Brainscape's Knowledge GenomeTM

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


See full index

Biology > Topic 5-Homeostasis > Flashcards

Topic 5-Homeostasis Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is homeostasis?

A

Homeostasis regulates that conditions inside the body and cells to maintain a stable internal environment, in response to change in both internal and external conditions.

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

What are automatic control systems?

A

They regulate your internal environment in your body, these include nervous and hormonal communication systems.

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

What is negative feedback?

A

Negative feedback counteracts changes when a level of something (e.g water or temp.) is too low or too high.

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

What happens during negative feedback if a level of something is too low?

A

Receptor detects a stimulus.
The co-ordination centre receives and processes the info and then organises a response.
Effector produces a response, which counteracts the change and restores the optimum level- level increases.

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

What happens during negative feedback if a level of something is too high?

A

Receptor detects a stimulus.
The co-ordination centre receives and processes the info and then organises a response.
Effector produces a response, which counteracts the change and restores the optimum level- level decreases.

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

What is the CNS?

A 
CNS= central nervous system 
In vertebraes (animals with backbones) this consists of the brain and spinal cord. 
In mammals the CNS is connected to the body by sensory neurones and motor neurones.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are sensory neurones?

A

The neurones that carry info as electrics impulses from the receptors to the CNS.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are motor neurones?

A

The neurones that carry electrical impulses from the CNS to effectors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are effectors?

A

All your muscles and glands, which respond to nervous impulses. Muscles contract in response and gland secrete hormones.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What can receptors form?

A

Receptors can form part of larger, complex organs. E.g the retina of the eye is covered in light receptor cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How is a response coordinated?

A 
Stimulus
Receptor 
Sensory neurone 
CNS 
Motor neurone 
Effector 
Response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are synapses?

A

Synapses connects neurones, the nerve signal is transferred by chemicals which diffuse across the gap. These chemicals then set off a new electrical signal in the next neurone.

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

Why are reflexes good?

A

Reflexes help prevent injury, reflexes are rapid, automatic responses to certain stimuli that don’t involve the conscious part of the brain.

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

What happens in the reflex arc?

A

The neurones in reflex arcs go through the spinal cord or through an unconscious part of the brain.
When a stimulus is detected by receptors, impulses are sent along a sensory neurone to a relay neurone in the CNS.
When the impulses reach a synapse between the sensory and relay neurone, they trigger chemicals to be released. These chemicals cause impulses along the relay neurone.
The same thing happens when the impulses reach a synapse between the relay and motor neurone.
The impulse travels along the motor neurone to the effector.
The muscle then contracts or the glands secretes the hormones.

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

What is the brain responsible for?

A

Responsible for complex behaviours.
The brain is part of the CNS.
Made up of billions of interconnected neurones.
Controls and coordinates everything.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the cerebral cortex?

A

Outer wrinkly part. At the front.

Responsible for: consciousness, intelligence, memory and language.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the medulla?

A

At the bottom.

Controls unconscious activities like breathing and your heartbeat.

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

What is the cerebellum?

A

The back bottom part of brain.

Responsible for muscle coordination.

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

3 way scientists study the brain?

A

Studying patients with brain damage.
Electrically stimulating the brain.
MRI scans.

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

How are do scientists study patients with brain damage?

A

If a small part of the brain has been damaged, the effect this has on the patient can tell you a lot about what the damaged part of the brain does.

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

How do scientists study the brain but electrically stimulating the brain?

A

The brain can be electrically stimulated by pushing a tiny electrode into the tissue and giving it a small zap of electricity. By observing what stimulating different parts of the brain does, it’s possible to get an idea of what those parts do.

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

How do scientists use MRI scans to study the brain?

A

A magnetic resonance imaging (MRI) scanner is a tube like machine that can produce a very detailed picture of the brains structures. Scientist use it to see what area of the brain is active when people are doing things like listening to music or trying to recall memory.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What consequences are there when messing with the brain?

A

Development of treatments for disorders of the nervous system.
Physical damage.
Increased problems with brain function.

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

What is the sclera?

A

Tough, supporting wall of the eye.

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

What is the cornea?

A

Transparent outer layer found at front of the eye. Refracts light into the eye.

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

What is the iris?

A

Contains muscles that allow it to control the diameter of the pupil.
Controls how much light enters the eye.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the pupil?

A

The hole in the middle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the lens?

A

The lens focuses the light onto the retina, which contains receptor cells sensitive to light intensity and colour.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are the ciliary muscles and suspensory ligaments?

A

Control shape of lens.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the optic nerve?

A

Carries impulses from the receptors of retina to the brain.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How do the iris adjust to bright light?

A

Bright light can damage the retina.
When bright light receptors enter the eye the pupil goes smaller, the circular muscles in the iris contract and the radial muscles relax. This reduces the amount of light that can enter the eye.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

How does the iris adjust to dim light?

A

Radial muscles contract and the circular muscles relax, which makes the pupil wider.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How does the eye adjust to focus on near objects?

A

Ciliary muscle contract, slackens the suspensory ligaments.
Lens becomes fat (more curved).
Increases the amount by which it refracts light.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

How does the eye focus on distant objects?

A

Ciliary muscles relax, tightens suspensory ligaments.
Lens goes thin (less curved).
Refracts light by a smaller amount.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is long-sightedness?

A

Unable to focus on near objects.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Why does long sightedness occur?

A

Lens is wrong shape and light doesn’t refract the light enough or eyeball is too short.
Images near are brought into focus behind the retina.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is short sightedness?

A

When someone can’t see distant objects.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Why does short sightedness occur?

A

Lens is wrong shape and refracts light too much or the eyeball is too long.
The image of the distant object are brought to focus in front of the retina.

39
Q

How can you treat long sightedness?

A

Convex lens. A lens that which curves outwards so the light refracts so it can focus on the retina.

40
Q

How can you treat short sightedness?

A

Concave lens. Curves inwards so light rays are refracted to focus on retina.

41
Q

Other term for long sightedness?

A

Hyperopia.

42
Q

Other term for short sightedness?

A

Myopia.

43
Q

3 treatments for vision defects?

A

Contact lenses.
Laser eye surgery.
Replacement lens surgery.

44
Q

How do contacts lenses work?

A

Thin lenses that sit on surface of the eye and shaped to compensate for fault in focusing.
Lightweight and invisible.
More convenient than glasses for sports.
Hard and soft lenses.
Soft lenses are more comfortable but carry more risk of infection that hard lenses.

45
Q

How does laser eye surgery work?

A

Laser vaporises tissue, changing the shape of the cornea.
Slimming cornea down makes it less powerful and improve long sight.
Changing the shape makes it more powerful so improves short sight.
Risk of infection in the eye or eye’s vision is worse than before.
Surgeon can precisely control how much tissue the laser takes off.

46
Q

How does replacement lens surgery work?

A

For long sightedness.
Replaces lens on eye.
Natural lens is removed and an artificial lens, made of clear plastic is inserted.
Higher risk than laser eye surgery as work inside eye.
Could damage retina, could lead to loss of sight.

47
Q

What is the thermoregulatory centre?

A

In brain.
Contains receptors that are sensitive to temp. of blood flowing through the the brain.
Also, receives impulses from temp. receptors in the skin.

48
Q

What does the thermoregulatory system do?

A

Keeps body temperature constant.

49
Q

Body temp. too high?

A

Temp. receptors detect that core body temp. is too high.
Thermoregulatory centre=coordination centre, receives info. from temp. receptors and trigger the effectors automatically.
Effectors produce a response and counteract the change. E.g sweat glands.

50
Q

Body temp. too low?

A

Temp. receptors detect that core body temp. is too low.
Receives info. from the temp. receptors and triggers the effectors automatically.
Effectors produce a response that counteracts change. E.g muscles.

51
Q

What can some effectors do?

A

Work antagonistically.
So as one heats another cools.
Work at the same time to get a precise temp.
This mechanism allows a more sensitive response.

52
Q

What happens when you’re too hot?

A

Sweat is produced in sweat glands and evaporates from the skin.
Transfers energy to the environment.
Blood vessels supplying the skin dilate so more blood flows close to the surface of the skin.
Helps transfer energy from the skin to the environment.

53
Q

What does the body do when it’s too cold?

A

Hairs stand up to trap an insulating layer of air.
No sweat is produced.
Blood vessels supplying skin capillaries constrict to close off the skins blood supply.
When you’re too cold you shiver (muscles contract automatically).
This needs respiration which transfers some energy to warm the body.

54
Q

What is vasodilation?

A

Blood vessels widen.

55
Q

What is vasoconstriction?

A

Blood vessels narrow.

56
Q

What are hormones?

A

Hormones are chemical molecules released directly into the blood.
Carried in the blood to other parts of the body, but only affect particular cells in particular organs (called target organs).
Long lasting effects.

57
Q

Where are hormones produced and secreted?

A

Various glands.
Called endocrine glands.
Make up the endocrine system.

58
Q

6 glands?

A 
Pituitary gland.  
Ovaries (only female). 
Tested (only male). 
Thyroid. 
Adrenal gland. 
Pancreas.
59
Q

Pituitary gland?

A

Produces many hormones.
Regulate body conditions.
Called ‘master gland’ as hormones act on other glands.

60
Q

Ovaries?

A

Produce oestrogen.

Involved in menstrual cycle.

61
Q

Testes?

A

Produce testosterone.

Controls puberty and sperm production in males.

62
Q

Thyroid?

A

Produces thyroxine.

Involved in regulating rate of metabolism, heart rate and temp.

63
Q

Adrenal gland?

A

Produces adrenaline.

Prepare the body for fight or flight response.

64
Q

The pancreas?

A

Produces insulin.

Regulates blood sugar levels.

65
Q

What are nerves?

A

Very fast action.
Act for short amount of time.
Act on a precise area.

66
Q

What are hormones?

A

Slower action.
Acts for a long time.
Acts in a general way.

67
Q

2 hormones control blood glucose level?

A

Insulin and glucagon. Used in a negative feedback cycle.

68
Q

What adds on takes out glucose in the blood?

A

Carbohydrates put glucose in.
Metabolism removes glucose.
Vigorous exercise removes lots of glucose.

69
Q

What happens to excess glucose?

A

Stored as glucagon in the liver and muscles.

70
Q

What monitors and controls blood sugar levels?

A

Pancreas.

71
Q

What must the blood sugar level in the blood be?

A

Kept steady.

72
Q

Blood glucose level too high?

A

Blood with too much glucose.
Insulin secreted by pancreas.
Glucose moves into the liver and muscle cells from the blood.
Insulin makes live turn glucose into glucagon.
Blood glucose reduced.

73
Q

Blood glucose level too low?

A

Blood with too little glucose.
Glucagon secreted by pancreas.
Glucagon makes liver turn glycogen into glucose.
Glucose released into blood by the liver.
Blood glucose increased.

74
Q

Type 1 diabetes?

A

Pancreas produces too little or no insulin.
Blood sugar levels can increase and kill someone.
People need insulin therapy- several injection of insulin throughout the day.
Insulting makes sure glucose is removed from blood quickly once the foods been digested.
Effective treatment.
Amount of insulin injected depends on diet and active levels.
Need to think about limiting intake of food rich in simple carbs. and doing regular exercise.

75
Q

Type 2 diabetes?

A

Person becomes resistant to their own insulin.
Also cause a person’s blood sugar level to rise to a dangerous level.
Obesity can increase your chance of developing type 2 diabetes.
Controlled by eating a carbohydrate-controlled diet and regular exercise.

76
Q

Function of kidneys?

A

Filter to clean the blood.
Produces urine by taking waste products out your blood. Substances are filtered out of the blood as it passes through the kidneys.
Known as filtration.

77
Q

What is selective reabsorption?

A

Useful substances (glucose, some ions and right amount of water) are absorbed back into the blood.

78
Q

Urine includes?

A

Urea.
Ions.
Water.

79
Q

Why is urea in urine?

A

Proteins can’t be stored by the body so any excess amino acids are converted into fats and carbohydrates, which can be stored. This occurs in the liver and involves a process called deamination.
Ammonia is produced as a waste product from this process.
Ammonia is toxic so it’s converted into urea in the liver. Urea is transported to the kidneys, where it’s filtered out of the blood and excreted from the body in urine.

80
Q

Why is ions in urine?

A

Ions such as sodium are taken into the body in food, then absorbed into the blood.
If ion content in the body is wrong, this could upset the balance between ions and water, meaning too much or little water is drawn into the cells via osmosis. Having the wrong amount of water can damage cells or mean they don’t work as well as normal.
Some ions are lost in sweat, but this amount is not regulated, so the right balance of ions in the body must be maintained by the kidneys. The right amount of ions is reabsorbed into the blood after filtration and the rest is removed via urine.

81
Q

Why is water in urine?

A

Body has to constantly balance the water coming in and out.
We lose water from our skin via sweat.
Lose water from the lungs when breathing out.
We can’t control how much we lose this way so the amount of water is balanced by the amount we consume and the amount removed by the kidneys in urine.

82
Q

How is the concentration of urine controlled?

A

A hormone called anti-diuretic hormone (ADH). This is released into the bloodstream by the pituitary gland.
The brain monitors the water content of blood and instructs the pituitary gland to release ADH into the blood.
Negative feedback occurs depending whether it’s too low or high.

83
Q

Water content is too high?

A

Receptor in brain detects that water content is too high.
The coordination centre in the brain receives the info. and coordinates a response.
The pituitary gland releases less ADH, so less water is reabsorbed from the kidney tubes.

84
Q

Water content is too low?

A

Receptor in brain detects that the water content is too low.
Coordination centre in the brain receives the info. and coordinates a response.
The pituitary gland releases more ADH so more water is reabsorbed from the kidney tubules.

85
Q

If kidneys don’t work properly?

A

Kidneys don’t work properly, waste substances build up in the blood and you lose your ability to control the levels of ions and water in your body. Eventually it results in death.

86
Q

How to treat kidney failure?

A

Dialysis treatment.

Kidney transplant.

87
Q

How does dialysis work?

A

Regularly keeps the concentrations of dissolved substances in the blood at normal levels, and remove waste substances.
In a dialysis machine the person’s blood flows between partially permeable membranes, surrounded by dialysis fluid. It’s permeable to things like ions and waste substances, but not big molecules like proteins.
The dialysis fluid has the same concentration of dissolved ions and glucose as healthy blood.
Useful dissolved ions and glucose won’t be lost form the blood during dialysis.
Only waste products and excess ions and water diffuse.

88
Q

How often people need dialysis?

A

Dialysis 3 times a week for 3-4 hours.

89
Q

Disadvantages of dialysis?

A

Cause blood clots.
Cause infections.
Not pleasant.
Expensive for NHS to run.

90
Q

Advantages of dialysis?

A

Buy a patient with kidney failure valuable time until a donor organ is found.

91
Q

How do kidney transplants work?

A

Healthy kidneys are usually transplanted from people who have died suddenly.
The person who died must be an organ donor or carry a donor card.
Kidneys can also be transplanted from people who are still alive but there’s a small risk to the person donating the kidney.

92
Q

Advantage of kidney transplant?

A

Transplants are cheaper than dialysis.

Put an end to the hours patients to have to spend on dialysis.

93
Q

Disadvantages of kidney transplants?

A

Risk is the donor kidney can be rejected by the
patients immune system. The patient is treated with drugs to prevent this.
Long waiting lists for kidneys.

Biology (5 decks)

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