The Nervous System

I. General organization of nervous system A.CNS 1. brain 2. spinal cord B. PNS 1. sensory 2. motor a. Somatic b. ANS -sympathetic -parasympathetic

II. Nervous Supporting Cells - neuroglia A.Astrocytes 1.Connect to capillaries 2.Mopping up chemical environment of brain as far as potassium ions and neurotransmitters

B. Microglia 1. spider-like phagocytes 2. debris, dead brain cells, bacteria

C. Ependymal cells 1. lines cavities in CNS 2. beating of cilia moves cerebrospinal fluid 3. fluid nourishes and cushions CNS

D. Oligodendrocytes 1. wrap axons of nerve cells with fatty layer 2. produces myelin sheath 3. speeds conduction

E. Glia cells in general 1. resemble neurons 2. not excitable 3. supportive cells 4. capable of repeated mitosis 5. gliomas-glial tumors

III. Neurons A. Structure 1. cell body 2. nissl bodies-rer 3. dendrites 4. axon 5. axon hillock 6. axon collateral 7. axon terminals 8. neurotransmitters 9. synaptic cleft

B. Myelin sheath 1. functions 2. PNS-Schwann cell 3. Node of Ranvier 4. Can form a pathway for regrowth of damaged axon 5. multiple sclerosis

C. Neurons classified by function 1. afferent 2. interneuron 3. efferent 4. ganglia 5. nuclei

D. Neurons classified by structure 1. multipolar 2. bipolar 3. unipolar

IV. Neuron physiology A. Resting membrane potential B. Action potential-nerve impulse

C. Propagation of action potential 1. diagram on board 2. a lot like dominoes 3.

D. Anatomy of a synapse 1. presynaptic membrane 2. synaptic cleft 3. postsynaptic membrane 4. synaptic vesicles 5. receptor sites for transmitter substance

E. Physiology of synapse 1. action potential arrives 2. Calcium ion channels open 3. synaptic vesicles fuse with membrane 4. transmitter substance released 5. diffusion of transmitter substance 6. binding to receptors 7. creates a graded potential 8. may bring postsynaptic membrane to threshold 9. nerve gas-blocks cholinesterase

F. You tube of synaptic events 3hk 3hk

V. Functional Anatomy of the Brain A. Introduction 1. difficult to talk about 2. two fistfuls of pinkish/gray 3. wrinkled 4. consistency of cold oatmeal 5. three pounds 6. hugely complex 7. four basic regions – a. Cerebral hemispheres – b. Diencephalon – c. Brain stem – d. cerebellum

B. Cerebral hemispheres 1. most important part 2. overshadows diencephalon and brain stem 3. mushroom cap covers top of stalk 4. gyri 5. sulci 6. fissures-ie longitudinal cerebral fissure

7. Lobes of cerebrum a. Frontal lobe controls mainly motor function b. Primary motor area is on the precentral gyrus -governs conscious motor control which can be mapped

Motor homunculus

c. Motor homunculus -specific regions of the precentral gyrus control specific body parts -finer the movements, the more brain area needed to control those movements

d. Premotor area -learned repetitive tasks Typing, playing piano Athletes learn tasks by visualizing motions Ingrained in this area

e. Broca’s area speech center Usually located left cerebral hemisphere Damage here causes inability to speak

8. Other important areas of cerebral hemispheres a. Primary somatic sensory area b. Visual area in occipital lobe c. Complex memory in the temporal lobe d. Note close proximity to olfactory area e. Anterior association area-higher intellectual reasoning and socially acceptable behavior

9. Sensory homunculus

C. Diencephalon 1.Thalamus a. Encloses third vent. b. Screens incoming sensory messages 2.Hypothalamus a. ANS center for body temperature and water balance b. Regulates pituitary 3.Epithalamus a. Pineal gland b. Choroid plexus

D. Brain stem 1. size of thumb 2. midbrain 3. pons 4. medulla 5. interchange for sensory and motor paths 6. nuclei for respiratory, blood pressure, heart rate, RAS

E. Cerebellum 1.Cauliflower shape 2.Controls balance and equilibrium 3.Produces smooth and coordinated muscular contractions

VI. Protection of the brain A. Meninges 1. dura mater 2. arachnoid 3. pia mater B. CSF 1. produced choroid plexi 2. flow 3. functions 4. hydrocephalus