Nerves and hormones Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What is a stimulus?

A

A change in the environment

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2
Q

What are the 5 senses and what are their receptors?

A

Sight - eyes have light receptors

Ears - sound and balance receptors

Nose - smell receptors, chemical stimuli

Tongue - taste receptors, chemical stimuli

Skin - nerve cells carry signals as electrical impulses from the skin receptors

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3
Q

What are receptors?

A

Groups of cells which are sensitive to a stimulus, changing stimulus energy into electrical impulses

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4
Q

What are effectors?

A

Something that does an action due to a stimulus (muscle or hormone glands)

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5
Q

What is a synapse?

A

A gap between neurones where the electrical signal turns into a chemical signal to cross the gap by diffusion

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6
Q

What is the CNS?

A

Located in the spine, the central nervous system is where the information from the sense organ goes

It consists of the brain and the spinal cord

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7
Q

Why are reflexes useful?

A

They are automatic responses and can reduce the chance of being injured as you act quickly without thinking

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8
Q

What is the route taken by the information in a reflex called?

A

The reflex arc

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9
Q

What does the reflex arc consist of?

A

Stimulus
Receptors receive the energy
Converts it into an electrical impulse and sends it across the sensory neurone
Message is passed through the CNS on the relay neurone
Message travels through the motor neurone to the effector
The effector activates when the electrical impulse hits

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10
Q

What do neurones look like and why?

A

They have branched endings to connect to other neurones and they’re long to speed up the impulse (fewer connections mean a quicker signal

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11
Q

What does the cornea do?

A

The transparent bit at of the sclera at the front of the eyeball. This bends light into the eye, focusing it on the retina

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12
Q

What is the pupil?

A

A hole in the eye to let light through

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13
Q

What is the iris?

A

A muscle which contracts and relaxes to control the size of the pupil and therefore the amount of light that enters

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14
Q

What is the lens?

A

A clear disc which is controlled by the ciliary muscles and suspensory ligaments. It focuses light rays in order to produce a clear image

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15
Q

What are suspensory ligaments and ciliary muscles?

A

Suspensory ligaments - sit either side of the lens and hold it in position

Ciliary muscles - attached to the suspensory ligaments and by contracting of relaxing, can position the lens

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16
Q

What is the sclera?

A

The white outer layer of the eye, it’s quite tough and strong so little damage can come to the eye

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17
Q

Why do you have a blind spot?

A

The optic nerve is attached to the retina, so there is a point on the retina where there are no light sensitive cells

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18
Q

What does the optic nerve do?

A

When sensors on the retina detect light, an electrical signal is emitted which travels up the optic nerve to the brain to be interpreted

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19
Q

What happens to the radial muscles in dim and bright light?

A

In bright light they relax so the pupil is smaller

In dim light they contract so the pupil gets bigger

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20
Q

What is accommodation?

A

When the lens changes shape to focus light

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21
Q

What do the ciliary muscles do to see distant and close objects?

A

Distance - the ciliary muscles relax which makes the suspensory ligaments to pull tight, making the lens go thin

Close - the ciliary muscles contract, slackening the suspensory ligaments so the lens becomes fat

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22
Q

Why does Myopia happen? (short sightedness)

A

The light focuses on front of the retina, so distant objects are blurry.
This can be because of a curved lens or the eyeball being too long

This can be fixed by wearing concave lens glasses to spread the light rays out so it focuses on the retina

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23
Q

Why does Hyperopia happen? (Long sightedness)

A

The light rays are focused behind the retina, so distant objects are in focus but near objects aren’t.
This could be because the lens is too flat or because the eyeball is too short

This can be treated by wearing convex lens glasses, bringing the light rays together so they focus on the retina

24
Q

What is binocular vision and why is it important?

A

When animals have two eyes, this judges depth perception and how fast things are moving

25
Q

How are hormones transported around the body?

A

They are chemicals released into the blood, that travel in the blood plasma but only affect particular cells (target cells) in particular places

26
Q

What are the differences between hormonal and reflex actions?

A 
Nerves: 
Transmits electrical impulses
Effects are very quick
effects are short lived
Messages transmitted through neurons
Endocrine:
Transmits chemical messages
effects take long to work
Effects last for ages (puberty)
Messages transmitted through blood plasma
27
Q

What are hormones?

A

Chemical messengers which travel in the blood to activate target cells

28
Q

What is the pituitary gland and what does it do?

A

Produces LH, FSH and ADH (controls water content)

Is located in the brain

29
Q

What does the pancreas do?

A

Produces insulin and enzymes

30
Q

What do the ovaries do?

A

Produce oestrogen which controls the menstrual cycle (builds the uterus lining)

Ovaries also control female sexual characteristics (puberty)

31
Q

What do the testes do?

A

Produce testosterone, which promotes male sexual characteristics such as deepening on voice and hair growth

32
Q

What is the differences between men and women in puberty?

A

Men - extra hair on face and body, muscles develop, penis and testicles enlarge, sperm production, deepening of voice

Female - extra pubic and underarm hair, hips widen, breasts develop, periods start

33
Q

How does the menstrual cycle work?

A

Day 1 is the period, where the lining is moved out of the body for 4 days

The womb lining builds up again from day 4-14 ready to receive an egg

The egg is released on day 14

The wall is maintained from 14-28. If no fertilised egg lands on it, the lining sheds again

34
Q

What are the properties of LH, FSH, oestrogen and progesterone?

A

FSH - produced in the pituitary gland, caused an egg to develop and makes ovaries produce oestrogen

Oestrogen - produced in ovaries, causing the uterus lining to thicken and stimulates LH whilst suppressing FSH

LH - produced by the pituitary gland, stimulates the release of the egg

Progesterone - maintains the lining of the uterus, produced in the ovaries

35
Q

Why is oestrogen used as contraception?

A

It stops the production of FSH, causing the egg to not grow

The pill is an oral contraception that contains oestrogen

36
Q

What are the advantages and disadvantages of the pill?

A

It’s over 99% effective at preventing pregnancy
It reduces the risk of getting cancer

It isn’t 100% effective
It can cause side effects (nausea, headaches, depression)
It doesn’t protect against STI’s

37
Q

How can FSH help women who have a low FSH level to have a child?

A

The increase in FSH will allow the egg to be developed and fertilised

But it doesn’t always work and more eggs than necessary could be released, leading to twins or triplets

38
Q

How does IVF work?

A

Hormones are given to the woman before collecting the eggs, as there needs to be multiple eggs in the Petri dish to ensure it works

Eggs are then collected from the women, put in a Petri dish and fertilised with the man’s sperm. These then develop into an embryo which is implanted back into the mother’s uterus

Several eggs must also be released back into the mother which could result in twins or triplets

39
Q

What are the advantages and disadvantages of IVF?

A

Couples can have a baby
You can check for abnormalities in the Petri dish

Could result in twins or triplets
It’s expensive
The IVF drugs can cause effects to the mother

40
Q

What is homeostasis?

A

Maintaining a constant internal environment.

41
Q

What are some examples of homeostasis?

A

Levels of CO2
Levels of oxygen
Water content
Body temperature

42
Q

What is negative feedback?

A

Changes in the environment trigger a response that counteracts the change
(A rise in body temperature causes a response that lowers body temperature)

So the level stays at the norm

43
Q

What happens a change in the environment exceeds the negative feedback limit?

A

If temperature changes so drastically, the negative feedback loop could not reverse it, leading to heatstroke for example

44
Q

How is water lost through the body?

A

Through the skin as sweat
Via the lungs in breath
Via the kidneys as urine

The balance between this can vary depending on temperature and water intake

45
Q

What is the human body temperature?

A

37 degrees Celsius

46
Q

What happens to your body when you’re too hot?

A

Hairs lie flat
Sweat is produced to evaporate, taking your heat with it, transferring heat to cool you
Blood vessels go to the surface of your skin to allow heat to go into the surroundings (vasodilation)

47
Q

What does your body do when you’re cold?

A

Hairs stand on end to trap a layer of air which insulates me
Little sweat is produced
Blood vessels constrict so less heat is transferred to the surroundings (vasoconstriction)
You shiver, as the movement generates heat in the muscles

48
Q

How is ion content regulated?

A

It’s regulated by the kidneys

Ions are taken into the body from food and are absorbed into the blood
If there is too many ions, they are released in sweat or urine

49
Q

What monitors and controls glucose levels?

A

The pancreas

50
Q

What produced insulin?

A

The pancreas

51
Q

What happens when glucose levels are too high?

A

Insulin is created by the pancreas

The insulin converts glucose into glycogen and stores it in the liver

52
Q

What happens when glucose is too low?

A

Insulin is not injected by the pancreas

Glucagon turns glycogen stored in the liver Into glucose

53
Q

What is the difference between type 1 and type 2 diabetes?

A

Type 1: the pancreas doesn’t produce insulin

Type 2: the body cells don’t react to insulin

54
Q

How to manage type 1 diabetes?

A

Injecting insulin into the blood, therefore excess glucose will effectively be stored as glycogen.

Avoiding foods rich in carbs and sugars

55
Q

How to manage type 2 diabetes?

A

Avoid fatty foods (watch your diet)

Exercise

Biology (11 decks)

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