BY 124 1st Edition Lecture 24 Outline of Last Lecture Chapter 46 I Asexual vs Sexual reproduction II Whip tail Lizards III Fertilization IV Male Reproductive System V Controlling Male Reproductive System VI Puberty in Males VII Parts of Female Reproductive System VIII Egg is Made IX Estrous Cycles X Menstrual Cycles Outline of Current Lecture Chapter 48 I Nervous System II Vertebrates III Basic types of neurons IV Neurons V Schwann Cells VI How does a neuron work VII Action Potential VIII What affects speed of Action potential IX Synapses X Potentials XI Neurotransmitters Chapter 50 I II III IV V Muscles Figure 50 26 Sliding Filament model figure 50 27 Figure 50 28 Figure 50 29 Figure 50 30 Current Lecture These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Chapter 48 I II III IV V VI Nervous System Figure 48 3 a Core things needed to make nervous system work i Need to sense ii Send the signal iii Process of material integration iv Output off information signal Vertebrates compared to invertebrates a Nerve cord single NOT paired b Spinal cord dorsal not ventral c Ganglia are not as apparent d Nerve cord hollow not solid e Brain is used to control body more so than spinal cord Basic types of neurons a Sensory neurons pick up changes in external and internal environment b Interneurons involved in the integration step mentioned above c Motor neurons relay info away from integration Neurons Figure 48 4 and Figure 48 13 a Dendrites receiving end of cell body b Cell body contains nucleus c Axon where signal is sent d Synaptic terminal e First neuron will be presynaptic cell because it is before the synapse where the signal is converted and the second neuron will be postsynaptic cell because it is after the synapse f Figure 48 13 neuron is from peripheral nervous system i Schwann cell create the myelin sheath ii Myelin sheath iii Node of Ranvier areas of no myelin g Oligodendrocytes are like schwann cells except they are located in the brain central nervous system i Collectively known as glia cells as well ii Astrocytes cover the capillaries in the brain Schwann cells a Create myelin b Help with insulation and increased conduction of signal c Myelin makes the signal travel faster than non myelinated neurons d Multiple sclerosis disease where myelin sheaths are destroyed How does a neuron work a Impulse electrical signal b Table 48 1 c Membrane is positive on outside and negative on inside VII VIII d Typical resting neuron is about 70 mV e Differences in potential are because of i Differences in ion concentration on outside vs inside 1 K is inside cell and Na is more common outside cell a Cl is located in extracellular matrix As are large anions like proteins f Use ion channels to transport proteins and charged ions across membranes i Some are open all the time ii Others are gated only open when there is a particular impulse iii K moves more readily across membrane because there are more open gated K channels 1 Can move out more This changes charges across the membranes 2 When K moves out it causes inside of cell to be more negative a Would be a problem but Na helps stabilize the charge difference iv Na K pump helps establish the equilibrium in the neurons across the membranes g Excitatory cell a cell that can be activated i Membrane potential of excitable cell at rest resting membrane potential 1 Changes with impulses Action Potential AP rapid change in the membrane potential of an excitable cell caused by stimulus triggered selective opening closing of voltage gated ion channels a Stimuli that open Na channels depolarize potential becomes more positive b Stimuli that open K channels hyperpolarize potential becomes more negative c Every cell has a threshold If this threshold is met then this fires the Action potential d Figure 48 11 VERY IMPORTANT i Resting state 70mV ii Depolarization need enough Na channels open to reach threshold iii Rising phase of action potential depolarization becomes positive 35 mV tons of channels open iv Falling phase of action potential K channels open and Na channels close which causes drop in charge v Undershoot refractory period hyperpolarization 1 Can t activate another action potential during this phase vi Stabilization uses Na K pump e All or none will either fire to the maximum or it won t fire at all It depends on if you reach threshold of not What effects speed of AP a The larger the diameter of the axon the faster the rate of transmission b Salutatory conduction jump i Involves myelin sheaths IX X XI ii Signal jumps from node to node Synapses a Electrical synapse they touch b Chemical synapses don t touch but are really close figure 48 i Space between Presynaptic neuron and postsynaptic neuron ii Calcium is used to open voltage gated channels in presynaptic neuron to transport neurotransmitters out by vesicles to be released into the synaptic cleft They move through the cleft and then attach to ligandgated ion channels Na is then used to depolarize the second neuron to allow neurotransmitters into postsynaptic neuron Potentials Figure 48 17 a Excitatory postsynaptic potentials EPSPs depolarize will fire b Inhibitory postsynaptic potentials IPSPs not going to fire c Summations i Temporal summation deals with timing ii Spatial summation deals with what is going on around neuron 1 Can have neuron potentials add up to reach threshold Neurotransmitters NT Table 48 2 a Need to know Acetylcholine and GABA b GABA major inhibitory NT in brain c Dopamine d Serotonin Chapter 50 VI VII VIII IX X Muscles Figure 50 26 a Muscles b Bundle of myofibrils c Actin and myosin Sliding Filament model figure 50 27 Figure 50 28 a Thin filament actin b Thick filament myosin c Hydrolyze ATP ADP P on myosin head with ATP d Cross bridge formed e ADP leaves f Filament moves g ATP comes in and detaches myosin head from actin filament Figure 50 29 a Expose myosin binding sites by binding Ca to troponin complex which allow for attachment of myosin head to actin Figure 50 30 a Sarcolemma kind of like membrane b Sarcoplasmic reticulum SR kind of like endoplasmic reticulum c T tubules d Myofibrils