Chapter 12 - Nervous Tissue
Ependymal cells
1 of 4 glial cells in the CNS. Lines cavities and produces cerebrospinal fluid (CSF). Function: Floats / protects brain, adds buoyancy, helps keep chemical stability of the brain.
Microglia
1 of 4 glial cells in the CNS. Macrophanges formed from monocytes, a special form of WBS that serve as the "dump trucks of the bloodstream". Function: remove dead tissue and foreign matter from the brain.
Oligodendrocytes
1 of 4 glial cells in the CNS. Wraps axons in CNS, wrapping called a myelin sheath (made up of fat) ,Function: Speeds the signal. Primarily occurs from fetal development to late adolescence.
Catecholamines: Epinephrine & Nerepinephrine
Adrenaline, Increases blood pressure (excites), Opens airways (relaxes)
Sensory Neurons
Detects stimuli and sends message to interneurons in the brain or spinal cord.
Sensory (afferent) division
Division of the PNS that carries signals from receptors to the CNS. Further divided into the somatic sensory division and the visceral sensory division.
Motor (efferent) division
Division of the PNS that carries signals from the CNS to the effectors. Further divided into somatic motor division and visceral motor division.
Astrocytes
Most prominent glial cell of the CNS. Has the most functions. -forms blood brain barrier that protects brain and spinal cord -produces nerve growth factor -helps keep glucose
Enkephalins & Endorphins
Natural pain killers
Acetylcholine
Neurotransmitter, neuromuscular juntions Excites: Skeletal muscle Inhibits: Cardiac muscle
Visceral motor division (automatic nervous system, ANS)
Part of the "motor (efferent) division" of the PNS. Carries signals to glands, cardiac muscles, and smooth muscle. Responses of these effectors is called the visceral reflexes.Further divided into sympathetic and parasympathetic division.
Somatic Motor Division
Part of the "motor (efferent) division" of the PNS. Carries signs of CNS to the effectors of the skeletal muscles. Produces both voluntary and involuntary muscle contractions.
Somatic sensory division
Part of the "sensory (afferent) division" of the PNS. Carries signals from receptors in the skin, muscles, bones & joints
Visceral sensory division
Part of the "sensory (afferent) division" of the the PNS. Carries signals from the viscera of the thoracic and abdominal cavities, such as the heart, lungs, stomach, and urinary bladder.
Sympathetic division
Part of the Visceral Motor Division in the PNS. Tends to arouse action ex. accelerating heart beat, increasing respiratory air flow.
Parasympathetic division
Part of the Visceral Motor Division of PNS. Tends to have a calming effect ex. slowing heartbeat also stimulates digestion.
Excitability,Conductivity, and Secretion
Properties of a Neuron
Alzheimer's Disease
Senile plague builds up between neurons, partly caused by astrocytes not functioning properly and producing NGF
L-1
Spinal Cord ends at which vertebra
Sensory, Interneurons, and Motor Neurons
Three functional classes of neurons
Central and Peripheral
Two Divisions of the Nervous System
Sensory and Motor
Two functional divisions of peripheral nervous system (PNS).
Schwann and Satellite Cells
Two types of Glial cells of the PNS
Diverging circuits
Type of neuron circuit. one cell synapses on others that each synapses others.....sends to a lots of different pathways.
Multiple Schelorosis
auto-immune disease of glial cells associated with degeneration (impairment) of oligodendrocytes.
Dendrite
branch-like ends of a neuron, serves as the primary site to receive signals from neurons (sensory ends).
Soma
cell body = perikaryon
Postsynaptic cell
cell that receives the transmission "cell it's talking to"
Motor neurons
effector neurons that receive message and effect change.
declarative
form of long term memory that refers to the retention of facts as text.
procedural
form of long term memory that refers to the retention of motor skills.
Converging circuits
input from many fibers on one neuron (respiratory center)....sent to one location
Interneurons
lie between sensory and motors neurons in CNS. send message of sensory neurons to motor neurons.
Serotonin
motivates you, involved w/ alertness, sleepiness and mood. targeted when you have depression.
Neurons
nerve cells
Peripheral Nervous System (PNS)
nerves that come off spine and brain, composed of nerves and ganglia. Regenerates.
Parallel after-discharging circuit
neuron diverges to stimulate several chains of neurons, each chain has a different synaptic length so they arrive at output a different times - allowing output neuron to go on firing after input has ceased.
Reverberating circuits
neurons stimulate each other in linear sequence but one cell re-stimulates the first cell to restart the process all over.
Gray matter
part of the brain that is the aggregate of somas.
myelinization
process of wrapping axons that provides protection but more importantly speeds the signal
Parkinson's Disease
progressive terminal disease, caused by a deficiency of the neurotransmitter, dopomine that inhibits unwanted motor contractions.
Satellite Cells
provide insulation and chemical stability of the neuron.
Nerve Growth Factor (NGF)
secreted by astrocytes, promotes synapse formation,prevents apoptosis(programmed cell death).
Dopamine
secretes when you are happy, elevates your mood inhibitor - unwanted motor muscle contractions
Nervous System
sets all our set points and ranges that are detected and effect changes to keep balance. Usually with endocrine system.
Schawann Cells
speeding signals by creating a myelin sheath similar to that of the olegodendrites.
Central Nervous System (CNS)
spinal cord and brain. Does not regenerate.
Glial cells
supportive cells of nervous system
Axon
the structure the message is sent through.
Axonal ends
transmitters are released from vesticles into the synapse, then the next cell gets the signal
Histamine
vasodilator, activates pain neuron/receptors causes blood vessels to dilate (lowers blood pressure) causes vessels to be leaky, increases capillary permeability
