The Nervous System PDF

**The Nervous System** **General functions of the nervous system:** - - **Nerve Tissue:** **Neuron structure:** - - - - - - - - - - - - - - - - **Neuroglia Cells:** - - - - - - - - - - - **Myelination:** - - - -...

**The Nervous System** **General functions of the nervous system:** - - **Nerve Tissue:** **Neuron structure:** - - - - - - - - - - - - - - - - **Neuroglia Cells:** - - - - - - - - - - - **Myelination:** - - - - **Classification of Neurons:** - - - - - - - - - - - - - - - - - **Nerves and Nerve Fibers:** *Draw a picture of a nerve (longitudinal section), labeling neurons and nerve fibers:* *Draw a sensory nerve, a motor nerve, and a mixed nerve. Using arrows, indicate the direction of movement of electrical impulses in each:* **[Basic Principles of Electricity:]** *Draw a cell membrane and show separation of charge (voltage) across the membrane:* *Add a voltage meter (into the above picture) measuring a potential across the 2 sides of the membrane.* Insulators - have high electrical resistance Conductors - have low resistance to current flow **[Electrical Potentials:]** - - - *Draw a cell with more negative charges on the inside of the cell membrane and more positive charges on the outside of the cell membrane.* **[Membrane Potentials That Act as Signals:]** - - - - **Graded Potentials (Local Potentials):** **Action Potentials (APs):** **Nerve Impulse Conduction:** **The Synapse:** **Synaptic Transmission:** **Neurotransmitter Substances:** monoamines - Acetylcholine (Ach) Epinephrine (Epi) = Adrenaline Norepinephrine (NE) = Noradrenaline Dopamine Seratonin amino acids - Glycine GABA glutamate peptides - enkephalins - relieve pain, opiate endorphins - relieve pain, opiate Substance P - causes pain **Neuromodulators:** **Synaptic potentials:** **Electrical Phenomena:** **More Terminology:** The ends of the axons are called axonal terminals, nerve terminals, synaptic knobs, or boutons. An axon has the same organelles as are found in the cell body and dendrites except for **Nissl bodies.** Substances are produced in the cell body and are transported down the axon (with microtubules and actin filaments). **[Spinal Cord:]** **[Ascending and Descending Tracts:]** **[Reflexes:]** [Knee-jerk reflex (patellar tendon reflex)]: [Withdrawal Reflex]: [Crossed Extensor Reflex]: [Use of reflexes:] Normal response: downward flexion (curling) of toes Autonomic Nervous System The autonomic nervous system is the part of the peripheral nervous system that operates continuously without conscious thought. Controls visceral activities, responds to emotional and physical stress. The autonomic system innervates the smooth and cardiac muscle and glands. It shunts blood from one area to another where it is needed, it speeds up or slows down the heart rate, it adjusts blood pressure and body temperature, it increases or decreases stomach secretions, secretions of glands, dilates pupils, etc. Autonomic activities are primarily regulated by reflexes where sensory input comes from receptors in the visceral organs and the skin. Motor impulses then travel out over cranial and spinal nerves. Usually the efferent fibers lead to ganglia outside the CNS. The impulses reaching the ganglia are then integrated and relayed to the visceral organs. **The visceral efferent nerve fibers** associated with these ganglia **make up the autonomic nervous system**. [Autonomic Nervous System has 2 sections:] **SEE TABLE 14.5, pg. 545 -- effects on organs! Know this table!** [Autonomic Nerve Fibers] **[Sympathetic Nervous System (Thoracolumbar division):]** **[Parasympathetic Division (Craniosacral Division):]** Preganglionic fibers -- long, myelinated Postganglionic fibers --short, unmyelinated **Autonomic Neurotransmitters:** **Actions of Autonomic Neurotransmitters:** **[Ach binds to two different receptor types]**: [**NE and Epi combine with adrenergic receptors**:] **[Enteric Nervous System:]**