1. Warm Up – Monday 5/1 Describe the function of each hormone.
State the name of the gland that secretes each hormone.
Skip “HCG” for now
(Epinephrine)

2. Pancreas
Adrenal glands
Testes
Pituitary gland
Ovaries
Embryo
Placenta

3. Hormones & the Endocrine System

5. What is the function of the endocrine system?
Maintains the internal environment in the body (the optimum biochemical environment)
Influences metabolic activities
Integrates and regulates growth and development.
Controls, maintains and initiates sexual reproduction, including gametogenesis, fetal growth and development and nourishment of the newborn

6. How are neurotransmitters different from hormones?

7. Neurotransmitters vs. Hormones
Neurotransmitters belong to the nervous system, whereas hormones belong to the endocrine system.
Transmission of neurotransmitters is across the synaptic cleft, whereas that of hormones is by blood.
Hormones are produced by endocrine glands while neurotransmitters are produced by neurons.
Target cells of neurotransmitters can be specific neurons or other cells, whereas that of hormones can be some distance from endocrine gland.
Action of neurotransmitters is extremely fast, which could be up to few milliseconds. In contrast, effect of hormones could be last for a long period which could be in the range of few seconds to few days.

8. What “parts” are associated?
Key endocrine glands:
Pineal gland
Pituitary gland
Thyroid gland
Thymus
Adrenal gland
Pancreas
Ovary (female)
Testes (male)
Endocrine glands from:

10. How does leptin contribute to the control of fat?
Secreted by adipose cells (fat storage cells)
Increases as the amount of adipose tissue (fat) increases
Hormone attaches to areas of the hypothalamus, which is the part of the brain that controls appetite.
Binding of leptin to receptors cause long term appetite inhibition
Research has found that most cases of obesity in humans are not due to insufficient leptin secretion, but rather than target cells are resistant to leptin.

12. How does melatonin work to control circadian rhythms?

13. How does melatonin work to control circadian rhythms?
Secreted by the pineal gland, controlled by areas of the hypothalamus and affected by exposure to light
Secretion increases in the evening and drops to a low level at dawn as it is removed from the blood by the liver
High levels causes drowsiness, thereby promoting sleep
Melatonin receptors found in kidneys – suggesting decreased urination during the night as adaptation

15. Central Dogma of the Endocrine System
A stimulus is received and processed.
Hormones are secreted by glands, directly into the blood.
They are carried to the target tissues/target site (the place of intended action).
The action of the hormone changes the condition of the tissue.

16. Homeostasis is Regulated by Negative and Positive Feedback Systems
Positive Feedback: causes a self-amplifying cycle where decreases lead to further decreases, and increases lead to further increases.
Example: release of oxytocin from the hypothalamus during labor causes further release of the hormone, and stimulates more contractions.
Negative Feedback: recognizes a change in the body, and activates mechanisms to reverse that change.
Examples: regulation of blood glucose, and thermoregulation

17. Examples of Positive Feedback Loop (change causes MORE of that change)
Blood clotting
Child birth

18. The Hypothalamus: The Body’s Thermostat
Thyroxin: hormone that regulates metabolism ; increased secretion of thyroxin results in higher rates of metabolism (heat production)

20. Hormones Involved in the Control of Blood Sugar
Glucagon:
Produced/secreted by alpha (α)cells of pancreas when glucose levels are LOW
Stimulates conversion of glycogen (stored in the liver) into glucose
Insulin:
Produced/secreted by beta (β) cells of pancreas when glucose levels are HIGH
Stimulates conversion of glucose to glycogen (i.e. reduces amount of glucose in blood)