PHIS 206 1st Edition Exam 1 Study Guide Lectures 1 9 Lecture 1 August 23 Introduction Homeostasis Homeostasis maintaining constancy Negative Feedback homeostatic response in the opposite direction Positive feedback homeostatic response in the same direction Lecture 2 August 26 Cell Structure Intracellular ICF inside cells LOW concentrations of Na HIGH concentrations of K Extracellular ECF outside cells HIGH concentrations of Na 15 20 greater LOW concentrations of K Separated by cell membrane permeable to Na and K simple diffusion random motion of molecules caused by heat Diffusion rate is proportional to conc of diffusion area Kelvin viscosity thickness mol size Not sensitive to temperature since it does not change much FIGG S EQUATION How Do Large Molecules Get Across Facilitated diffusion proteins embedded in membranes can weakly bind certain molecules carrier proteins the side that the molecules attaches has higher concentrations NO ENERGY for facilitated or simple diffusion Lecture 3 August 28 Diffusion Osmosis and Transport Osmosis Osmotic Pressure Water diffusing down its own gradient hydrostatic pressure depends on height of column Membrane water can cross easily but water soluble big molecules cannot cross freely Osmotic Pressure force exerted on water as it goes downhill Van t Hoff pressure exerted on molecules would be exactly the same as pressure exerted by any gas Cell Membrane Actual concentration of biological fluids 310 mM millimols osmolarity Osm introduced to measure molarity of all osmotic substances Osmosis is the only mechanism that deals with water in our bodies Active Transport Molecules move uphill low to high concentrations Requires Energy b c molecules move in the opposite direction ATP ADP basic subunit of biological systems P1 inorganic phosphate ENERGY Membrane ATPase sodium pumped out of cell potassium pumped into cell For stable K levels the rate of diffusion rate of pump pumping K into cell Inside Outside K high K low Na low Na high Lectures 4 and 5 August 30 September 4 Cellular Neurophysiology Nervous System Units 2 Basic Types of Cells 1 Neurons businessman info transferred from one place to another plural nodes 2 Glia glue provide environment that allows neurons to do their job Glial Cells 4 Types 1 Oligodendroglia glial cells that have many branches wrap around axons in neurons insulators in brain spinal chord 2 Schwann Cells glial cells wrapped around an axon 1 thing wrapped around are NOT branched in the nerves leading to brain and spinal 3 Astroglia points will touch nearest capillary and nearest neuron facilitates movement of nutrients waste products between blood stream and nerve cells 4 Microglia heals damage to nerve cells accumulates site of injury in masses Neurons 2 ways to classify 1 Functional which direction information is travelling sensory neurons afferent info towards CNS motor neurons efferent info away from CNS muscles interneurons towards each other neuron to neuron 2 Structural dendrite branches soma body axon exterior of cell membrane terminals distilling neurons Neurons have ONE axon but MANY dendrites bipolar neuron dendrite and axon connect to different places of soma uniport both come from single projection 1 place where information comes out multiport single axon many dendrites many routes out Some axons are wrapped in Schwann cells in many ways and so tightly so almost no cytoplasm is left and lots of cell membrane is Wrap in segments but always spaces Nodes of Ranvier myelin sheath coated axon with a substantial layer of liquids myelinated axons tightly wrapped Schwann cells Electrical Properties of Membranes cell membrane on the outside in the inside resting potential usually 70 mV stimuli gradient responses mimics if gradient up then stimuli up If voltage exceeds threshold then single spike constant suprathreshold Action potential spike CAN move created by stimulating the threshold Threshold stationary measure on soma of cell nothing on axon All or nothing either generate action potential or do not Grading potentials only occur in the soma body changes in mV Refractory period resistance to responding to a stimulus Consequences limits the of action potentials in a nerve Voltage gated channels embedded in neurons can be open or closed for a specific ion The voltage gradient across the membrane determines whether it is open when threshold is reached or closed Neurons Inhibited neuron becomes MORE and harder to reach threshold with a stimulus Excited neuron becomes LESS and easier to reach threshold with a stimulus Myelinated axons can transmit action potentials faster Myelinated and Nonmyelinated Action potentials can only go AWAY from the soma synapse where axon terminal pre synaptic of one neuron comes into contact with the dendrites or soma of another neuron post synaptic synaptic cleft does not let cytoplasm interact Neurotransmitters One neuron only releases one neurotransmitter Most common neurotransmitter Acetylcholine ACh ACh in the synapse binds to receptors in the post synaptic cell actively transported Acetylcholine Acetate Choline Neurons Convergence several neurons are postsynaptic to 1 neuron Divergence 1 neuron is postsynaptic to many neurons Convergence Excitatory neurons decreases input of membrane potential Inhibitory neurons increases input of membrane potential When the excitatory inhibitory then change is called Excitatory Postsynaptic Potential EPSP When the inhibitory excitatory then change is called Inhibitory Postsynaptic Potential IPSP MORE NEGATIVE Lectures 6 and 7 September 6 September 9 Central Nervous System Peripheral Nervous System Every neuron apart from the CNS Afferent nerve impulses to the brain Efferent nerve impulses away from the brain A Somatic part that control the muscle s activity B Autonomic controls efference that goes to other organs internally Central Nervous System Brain between it and the skull is called meninges Dura mater outer furry layer tough mother Arachnoid mater extremely vascular and looks like a spider web involved in generating the cerebral spinal fluid that goes to the brain Pia mater follows all convolutions attached closer to brain Brain Protection Cerebrospinal fluid fluid b w the meninges cushions the brain buoyancy density brain stays in place the fluid does not rise or fall Brain capillaries are more selective Sometimes referred to as the blood brain barrier Keeps toxic foreign things away from the brain does not include the HYPOTHALAMUS Anatomy