Week 12

Week 12 - Week 12 Homeostasis: tendency of living things to...

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Week 12 Homeostasis: tendency of living things to try to maintain their structure and regulate their internal environment o The minute you stop homeostasis, you begin to decompose o Negative feedback: a change in one direction causes a series of events in the other direction to counteract the change Biological: body temp (37C 97.6F) Physical: house thermostat o Positive feedback: initial change in one direction sets off a series of events that intensifies a change in that direction Growing population Oxytocin? is a chemical in the body that causes contractions in childbirth Hormone given off by brain that makes that uterus muscle contract. Sends another signal to the oxytocin in the hypothalamus Pertussis: human hormone that exands uterine ewalls preganant or not o Biological Real Life: population explosion “snowball” effect Hypothalamus: control center in your brain in the environment and sensing o Tells you when you are cold and sends to nervous system for you to shiver to maintain temperature in your body when you are cold or warming up o Sensors are your nerves All about sensors and effectors Organization of the animal body: Cells tissue organs organ systems 4 types of tissues o Cells and/or non-cellular components—not living o (Cells are smallest living component in your body) o 1. Epithelial Tissue: cells from continuous sheets called membranes, cover body and line all body cavities; FORMS BARRIER Part of the skin is epithelial tissue, skin is an organ that has all 4 tissues types SKIN IS NOT A TISSUE TYPE Nervous tissue, connective tissues, muscle tissue Examples: lining of lungs and blood vessels: capillaries Lining of trachea, reproductive organs Can line outside of the heart—heart has skin all around it, also has connective tissue holding it in place o 2. Connective Tissue: surrounded by large quantities of extracellular substances (between the living cells) which are secreted from the cells of the connective tissue Has non -living components that the cells are making and giving off Examples:
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cartilage: Ear, tip of your nose o cartilage give off compound called collagen that is solid but flexible Blood: plasma: (red, carry O2 and white blood cells immune response), plate reforming cells. o Consist of living and non- living, cells in blood stream are alive but the plasma and platelets within it are considered non-living Dermis (skin), fat cells, blood and lymph, tendons and ligaments, cartilages, bone (bone matrix, central canal, bone cells)—blood cells made in your bone o 3. Muscle Tissue: tissue specialized for contraction. Cells that contain ACTIN and MYOSIN When you contract them they get shorter and when you relax them they get longer Each striation can contract o 4. Nerve: Specialized to generate and conduct electrical signals Brain has almost a trillion cells that make a very special organ Nerve cell: not your typical type of cell, have undergone maturation to
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This note was uploaded on 01/19/2012 for the course BIO 1002 taught by Professor Hrinchevich during the Fall '10 term at LSU.

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Week 12 - Week 12 Homeostasis: tendency of living things to...

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