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31 Cards in this Set
- Front
- Back
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3 Overlapping Functions: |
a) Sensory Input via millions of sensory receptors…senses changes inside &outside the body b) Integration– Analyzes sensory info, stores info, makes decisions; it interprets the infoand decides how to react c) Motor Output – Activates effector organs (muscles, glands) to respond |
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2 Major Parts of the NervousSystem: |
1. Central Nervous System - Brain & Spinal Cord 2. Peripheral Nervous System – Parts outside the central nervous system |
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Sensoryaka (Afferent) Division |
Convey info FROM sensory receptors TO the CNS Afferent – going in |
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Motor aka (Efferent) Division |
Carry impulses from CNS to effector organs
Efferent – going out |
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Somatic Motor |
Voluntary, conscious control of skeletal myos |
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Autonomic Motor |
“Visceral” nerve fibers (involuntary) * Motor fibers that conduct nerve impulses from CNS to smooth & cardiac myo & glands |
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2 Classes of Cell in Nerve Tissue: |
1. Neuron– “THE” Functional Cell 2. Neuroglia– aka Glial Cell (Glia); supportive cell, does not conduct impulses; 6different cells (4 in CNS (Central Nervous System), 2 in PNS (PeripheralNervous System)) |
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CNS Neuroglia |
–Outnumber neurons in CNS 10-1 -Make up ½ the mass of the brain |
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Astrocytes (CNS Neuroglia) |
- Support & brace neurons - Anchor neurons to blood vessels - Guide the migration of young neurons - Help form synapse [synaptic cleft/gap..place of joining] -Control chemical environment around neurons by buffering K+ and recapturing neurotransmitters |
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Microglia Cells (CNS Neuroglia) |
-Cantransform to macrophage -By the useof phagocytosis, can get rid of microorganisms & cellular debris |
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EpendymalCells (CNS Neuroglia) |
-Line central cavities of CNS -Help create cerebrospinal fluid (CSF) and circulate it throughout the CNS. Cilia wave causing the CSF movement |
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Oligodendrocytes (CNS Neuroglia) |
-Function similar to PNS SchwannCells -Create an insulating coveringaround neuron [Myelin sheath] |
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(PNSNeuroglia) Satellite Cells |
-Surround cell bodies of PNS -Similar to astrocytes of CNS |
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(PNS Neuroglia) Schwann Cells |
-Surround Peripheral NS -Neurons -Vital in regeneration of damaged PNS Neurons |
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Neuron (aka) Nerve Cells |
-Conduct messages in the form of nerve impulses -They have “Extreme Longevity” -They are amitotic –cannot divide…no mitosis -Have very high metabolic rate -Must have large amounts of O2 & glucose constantly. Function for a very short time without O2 |
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Parts of a Neuron |
-Cell Body (aka) Soma -Dendrites -Axons |
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Cell Body (aka) Soma |
Major biosynthetic center of the cell -In CNS they are called nuclei -In PNS they are called ganglia |
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Dendrites |
Short branches receive input |
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Axons |
Conduct impulses away from Soma. -Long axons are called nerve fibers -The enlarged ends called axon terminals -The conducting portion of the neuron generates nerve impulses and transmits them |
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Myelin Sheath |
-Formed by Schwann Cells -Gaps in the sheath car called Nodes of Ranvier |
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Neurilemma |
Outer collar of perinuclear cytoplasm &nucleus |
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Functional Classificationsof Neurons |
1. Sensory (Afferent) 2. Motor (Efferent) 3. Interneurons (Association neurons) |
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1. Sensory (Afferent) |
TO the CNS -Cell bodies are in sensory ganglia outside CNS |
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2. Motor (Efferent) |
AWAY from CNS |
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3. Interneurons (Association neurons) |
A neuron whose primary function is to connect neurons…likesensory to motor |
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Membrane Potentials |
When a neuron is adequately stimulated, an electrical impulseis generated and conducted along the length of an axon. This response is called ActionPotential (AP) – (aka) Nerve impulse |
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Na+ |
Makes the outside more positive. The inside (dueto abundance of (-) ions) is morenegative..with K+ leaking in and out. *Far less Na+ inside |
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Sodium gates in the membrane |
Can open in response to “electrical” potential changes. -These voltage-gated channels open in response to changes in membrane potential--thus participating in conduction of AP -Can go from -70mV to +30mV (peak) -Immediately after peak, K+ gates open..repolarizationbegins |
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The impulse from one nerve cell is communicatedto another nerve cell (or effector) via the: |
Synapse |
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Synaptic Cleft |
-Separates first nerve & 2nd nerve -It prevents an impulse from being transmitted directly fromone neuron to another (without neurotransmitter) |
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Neurotransmitters |
Substances released at axon terminals to propagate a neural impulse in a 2nd neuron… -It binds to receptors, thus opening ion channels *We have already seen Acetylcholine as an excitatory neurotransmitter secreted by motor neurons innervating skeletal myo. |
