Consists of brain and spinal cord

Neurons- Glial Cells

Support cells consist of oligodendrocytes, astrocytes, microglia and ependymal cells. 

Astrocytes- most numerous, gray matter in CNS, movement of metabolites and wastes to and from neurons, repair and scar formation in brain

Microglia-phagocytotic, cleans up debris

Ependymal-forms lining of neural tube, ventricular system

Located outside of the brain and spinal cord

Neurons- Schwann Cells (support cells), separated by nodes of Ranvier which increase nerve production

Afferent (Sensory)- carry info to CNS

Efferent (Motorneurons)- carry info from CNS to effector organs

Axons- long efferent processes, carry impulses away from cell

Dendrites-main source of info for cell, take messages to cell

Cell membranes contain ion channels which generate action potentials.These channels are guarded by voltage dependent gates tht open/close with changes in membrance potential

1.Resting/polarized state- phase continues until threshold potential is reached and ion channels open

2. Depolarization-membrane becomes permeable to sodium ions and membrane becomes positive.

3. Repolarization- polarity of resting membrane potential is re-established by closure of sodium channels and opening of potassium channels. OUtflow of potassium returns membrane potential to negativity.

Small molecules that incorporate positively charged nitrogen atom, amino acids, peptides and monamines. The process of neurotransmission involves synthesis, storage, and release of neurotransmitters and reaction of a neurotransmitter with receptor, they are stored in synaptic vesicles.

They control neural function, by causing excitation or inhibition of action potentials

Nervous System begins as hollow tube which becomes brain and spinal cord.

Gray Matter-cellular portion (cell columns)

White Matter- Tract System of CNS

Afferent neuron axons form dorsal roots (Sensory) or nerves and exiting efferent (motor) neurons form ventral roots

CNS and associated peripheral nerves consist of 43 segments, 33 of which form spinal cord/nerves and 10 of which form brain/cranial nerves

Basic pattern of CNS- central cavity surrounded by inner core of gray matter and superficial layer of white matter

PNS and CNS afferent and efferent neurons are repeated as cell columns

IA Neuron- (Input Association)- distribute afferent info to reflex and rostral segments of CNS

OA Neuron- (Output Association)- lower motor neurons which project to effector muscles.

Peripheral nerves that carry info to and from spinal cord.  32 or more pairs

8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 2 or more coccygeal

Each spinal nerve enters thru intervertebral foramen, mixed nerves bc have both efferent/afferent axons, 

Spinal nerves form complicated nerve networks called plexuses

Contains cerebellum, pons and medulla oblongata

Brain stem is composed of medulla and pons- vital centers are located in reticular formation in brain stem, include respiratory, cardiovascular and vasomotor centers (coughing, vomiting).

Pons- composed of conduction fibers, mastication of food, jaw movement

Cerebellum- fine motor movement

Consists of telencephalon and diencephalon

Diencephalon forms core of forebrain- which includes thalamus( relays info going to from), hypothalamus-homeostatic control

Telencephalon forms cerebral hemispheres- temporal, parietal, occipital, frontal

Connective tissue sheaths that protect brain and spinal cord

Pia Mater- covers surface of brain and spinal cord, protective tissue layer

Arachnoid Mater- Encloses entire CNS

Subarachnoid Space- Contains CSF (cerebrospinal fluid)

Dura Mater- Outside sheath of connective tissue major source of protection

CSF

Cerebrospinal Fluid

The ventricular system is a series of CSF filled cavities in brain. CSF consists of 99% H20, humans secrete 500ml/day continuously being absorbed

Provides a supporting and protective fluid for brain and spinal cord, maintains constant ionic environment. Produced by choriod plexuses 

Maintains Homeostasis

Involved in regulating vital visceral fuctions such as blood pressure and flow.

Represented in both CNS and PNS

An efferent system 

2 Divisions- Sympathetic and Parasympathetic

Part of Autonomic system

Includes maintaining body temp, respiration, digestion, elimination, fight or flight response

2nd Division of Autonomic System

Functions include conservation of energy, resource replenishment and storage, maintenance of organ function. Slows down heart rate, secretions and gasto function. Deals with conservation of energy, resource replenishment

Both divisions of ANS consist of 2 neuron pathway: a preganglionic and posttganglionic neuron. Acetylcholine- preganglionic neurotransmitter for both divisions

postganglionic neurotransmitter is Acetylcholine for parasympathetic but norepinephrine and ephinephrine for sympathetic postganglionic neurons

These are cell membrane receptors that resond to acetlycholine.

2 types:

Muscarinic-postganglionic fibers of parasympathetic system

Nicotinic- Autonomic Ganglia

Include norepinephrine, epinephrine and dopamine

synthesized in sympathetic nervous system

Cause excitation or inhibition of smooth muscle contraction. 2 types of receptors- alpha- cause vasoconstriction and beta- cause vasodilaton