The Endocrine System 35.3

The Endocrine System Body has two systems for control Body has two systems for control Electrical  Nervous system Chemical  Endocrine system Chemical compounds released into the blood stream Chemical compounds released into the blood stream Hypothalamus: 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

Types of Hormones Two types of hormones: Two types of hormones: 1)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

Types of Hormones Two types of hormones: Two types of hormones: 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

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

Human Growth Hormone hGH: hGH: – released when cell/body is actively growing – Binds to liver cells to signal release of glucose – Blood sugar rises so cell have energy source while growing Negative Feedback: Negative Feedback: – Cells slow growth and use less energy – Increase in blood sugar level signals release of insulin – Liver and muscle cells take and a store extra glucose

Water Levels in the Blood Blood consists of blood cells, white blood cells and plasma (water and various other molecules) Blood consists of blood cells, white blood cells and plasma (water and various other molecules) Plasma thickness is highly regulated by Antidiuretic Hormone (ADH) 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 H 2 O levels in the blood After losing water through exercise or by taking in diuretics (alcohol, coffee, sugar drinks), ADH is released due to low H 2 O levels in the blood Kidneys react to ADH and start absorbing as much water as possible Kidneys react to ADH and start absorbing as much water as possible Signal also informs us we need water (thirsty) Signal also informs us we need water (thirsty)

Additional Endocrine Glands Adrenal 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? Why releases all these hormones at once?

Additional Endocrine Glands Fight or Flight Response (Adrenaline Rush) 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

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

Review Bruce and Batman get into a fight. Batman punches Bruce in his shoulder. The pressure from Batman’s fist pass into the skin, muscle tissue and bones in Bruce’s body. Pressure sensors are fired and an electrical signal is sent. Bruce and Batman get into a fight. Batman punches Bruce in his shoulder. The pressure from Batman’s fist pass into the skin, muscle tissue and bones in Bruce’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 The pituitary gland releases endorphins (pain numbing hormones) which enter the blood stream 3) Where in Bruce’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

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

Review After a series of fast punches from Bruce, Batman gives up and runs away. Bruce 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. After a series of fast punches from Bruce, Batman gives up and runs away. Bruce 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 Bruce’s blood sugar level? 11) What type of system is this called? Insulin Steroid Negative Feedback Inhibition

Review Now the fight is over Bruce feels hungry. His shoulder bone has taken damage in the fight. Now the fight is over Bruce feels hungry. His shoulder bone has taken damage in the fight. 12) What gland will slow Bruce’s metabolism until he gets food? 13) What element is needed to fix the bone and where can Bruce get is from? 14) What hormone will increase the absorption of Ca + from Bruce’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