1. SC30244 Biology
Hormones

2. Introduction: What is the endocrine system?

3. Hormones The endocrine system Endocrine glands
Contents
Hormones
The endocrine system
Endocrine glands
Blood glucose regulation
Summary quiz

4. Hormones and the endocrine system
What exactly are hormones?
What effect do hormones have on the body?
To understand hormones you need to know about the endocrine system and how it works.

5. The endocrine system
1) The endocrine and nervous systems coordinate the body’s organs so that they work together.
The endocrine system is based on the production of chemical messengers called hormones.
They are produced by glands (endocrine glands) in different parts of
the body. These chemical messengers are produced in very small quantities and are transported in the blood.
Hormones control body processes that require several organs of the body to interact for a combined effect.

6. What do hormones do?
2) Hormones travel slower than nervous impulses but cause longer-lasting effects.
They are delivered to all parts of the body but can have local effects.
Hormones are used to stabilize the body’s internal environment through homeostasis and also coordinate longer-term processes such as
growth and sexual development.
Over- or under-activity of some endocrine glands can cause functional disorders such as diabetes.

7. Which body system?

8. Hormones The endocrine system Endocrine glands
Contents
Hormones
The endocrine system
Endocrine glands
Blood glucose regulation
Summary quiz

9. Endocrine glands – thyroid
Produces the hormone thyroxine:
Regulates rate of metabolism.
Excess causes hyperactivity.
Deficiency causes weight gain and sluggishness.
thyroid

10. Endocrine glands – adrenal glands
Produce the hormone adrenalin.
Adrenaline causes the ‘fight or flight’
response resulting in:
Increased heart rate and breathing rate.
Blood diverted to the muscles.
Increased respiration to increase the amount of glucose in the blood.
adrenal glands

11. Endocrine glands – reproductive organs
In females, ovaries produce several
hormones:
oestrogen
Controls development of female secondary sexual characteristics.
Regulates menstrual cycle.
progesterone
Thickens wall of female uterus.
Prevents contractions until a baby is being born.
ovaries

12. Endocrine glands – reproductive organs
In males, testes produce the hormone
testosterone:
Promotes development of male secondary sexual characteristics.
testes

13. Endocrine glands – pancreas
Produces the hormone insulin:
Main Function: Controls the conversion of blood glucose to insoluble glycogen, which is stored in the liver.
Other functions (don’t write down): Increases metabolic rate by stimulating cellular glucose uptake.
Increases protein synthesis in some cells.
Deficiency causes the condition “sugar diabetes”, where the blood sugar level is unregulated.
pancreas

14. Endocrine glands – pancreas
Produces the hormone glucagon:
Controls the conversion of insoluble glycogen to glucose in the liver.
pancreas

15. Endocrine glands – pituitary gland
Produces several hormones:
growth hormone
Promotes bone and muscular growth.
antidiuretic hormone (ADH)
Controls reabsorption of water into the blood by kidneys.
thyroid stimulating hormone (TSH)
Controls function of thyroid gland.

16. Endocrine glands – pituitary gland
Produces several specific hormones
in females:
follicle stimulating hormone (FSH)
Causes the follicle in the ovary to develop and secrete oestrogen.
luteinizing hormone (LH)
With FSH and other hormones causes ovulation.

17. Name that gland

18. Match hormones to glands

19. Hormones The endocrine system Endocrine glands
Contents
Hormones
The endocrine system
Endocrine glands
Blood glucose regulation
Summary quiz

20. Negative feedback
Some hormones affect only one target organ, but most affect more than one.
When the hormone has had the desired effect, further production of the hormone needs to be controlled.
Hormone production is controlled by a process called negative feedback.
The regulation of blood glucose level is an example of negative feedback.

21. Negative feedback – blood glucose
Which of these parts of the body are involved in the negative feedback process that regulates blood glucose?
and the liver are all involved
in regulating blood glucose.
The brain,
the pancreas

22. Negative feedback – high blood glucose
The brain detects the level of glucose in the blood.
When the level of blood glucose increases above normal, what hormone does the pancreas release?
increased blood glucose

23. Negative feedback – high blood glucose
The pancreas is stimulated to release insulin.
What effect does this have?
The insulin stimulates the liver to take glucose from the blood and convert into glycogen, which is stored in the liver.
increased blood glucose
insulin

24. Negative feedback – high blood glucose
The level of glucose in the blood decreases, causing the pancreas to stop producing insulin.
What would happen if the pancreas kept on producing insulin?
increased blood glucose
insulin
blood glucose
returns to normal

25. Negative feedback – low blood glucose
Negative feedback also occurs when the blood glucose level decreases below normal.
This time the brain detects decreased blood glucose and so the pancreas is stimulated to release which hormone?
decreased blood glucose

26. Negative feedback – low blood glucose
The pancreas produces the hormone glucagon.
Glucagon stimulates the liver to convert glycogen back to glucose and release this glucose into the bloodstream.
decreased blood glucose
glucagon

27. Negative feedback – low blood glucose
The level of glucose in the blood increases, causing the pancreas to stop producing glucagon.
What would happen if the pancreas kept on producing glucagon?
decreased blood glucose
glucagon
blood glucose
returns to normal

28. Blood glucose activity

29. When hormones go wrong – diabetes
What happens if the pancreas is unable to produce the hormone insulin?
Lack of insulin production means that the blood glucose level is unregulated and causes
the condition known as “sugar diabetes”.
After a person with diabetes has eaten, their blood glucose level increases. What happens to this glucose?
The absence of insulin means that glucose is not converted to glycogen and stored in the liver, so the blood of a
diabetic contains extra glucose.

30. When hormones go wrong – diabetes
Glucose is essential for
the body, so why is excess glucose a danger for people with diabetes?
The ability of the kidneys to
absorb glucose is also exceeded, so the excess is excreted in urine.
When the glucose is used up, coma and convulsions may occur. So how is diabetes controlled?
Regular insulin injections and a careful diet can control the condition.

31. Hormones The endocrine system Endocrine glands
Contents
Hormones
The endocrine system
Endocrine glands
Blood glucose regulation
Summary quiz

32. Multiple-choice quiz