1. Endocrine System
Noadswood Science, 2016

2. Endocrine System To explain the functions of the endocrine system
Saturday, April 14, 2018
Endocrine System
To explain the functions of the endocrine system

3. Precise Learning
Students should be able to describe the principles of hormonal coordination and control by the human endocrine system.
The endocrine system is composed of glands which secrete chemicals called hormones directly into the bloodstream. The blood carries the hormone to a target organ where it produces an effect. Compared to the nervous system the effects are slower but act for longer.
The pituitary gland in the brain is a ‘master gland’ which secretes several hormones into the blood in response to body conditions. These hormones in turn act on other glands to stimulate other hormones to be released to bring about effects.
Students should be able to identify the position of the following on a diagram of the human body:
pituitary gland
pancreas
thyroid
adrenal gland
ovary
testes
Students should be able to explain the roles of thyroxine and adrenaline in the body (higher tier only)
Adrenaline is produced by the adrenal glands in times of fear or stress. It increases the heart rate and boosts the delivery of oxygen and glucose to the brain and muscles, preparing the body for ‘flight or fight’ (higher tier only)
Thyroxine from the thyroid gland stimulates the basal metabolic rate. It plays an important role in growth and development (higher tier only)
Thyroxine levels are controlled by negative feedback (higher tier only)

4. Hormones
Hormones are chemical molecules released directly into the blood to regulate bodily processes (carried in blood plasma) affecting particular target organs
Hormones are produced and secreted by various glands (endocrine glands) which make up the endocrine system

5. Glands
Label the glands of the endocrine system

6. Target Organs
The table shows the target organs and effects of the glands and hormones…
Gland
Hormone
Target Organ
Effect
Adrenal gland
Adrenalin
Liver, heart etc…
Fight or flight
Ovary
Oestrogen
Progesterone
Ovaries, uterus, pituitary gland
Puberty, menstrual cycle
Pancreas
Insulin
ADH (anti-diuretic hormone)
Liver
Kidney
Blood sugar
Water level control
Pituitary gland
FSH (follicle stimulating hormone)
LH (luteinising hormone)
Ovaries
Egg maturation
Egg release
Testes
Testosterone
Male reproductive organs
Puberty

7. Adrenaline
Higher Tier

8. Adrenaline
Higher Tier

9. Adrenaline
Adrenaline is a hormone released by the adrenal glands (located above the kidneys)
It is released in response to stressful or scary situations – the brain detects fear or stress and sends nervous impulses to the adrenal glands which secrete adrenaline
Adrenaline prepares the body for a ‘fight or flight’ response by increasing oxygen and glucose to the cells in the brain and muscles
Higher Tier

10. Thyroxine
Thyroxine is a hormone released by the thyroid gland (found in the neck)
It helps regulate basal metabolic rate as well as stimulating protein synthesis for growth and repair
Thyroxine is released in response to thyroid stimulating hormone (TSH) which is released from the pituitary gland
Higher Tier

11. Negative Feedback
Levels of thyroxine can go above or below normal levels – this levels are brought back to their normal range by negative feedback
Higher Tier

12. Negative Feedback
When the level of thyroxine in the blood is too high secretion of thyroid stimulating hormone (TSH) is inhibited reducing the amount of thyroxine
When the level of thyroxine in the blood is too low TSH starts up again and thyroxine levels increase
Higher Tier

13. Practice Question Give two roles of thyroxine in the body
Name the glands which release adrenaline
What are hormones secreted from?
Pierre is surprised when a dog jumps at him – his heart beats faster. Name the hormone causing this response and explain the purpose of it

14. Answers
Give two roles of thyroxine in the body – regulating basal metabolic rate and stimulating protein for growth and development
Name the glands which release adrenaline – adrenal glands
What are hormones secreted from – endocrine glands
Pierre is surprised when a dog jumps at him – his heart beats faster. Name the hormone causing this response and explain the purpose of it – adrenaline increases oxygen and glucose to cells ready for ‘fight or flight’