Topic 5- Homeostasis And Response

Question 1

What is homeostasis?

Answer 1

Maintenance of a constant internal environment to maintain optimum conditions for cellular functions

Question 2

Give examples of conditions maintained by homeostasis in the body

Answer 2

Blood glucose concentration
Body temperature
Water levels

Question 3

What 2 types of response are used in body control systems

Answer 3

Nervous and chemical

Question 4

What 3 components do all control systems have?

Answer 4

Receptors
Effectors
Coordination centres

Question 5

What does a receptor do?

Answer 5

Detects changes in the environment

Question 6

What do coordination systems do?

Answer 6

Obtain and process info from receptors

Question 7

What do effectors do?

Answer 7

Bring about response to stimuli

Question 8

What is the importance of enzymes in the body?

Answer 8

Control cell functioning

Question 9

What’s the name of the body’s coordination system involving hormones?

Answer 9

Endocrine system

Question 10

What is a hormone?

Answer 10

Chemical messenger secreted by a gland.

Travels in blood to target organ

Question 11

What type of organ secretes hormones?

Answer 11

Glands

Question 12

Which gland controls many other glands?

Answer 12

Pituitary gland

Question 13

What is the role of the pituitary gland?

Answer 13

1. Secretes human growth hormone
2. Stimulates thyroid gland
3. Stimulates ovulation and production of oestrogen
4. Stimulates production of sperm and testosterone

Question 14

What is the role of the thyroid gland?

Answer 14

Secretes hormone thyroxine

Controls metabolism, heart rate, body temp

Question 15

What is the role of the pancreas?

Answer 15

Secrete insulin

Control blood glucose levels

Question 16

What is the role of the adrenal gland?

Answer 16

Secretes adrenaline

Controls body’s fight or flight response

Question 17

What is the role of the ovaries?

Answer 17

Secretes oestrogen

Coordinates menstrual cycle

Question 18

What is the role of the testes?

Answer 18

Secrete testosterone

Coordinates sperm production

Question 19

Which organ monitors and controls blood glucose concentration?

Answer 19

Pancreas

Question 20

How does pancreas respond when blood glucose levels too high?

Answer 20

Secretes insulin
Insulin binds to receptors on liver and muscles
Causes excess glucose to be converted to glycogen and stored

Question 21

How does pancreas respond when blood glucose levels are too low?

Answer 21

Secretes glucagon
Glucagon binds to liver cells
Glycogen converted into glucose and released into blood

Question 22

How is blood glucose concentration controlled using a negative feedback loop?

Answer 22

1. When concentration raises or falls below optimum, a hormone secreted by pancreas
2. The action of either hormone (insulin/glucose) brings back concentration to correct level

Question 23

What is type 1 diabetes?

Answer 23

When pancreas doesnt produce sufficient insulin to control blood sugar levels
Levels often high- excessive urination, tiredness and weight loss

Question 24

How can type 1 be treated?

Answer 24

Insulin injections before meals- glucose into glycogen

Attempts using pancreas transplants

Question 25

What is type 2 diabetes?

Answer 25

Body cells stop responding to insulin- uncontrolled blood glucose levels. Linked with old age and obesity

Question 26

How can type 2 be treated

Answer 26

Carefully controlled diet Regular exercise Losing weight

Question 27

What is the function of reproductive hormones during puberty?

Answer 27

Males; development of secondary sexual characteristics | Females; development of secondary sexual characteristics and the maturation of eggs

Question 28

What is the main male reproductive hormone?

Answer 28

Testosterone

Question 29

What is the main female reproductive hormone?

Answer 29

Oestrogen

Question 30

What is the menstrual cycle?

Answer 30

Monthly cycle of changes that occur in females involving shedding of the uterus lining and ovulation

Question 31

Describe events of menstrual cycle

Answer 31

1. Uterus lining thickens and eggs mature in ovaries 2. Egg released form an ovary 3. Both egg and uterus are shed during menstration

Question 32

What is ovulation?

Answer 32

Release of a mature egg from ovaries

Question 33

Name 4 main hormones involved in menstrual cycle

Answer 33

1. Oestrogen 2. Progesterone 3. LH (luteinising hormone) 4. FSH (follicle stimulating hormone)

Question 34

What is the role of FSH?

Answer 34

Secreted by pituitary gland Controls maturation of eggs within ovaries Triggers production of oestrogen by ovaries

Question 35

What is the role of oestrogen?

Answer 35

Produce by ovaries Causes regrowth of uterus lining Triggers LH production and restricts FSH

Question 36

What is the role of LH?

Answer 36

Produced in pituitary gland | Triggers ovulation

Question 37

What is the role of progesterone?

Answer 37

Secreted from follicle of ovary | Sustains uterus lining

Question 38

How do fertility drugs increase the chance of pregnancy?

Answer 38

Contain FSH Stimulate oestrogen production Contain LH Triggers ovulation

Question 39

What is negative feedback?

Answer 39

Type of control where body responds to an increase or decrease in factor by returning it to optimum level

Question 40

What are the effects of adrenaline?

Answer 40

Increase in breath and heart rate- oxygen and glucose to body Dilation of pupils Increased mental awareness

Question 41

What is IVF?

Answer 41

- mother given FSH and LH- stimulates maturation of eggs and ovulation - eggs fertilised using sperm in lab- develop into embryos - 1 or 2 inserted into mother’s womb

Question 42

What are 2 advantages of fertility treatment?

Answer 42

- allow infertile couples to have children | - can store a female’s eggs for later

Question 43

What are the disadvantages of fertility treatment?

Answer 43

- can be expensive - has low success rate- especially for older couples - increases chance of multiple pregnancies- dangerous - side effects of fertility drugs

Question 44

What is thyroxine?

Answer 44

Released by thyroid gland | Triggered by the TSH. Controls body’s metabolic rate, growth and development

Question 45

How is the release of thyroxine controlled by negative feedback?

Answer 45

- levels of blood thyroxine falls- detected by receptors - pituitary releases more TSH - more thyroxine produced and released by thyroid gland - blood thyroxine levels return to normal