Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOLOGY PAPER 2 > B5 HOMEOSTATIS > Flashcards

B5 HOMEOSTATIS Flashcards

1
Q

What is homeostasis

A

Maintaining a stable internal environment through the regulations of conditions around the body 

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the three things that homeostasis control?

A
  • blood glucose concentration
  • Body temperature
  • water levels 
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What do receptors do?

A

They detect stimuli, which is a change in the environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What do coordination centres do and give two examples of a coordination centre?

A

The process the information received from the receptors

Brain and spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does an effector do and give two examples of an effector

A

Effectors carry out the change to bring the conditions in the body back to optimum levels

Muscles or glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the nervous system

A

Very fast and precise electrical impulses through nerves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does the nervous system work

A
  1. Receptor cells convert a stimulus into an electrical impulse
    2.the electrical impulse travels along sensory neurones to the central nervous system
  2. In the cps, the information is processed and the appropriate response is coordinated resulting in an electrical impulse being sent along motor neurones to the effectors
  3. The effectors carry out the response - this may be muscles contracting or glands secreting hormones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe an automatic response through a reflex arc

A
  1. Stimulus is detected
    2.impulses are sent across a sensory neurone
  2. In the CNS the impulse passes to a relay neurone
  3. Impulses are sent along a motor neurone
  4. Impulse reaches effector and results in the appropriate response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does an impulse cross a synapse

A
  1. When the impulse reaches the end of the first neurone, a chemical is released into the synapse
  2. This chemical diffuses across the synapse
  3. When the chemical reaches the second neurone it triggers the impulse to begin again in the next neurone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does the cerebral cortex control (5)

A
  • consciousness
  • intelligence
  • memory
  • language
  • senses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does the cerebellum control (2)

A
  • balance
  • muscle control
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does the hypothalamus control (2)

A

-regulates body temperature
- sends signals to the pituitary gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What two things does the medulla control

A

Unconscious activities
Breathing, beating of heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does the brain stem control

A

-controls basic functions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why is investigating the brain difficult

A
  1. It’s complex and delicate
  2. It is easily damaged
  3. Drugs given to treat diseases can’t always reach the brain because of the membranes that surround it
    4.it is not understood which part of the brain does what
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are 3 ways scientists study the brain

A
  1. Studying those with brain damage - observing the changes in an individual following damage on a certain area of the brain can provide information on the role this area has
  2. Electrically stimulating different parts of the brain - by pushing an electrode into the brain. The stimulation may result in a mental or physical change which provides information on the role this area of the brain has played in
  3. Using MRI scanning techniques - scanner can be used tocreate an image of the brain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the role of the retina

A

Layer of light sensitive cells found at the back of the eye - impulses are sent to the brain which interprets the information to create an image

Cone cells: colour of light (bright light)

Rod cells: helpful in low light and night vision → they are more sensitive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does the optic nerve do

A

Carries impulses from retina to brain to form an image

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the sclera

A

White outer layer which supports the structure inside the eye - it is strong to prevent damage to the eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the cornea

A

The see through layer at the front of the eye -it allows light through and the curved surface bends and focuses light onto the retina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the iris and what does it do

A

Muscles that surround the pupil.

In bright light- circular muscles contract and radial muscles relax to make pupil smaller - avoiding damage to retina

In dim light - circular muscles relax and radial muscles contract to make the pupil larger - so more light can enter to create a better image

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the process of accommodation when focusing on a near object

A
  • Ciliary muscles contract
  • suspensory ligaments loosen
  • lens is then thicker and more curved - this refracts the light more
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the process of accommodation when focusing on a distant object

A

-Ciliary muscles relax
- suspensory ligaments tighten
- lens then becomes thinner - light is refracted less

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What causes hyperopia? And what is the solution

A

Long sighted

Lens is too flat so it can not refract enough right,

Glasses with convex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is myopia and how is it treated

A

Short sightedness

Lens is too curved so distant objects appear blurry

Concave lens glasses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are 3 alternative treatments for myopia/ hyperopia

A

Contact lenses-they work in the same way as glasses but allow activities such a sport to be carried out hard or soft contact lenses last for different length s of time

Laser eye surgery -Laces can be used to either reduce the thickness of the cornea so that it refracts less light to treat myopia or change its curvature so it reflects more strongly to treat hyperopia

Replacement lens -hyperopia can be treated by replacing the lens with an artificial one made of clear plastic. the risks include damage to the retina

27
Q

What two things occur when the body temperature becomes too high

A

Sweat is produced from sweat glands → sweat evaporates from skin surface resulting in an increased heat energy transfer away from body

Blood vessels expand And more blood flows closer to the surface of the skin (vasodilate ) so more heat energy is transferred to surroundings

28
Q

What does the body do when internal temperature is too cold?

A

Constrict blood vessels that line near the surface of our skin vasoconstriction so less blood flows near surface which means less heat loss

Hairs stand on end to create an insulating layer trapping warm air

skeletal muscles contract rapidly to generate heat from respiration →(shivering )

29
Q

What is the endocrine system?

A

It is a network of glands that make hormones

30
Q

What does the pituitary gland do?

A

 produces multiple hormones and some tell the body what to do some other glands to release their own hormone

31
Q

What does the pancreas do

A

Secretes insulin and glucagon

Controls blood glucose levels

32
Q

What two things does the thyroid gland do?

A

Secretes thyroxine

Controls metabolic rate heart rate and temperature

33
Q

What does the adrenal gland do?

A

Secretes adrenaline
Involved in fight or flight response

34
Q

What do the ovaries do?

A

Secretes oestrogen
Is involved in the menstrual cycle and the development of female secondary sexual characteristics

35
Q

What do the testes do?

A

Secrete testosterone
Is involved in a production of sperm and the development of male secondary sexual characteristics

36
Q

What are the three differences between the nervous system and the endocrine system?

A

Endocrine relies on hormones- nervous system relies on electrical impulses

Hormones spread slowly and their affects last longer whereas in the nervous system it’s very fast and often the effects don’t last very long

Hormones act more generally whereas in the nervous system it’s in one specific area and they are precise

37
Q

What does your body do if glucose levels are too high?

A

The pancreas detects the high glucose levels and stop the production of glucagon

The pancreas then releases insulin

Insulin binds to the receptors on certain cells such as muscle or liver cells and communicates to them to take some glucose that is flowing in the bloodstream and store them as glycogen

38
Q

What does the body do if there are low levels of glucose?

A

The production of insulin is stopped
The pancreas then secretes glucagon
Glucagon then bind to cells, especially liver and breaks down the glycogen to glucose then releases the glucose into the blood

39
Q

What is type one diabetes and what is the solution?

A

It is normally in children or teens (inherited)

-This is where the pancreas stops producing insulin
-Blood glucose levels rise too high which makes people feel ill and could kill them
-Glucose is excreted with urine and lots of urine is produced leaving the individual very thirsty

-inject insulin into abdomen or thigh
-If they’ve eaten more carbs inject more insulin
-if they exercise inject less insulin because the muscles absorb more glucose from the blood

40
Q

What is type two diabetes? What causes it? What is the solution?

A

When the body is resistant to insulin -body doesn’t respond to insulin anymore
Cells wont take in glucose from the bloodstream

Normally in order people due to an unhealthy diet

Healthy low sugar diet
Regular exercise

41
Q

What are three waste products that are processed at the kidney?

A

Water ions urea

42
Q

What happens if water levels are too low in the body?

A

Hypothalamus sends signal to the pituitary gland
Pituitary gland releases hormone called ADH
ADH goes to the kidneys and communicates to them to re-absorb more water - then produce less urine

43
Q

What happens if water levels are too high?

A

Hypothalamus stop sending signals to the pituitary gland
So it won’t release as much ADH
So the tubules contain more water and more urine produced

44
Q

What are two ways to treat people with kidney failure?

A

Dialysis- The function of the kidneys is carried out using an artificial membrane
-Blood moves between partially permeable membrane and surrounded by dialysis fluid which has the same concentration of ions and glucose as healthy blood

Kidney transplant -provided the individual with a healthy kidney
-This is the only cure
-are transplanted from people who have died suddenly or from people still alive who donate
-This means the person does not need to visit the hospital as regularly as they did when undergoing dialysis and it is cheaper than the overall cost of dialysis

45
Q

What are the negatives of dialysis and a kidney transplant

A

Dialysis
-Expensive
-Possibility of blood clots forming
-Have to follow a strict diet
-Takes up a lot of time
-Buildup of waste products between sessions can leave people feeling ill

Kidney transplant
-Kidney can be rejected
-Vulnerable to diseases
-not enough available

46
Q

What happens to our cells when there’s too much water versus when there’s too little water?

A

much water: cells swell and possibly burst
Little water : cells lose the water and shrink

47
Q

What does the follicle stimulating hormone do? And where is it produced?

A

Produced in the pituitary gland

Causes the maturation of an egg in the ovary

Stimulates the ovaries to produce oestrogen

48
Q

What does oestrogen do? And where do we find it?

A

Causes the lining of uterus to grow again

Stimulates the production of LH and inhibits the secretion of more FSH

Produced in ovaries

49
Q

What does the luteinising hormone do? And where do we find it?

A

Produced in pituitary gland

Stimulates release of egg

50
Q

What does progesterone do and where is it produced?

A

Produced in the ovaries and secreted from the egg follicle

Maintains lining of the uterus and support a pregnancy if the egg is fertilised

Inhibits the release of both FSH and LH

51
Q

What happens in the first stage of the menstrual cycle and how long does the menstrual cycle last?

A

28 days

  1. Menstruation.
    -Bleeding period lasting around four days due to breakdown of uterus lining
52
Q

What happens during the second stage of the menstrual cycle?

A

Lining builds up again and becomes thick spongy layer with lots of blood vessels in it
Last 10 days up to day 14
-To prepare uterus lining for fertilised egg

53
Q

What happens during the third stage and what is it called?

A

Ovulation
-Egg is being released from the ovaries which only takes one day

54
Q

What is the fourth stage of the menstrual cycle?

A

Maintaining lining of uterus ‘

If no fertilised egg has made it to the uterus, then the uterus will start to break down

If there is a fertilised egg, it will slowly implant into the uterus lining and slowly developing into a fetus

55
Q

What are 5 hormonal method of contraception?

A

-The contraceptive pill which contains a mix of oestrogen and progesterone
The side effects include changes in mood, depression, breast pain, increased blood pressure, and breast enlargement

The contraceptive patch - contains oestrogen and progesterone
Lasts only one week

The contraceptive implant-releases a continuous amount of progesterone which prevents the ovaries from releasing the egg and thickens the mucus in the cervix sperm and fertilised egg from embedding the uterus
-Last for three years

The contraceptive injection-made up of progesterone
Last 2 to 3 months

The IUD-releases progesterone
T-shaped and inserted into the uterus

56
Q

What are 5 non- hormonal method of contraception?

A

Condoms or diaphragm
Diaphragm fit over the cervix and not very reliable

Spermicides- these kill or disabled sperm but only 70 to 80% effective

Copper intrauterine device-kills sperm in the uterus

Surgical procedures - I have a cutting and tying the fallopian tubes or sperm duct

Abstaining from sexual intercourse

57
Q

What happens in IVF and what are the benefits and con?

A

-The mother is given FSH and LH to encourage maturation eggs
-These are extracted from the mother and fertilised in the lab using sperm
-The fertilised egg developed to embryos and then one or two are inserted in the uterus

Benefits - provides your way for an infertile couple to have a child

Con - it is physically stressful as women may have reactions to hormone such as feeling sick
- It is emotionally stressful because it may not work- the success rate is 26%
-multiple embryos lead to multiple birth so higher risk of complications, miscarriage and stillbirth
-Some people are against IVF due to it being unethical since some embryos are unused and destroyed

58
Q

Describe the negative feedback process of thyroxine in the body

A

If levels of thyroxine are low, the pituitary gland releases TSH which inhibits the release of thyroxine

59
Q

What is an auxin

A

A hormone that moves to the shaded side of the shoot
They stimulate the cells to grow more here

60
Q

What does it mean if a shoot shows negative gravitropsim

A

Auxin moves to lower side

Cells of shoot grow more on the side with most auxin, so it stimulates cells to grow more here

This makes the bend and grow away from the ground

This is beneficial as light levels are likely to be higher further away from the ground

61
Q

Describe what happens when a root shows positive gravitropism

A

Auxin moves to the lower side

The shows of the grow more on the side with less auxin so it stimulates cells to grow on the upper side

This makes the root bend and grow downwards

This is beneficial as there are more likely to be increased levels of water and nutrients lower down and it provides stability for the plant

62
Q

What are the three uses of AUXINS

A

As weed killers
-Many weeds are broadleaved
- They have been synthesised so they only affect broadleaved plants
-The increased amount of auxins causes the cells to grow rapidly which results in the weed dying

As rooting powders
-Plants with desirable features are cloned to make more plants with the same feature
-One way to clone plant is to take a cutting from the original plant
-Rooting powder containing auxin is applied to it and it is placed in the ground
-Roots screw and the new plant begins to grow very quickly

To promote growth into tissue culture
-Another way to clone plant is to use tissue culture
-cells from the plant are taken and placed in a growth medium containing lots of nutrients
-The hormone is then added and the cells begin to form roots and shoots

63
Q

How is Ethene used for the ripening of fruits?

A

-Fruit is picked when it is not ripe
-it is firm which means that during transport it gets less bruised and damaged
-When it is needed to be sold, it is exposed to ethene and warmer temperatures
-Ethan is involved in controlling cell division and stimulates enzymes that result in fruit ripening
-this reduces wastage as more fruit is suitable to be sold and does not ripen too too early

64
Q

What are the three uses of gibberellins?

A

Ending seed dormancy
-In the brewing industry, the germination rate of barely seeds is increased to make a malt

Promoting flowering
-Instead of requiring certain conditions such as longer days and low temperatures to flower applying this hormone all allows it to flower in any conditions with bigger flowers

Increasing fruit size
-The seeds and fruit produce gibberellins to increase fruit size
-This means that seedless fruit is generally smaller
-Seedless fruit can be sprayed with gibberelins to increase their size

BIOLOGY PAPER 2 (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions