Chapter 11- The Nervous System

- Brain

-Spinal Cord
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Terms in this set (21)
- Brain

-Spinal Cord
Central Nervous system:
- Somatic (Sensory)

-Autonomic ( Sympathetic / Parasympathetic)
Peripheral Nervous system:
Neuron
-is the basic units of communication in
nearly all nervous systems.

-Monitor information in and around the body and
issue commands for responsive actions.
excitable cells
• Neurons are __________ ______ - undergo a change in
charge [voltage] across the plasma membrane.
Axon hillock
__________ _____ is last site in the soma where membrane potentials propagated from synaptic inputs are summated before being transmitted to the axon.

-Where AP starts
- Sensory

-Interneurons

-Motor
Three classes of neurons:
Sensory Neurons
converting external stimuli from the
environment into internal stimuli. Connect to CNS.
Example: olfactory neurons
Interneurons
(relay neurons)
- connects afferent neurons (signals to CNS from receptors) and efferent neurons (send
nerve impulses away from CNS to organs, etc.) in neural
pathways.
Motor Neuron
project their axons outside the CNS and directly or
indirectly control muscles. ALS (Lou Gehrig's Disease) is this type of neuron disease.
- Afferent

-Efferent
Two types of neurons:
Afferent Neuronscarry nerve impulses from receptors or sense organs toward the central nervous system. From Latin "meaning carrying into." Olfactory neurons are afferent neurons.Efferent Neuronsmotor or effector neurons - carry nerve impulses away from the central nervous system to muscles or glands. A motor neuron is this type of neuronNeuroglia (Glial Cells)• Make up more than half the volume of the vertebrate nervous system. • Make up 50% of brain tissue. • A variety of cells that metabolically assist, structurally support, and protect the neurons. • Astrocytes, oligodendrocytes, and microglia are examplesAstrocytes• are the largest and most numerous of the glial cells in the brain and spinal cord. • (mean "star cells" because of their shape). • Contribute to the blood-brain barrier, regulate the chemical environment around cells, maintenance of extracellular ion balance respond to injury, release regulatory substances that influence nerve cells, provide nutrients, and a role in the repair and scarring process of the brain and spinal cord.Microglia• are macrophages derived from bone marrow • are scavengers, engulf dead cells and other debris. In Alzheimer's disease, they are found associated with dying nerve cells and b-amyloid plaquesOligodendrocytes cellsare glial cells that wrap axons with *myelin sheaths in CNS* which improves the speed and reliability of impulse conduction. • 1. Their main function is myelination of axons exclusively in the central nervous system. • 2. also produce substances that *inhibit the regeneration of axons in the adult CNS.* • 3. Provide a *supporting role* for neurons.synapseA chemical _________ is the junction across which a nerve impulse passes from an axon terminal to the dendrite of a second neuron, to a muscle cell, or to a gland cellcalciumWhen a neuron is excited, _________ is released from small vesicles within the cytoplasm of the axon terminal, and then neurotransmitters are released from vesicles into the synapse.exocytosisNeurotransmitter release occurs by _________Resting Potential of a NeuronCharge difference across the plasma membrane of a neuron. • Fluid just outside cell is more positively charged than fluid inside. • Potential is measured in *millivolts.* • Resting potential of the plasma membrane of a neurons is usually minus 70 millivolts (-70 mV). • This membrane potential is true for all cells (neurons, somatic cells) in body.Action Potentialis a transient alteration of the transmembrane voltage (or membrane potential) across an excitable membrane in an excitable cell (such as a neuron) generated by the activity of voltage-gated ion channels embedded in the membrane