Term
| endocrine and nervous system |
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Definition
| maintain internal coordination |
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Term
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Definition
| communicates by means of chemical messengers (hormones) secreted into the blood |
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Term
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Definition
•employs electrical and chemical means to send messages from cell to cell
•carries out its task in three basic steps:
•sense organs receive information about changes in the body and the external environment, and transmits coded messages to the spinal cord and the brain
•brain and spinal cord processes this information, relates it to past experiences, and determine what response is appropriate to the circumstances
•brain and spinal cord issue commands to muscles and gland cells to carry out such a response |
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Term
| central nervous system (CNS) |
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Definition
–brain and spinal cord enclosed in bony coverings
•enclosed by cranium and vertebral column |
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Term
| peripheral nervous system (PNS) |
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Definition
–all the nervous system except the brain and spinal cord
–composed of nerves and ganglia |
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Term
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Definition
| a bundle of nerve fibers (axons) wrapped in fibrous connective tissue |
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Term
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Definition
| a knot-like swelling in a nerve where neuron cell bodies are concentrated |
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Term
| sensory (afferent) division |
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Definition
–carries sensory signals from various receptors to the CNS
–informs the CNS of stimuli within or around the body
–somatic sensory division
–visceral sensory division |
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Term
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Definition
| carries signals from receptors in the skin, muscles, bones, and joints |
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Term
| visceral sensory division |
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Definition
–carries signals from the viscera of the thoracic and abdominal cavities
•heart, lungs, stomach, and urinary bladder |
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Term
| motor (efferent) division |
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Definition
| carries signals from the CNS to gland and muscle cells that carry out the body's response |
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Term
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Definition
–carries signals to skeletal muscles
•output produces muscular contraction as well as somatic reflexes –involuntary muscle contractions |
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Term
| visceral motor division (autonomic nervous system) |
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Definition
-carries signals to glands, cardiac muscle, and smooth muscle
•involuntary, and responses of this system and its receptors are visceral reflexes
•sympathetic division
•parasympathetic division |
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Term
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Definition
–tends to arouse body for action
–accelerating heart beat and respiration, while inhibiting digestive and urinary systems |
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Term
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Definition
–tends to have calming effect
–slows heart rate and breathing
–stimulates digestive and urinary systems |
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Term
| Universal Properties of Neurons |
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Definition
•excitability (irritability)
•conductivity
•secretion |
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Term
| excitability (irritability) |
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Definition
| –respond to environmental changes called stimuli |
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Term
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Definition
| –neurons respond to stimuli by producing electrical signals that are quickly conducted to other cells at distant locations |
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Term
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Definition
| –when electrical signal reaches end of nerve fiber, a chemical neurotransmitter is secreted that crosses the gap and stimulates the next cell |
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Term
| sensory (afferent) neurons |
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Definition
| –specialized to detect stimuli |
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Term
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Definition
| conducting signals toward CNS |
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Term
| interneurons (association) neurons |
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Definition
–lie entirely within the CNS
–receive signals from many neurons and carry out the integrative function
–90% of all neurons are these kind of neurons |
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Term
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Definition
| –send signals out to muscles and gland cells (the effectors) |
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Term
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Definition
| neurons that conduct signals away from the CNS |
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Term
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Definition
–the control center of the neuron
–also called neurosoma, cell body, or perikaryon |
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Term
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Definition
•many proteins made in soma must be transported to axon and axon terminal
–to repair axolemma, serve as gated ion channel proteins, as enzymes or neurotransmitters |
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Term
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Definition
occurs at a rate of 20–400 mm/day
–fast anterograde transport
–fast retrograde transport |
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Term
| slow axonal transport or axoplasmic flow |
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Definition
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Term
| fast anterograde transport |
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Definition
-up to 400 mm/day
•organelles, enzymes, synaptic vesicles and small molecules |
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Term
| fast retrograde transport |
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Definition
•for recycled materials and pathogens -rabies, herpes simplex, tetanus, polio viruses
–delay between infection and symptoms is time needed for transport up the axon |
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Term
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Definition
| –support and protect the neurons |
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Term
| four types of neuroglial cells occur only in CNS |
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Definition
–oligodendrocytes
–ependymal cells
–microglia
–astrocytes |
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Term
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Definition
| •form myelin sheaths in CNS |
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Term
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Definition
•lines internal cavities of the brain
•secretes and circulates cerebrospinal fluid (CSF) |
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Term
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Definition
| •small, wandering macrophages formed white blood cell called monocytes |
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Term
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Definition
•most abundant glial cell in CNS
•cover entire brain surface and most nonsynaptic regions of the neurons in the gray matter of the CNS |
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Term
| two types of neuroglial cells occur only in PNS |
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Definition
–Schwann cells
–satellite cells |
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Term
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Definition
•envelope nerve fibers in PNS
•produces a myelin sheath similar to the ones produced by oligodendrocytes in CNS
•assist in the regeneration of damaged fibers |
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Term
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Definition
•provide electrical insulation around the soma
•regulate the chemical environment of the neurons |
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Term
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Definition
| masses of rapidly dividing cells |
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Term
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Definition
–meninges (protective membranes of CNS)
–most come from glial cells that are mitotically active throughout life |
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Term
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Definition
| grow rapidly and are highly malignant |
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Term
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Definition
–an insulating layer around a nerve fiber
–formed by oligodendrocytes in CNS and Schwann cells in PNS |
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Term
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Definition
–production of the myelin sheath
–dietary fat is important to nervous system development |
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Term
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Definition
•myelin replaced by hardened scar tissue
•onset between 20 and 40 and fatal from 25 to 30 years after diagnosis |
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Term
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Definition
| a hereditary disorder of infants of Eastern European Jewish ancestry |
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Term
| Conduction Speed of Nerve Fibers |
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Definition
•speed at which a nerve signal travels along a nerve fiber depends on two factors
–diameter of fiber
–presence or absence of myelin
•signal conduction occurs along the surface of a fiber
–larger fibers have more surface area and conduct signals more rapidly
–myelin further speeds signal conduction |
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Term
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Definition
–cellular mechanisms for producing electrical potentials and currents
–basis for neural communication and muscle contraction |
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Term
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Definition
| a difference in the concentration of charged particles between one point and another |
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Term
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Definition
–a flow of charged particles from one point to another
–in the body, currents are movement of ions, such as Na+ or K+ through gated channels in the plasma membrane
•living cells are polarized |
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Term
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Definition
out 3 Na+ for every 2 K+ it brings in
–works continuously to compensate for Na+ and K+ leakage, and requires great deal of ATP
•70% of the energy requirement of the nervous system |
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Term
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Definition
-disturbances in membrane potential when a neuron is stimulated
•when neuron is stimulated by chemicals, light, heat or mechanical disturbance |
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Term
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Definition
| case in which membrane voltage shifts to a less negative value |
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Term
| Characteristics of Local Potentials |
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Definition
| –are reversible-when stimulation ceases, K+ diffusion out of cell returns the cell to its normal resting potential |
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Term
| Signal Conduction in Unmyelinated Fibers |
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Definition
•Na+ and K+ gates open and close producing a new action potential
•by repetition the membrane distal to that is excited |
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Term
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Definition
gap between neurons was discovered by Ramón y Cajal through histological observations
-electrical synapses do exist |
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Term
| synaptic knob of presynaptic neuron |
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Definition
| contains synaptic vesicles containing neurotransmitter |
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Term
| Neurotransmitters and Related Messengers |
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Definition
| more than 100 neurotransmitters have been identified |
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Term
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Definition
•in a class by itself
•formed from acetic acid and choline |
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Term
| Function of Neurotransmitters at Synapse |
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Definition
| •they alter the physiology of that cell |
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Term
| degradation in the synaptic cleft |
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Definition
| –enzyme acetylcholinesterase (AChE) in synaptic cleft degrades ACh into acetate and choline |
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Term
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Definition
| immediate, short-and long-term memory |
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Term
| types of long-term memory |
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Definition
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Term
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Definition
| retention of events that you can put into words |
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Term
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Definition
| retention of motor skills |
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Term
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Definition
•100,000 deaths/year
–11% of population over 65; 47% by age 85
•memory loss for recent events, moody, combative, lose ability to talk, walk, and eat
•show deficiencies of acetylcholine (ACh) and nerve growth factor (NGF)
•diagnosis confirmed at autopsy
–atrophy of gyri (folds) in cerebral cortex
–neurofibrillary tangles and senile plaques
–formation of beta-amyloid protein from breakdown product of plasma membranes
•genetics implicated
•treatment -halt beta-amyloid production
–research halted due to serious side effects
–Give NGF or cholinesterase inhibitors |
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Term
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Definition
•progressive loss of motor function beginning in 50's or 60's -no recovery
–degeneration of dopamine-releasing neurons
•dopamine normally prevents excessive activity in motor centers (basal nuclei)
•involuntary muscle contractions
–pill-rolling motion, facial rigidity, slurred speech,
–illegible handwriting, slow gait
•treatment -drugs and physical therapy
–dopamine precursor (L-dopa) crosses brain barrier –bad side effects on heart & liver
–MAO inhibitor slows neural degeneration
–surgical technique to relieve tremors |
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