The Nervous System Flashcards
Primary functions of the nervous system
- Sensory input
- Integration
- Motor output
The two divisions of the nervous system
Central Nervous System & Peripheral Nervous System
Two functional divisions of the peripheral nervous system
Sensory (Afferent) & Motor (Efferent)
The Central Nervous System is made up of the…
Brain and Spinal Cord
The Peripheral Nervous System is made up of the…
Spinal nerves and Cranial Nerves
______ Nervous System: conduct impulses from CNS to skeletal muscles. Voluntary
Somatic
______ Nervous System: regulates smooth and cardiac muscle and glands
Autonomic
Two functional subdivisions of the autonomic nervous system
Sympathetic and Parasympathetic
small cells that surround and wrap
delicate neurons
neuroglia
excitable cells that transmit
electrical signals
neurons
Most abundant, versatile, and highly branched glial cells. Support and brace neurons
Astrocytes
Migrate toward injured neurons. Can transform to phagocytize microorganisms and neuronal debris
Microglial cells
Form permeable barrier between cerebrospinal fluid (CSF) in cavities and tissue fluid bathing CNS cells
Ependymal cells
Processes wrap CNS nerve fibers, forming insulating myelin sheaths
Oligodendrocytes
Surround all peripheral nerve fibers and form myelin sheaths in thicker nerve fibers in PNS. Vital to regeneration of damaged peripheral nerve fibers
Schwann cells
movement away from cell body. Examples: mitochondria, cytoskeletal elements, membrane components, enzymes
anterograde
movement toward cell body. Examples: organelles to be degraded, signal molecules, viruses (i.e. rabies), and bacterial toxins
retrograde
Myelin sheath gaps between adjacent schwann cells
Nodes of Ranvier
-3 or more processes
-1 axon, others dendrites
-Most common; major neuron in CNS
Multipolar
-2 processes
-1 axon and 1 dendrite
-Rare, e.g., Retina and olfactory mucosa
Bipolar
1 short process
unipolar
-Transmit impulses from sensory receptors toward CNS
-Almost all are Unipolar
-Cell bodies in ganglia in PNS
Sensory-Afferent
-Carry impulses from CNS to effectors
-Multipolar
-Most cell bodies in CNS (except some autonomic neurons)
Motor- Efferent
-Lie between motor and sensory neurons
-99% of body’s neurons
Interneurons
Action potentials are ___ distance
long
Graded potentials are ___ distance
short
Two main types of ion channels
leakage and gated
The resting membrane potential voltage
-70mV
Plays an important role in membrane potential
K+
decrease in mem. potential
depolarization
increase in mem. potential
hyperpolarization
- autoimmune disease
- myelin sheaths in CHS are destroyed
- symptoms: double vision, urine incontinence
-lack of treatment causes disability, muscle weakness, and white spaces in brain
Multiple Sclerosis
synthesized from acetic acid and choline by choline acetyltransferase, degraded by acetylcholinesterase
acetylcholine
- dopamine, NE and E
- synthesized from amino acid tyrosine
Catecholamines
- serotonin (tryptophan) and histamine (histidine)
Indolamine
