SAS 9 - The Nervous System (Part 1) Flashcards
What are the major functions of the nervous system?
- Receive sensory inputs
- Integrating information
- Controlling muscles and glands
- Maintaining homeostasis
- Establishing and maintaining mental activity
It consists of the brain and the spinal cord
Central Nervous System
It consists of all the nervous tissue outside the CNS
Peripheral Nervous System
It conducts action potentials FROM SENSORY RECEPTORS to CNS by SENSORY neurons
Sensory (Afferent) Division
It conducts action potentials FROM CNS to effector organs, by MOTOR neurons
Motor (Efferent) Division
The type of nervous system under efferent division that innervates skeletal muscle, under VOLUNTARY control
Somatic Nervous System
The type of nervous system under efferent division that innervates cardiac, smooth muscle, under INVOLUNTARY control
Autonomic Nervous System
A subdivision of the PNS that has both the sensory and motor neurons, contained wholly in the digestive tract
Enteric Nervous System
Receives stimuli, conduct action potentials, transmits signals to other neuron or effector organs
Nerve Cells / Neurons
A part of the nerve cells, contains nucleus and PROCESSES stimulus
Cell Body
A part of the nerve cells, extensions on the neuron cell body, RECEIVE stimulus FROM other neurons or sensory receptors
Dendrites
A part of the nerve cells, single long process; transmits stimulus TO a gland, muscle organ, or other neuron
Axon
These are the SUPPORTIVE CELLS of the PNS and CNS, they do not conduct action potentials but carry out different functions that enhance neuron function and maintain normal conditions
Neuroglia / Glial Cells
These are fatty, PROTECTIVE WRAPPING around axons of some neurons that are formed by oligodendrocytes (CNS) and Schwann Cells (PNS), serves as insulator that prevents ALMOST all ion movements across cell membrane
Myelin Sheaths
Gaps in the myelin sheath
Node of Ranvier
Consists of groups of NEURON CELL BODIES AND THEIR DENDRITES, where there is very LITTLE myelin
Gray Matter
A part of the gray matter, it is located on the surface of the brain
Cortex
CLUSTERS of gray matter located deeper within the brain
Nuclei
A cluster of neuron cell bodies in the PNS
Ganglion
Consists of bundles of PARALLEL AXONS WITH THEIR MYELIN SHEATHS, which are WHITISH in color
White Matter
Found on the CNS which propagate action potential from one area of the CNS to another
Nerve Tracts / Conduction Pathways
Bundles of axons located in the PNS
Nerves
Occurs in UNMYELINATED axons, an action potential in one part of the cell membrane stimulates local currents in in adjacent parts
Continuous Conduction
Occurs in MYELINATED axons, an action potential ‘jumps’ from one node of ranvier to the next along the length of the axon
Saltatory Conduction
