Anatomy and Physiology Exam 1 Figueroa Homeostasis Balance equilibrium dynamic process found in all living systems endocrine and nervous system works together for this constantly adjusting to maintain a relatively constant condition o Large changes exterior small changes interior to the body o ex blood pressure glucose levels and body temp Homeostatic Control Mechanism imbalance balance 1 Stimulus reacts to change 2 Change detected by receptor 3 Receptor inputs information along afferent pathway control center 4 Output information to effector 5 Response of effector back to homeostasis Body fluids Intracellular fluid the inside our cells Extracellular fluid all body fluids outside the cell interstitial fluid fluid between cells in tissue plasma the fluid component of blood lymph the fluid in our lymphatic vessels cerebrospinal fluid CSF the fluid within the CNS Synovial fluid the fluid within most joints Negative Feedback System most IMPORTANT feedback system focus more on this type for test Negative because it gives an opposite response for example if blood pressure is too high you need to lower it one way is by vasodilation or the expansion of blood vessels which lowers pressure 3 essential components receptor detects changes in controlled conditions control center decide the type and amount of the response the body needs sends signals to the effector effector reacts to signals from the control center and produces the required response Ex Body Temp if the body temperature is too high or too low it can cause different system disorders normal temp 98 6C thermoreceptors detect both increasing and decreasing body temps they then send impulses to the brain neurons in the hypothalamus control heat balance if too hot sweat glans are stimulated if too cold you shiver shake Positive Feedback System Positive because it continues enhances the direction in which stimulus is going must be stopped or limited by an OUTSIDE event Ex Control of Labor contractions begin receptors realize that the cervix is being stretched so it tells the control center the control center sends signals to the effectors to contract the muscles even more stopped once the baby is born leaves the body Blood pressure regulation 3 components o Baroreceptors detects change in blood pressure to communicate with the brain o Brain interprets info to send to heart and blood o Heart and blood vessels take info from brain and alteres the pressure o Beta cells in hyperglycemia o Alpha cells in hypoglycemia Cells are made of 3 pars 1 plasma membrane flexble outer surface of the cell 2 cytoplasm numerous organelles surrounded by cytosol 3 nucleus large organelle with DNA and the cells chromosomes The Plasma Membrane The fluid mosaic model Membrane lipids Lipid bilayer forms the fabric of the membrane Composed of phospholipid molecules Head polar and hydrophilic philic means it likes water if water soluble Tail hydrophobic phobice means it is afraid of water insoluble in water Uncharged nonpolar It is made up of two fatty acid chains Membrane Proteins Integral proteins firmly inserted into the lipid bilayer some only protrude from only one membrane surface most are transmembrane span the entire width of the membrane and stick out both sides most are involved in transport some clump together to form channels or pores through which water soluble molecules or ions can move through others are carriers that bind to a substance and then move it through the membrane receptors Peripheral proteins are not embedded in the lipid they attach loosely to integral proteins Functions transport from one side to the other enzymatic activity substrate to produce products Receptors for signal transduction Neurotransmitters Hormones Membrane Transport Rate of diffusion primarily depends on concentration gradient high low process Passive no energy used Diffusion the tendency of molecules or ions to move from high concentration to low concentration along their concentration gradient Nonpolar simple diffusion Polar carrier mediated facilitated diffusion Ions ion channel passive transport no energy concentration gradient occurs if lipid soluble small assisted by carrier molecule lipid soluble substances and nonpolar oxygen and carbon dioxide dependent on the concentration gradient Facilitated Diffusion assisted Limited by the number of protein channels available Amino acids ions and Glucose travel via Simple Diffusion unassisted diffusion nonpolar and lipid soluble Carriers binding to protein carriers in the membrane and ferried across for bigger molecules amino acids and glucose Channels moves through water filled protein channels ions electrolytes use channnels Osmosis the diffusion of a solvent such as water through a selectively permeable membrane membrane Solutes attract water so always travel toward higher solute Occurs when the concentration of a solvent is different on opposite sides of a Osmolarity total concentration of a solute in a solution Tonicity of osmosis most of our body is in osmotic equilibrium Isotonic solutions with the same solute concentration as the cytosol Hypertonic solution has a higher solute concentration than the cytosol nothing happens loses water shrivels up Hypotonic solution has a lower solute concentration gains water cell expands if RBC ruptures hemolysis Active Process Active Transport Carrier mediated facilitated diffusion Requires carrier protein that combine specifically and reversibly with the Solute pumps move solutes most ions against their concentration gradient transported substance ATP is needed Primary Active transport ATP is source of energy requires carrier proteins Antiports transport mechanism that moves two substances in opposite directions ATP is energy ATPase breaks ATP into ADP as well as transports it Ex Sodium Potassium Pump Carrier is called sodium potassium ATPase K inside the cell is 10x higher in concentration than outside of the cell Na is higher in concentration outside never have more Na inside 3 Na leaves goes out of the cell and 2 K move into the cell the result the Na K pump the Na provides energy for the Secondary Active transport Secondary Active transport ion gradient is source of energy transport driven indirectly by energy stored in ionic gradients created by the primary active transport pumps Symports transport mechanism that moves the substance in the same direction Glucose and Amino Acids need Na to enter Glucose has a different transporter that AAs but move in the same
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