Brainscape's Knowledge GenomeTM

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


See full index

Biology > P2-Topic 5-Homeostasis > Flashcards

P2-Topic 5-Homeostasis Flashcards

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

what is homeostasis 2

A

the maintenance of a
constant internal environment

to maintain optimum conditions for enzyme and cellular function

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

3 examples of condition ,maintained by homeostasis in the body

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 type of automatic control responses are used in the body 2

A

nervous

chemical

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

what three things do all control systems have

A

receptors
coordination centers
effectors

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

what is the function of a receptor?

A

cells that detect changes in the

environment (stimuli).

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

What is the function of a coordination center? 2

A

(brain,spinal cord,pancreas)

receive and process information from receptors

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

What is the function of an effector? 2

A

(muscles or glands)
bring about
responses to stimuli

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

What is the function of the nervous system?

A

enables humans to react to their surroundings and to coordinate their behaviour

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

How does a stimulus lead to a response being carried

out by the body? 4

A

Stimulus is converted into an electrical impulse by the receptors

electrical impulse passes along sensory neurones to the central nervous system (CNS).

CNS coordinates an appropriate response and an electrical impulse is sent along motor neurones to the
effector, which carries out the response.
(muscles contracting, gland secreting hormones)

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

What sequence of events describes how

the nervous system works 5

A

stimulus receptor coordinator effector response

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

What is a reflex action? 2

A

automatic and rapid
response that does not involve any
conscious input from the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why are reflex actions important? 1

A

Reflex actions aid survival by preventing

harm to the body

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

Describe how a reflex action occurs via a reflex arc

5

A

stimulus detected by a receptor

electrical impulse passes along a sensory neurone to the spinal cord (part in CNS).

At a synapse between a sensory neurone and a relay neurone, a
chemical diffuses across the gap and stimulates a new impulse which
passes along the relay neurone

same process happens at a synapse between a relay neurone and a
motor neurone.

the effector, carries out an appropriate response

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

What is the difference between a reflex pathway and a

conscious pathway?

A

reflex pathway, the coordination centre
is a relay neurone found in the spinal
cord/unconscious parts of the brain.

conscious pathway, the coordination centre is in the conscious part of the brain

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

examples of reflex arcs 2

A

pupils getting smaller to avoid damage from bright lights,

moving your hand from a hot surface to prevent damage.

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

what are synapses and role 4

A

gaps between two neurons.

impulse reaches the end of the first neuron, a chemical is released into
the synapse.

chemical diffuses across the synapse.

When the chemical reaches the second neuron, it triggers the impulse to begin
again in the next neuron.

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

where is the cerebral cortex? and function 4

A

emotions, language, memories and conscious thought.

folded(squishy) outer layer of the brain

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

What is the function of the cerebellum?2

A

-back
controls muscular
coordination

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

What is the function of the medulla? 3

A

at the top of the spinal cord.

unconscious things
heartbeat, breathing and swallowing.

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

Why is the investigation and treatment of the brain difficult? 3

A

complex and delicate organ

easily damaged and destroyed

Drugs given to treat diseases cannot always reach the brain because of the membranes that surround it

The exact function of each part of the brain is not known

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

What methods are used by scientists to determine

brain function?

A

Studying symptoms of patients with brain damage

Electrical stimulation of the brain

MRI scans

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

What stimuli are the receptors of the eye sensitive to? 2

A

Light intensity

colour of light

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

What are the two main functions of structures in the eye?

A

Focusing on near or distant objects -
accommodation.

Adaptation to dim light.

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

Describe the structure and function of the

retina 2

A

receptors that are sensitive to light intensity and colour of light.

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

Describe the structure and function of the

optic nerve 2

A

squiggle, vein bit at the bottom

carries impulses from receptors in the retina to the brain.

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

Describe the structure and function of

the sclera 2

A

tough outer layer of the eye

supports and protects the eye.

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

Describe the structure and function of

the cornea 2

A

transparent layer at the front of the eye.

refract (bend) light rays as they enter the eye.

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

Describe the structure and function of

the iris 1

A

controls the size of
the pupil by contracting or
relaxing.

allows the
eye to adjust to bright and
dim lighting

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

Describe the structure and function of the ciliary

muscles and suspensory ligaments

A

control the shape of the lens to focus the light.

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

Describe how the iris alters the size of the pupil

in both bright and dim light 3

A

Bright light: circular muscles contract and radial muscles relax - makes pupil smaller to avoid retinal
damage.

Dim light: circular muscles relax and radial muscles contract - makes pupil larger so more light can enter the eye.

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

What is accommodation? 1

A

process of changing the shape of the lens to focus on near or distant objects.

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

How does the eye focus on a nearby object? 3

A

ciliary muscles contract

suspensory ligaments loosen

Lens becomes thicker and more curved -
light rays are refracted strongly.

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

How does the eye focus on a far away object? 3

A

Ciliary muscles relax

Suspensory ligaments tighten

Lens becomes thinner - light rays are
refracted weakly

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

What is myopia and treated? ? 3

A

short-sightedness, lens is too curved, so distant objects appear blurry.

glasses with a concave lens,to spread out light rays to be focused on the retina

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

What is hyperopia and treated?

A

long-sightedness- lens is too flat, so it cannot refract light enough

glasses with a convex lense, brings the light rays together so they can be focused on the retina

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

What are the two types of contact lenses?

2

A

Hard - rigid material, last a long time, must be kept
sterile.

Soft - flexible material, last for a shorter time, more
comfortable.

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

What is laser eye surgery? 2

A

lasers can be used to reduce the thickness of the cornea (so it refracts light less) to treat myopia

change its curvature (so it
refracts light more strongly) to treat hyperopia

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

How can replacement lenses be used to

treat visual defects 3

A

Hyperopia can be treated by replacing the lens with an artificial one made of clear plastic (or adding the plastic on top of the natural
lens).

risks: damage to retina or cataracts developing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What are the risks of lens replacement?

A

Risks of lens replacement include retinal

damage, cataracts and infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Where is body temperature controlled in the body?

A

controlled by the thermoregulatory centre in the hypothalamus
of the brain.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

How is temperature monitored by the body?

2

A

Thermoregulatory centre has receptors that monitor the temperature of the blood

receptors in the skin that send impulses to the thermoregulatory centre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What physiological changes occur when the body
temperature is too high?
3

A

Vasodilation - blood vessels near the surface of the skin dilate - more heat is radiated away

Sweating - evaporation of water takes away heat energy from the surface of the skin.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What physiological changes occur when the

body temperature is too low? 4

A

Vasoconstriction - blood vessels near the surface of the skin constrict - less heat radiated away.

Shivering - respiration allows muscles to contract.
exothermic process, so heat energy is released.
Sweating stops

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is the menstrual cycle?2

A

monthly cycle of physical changes in females

shedding of the uterus lining (menstruation) and ovulation

45
Q

Describe the events of the menstrual cycle 3

A

-Uterus lining thickens and eggs begin to mature in the
ovaries.

  • An egg is released from one of the ovaries (ovulation)
  • uterus lining remains thick.

● If the egg is fertilised, pregnancy may occur. If not,
both the egg and the uterus lining are shed during
menstruation

46
Q

What is ovulation?

A

release of a mature egg from

the ovaries, approximately every 28 days

47
Q

Name the four main hormones involved in the menstrual cycle

A

● Oestrogen
● Progesterone
● Follicle stimulating hormone (FSH)
● Luteinising hormone (LH)

48
Q

What is the role of FSH in the menstrual cycle? 2

A

secreted by the pituitary gland

causes an egg to mature in an ovary.

49
Q

What is the role of oestrogen in the

menstrual cycle? 2

A

produced by the ovaries and released due to the action of FSH

causes the lining of the uterus to thicken

50
Q

What is the role of LH in the menstrual cycle?2

A

produced in the pituitary gland as a
result of oestrogen

(ovulation) makes the ovary release the egg into the oviduct (fallopian tube)

51
Q

What is the role of progesterone in the

menstrual cycle? 2

A

produced by ovaries

maintains the lining of the uterus and keeps it intact.

52
Q

what happens if the egg isn’t fertilised

A

progesterone levels fall.

causing the uterus to shed its lining= period

menstrual cycle repeats roughly every 28 days.

53
Q

what does oestrogen do during the menstrual cycle 3

A

stops the pituitary gland from releasing FSH so eggs don’t mature.

causes the pituitary gland to release LH. causes ovulation.

Ovulation then causes the ovaries to release more progesteron

54
Q

what does progesterone do during the menstrual cycle 2

A

maintains the lining of the uterus.

helps oestrogen to stop the production of more FSH and LH.

55
Q

What are oral contraceptives and how it prevents pregnancy?2

A

contains oestrogen and/or progesterone
hormones

stop FSH production so that no eggs mature

56
Q

What are other types (4) of hormonal contraception and hhow do they prevent pregancy

A

Injections, implants, skin patches and some intrauterine devices (IUDs

slowly release progesterone to prevent eggs maturing or being released

57
Q

what are non-hormonal (barrier) methods and how do they prevent pregnancy
3

A

Condoms and diaphragms physically prevent sperm from reaching the egg.

Spermicides are chemicals that damage or kill sperm to prevent pregnancy.

Surgical sterilisation prevents pregnancy by cutting the sperm ducts in men or the oviducts in women

58
Q

what are some disadvantages of some contraceptives 5

A

whether or not they protect against sexually transmitted infections (STIs

how reliable and effective the contraceptive is

forget about taking an oral contraceptive or putting on a condom, or you do it incorrectly, they won’t work

Surgical sterilisation is irreversible

side effects.

catholic churches says unethical except natural methods

59
Q

how are hormones used to increase the chance of fertility 2

A

fertility drugs contain FSH - which
stimulates oestrogen production and the
maturation of eggs in the ovary.

They also contain LH which triggers ovulation

60
Q

What is IVF and the stages? 3

A
  • Mother is given FSH and LH - stimulates maturation of eggs and ovulation.
  • Eggs fertilised using sperm in a laboratory to develop into embryos.

● 1 or 2 embryos are inserted into the mother’s womb

61
Q

What are the advantages of fertility treatment?

A

● Allows infertile couples to have children of their own

● Can store a woman’s eggs for later

62
Q

What are the disadvantages of fertility treatment?

A

• it is very emotionally and physically stressful
• the success rates are not high
• it can lead to multiple births which are at risk to both the babies and the mother
-very expensive

63
Q

Give the name of the body’s coordination

system which involves hormones

A

The endocrine system

64
Q

What is a hormone?3

A

chemical messenger
secreted by a gland.
travels in the blood to a target organ, to cause a response

65
Q

What type of organ secretes hormones?

A

Glands

66
Q

Why is the pituitary gland considered a

‘master gland’?2

A

-controls many other glands in the
body

-secretes a wide range of hormones,
some of which may stimulate other
endocrine glands

67
Q

What is the role of the pituitary gland in the endocrine

system?4

A

● Secretes human growth hormone - controls human
growth.
● Stimulates the thyroid gland.
● Stimulates ovulation and the production of oestrogen in
the ovaries.
● Stimulates the production of sperm and testosterone in
the testes.

68
Q

What is the role of the thyroid gland in the

endocrine system?

A

Secretes the hormone thyroxine - controls
metabolism, heart rate and body
temperature.

69
Q

What is the role of the pancreas in the

endocrine system?

A

Secretes the hormone insulin - controls

blood glucose levels.

70
Q

What is the role of the adrenal gland in the endocrine system?

A

Secretes adrenaline - controls the body’s

‘fight or flight’ response

71
Q

What is the role of the testes aand ovaries in the endocrine system?

A

Secrete oestrogen, coordinates themenstrual cycle and the development of female secondary sexual characteristics.

Secrete testosterone, which coordinates the production of sperm and the development of male secondary sexual characteristics.

72
Q

Which organ monitors and controls blood glucose concentration?

A

The pancreas

73
Q

explain how insulin controls blood glucose (sugar) levels in the body if it is too high.3

A

pancreas produces the hormone insulin

causes glucose to move from the blood into the cells.

In liver and muscle cells excess glucose is converted to glycogen for storage.by receptors on liver

74
Q

How does the pancreas respond when blood glucose levels are too low 3

A

The pancreas secretes the hormone
glucagon.

Glucagon binds to liver cells,

causing glycogen to be converted into
glucose and released into the blood

75
Q

How is blood glucose concentration controlled using a negative feedback loop? (higher only) 2

A

When blood glucose concentration rises or falls below the optimum, a hormone is secreted by the pancreas.

● The action of either hormone (insulin or glucagon) helps bring back the concentration to the correct
level.

76
Q

What is Type 1 diabetes?

A

an autoimmune disorder

the pancreas does not produce sufficient
insulin to control the blood glucose concentration.

so blood glucose levels are often very
high, leading to excessive urination, tiredness and weight loss

77
Q

How can Type 1 diabetes be treated?2

A

Insulin injections before meals - allows
glucose to be converted into glycogen.

● Limiting carbohydrate intake.
● Attempts using pancreas and pancreatic cell transplants; investigations into genetic
engineering of pancreatic cells.

78
Q

What is Type 2 diabetes?2

A

the body cells no longer respond to insulin produced by the pancreas.

linked with increasing age and obesity

79
Q

How can Type 2 diabetes be treated? 4

A 
Following a carefully-controlled diet
● Doing regular exercise
● Losing weight
● Use of drugs which increase insulin
production and effectiveness
80
Q

What is osmosis?

A

movement of water from a
dilute solution to a concentrated solution
through a partially permeable membrane

81
Q

ways water is lost from the body?3

A

● During exhalation via the lungs
● Sweating
● Urine (some reabsorbed in the kidney)

82
Q

In what ways are ions lost from the body?

2

A

Sweating

● Urine (some reabsorbed in the kidney)

83
Q

How are excess amino acids excreted from the body?4

A

The liver converts excess amino acids into ammonia.

Excess amino acids are deaminated in the liver to form ammonia.

Ammonia is toxic, so converted into urea

Urea is excreted from the body via sweat and urine

84
Q

How do the kidneys maintain the balance of water and other substances in the body? 2

A

● Filter blood in order to remove waste
products eg. urea.

● Selectively reabsorb useful molecules eg.glucose, water, ions.

85
Q

What is the full name of the hormone ADH?

A

Anti-diuretic hormone

86
Q

Where is ADH secreted in the body?

A

The pituitary gland of the brain

87
Q

How does ADH affect the reabsorption of water in the kidneys?

A

● When the blood is too concentrated, the pituitary gland secretes more ADH.

● ADH travels in the bloodstream to the kidney and increases the permeability of kidney tubules to water.

● More water is reabsorbed in the kidneys so a smaller volume of more concentrated urine.

88
Q

Why is kidney failure dangerous? (biology only) 3

A

kidneys may be unable to filter the blood properly
leading to:
● A build-up of toxic molecules (eg. urea) in the body.
● An uncontrolled ion and water balance and cells being damaged as a result of osmosis.

89
Q

What are the two main ways of treating kidney failure?

A

● Dialysis

● Transplant

90
Q

What is kidney dialysis? 3

A

use of a specialist machine to carry out the function of kidneys

Dialysis fluid contains the same concentration of glucose and
ions as healthy blood.

As a result, only excess and waste molecules are lost from the blood, and
glucose and ions remain acroos a partially permeable membrane

91
Q

Advantages and disadvantages of kidney dialysis 3

A

+no shortage of diialysis machines

  • requires frequent treatments and a controlled diet
  • expensive in the long run
92
Q

Advantages and disadvantages of kidney transplants 4

A

+allow paitentss to live a normal life

+onlyexpensive initially

  • shortage of kidney donars
  • paitents have to take anti-rejection drugs for rest of life
93
Q

What is negative feedback? 2

A

type of control where the body responds to an increase or decrease in a factor by returning it to the optimum level.

94
Q

What is thyroxine? 2

A

hormone released by the thyroid gland.

Its release is triggered by the
thyroid stimulating hormone (TSH).

Thyroxine controls the body’s metabolic rate, growth and development

95
Q

How is the release of thyroxine controlled by

negative feedback? 4

A

Levels of blood thyroxine falls - detected by receptors in the brain.

● Pituitary gland releases more TSH.

● More thyroxine produced and released by the thyroid gland.

● Blood thyroxine level returns to normal.

96
Q

What is adrenaline?

A

hormone secreted by the adrenal gland in times of stress

responsible for the ‘fight or flight response’.

97
Q

What are the effects of adrenaline?

A

● Increase in heart and breathing rate - delivers oxygen and glucose to the body.
● Stored glycogen converted to glucose.
● Dilation of pupils.
● Increased mental awareness.
● Blood diverted away from digestive system to muscles

98
Q

What is phototropism and gravitropism 30

A

p-growth in response to light
g- growth in response to gravity (geotrophism)

all done by shoot or root

99
Q

What is a tropism?

A

A tropism is the response of a plant to a specific stimulus

100
Q

What is auxin? 3

A

plant hormone

controls the growth of a plant’s shoots and roots

can increase or decrease the growth rates of roots and shoots.

101
Q

How do plant shoots show positive phototropism? 4

A

.When a shoot grows, auxin builds up on the shaded side of the shoot.

● the shaded side grows faster

the shoot bends towards the light.

photosynthesis can occur at a faster rate

102
Q

How do plant shoots show negative gravitropism?4

A

horizontal shoot, auxin gathers on the lower side due to gravity.

● Cells on the lower side of shoot grow more

shoot bends away from the direction of gravity.

● more light available for photosynthesis

103
Q

How do plant roots show positive gravitropism?4

A

horizontal root, auxin builds up on the lower side

causing cells to grow less.

root bends in the direction of gravity

more water and nutrients are available to the plant roots

104
Q

What are gibberellins?

A

Gibberellins are a type of plant hormone

involved in seed germination.

105
Q

What is ethene?

A

Ethene is a type of plant hormone

involved in cell division and ripening.

106
Q

What are the uses of auxins?3

A

● Weedkillers - auxin causes cells to grow at a rapid rate, causing plant death.
● Rooting powder - auxin causes new plant to grow very quickly.
● Tissue culture - auxin promotes growth of roots and shoots..

107
Q

What are the uses of ethene?

A

to control ripening of fruit during

storage and transport.

108
Q

What are the uses of gibberellins?

A

● Termination of seed dormancy
● Promotion of flowering
● Increase of fruit size

Biology (11 decks)

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