-The process by which organisms maintain, control, and coordinate their internal environment with a constantly changing external environment -It is all of the activities that help to maintain an organism s
Homeostasis: the ability to maintain relatively constant internal conditions even though the external world changes continuously Within cells Within body
1.Nervous System nerve control (action/reaction) 2. Endocrine System- chemical control (hormones/receptors) -Process by which the product of a system shuts Down a system or limits its operation Ex: Home heating system Blood Sugar Level Shivering Menstrual Cycle
Homeostasis Maintained until another change occurs Change Detected/ System turned on System Limited or Shut down System Responds with production Homeostasis achieved
How does the Endocrine System maintain homeostasis? -Chemical control (hormones) What are the functional units of the endocrine system? -Hormones -Glands
What is a hormone? -A protein chemical messenger that travels through The blood stream How do hormones work? -They are SPECIFIC (remember enzymes!) -They bind to RECEPTORS on the surface of cells based on their shape What are receptors? -Proteins on the surface of cells that enable cell-to-cell communication This is how cells TALK to each other!!!
Receptor Cell Membrane Hormone Hormone Receptor
Remember Neurotransmitters?
2 Types: Duct- Glands with secretions that travel through short tubes -Ex: Saliva, tears Ductless- Glands with secretions that travel directly through bloodstream -Hormones
Gland: Hypothalamus Location: Brain Hormone: Function: -Produces hormones that influence the pituitary gland -Recognizes hunger, thirst, fatigue, Anger, blood sugar level, body temp
Gland: Location: Hormone: Pituitary Master Gland Base of brain 1. Growth-Stimulating Hormone (GSH) 2. Thyroid-Stimulating Hormone (TSH) 3. Follicle-Stimulating Hormone (FSH) Function: 1. Stimulates growth of long bones 2. Stimulates thyroid gland 3. Stimulates activity in gonads (ovaries/testis) Gland: Thyroid Location: Neck Hormone: Thyroxin Function: Regulates metabolism (thyroxin production regulated by iodine)
Gland: Parathyroid Location: Thyroid Gland Hormone: Parathormone Function: -Regulates calcium levels (for nerve function, blood clotting, and teeth/bone growth) Gland: Adrenal Location: Kidneys Hormone: Adrenaline Function: -Increases metabolism and gives you energy for emergencies ( Fight or Flight )
Gland: Pancreas Gland Location: Pancreas Hormone: 1. Insulin 2. Glucagon Function: 1. Decreases blood sugar level 2. Increases blood sugar level Gland: Gonads Location: 1. Ovaries (females) 2. Testis (males) Hormone: 1. Estrogen 2. Testosterone Function: -Development of secondary sex characteristics -Release egg (females) -Produce sperm (males)
1.Eating causes an INCREASE in glucose 2. Pancreas releases INSULIN 4.Glucose in the bloodstream is decreased, causing pancreas to turn off insulin production (HOMEOSTASIS is restored) 3. Insulin matches with RECEPTORS on muscle cells, allowing glucose to enter the cell and make ATP
Diabetes- disorder in which the pancreas produces too little insulin. (Very high sugar levels may damage organs and tissues.) Type I- Juvenile Diabetes (before 15yrs usually born with) Type II- Adult-onset (after 40yrs usually due To poor eating habits) Caused by: Genetics, poor diet Treatment: Insulin injections, change diet Goiter-Disorder in which the thyroid gland malfunctions causing it to become enlarged. Thyroid is either overactive or under active Caused by: Too much iodine (overactive) Treatment: Too little iodine (under active) Change diet, medication
Dwarfism- Disorder in which the pituitary gland does not secrete enough growth stimulating hormone during childhood. Growth is stopped Caused by: Genetics Treatment: Administer growth hormone Gigantism= Too much growth hormone!!
1-Nervous system responds FASTER and effects Last a shorter period of time -Endocrine System takes a LONGER time to Respond and effects last longer 2.Nervous System=Nerve Control Endocrine System=Chemical Control 1. BOTH maintain HOMEOSTASIS 2. Both secrete chemicals Hormones=Endocrine System Neurotransmitters=Nervous System