Endocrine System The making and sending of hormones

How it works Sends signals directly into blood stream (remember, takes less than a minute for blood to circulate through entire body!) Signals are specific shape, and will bind to cells that have the proper receptor shape Signal tells cell to do a specific function

Hormones vs. neurotransmitters Neurotransmitters released into small space called synapse between two nerves. ONLY ACTS IN THIS AREA Hormones released in larger levels into blood stream to tell whole body what to do

Receptor Proteins Proteins embedded into cell membrane, each with specific shape receptor Designed to receive a specific signal in blood stream – *many drugs act by blocking these receptors so certain signals (ex. Pain) cannot be received OR by blocking the receptors responsible for breaking down a message, keeping that message in the body for longer)

Target Cells Certain cells within the body that are supposed to react when a signal is sent out Example- pancreas and liver communication – Pancreas senses too much glucose in blood, sends out insulin – Liver gets insulin signal, reacts by storing glucose away as glycogen – If too little glucose, glucagon sent out and glycogen is broken down by liver

Negative Feedback The response to the original signal gets to a certain concentration and causes the organ to stop reacting – Example- when enough insulin is in the blood stream, insulin turns the pancreas off, telling it to stop making insulin. – *This keeps the body at a level state (homeostasis) since it can monitor how much of each chemical is in your body and make sure that there is never too much released at one time.

Glands Adrenal gland Testes Ovaries Pineal gland Pituitary gland Thymus Thyroid Pancreas

Adrenal Located above kidneys Releases stress hormones into blood stream – Corticosteroids – Epinepherine Fight or flight response

Sex glands Testes- primarily makes testosterone, responsible for development of male characteristics Ovaries- release estrogen and progesterone. – Estrogen- results in development of female characteristics – Progesterone- works with estrogen to regulate menstrual cycle

Birth Control Pills A combination of estrogen and progesterone keep female ovulating each month counteracting the chemicals given off by any fertilized egg – Also thicken cervix and thin uterine wall to prevent sperm from reaching egg and to prevent egg from implanting in uterus

Pineal Near base of brain, just above cerebellum Make serotonin and melatonin, regulating sleep cycles

Pituitary Below hypothalamus Makes many hormones to regulate homeostasis in the body – Growth hormone – Hormones in menstrual cycle (FSH, LH) – Stress hormones

Thymus Lobed, behind breastbone Site of creation of T-Cells – Where they are “educated” Creates hormones that stimulate antibody production during immune responses

Thyroid In neck Produces chemicals regulating metabolism Chemicals produced by iodine and tyrosine (an amino acid)

Pancreas At base of stomach Releases insulin and glucagon, controlling amount of glucose in blood stream Makes digestive enzymes

Abuse of Endocrine System Steroids – Body makes version of HGH, tells everything inside to “get bigger” – In children,  bone growth – In adults,  muscle development New MLB contract requires blood testing for HGH – Barry Bonds, etc. have been accused of using this

Barry Bonds Comparison

Diseases of… Diabetes Hyperthyroidism Osteoporosis Klinefelter’s and Turner‘s Syndromes Goiters

Diabetes Type I- you are born with- a genetic defect causes body to not be able to make insulin properly – Body cannot regulate glucose levels Type II

Hyperthyroidism Thyroid producing too much hormone – Results in metabolic rate speeding up – Can lead to rapid weigh loss, increased heart rate, etc.

Osteoporosis Largely result of estrogen or testosterone production decreasing – Tends to affect those around age 50 – Sex chemicals change levels of calcium and phosphate available to can be used in making new bone tissue Result- brittle bones that are easily broken

Klinefelter’s and Turner’s Syndroms Klinefelter’s- XXY or XXX – More common- xxy- develop as male but over time begin to develop female characteristics like breasts – Result of change in hormone levels- drop in T, increase in FSH, estrogen, etc. Turner’s- X only – Develop as female, but usually have non-working ovaries Both result of error in meiosis- second most common disorder involving chromosome nondisjunction

Goiters Result of low iodine levels Thyroid cannot make hormones without iodine, so gets bigger to compensate Solution- iodized salt