Brainscape's Knowledge GenomeTM

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


See full index

Biology yr11 > Topic 7 Animal Coordination, Control and Homeostasis > Flashcards

Topic 7 Animal Coordination, Control and Homeostasis Flashcards

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

What is the endocrine system?

A

A network of glands that produce and

secrete hormones into the bloodstream

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

What is a hormone?

A

● A cell signalling molecule produced by
endocrine glands and released into the blood
● Travels to a target organ and binds to
receptors on effectors initiating a response

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

Compare the endocrine and nervous systems (4)

Endocrine system Nervous system

A

Compare the endocrine and nervous systems (4)
Endocrine system Nervous system

Uses hormones
Uses nerve impulses

Hormones travel in the bloodstream to
the target organ
Nerve impulses travel via neurones to
the effectors

hormones have a Slower response
Nerves have a Faster response

Lasts until all hormones have broken
down which takes a long amount of time
Lasts until the nerve impulse stops which
takes a short amount of time

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

What is the pituitary gland?

A

Described as the ‘master gland’
Endocrine gland that produces hormones which
control other glands (e.g. adrenal glands)

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

What are the adrenal glands?

A

Endocrine glands that produce

adrenaline

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

Where are the adrenal glands located?

A

Above the kidneys

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

What is adrenaline?

A

A hormone produced by the adrenal glands
that is involved in the ‘fight or flight’
response (where the body prepares to
confront danger or flee from it)

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

State the effects of adrenaline on the body (4)

A

● Increases heart rate
● Increases blood pressure
● Increases blood flow to muscles
● Increases blood glucose levels

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

Describe how adrenaline increases heart rate and

blood pressure

A

● Secreted by the adrenal glands, travels in the blood to the heart
● Binds to specific receptors on cells in the heart
● Causes heart muscle to contract more forcefully and frequently
● ∴ heart rate increases, blood pressure increases

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

Describe how adrenaline increases respiration at

muscle tissues

A

● Adrenaline binds to specific receptors on cells in the liver
● Triggers breakdown of glycogen stores and release of glucose
∴ blood glucose levels increase
● Increased heart rate causes greater blood flow to muscles
● ∴ muscle cells receive more oxygen and glucose for respiration

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

What is negative feedback?

A

● A corrective mechanism that allows only small shifts
from a set point
● It reverses a change in conditions e.g. if the concentration
of a hormone increases, negative feedback systems work
to reduce the concentration back to normal level

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

What is the thyroid gland?

A

Endocrine gland that produces thyroxine

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

Where is the thyroid gland located?

A

In the neck

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

What is thyroxine?

A

A hormone secreted by the thyroid gland
that controls metabolic rate, heart rate
and temperature.

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

What is metabolic rate?

A

The rate at which biochemical reactions

occur in cells

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

Describe how thyroxine is released

A

● Hypothalamus secretes TRH
● TRH stimulates secretion of TSH from pituitary gland
● TSH stimulates the release of thyroxine from the
thyroid gland

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

What does TRH stand for?

A

Thyrotropin releasing hormone

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

What does TSH stand for?

A

Thyroid-stimulating hormone

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

Describe how a negative feedback system controls

blood thyroxine levels

A

● If blood thyroxine levels increase above a set point, TRH and TSH
secretion is inhibited. Less thyroxine is produced by the thyroid gland.
Thyroxine levels return to normal.
● If blood thyroxine levels decrease below a set point, TRH and TSH
secretion is increased. More thyroxine is produced by the thyroid
gland. Thyroxine levels return to normal.

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

How do the ovaries act as an endocrine gland?

A

They secrete oestrogen into the

bloodstream

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

How do the testes act as an endocrine gland?

A

They secrete testosterone into the

bloodstream

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

What is the menstrual cycle?

A

The cycle in women (typically lasting 28 days) that involves:
● Shedding of uterus lining (menstruation)
● Repair of uterus lining
● Release of an egg (ovulation)
● Maintenance of uterus lining

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

Describe the stages of the menstrual cycle

A

● Days 1-4: if fertilisation and implantation do not occur the uterus
lining sheds and the egg is expelled with it (menstruation)
● Days 4-14: uterus lining thickens and blood vessels grow in
preparation for the implantation of an egg
● Day 14: egg released from a follicle into the oviduct (ovulation)
● Days 14-28: uterus lining maintained so implantation can occur

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

Name the hormones that control the menstrual cycle

4

A

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

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

Describe the role of FSH in the menstrual cycle

A

● Secreted by the pituitary gland
● Transported in the bloodstream to the ovaries
● Triggers the development of a follicle in the
ovaries which releases oestrogen

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

Describe the role oestrogen plays in the menstrual

cycle

A

● Secreted by the ovaries
● Repairs and thickens the uterus lining
● Inhibits secretion of FSH from the pituitary gland
● Stimulates secretion of LH from the pituitary gland

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

Describe the role of LH in the menstrual cycle

A

● Secreted by the pituitary gland
● Transported in the bloodstream to the ovaries
● Surge in LH triggers ovulation
● Stimulates follicle remains to develop into a corpus luteum
which then secretes progesterone

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

What is a corpus luteum?

A

● Temporary endocrine structure
● Mass of cells that releases progesterone
● Degenerates after a few days

29
Q

Describe the role of progesterone in the menstrual

cycle

A

● Secreted by the corpus luteum
● Stimulates the growth of blood vessels in the uterus lining (in
preparation for implantation)
● Inhibits the release of FSH and LH
● If no implantation occurs, progesterone levels decrease and the
uterus lining sheds. FSH increases and the cycle starts again.

30
Q

What happens to progesterone levels if fertilisation

and implantation occur?

A

The placenta produces progesterone so
levels remain high. This prevents further
ovulation and maintains the uterus lining.

31
Q

What are contraceptives?

A

A method or device utilised to prevent

pregnancy

32
Q

Which hormones can be taken to prevent

pregnancy?

A

● Progesterone taken on its own

● Progesterone combined with oestrogen

33
Q

How does progesterone prevent pregnancy? (3)

A

● Sperm find it more difficult to enter the uterus as the
cervical mucus is thickened
● Thins the uterine lining, reducing the likelihood of egg
implantation
● Prevents ovulation in some women (but not all)

34
Q

How does oestrogen prevent pregnancy?

A

Oestrogen inhibits FSH, preventing

ovulation

35
Q

Outline how progesterone can be administered as a

contraceptive (2)

A

● Mini-pill taken daily

● Injection

36
Q

Outline how progesterone and oestrogen can be

administered as a contraceptive (2)

A

● Combined pill
(taken continuously for 21 days then paused for 7 days)
● Skin patch
(worn continuously for 3 weeks then without for 1 week)

37
Q

What are the benefits of hormonal contraceptive

methods? (3)

A

● 99% effective when used properly
● Generally longer lasting than non-hormonal methods
● Used to treat other conditions e.g. painful/heavy periods

38
Q

What are the risks of hormonal contraceptive

methods? (4)

A

● Side effects e.g. mood changes, acne, bloating
● Do not protect against STIs
● May involve uncomfortable medical procedures
● Not effective if used incorrectly

39
Q

Describe the barrier methods of contraception

A

Prevent the sperm and egg meeting

e.g. condoms, diaphragms (fit over cervix)

40
Q

What are the benefits of barrier methods of

contraception? (3)

A

● Condoms are simple and quick to use
● Condoms prevent the spread of STIs
● No side effects

41
Q

What is the main risk of barrier methods of

contraception?

A

Less effective than hormonal methods

e.g. condom may split whilst in use.

42
Q

What two methods (involving hormones) are used to

treat infertility?

A

● Clomifene therapy

● IVF

43
Q

Describe the role of hormones in IVF

A
  1. FSH and LH given to a woman to stimulate egg
    production and ovulation
  2. Eggs retrieved from the woman’s ovaries and
    fertilised in vitro
  3. Resultant embryo transferred to the woman’s uterus
44
Q

Outline clomifene therapy

A

● Prescription of clomifene drug to women who do not
ovulate regularly
● Stimulates secretion of more FSH and LH which
triggers egg production and ovulation

45
Q

What is homeostasis?

A

The maintenance of a stable internal
environment in the body despite
fluctuations in internal and external
conditions.

46
Q

Why is homeostasis important?

A

To ensure optimum conditions for enzymes

and cellular processes in the body

47
Q

State three conditions within the body that must be

controlled by homeostasis

A

● Temperature
● Blood glucose concentration
● Water levels

48
Q

Which organ is responsible for the maintenance of

blood glucose concentrations?

A

Pancreas

49
Q

How are blood glucose concentrations controlled?

A

Controlled by the hormones insulin and
glucagon which are secreted by the
pancreas

50
Q

Insulin and glucagon are antagonistic hormones.

What does this mean?

A

They have opposite effects which

counteract one another.

51
Q

Describe the role of insulin in the regulation of blood

sugar levels

A

● Causes liver and muscle cells to increase their
uptake of glucose from the blood
● Glucose is converted into glycogen, a storage
molecule

52
Q

Describe the role of glucagon in the regulation of

blood sugar levels

A

● Causes the breakdown of glycogen to
glucose in the liver
● Glucose is released into the blood

53
Q

What is the control of blood glucose concentration

an example of?

A

Negative feedback

54
Q

Describe what happens when blood glucose

concentrations become too high

A

● Blood glucose concentration increases above a set point
● Pancreas secretes insulin and stops producing glucagon
● Liver and muscle cells increase uptake of glucose
● Glucose is converted to glycogen and stored
● Some glucose may be stored as lipid in tissues
● Blood glucose concentration decreases, returning to normal level

55
Q

Describe what happens when blood glucose

concentrations become too low

A

● Blood glucose concentration decreases below a set point
● Pancreas secretes glucagon and stops producing insulin
● Liver cells convert glycogen into glucose which is released into blood
● Blood glucose concentration increases, returning to normal level

56
Q

What is diabetes?

A

A condition where the homeostatic
control of blood glucose levels stops
working.

57
Q

What is the cause of type 1 diabetes?

A

Pancreas does not produce enough

insulin

58
Q

How is type 1 diabetes treated? (3)

A

● Daily insulin injections at meal times
● Limiting intake of refined sugars
● Regular exercise

59
Q

What is the cause of type 2 diabetes?

A

Person develops insulin resistance or
doesn’t produce enough insulin (often
due to obesity)

60
Q

How is type 2 diabetes treated? (3)

A

● Balanced diet
(eating fewer simple sugars and replacing them with more
complex carbohydrates)
● Exercise
● Medication or insulin injections (however, these are
less effective)

61
Q

How does exercise help to control diabetes?

A

Exercise increases respiration in muscle
cells. Excess glucose is removed from
the blood to produce energy in the form
of ATP.

62
Q

Why are type 2 diabetics advised to replace simple

A

● Simple carbohydrates are broken down quickly so
can raise blood glucose levels rapidly.
● Complex carbohydrates take longer to break
down so have a reduced effect on blood glucose
levels.

63
Q

What is the Body Mass Index (BMI)?

A

A value based on height and mass used to
categorise an individual as underweight, normal
weight, overweight or obese.

64
Q

How is BMI calculated?

A

Mass

(height) 2

65
Q

What BMI values indicate obesity and an increased

risk of type 2 diabetes?

A

BMI value larger than 30

66
Q

How is an individual’s waist-to-hip ratio calculated?

A

Hip circumference

67
Q

What does a waist-to-hip ratio higher than 1.0 in

males or 0.85 in females indicate?

A

● Abdominal obesity

● Increased risk of developing type 2 diabetes

68
Q

What is osmoregulation?

A

The maintenance of constant water

levels in the body fluids of an organism

Biology yr11 (5 decks)

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