Homeostasis

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 * Bio Notes:**
 * Introduction to homeostasis & The urinary system. ﻿**
 * Rabeea Fatima**
 * Video- Homeostasis﻿**

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 * Video(s) - Urinary system**




 * Biology Notes:**
 * May 19th, 2011**
 * "Importance of the Endocrine System"**
 * Danielle Hemet**

VIDEO: Endocrine System []

Hormones: [Did you know: The word hormone comes from the Greek word "hormon" meaning to excite or put into motion]
 * important for integrating body functions
 * regulators
 * produced by cells in one part of the body, and affect cells in other areas of the body
 * small amounts of hormones are required to alter our metabolism

VIDEO:Hormones []

Endocrine Hormones: Chemical Control Systems: In order to integrate body functions we need... Nervous System: Endocrine System: Hypothalamus: Pituitary Gland The posterior lobe stores and releases hormones produced by the hypothalamus (ie: ADH or antidiuretic hormone). However, the anterior lobe produces it's own hormones that are released under control of the hypothalamus. It also stores regulator hormones (ie: thyroid stimulating hormone, TSH). VIDEO:
 * These hormones are produced in glands, secreted into blood DIRECTLY
 * Two types:
 * 1) Non-Target Hormones
 * 2) Target Hormones
 * Non-Target Hormones affect many cells in body (ie: Insulin makes many cells absorb glucose; growth hormone affects many cells)
 * Target Hormones affect specific cells and tissues only (ie: Gastrin affects the stomach only)
 * enables the body to adjust quickly to changes in the enviroment
 * maintains control over a long period of time (growth hormone)
 * part of the NERVOUS SYSTEM
 * regulates pituitary gland (ENDOCRINE SYSTEM) through nerve stimulation
 * pituitary gland stimulates endocrine glands to secrete chemicals that affect nerve activity of hypothalamus
 * hypothalamus-pituitary gland complex demonstrates the interaction between two systems, the endocrine and nervous systems
 * the "MASTER GLAND" meaning it has control over other endocrine glands
 * small sac-like structure connected to the hypothalamus (proximity-wise, very close to the hypothalamus, making it easier to control)
 * produces and stores hormones (double duty!)

Protein Hormone vs: Steroid Hormone Steroid Hormones: Above: Steroid Hormone Action...Retrieved from: []
 * BIO TEXTBOOK: Fig.6 pg. 376
 * Made from cholesterol
 * soluble in fat
 * include the male and female sex hormones and cortisol

Mode of Action: Protein Hormones: Above: Protein Hormone Action...Retrieved from: [] Mode of Action: __**Hormones Affecting Blood Sugar**__ Islets of langerhans - cells that produce hormones -alpha produce glucagon, secreted when blood sugar is low: liver converts glycogen to glucose and brings blood sugar level back to normal (ie: fasting) -beta produce insulin, secreted when blood sugar is high (converts glucose to glycogen, allows body cells to be permeable to glucose)
 * 1) Hormone diffuses from cell
 * 2) Diffuses into target cell/ attaches to receptor molecules in cytoplasm
 * 3) Hormone receptor complex moves into nucleus and attaches to DNA
 * 4) A gene in activated in DNA, which initiates protein synthesis.
 * chains of amino acids
 * soluble in H20
 * insulin and growth hormone are examples
 * BIO TEXTBOOK: Fig. 5 pg. 375
 * 1) Released from cell
 * 2) Attaches to receptor site on outside of cell membrane
 * 3) Hormone receptor complex promotes the formation of cyclic AMP (ATP -> cyclic AMP)
 * 4) cyclic AMP acts as a messenger, activating enzymes in the cytoplasm to carry out their normal functions.
 * NOTE:**
 * Cells DO NOT affect all cells. Cells may have receptors for one hormones but not for another.**
 * Also, hormones DO NOT affects cells directly, they attach to receptors that initiate a series of events within a cell.**

- insufficient insulin production -kidneys can't reabsorb glucose, lots of it in urine -without insulin, cells can't take in glucose, resulting in low energy -there are three types: >> >> >>
 * Diabetes Mellitus:**
 * 1) Type 1
 * born with
 * early degeneration of Islets of Langerhans (beta cells) no insulin production
 * 10% of cases are this type
 * need insulin injections to live
 * diagnosed as a child
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 * 1) Type 2
 * 90% of cases are adult-onset diabetes
 * insulin production lowers with age, or insulin ineffective/does not function properly
 * avoidable in theory
 * if you live a healthy lifestyle, healthy diet, keep weight in check, meds, etc
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 * 1) Type 3
 * Temporary (usually)
 * 2-4% of pregnancy
 * increased risk of diabetes to mother and baby
 * [|http://www.youtube.com/watch?v=A-8de9LuVJ]

__Nerve Impulse/Action Potential Animations__
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 * Fetal Pig Dissection**
 * []**
 * [|http://www.execulink.com/~ekimmel/fetal0.htm]**


 * Cow's Eye Dissection**
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May 30th, 2011 "Importance of the Nervous System" Moe Qureshi **



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