PHIS 206 1st Edition Exam 1 Study Guide Cell Physiology Cell Physiology General Physiology Physiology about everything that stops happening when you die what keeps your systems going when you re alive Harvey discovered circulation of blood o If you rub garlic on your feet you can later smell it on your breath circulation o KNOWLEDGE COMES FROM THE LIVING not from dissecting dead bodies Homeostasis keeping things the way that they used to be stays the same implies that you must have recovery from pertervement Homeostasis not changing overtime o Done by homeostatic mechanisms Feedback somewhere there is a sensor that detects change and will initiate response exactly in opposite direction called negative feedback Positive Feedback sensor detects and makes response in same direction o Feedback systems a change in the environment initiates a change in the body Negative feedback changes occur that lead body back toward homeostasis most common Positive feedback increases the change away from homeostasis very rare usually pathological Cells 80 Water 15 Protein 2 Lipid 3 Misc Cell Membrane or Plasma Membrane separates the intracellular fluid from the extracellular fluid flat sheet made of 2 layers have channels fat soluble crosses easily water soluble if small go through channel if too big can t get through without special mechanisms Fluid in body Intracellular fluid ICF inside cells Extracellular fluid ECF outside cells ICF K Na ECF k Na Intracellular Fluid Extracellular Fluid lots of K Potassium Low concentration of K not so much Na Sodium Na high concentration Cell Membranes do not allow ions to get in Diffusion Random movement molecules in a medium Heat makes molecule move Water molecules attract one another Concentration determines Diffusion Diffusion Rate Concentration Difference x Area x Temperature Thickness x Molecular Size x Viscosity Concentration of O2 is always higher on the outside Simple diffusion o Random movement of molecules under the influence of heat o Diffusion rate net movement of some molecules across a barrier membrane Increased amount of molecules moving increased diffusion rate Influenced by differences in concentrations on either side of the membrane The greater concentration difference the greater net movement o Size of molecules influences diffusion Small molecules diffuse at a greater rate requires less energy to move o Surface area influences diffusion Greater area greater diffusion rate o Length of diffusion path influences diffusion Greater length decreased diffusion o Viscosity resistance of liquid to flow Greater viscosity decreased diffusion Water has a high viscosity o Temperature influences diffusion Increased temperature increased diffusion more rapid diffusion We usually have very little temperature change in our bodies o Sodium and potassium can both diffuse across membranes Large water soluble membranes use special mechanisms to cross Facilitated Diffusion provision by the cell by the pathway Facilitated Diffusion Mechanism for providing a pathway across a membrane that a cell wouldn t otherwise have Membranes have layers of lipids and aqueous channels Molecules that are lipid soluble can dissolve right through the lipids Water soluble molecules small can go through aqueous pores Specific proteins carrier proteins are embedded in lipid membrane Parts of proteins flip flop back and forth to transport molecules across the membrane Reversibly bind and release molecules Where concentration of molecules is high they bind more molecules No energy required Osmosis there is almost no other method for getting water across cell Water molecule is tiny can diffuse through pores extremely fast Osmosis diffusion of water Water always flows to the more concentrated content Osmotic pressure depends on the total solute concentration Water diffuses from an area of high concentration to an area of low concentration Change the concentration of water by adding solutes Hydrostatic pressure the force that opposes diffusion Unit of total 1 osmol 1 L 1 OSM 1 1000 osmol 1 L 1 mOSM Biology fluids around 300 mOSM 1 Mole of gas in a 1 L container it exerts 22 4 ATM Atmosphere Osmotic pressure For every 1 OSM difference generate 22 4 ATM 1 mOSM generates 1 1000 x 22 4 ATM 1 atmosphere is 760 mM of Mercury 22 4 ATM 15 000 mMHg 1 mOSM 15 mm Hg biologically significant pressure Average artery pressure 100 mm Hg Isotonic the same Hypotonic the one has lower osmolarity Relative to osMolarity Hypertonic the one has more osmolarity Van t Hoff discovered that sucrose molecules exert same pressure as any other molecule that can t cross a membrane o Liquid molecules exert same pressure in gas phase o 1 mole liter 22 4ATM o 1 ATM 760 mmHg o 22 4 ATM 15 000 mmHg o 0 31 the concentration of the sum of our blood plasma 310 mOsm Active Transport any system that will move a molecule uphill Most Important in Physiological terms Inside Outside K hi K low only form biology finds useful energy is the destruction of ATP Na l Na High ATP ADP Energy Active transport o Requires energy input to occur o ATP ADP energy o ATPase enzyme coverts ATP to ADP with the release of energy o Also called a sodium pump Na P ATPase pump Located in membrane Uses ATP to pump potassium in diffuses out and sodium out diffuses in Molecular pump constantly exchanging sodium and potassium go uphill in concentration gradian Osmolarity Osm o The added concentration of the molarities of everything the solutes in the plasma o Can be obtained by measuring osmotic pressure o The difference in osmolarity never lasts long due to osmotic pressure restores the balance Nervous System Cell physiology of two nerves Two Main Types 1 Neuron do things that we normally think of a nervous activity business end 2 Glia do not transport information provide environment for neurons A nerve is a bunch of neurons held together in a protective sheath Can send smaller messages to individual or small groups of cells Endocrine messages circulate in the bloodstream o Gradual decay stay in system longer Neural messages have target cells they deliver messages to Neurons bring information from one place to another Glial cells maintain the environment that allows neurons to operate Neuron Cell body Soma usually only has one receive info Dendrites extra extensions receive info Axon fibourous extension from Soma takes info out Sensory Afferent Into CNS Motor Efferent Away from CNS Sensory afferent in Motor efferent out Interneuron everything inbetween most