Nervous Sys Review Flashcards
- Sensory input
- integration
- motor output
functions of the nervous system
Info gathered by sensory receptors about internal and external changes
sensory input
interpretation of sensory input
integration
activation of effector organs (muscles and glands) produces a response
motor output
this system includes: brain and spinal cord, integration and command center
Central Nervous System
paired spinal and cranial nerves carrying msgs to and from the CNS
PNS : peripheral nervous system
- sensory_(afferent) division
- Somatic afferent fibers—convey impulses from skin, skeletal muscles, and joints
- Visceral afferent fibers—convey impulses from visceral organs
- motor_(efferent) division
* Transmits impulses from the CNS to effector organs
2 functional divisions of the PNS
- Somatic (voluntary ) nervous system
* Conscious control of skeletal muscles - Autonomic (_involuntary ) nervous system (ANS)
- Visceral motor nerve fibers
- Regulates smooth muscle , cardiac muscle, and glands
- Two functional subdivisions
- sympathetic
- parasympathetic
motor divison of PNS
- neurons- excitable cells that transmit signals
- neuroglia- supporting cells
- astrocytes (CNS)
- microglia (cNS)
- ependymal (CNS)
- oligodendrocytes(CNS)
- satellite cells (PNS)
- schwann cells (PNS)
2 principal cell types
- Most abundant , versatile , and highly branched glial cells
- Cling to neurons , synaptic endings, and capillaries
- Support and brace neurons
- Help determine capillary permeability
- Guide migration of young neurons
- Control the chemical environment
- Participate in information processing in the brain
astrocytes
- Small, ovoid cells with thorny processes
- Migrate toward injured neurons
- Phagocytize microorganisms and neuronal debris
microglia
- Range in shape from squamous to columnar **
- May be ciliated
- Line the central cavities of the brain and spinal column
- Separate the CNS interstitial fluid from the cerebrospinal fluid in the cavities
ependymal cells
- Branched cells
- processes wrap CNS nerve fibers, forming insulating myelin sheaths
oligodendrocytes
- surround neuron cell bodies in the PNS
satellite cells
- Surround peripheral nerve fibers and form myelin sheaths
- Vital to regeneration of damaged peripheral nerve fibers
schwann cells (neurolemmocytes)
- Electrical signaling
- Cell-to-cell interactions during development
plasma membrane functions of neurons
- biosynthetic center of a neuron
- Spherical nucleus with nucleolus
- Well-developed golgi_ apparatus
- rough ER called nissl bodies (chromatophilic substance)
- axon hillock
- clusters of cell bodies are called nuclei in the CNS, ganglia in the Pns
cell body (soma)
cone shaped area from which axon arises
axon hillock
- tracts in the CNS
- nerves in the CNS
these are bundles of processes
- Short, tapering, and diffusely branched
- receptive(input) region of a neuron
- Convey electrical signals toward the cell body as graded potentials
dendrites
- long axon - nerve fibers
- occasional branches -axon callaterals
- numerous terminal branches - telodendria
- knoblike axon terminals - synaptic knobs or boutons
- secretory region of neuron
- release neurotransmitters to excite or inhibit other cells
the axon
- conducting region of neuron
- generates and transmits nerve iimpulses(action potentials) away from the cell body
axons functions
molecules and organells are moved along axons by motor molecules in 2 directions :
- anterograde- toward axonal terminal
- ex.mitochondria, membrane components, enzymes
- retrograde- toward cell body
- ex. organelles to be degraded, signal molecules, viruses, adn bacterial toxins
segmented protien lipoid sheath around most long diameter axons functioning to
- protect/insulate the axon
- increase speed of nerve impulse transmission
myelin sheath