CNS 1. Brain 2. Spinal Cord B. Periphera

I. Functional/ Anatomical Divisions A. Central Nervous System: CNS 1. Brain 2. Spinal cord

B. Peripheral Nervous System: PNS 1. functions in general

2. Divisions 1. Afferent division 2. Efferent division a. Somatic b. Autonomic i. Sympathetic ii. Parasympathetic

II. Nervous Tissue/Cells A. Neurons 1. general structure 2. Types 1. Motor neuron 2. Sensory neuron 3. Interneuron

B. Schwann Cells 1. neurolemma 2. PNS cells

1. Glial cells types and functions : 1. Oligodendrocytes 2. Astrocytes 3. Microglia 4. Ependyma

C. Nerve cell impulse transmission: the electricity! 1. Essentially the same as described in muscle impulse. 2. Neuron not carrying an impulse is said to be ______, where the Na+ ions are more abundant on the outside and the K+ ions are most abundant on the inside. 3. A stimulus, like a ______that is released from another neuron makes the neuron cell membrane (more or less?) permeable to Na+. This causes ______of the membrane, where the inside becomes more positively charged than the outside. 4. This initial reversal of charge is propagated down the axon (saltatory conduction in myelinated axons) to the axon terminals. 5. The electrical impulse then causes the release of the ______which diffuses across the ______and binds with the receptor cells.

CNS structure and Function: 1. Spinal Cord: a. Protection: i. bony vertebra inside the vertebral foramen 1. diameter is @ ¾ “ 2. spinal cord extends from ______3. Cauda equina ______a. Lumbar puncture ii. meninges coverings to L3-L4 1. Three layers of connective tissue coverings a. Dura mater (hard mother) forms outer most covering of spinal cord i. Space between dura mater and walls of vertebral canal is called the ______space = loose c.t,. blood vessels and fat ii. Epidural block b. Arachnoid membrane i. Made of epithelia tissue, collagen and elastic fibers for a “cob web” appearance ii. Cerebral spinal fluid circulates in the central canal and subarachnoid space

c. Pia Mater (delicate mother) innermost of meninges i. Contains connective tissue and all the blood vessels that service the spinal cord are found here. ii. Firmly bound to the neural tissue

iii. Cerebral spinal fluid (CSF) 1. Functions to a. ______b. ______c. ______2. Formed in the brain by the______

b. Cross-sectional structure i. “butterfly” shape of grey matter surrounds central canal. 1. contains the soma of motor neurons and interneurons ii. white matter surrounds grey matter 1. made of myelinated axons and dendrites of interneurons 2. nerve tracts: groups of neurons within the CNS iii. spinal nerves exit spinal cord 1. dorsal root made of sensory neurons = info in and dorsal root ganglia contain soma of those neurons a. Shingles and chicken pox 2. ventral root made of motor neurons = info out 3. together form a “spinal nerve” = mixed nerve c. Spinal Reflexes i. Reflex arc= pathway of nerve impulses in reflex ii. Five parts to reflex arc 1. receptors (for pain, stretch, position etc.) detect info 2. sensory neurons relay info to spinal cord 3. CNS (aka spinal cord) integrates info (interneurons) 4. motor neurons transmit response 5. effector organ performs response iii. Types of reflexes: 1. Stretch reflex occurs when a muscle that is stretched will automatically contract. Example: Patellar reflex 2. Flexor reflexes or withdrawal reflexes are in response to a painful stimulus. 3. Babinski reflex: used to test spinal cord integrity.

2. Brain a. Major “divisions of the brain i. Brain stem 1. medulla –attaches to the spinal cord a. functions in “vital signs” with centers for heart rate, vasoregulation, respiration b. non”vital” centers like vomiting, coughing, sneezing and hiccoughing c. contains motor and sensory nuclei (attachment) for five cranial nerves (VII, IX, X, XI, and XII) 2. pons a. anterior to medulla, connects brain to lower part of brain stem b. respiratory centers c. contains motor and sensory nuclei for four cranial nerves (V, VI, VII and VIII) 3. midbrain a. encloses the cerebral aqueduct (CSF) b. visual and auditory reflexes c. righting reflexes for head d. areas that release dopamine if damaged result in Parkinson’s disease (difficulty starting voluntary movements because opposing muscles never relax) e. contains motor and sensory nuclei for two cranial nerves ( III, and IV) ii. Cerebellum 1. Two primary functions a. Adjusting postural muscles of body (balance and equilibrium) b. Programming and fine-tuning movements controlled at conscious and unconscious levels c. Can be affected by alcohol (temporary), stroke or trauma (permanently) resulting in ataxia a disturbance in balance iii. Hypothalamus 1. Seven functions 2. Regulates and coordinates ANS with CNS 3. Links to endocrine system 4. forms floor of third ventricle (CSF) iv. Thalamus 1. Encloses the third ventricle (CSF) 2. functions concern sensations 3. integrates sensory info for cerebrum interpretation v. Cerebrum (Cerebral hemispheres) 1. Right and left cerebral hemispheres a. Separated by longitudinal fissure b. Connected by Corpus callosum c. Sulci and gyri (grooves and bumps) d. Each contain a lateral ventricle (CSF) 2. Three main points about cerebral hemispheres: a. Each cerebral hemisphere receives sensory information from and sends motor information to the opposite side of the body b. The two hemispheres have different functions even though they appear identical c. Assignment of a specific function to a specific region of the cerebral hemisphere is imprecise. 3. Regions of the cerebral cortex include: a. Frontal lobes b. Parietal lobes c. Temporal lobes d. Occipital lobes e. Association areas Cerebral Spinal Fluid b. Formation: i. Choroid plexuses found in the ventricles of the brain 1. clusters of thin walled capillaries covered by a layer of ependymal cells c. Composition: i. Similar to plasma but has: 1. less protein 2. more Vitamin C 3. more Na+, Cl-, Mg++, H+ 4. less Ca++ and K+ d. Hydrocephalus i. When something (like a tumor) obstructs circulation or drainage, CSF accumulates and exerts pressure on the brain. ii. Babies heads swell, due to flexible skull. Adults results in brain damage. iii. Treated by placing a shunt in the ventricles of brain to drain the excess fluid into a vein in the neck 3. Plantar reflex vs. Babinski’s reflex: a. Plantar reflex normal reaction to rubbing a blunt object along the lateral aspect of the sole of the foot i. Toes curl (flex) ii. Tests for the integrity of spinal cord from L4 to S2 and indirectly determines if corticospinal tracts are working b. Babinski sign (reflex) i. Blunt object on sole of foot results in dorsiflexion of the great toe and the small toes fan laterally ii. Normal response in infants < 1 year old due to incomplete myelination of N.S. iii. Not normal in adults and is a results from damage to the primary motor cortex or the corticospinal tracts. 4. Lateralization of brain: unique abilities of each hemisphere or the division of labor a. Left cerebral hemisphere is dominant in 90% of people i. Deals with logic, language and math skills ii. Most people with left cerebral dominance are right handed b. Right cerebral hemisphere i. Deals with visual spatial skills, intuition, emotion and creative skills ii. Dominant in 10% of people or will share functions equally with Left hemisphere iii. Typically Right cerebral dominant people are left handed and male