1. The Endocrine System

2. The Endocrine System Body has two systems for control
Electrical Nervous system
Chemical Endocrine system
Chemical compounds released into the blood stream
Hypothalamus:
Area of the brain that turns electrical signals into chemical signals
Changes in homeostasis turn on the pituitary gland
Pituitary gland releases hormones into the blood stream

3. Types of Glands Gland organ that secrets chemicals
Exocrine glands release chemicals from the body or into the digestion system (Pancreas)
Endocrine glands release chemicals directly into the blood (Pituitary)
Prostaglandins released by any cell for local communication

4. Types of Hormones Two types of hormones: Steroids
- lipid-soluble; easily diffuses into cells through the plasma membrane
- inside the cell steroids react receptors that activate mRNA synthesis
Examples:
Cholesterol signals production of bile; Vitamin D
Testosterone signals males to develop male characteristics during puberty

5. Types of Hormones Two types of hormones: Examples:
2) Amino Acid Hormones
- bind to specific receptors on the plasma membrane
- Receptor on target cell will then activate an enzyme, open an ion channel in the membrane, or start some chain reaction
Examples:
Serotonin regulates mood, appetite, and sleep
Insulin regulates blood sugar level

6. Hormones And Target Cells
Hormones are designed to attach to a specific binding sites (receptors) on a specific type of cell (target cell)
They can have one or multiple binding sites
Regulated by Negative Feedback Inhibition
Chain reaction from binding to receptor releases signal that stops the release of the hormone

7. Blood Sugar Regulation
Glucose is major source of energy (cellular respiration)
Regulated by two opposing hormones and negative feedback inhibition
Glucagon promotes breakdown of glycogen to release glucose; happens when hungry or during exercise
Insulin lowers glucose levels after eating
Diabetes cannot regulate glucose because defective or missing insulin

8. Water Levels in the Blood
Blood consists of blood cells, white blood cells and plasma (water and various other molecules)
Plasma thickness is highly regulated by Antidiuretic Hormone (ADH)
After losing water through exercise or by taking in diuretics (alcohol, coffee, sugar drinks), ADH is released due to low H2O levels in the blood
Kidneys react to ADH and start absorbing as much water as possible
Signal also informs us we need water (thirsty)

9. Additional Endocrine Glands
Adrenal Glands:
Located onto top of the kidneys; made of two parts
Outer portion releases steroids
Ex: Glucocorticoids and Aldosterone which raise blood sugar and blood pressure
Inner portion releases Amino acids hormones
Ex: Epinephrine and Norepinephrine which raise heart rate, blood pressure, and respiration
Why releases all these hormones at once?

10. Additional Endocrine Glands
Fight or Flight Response (Adrenaline Rush)
Instinct when in conflict to fight the enemy or run for safety
Results in raised heart rate, reaction time, blood pressures, respiration rate
Sometimes you may empty waste to be as light as possible

11. Thyroid/Parathyroid Gland
Thyroid releases hormones to regulate growth, metabolism, and development
Examples:
Thyroxin- regulates energy use in the body
Calcitonin- regulates calcium levels
Parathyroid releases hormones to regulate mineral intake and use
Parathyroid Hormone (PTH)- regulates calcium, phosphate, and magnesium levels

12. Review
Neo and Batman get into a fight. Batman punches Neo in his shoulder. The pressure from Batman’s fist pass into the skin, muscle tissue and bones in Neo’s body. Pressure sensors are fired and an electrical signal is sent.
1) Where does the signal go?
2) What endocrine gland is activated because of the signal?
The pituitary gland releases endorphins (pain numbing hormones) which enter the blood stream
3) Where in Neo’s body do they go?
4) How do the endorphins react to the muscles cells?
The Hypothalamus
Pituitary Gland
Muscle cells in the shoulder
Bind to receptors on the plasma membrane

13. Review
As the fight continues, Batman is throwing many punches at Neo. Neo is quickly learning to dodge them so not to take any damage. Neo’s reflexes are increasing and he is moving faster
5) What has happened to Neo?
6) What gland has caused this to happen?
7) What hormones are causing this increase in speed?
8) What physical changes has Neo’s body gone through because of the hormones?
He is in “Fight or Flight Mode”
Adrenal Gland
Glucocorticoids, aldosterone, epinephrine, norepinephrine
Increase heart rate, breathing, blood pressure, etc…

14. Review
After a series of fast punches from Neo, Batman gives up and runs away. Neo starts to relax after a few minutes. His breathing is normal and his heart slows down. However, his glucose levels are still high. The glucocorticoid is still active.
9) What type of hormone is glucocorticoid?
10) What hormone must be released to lower Neo’s blood sugar level?
11) What type of system is this called?
Steroid
Insulin
Negative Feedback Inhibition

15. Review
Now the fight is over Neo feels hungry. His shoulder bone has taken damage in the fight.
12) What gland will slow Neo’s metabolism until he gets food?
13) What element is needed to fix the bone and where can Neo get is from?
14) What hormone will increase the absorption of Ca+ from Neo’s lunch? What gland will produce this?
15) What hormone will increase the Ca+ in the blood so repairs can start?
Thyroid gland
Calcium
PTH from the Parathyroid gland
Calcitonin