Lecture 4 Outline of Last Lecture I. Continuation of last lecture II. Division of the nervous system III. Tw o c l a s s e s o f n e u r a l t i s s u e IV. Blood-brain barrier V. Cerebrospinal fluid Outline of Current Lecture I. Cerebrospinal fluid II. Gray matter III. Orientation IV. Major structures of the CNS V. Tw o c l a s s e s o f n e r v o u s t i s s u e VI. Resting membrane potential Current Lecture I. Cerebrospinal fluid (CSF) A. Glia support the CNS B. Cerebrospinal fluid bathes the CNS. The brain floats in the CSF reducing its weight by about 95% C. Helps with shock absorption D. Trans po rt nu tr ie nt s to t he br ai n an d waste a wa y fr om th e br ai n II. Gray matter Psy 3061 1st Edition 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. !A. gray matter mostly consists of uncovered (unmyelinated) cell bodies and dendrites —> composed of neurons B. many layers in gray matter C. white matter consists of oligodendrocyte covered (mylinated) axons D. fissures separate the major landmarks of the brain III. Orientation A. medial: towards center of body B. lateral: towards outside of body (e.g. hand) C. medial separates two hemispheres from each other D. coronal: head on view E. anterior/posterier IV. Major structures of the CNS A. hindbrain —> myelenocephalon and metencephalon 1. mylencephalon —> medulla 2. metencephalon a) pons: bridges the medulla and thalamus b) cerebellum: little brain c) reticullar formation B. midbrain —> mesencephalon 1. tectum —> superior colliculi and inferior colliculi 2. tegmentum —> periacqueductal grey and substantia nigria and red nucleur a) important stops for visual and auditory information before it goes to other part of the brain that process it (knowing where all these structures are and their names are enough for the first exam) C. forebrain —> telencephalon and diencephalon1. diencephalon —> thalamus and hypothalamus (hypothalamus is underneath thalamus) 2. these two structures have many sub nuclei with important functions that will be discussed later 3. telencephalon a) basal ganglia —> important for movement (1) striatum: caudate and putamen (2) globus pallidus (3) nucleus accumbens b) limbic system (a) amygdala: understanding and processing emotion (b) cingulate cortex (c) hippocampus (d) fornix: connecting hippocampus and hypothalamus/mammilary bodies c) cerebrum/cerebral cortex/neocortex V. Tw o c l a s s e s o f n e r v o u s t i s s u e A. nerve cells (or neurons) —> excitable tissue B. glial cells —> support neuronal structure and function C. all living cells are more negative on the inside (intracellular space) than out (extracellular space) D. neurons have two activity levels 1. resting potential: ~70 millivolts is the valanced state of electrochemical forces 2. action potential: a brief flip in the polarity of trans-membrane electrical potential —> electrical impulse VI. Resting membrane potentialA. resting membrane potential: the balance of electrochemical forces across a selectively permeable membrane creates a resting membrane potential a) selective permeability (1) intracellular and extracelluar space are separated by a membrane (2) channels allow for certain chemicals to pass, some have electrical charge (ions Na+ and K+) but some do not (O2, CO2, H2O). b) concentration gradient (1) atoms and molecules diffuse from places where they are highly concentrated to where they are less concentrated (2) if there is a semi permeable membrane, some stuff will stay on outside and some will stay inside c) electrical gradient (1) ion —> that which goes (2) positive charge: fewer electrons than protons; positively charged (e.g. Na+, K+) (3) negative charge: more electrons than protons; negatively charged (e.g. Cl-) (4) electrostatic forces cause positive to flow towards negative and vice versa (5) ions are “balanced” while neuron is at rest (resting potential) —> key is to keep more positive charges on the outside d) sodium-potassium pump (1) constantly keeps homeostasis (2) protein in cell membrane that takes two potassium form the outside, brings them inside, and swaps for three sodiums over and over again (3) helps keep intracellular space charged negatively relative to the extracellular space (4) ions are balanced while neuron is at rest (resting