B11 - Hormonal Coordination

Question 1

The endocrine system

Answer 1

• glands produce hormones
• hormones are chemicals which travel in the blood (capillaries)
• to reach their target organ which has an effect

1. Thyroid (throat)
2. Adrenal (below pancreas)
3. Testes
4. Pituitary (in brain)
5. Pancreas
6. Ovaries

Question 2

How does a hormone travel?

Answer 2

• secreting cell
• to blood stream
• deposited to target cell

Question 3

Adrenaline

Answer 3

• found in the adrenal gland
• prepares body for action

Increasing heart/breathing rate to supply more O2 and glucose to muscles and brain
Prepared body for action in stressful situations
‘Fight or flight’ response
Increases awareness
Pupils dilate
Not controlled by negative feedback

Question 4

Testosterone

Answer 4

Testes
Male sexual development

Question 5

Insulin/glucagon

Answer 5

• pancreas
Blood sugar

Question 6

Oestrogen and progesterone

Answer 6

Ovaries
For menstruel cycle

Question 7

Thyroxine

Answer 7

Thyroid
Metabolic rate
Controlled by negative feedback

Question 8

ADH/FSH/LH/TSH

Answer 8

Pituitary
Water level/female sexual development/regulates thyroid

Question 9

Control of blood sugar - glucagon and insulin (negative feedback)

Answer 9

• when blood sugar goes up, body lowers it (responding with the opposite)

Question 10

Control of blood sugar process

Answer 10

1. High blood sugar after food
   Promotes insulin release
2. Detected by pancreas
3. Pancreas secretes insulin which stimulates formation of glycogen
4. So liver converts glucose to glycogen
5. This reduces blood sugar levels
6. Low blood sugar (after exercise)
   Promotes glucagon release
7. Detected by the pancreas
8. The pancreas secretes glucagon which stimulates the breakdown of glycogen and the liver converts glycogen to glucose
9. This raises blood sugar and increases blood sugar levels

Question 11

What is glycogen?

Answer 11

• store of glucose - storage molecule made of many glucose molecules

Question 12

What hormone is released if blood sugar is too high?

Answer 12

• insulin
• causes blood glucose to be stored as glycogen in liver (and muscles)
• decrease blood sugar

Question 13

What hormone is released if blood sugar is too low?

Answer 13

• glucagon
• causes liver to release glucose from glycogen stores
• increased blood sugar

Question 14

What is glucagon?

Answer 14

• hormone that raises blood sugar

Question 15

Thyroxine production

Answer 15

TSH (thyroid stimulating hormone) from the pituitary, which stimulates the thyroid to produce thyroxine (from iodine, hence iodised salt) that stimulates the basal metabolic rate - plays an important role in growth and development

Question 16

Thyroxine production process

Answer 16

When your thyroxine level increases
Pituitary produces less TSH
Thyroid makes less thyroxine
Normal thyroxine
Thyroxine level decreases
Pituitary produces more TSH
Thyroid makes more thyroxine
Normal thyroxine

Question 17

Type 1 Diabetes

Answer 17

Caused by genes so it is inherited
No insulin produced
Blood sugar remains very high after a meal (hyperglycaemia)
This can damage blood vessels and organs
No glycogen is stored
No release of glycogen when blood sugar low (hypoglycemia)
Can lead to a coma

Treatment: low carb diet and limited sugars
Insulin injections after meals
Exercise after meals
Carry a source

Question 18

Type 2 Diabetes

Answer 18

Caused by environmental factors eg obesity
Body doesn’t respond to insulin produced
Don’t need to use insulin injections

Treatment: low carb diet and limited sugars
Exercise after meals
Carry a source of carbs
If this doesn’t work, drugs may be needed

Question 19

Hormonal control of the menstrual cycle

Answer 19

1) increase in FSH (stimulates follicle)
2) FSH stimulates egg maturation
3) FSH stimulates release of oestrogen by ovaries (positive feedback)
4) oestrogen causes the uterus lining to thicken
5) as oestrogen levels rise, it inhibits FSH production
6) oestrogen also stimulates LH production (luteinising)
7) LH stimulates ovulation
8) A yellow body is left after releasing the egg (corpus luteum)
9) the yellow body in the ovary produces progesterone
10) progesterone inhibits LH and FSH production
11) progesterone maintains thickness of the uterus wall
12) if no fertilisation happens, progesterone levels drop as yellow body breaks down
13) period starts

Question 20

Hormone/ gland / function / feedback - FSH

Answer 20

FSH
pituitary
Egg maturation
Stimulates oestrogen

Question 21

Hormone / gland / function / feedback - oestrogen

Answer 21

Oestrogen
Ovary
Thickens uterus lining
Inhibits FSH

Question 22

Hormone / gland / function / feedback - LH

Answer 22

LH
Pituitary
Stimulates ovulation
Stimulates progesterone

Question 23

Hormone / gland / function / feedback - progesterone

Answer 23

Progesterone
Yellow body
Maintains uterus lining for around 10 days
Inhibits LH/FSH

Question 24

Hormonal contraception (the pill)

Answer 24

Oestrogen (inhibits FSH so no eggs develop)
Progesterone (inhibits LH and FSH so no eggs released)
Combined pill (both so more effective)

Can be oral, patch or implant

Question 25

Why may a couple not use protection?

Answer 25

Past the menopause
Pregnant
Wanting to concieve
Not having sex

Question 26

Endocrine system compared to the nervous system

Answer 26

Effects of hormones, often slower, but longer lasting

Question 27

Other contraceptive methods

Answer 27

Oral contraceptives
Hormonal injections, implants and patches
Barrier methods (condoms and diaphragms)
Intrauterine devices
Spermicidal agents
Abstinence
Surgical sterilisation

Question 28

IVF

Answer 28

In vitro fertilisation uses FSH and LH to stimulate maturation of eggs that are collected, fertilised, allowed to start development and replaced in the uterus
Emotionally and physically stressful, often unsuccessful, can lead to risky multiple births