Nervous System Flashcards
The nervous system is composed of two major divisions:
the central nervous system (CNS)
the peripheral nervous system
(PNS).
The CNS includes the ___ and ____
Brain, spinal cord
the PNS includes all the ___ that conduct impulses to and from the CNS.
nerves
The ___ division includes nerves and tracts leading toward the CNS— the sensory nerves and sensory tracts.
afferent
The ___ division includes nerves and tracts leading away from the CNS— the motor nerves and motor tracts.
efferent
The nervous system can be instead subdivided into the somatic nervous system (SNS) and the autonomic nervous system (ANS).
The ___ is concerned mainly with pathways that monitor ___ sensors (general senses) and regulate ___ effectors (skeletal muscles).
SNS
The ___ mainly monitors and regulates subconscious visceral activities that involve cardiac muscle, smooth muscle, glands, and adipose tissue.
ANS
The ___ is the cell type that conducts impulses, or action potentials.
neuron
(those electrical impulses that send signals around your body) are nothing more than a temporary shift (from negative to positive) in the neuron’s membrane potential caused by ions suddenly flowing in and out of the neuron
Action potential
The ___ support the neurons in any number of ways.
neuroglia (glial cells)
Types of neurons
Unipolar
Bipolar
Multipolar
having a single projection from the cell body
Unipolar
Having two projections from the cell body;
Bipolar
Having many projections
Multipolar
It is a large region made up of the nucleus and surrounding cytoplasm
cell body, or soma
Packets of rough endoplasmic reticulum (ER) in the soma produce ___.
These packets are still sometimes called _____ after their discoverer, Franz Nissl.
neurotransmitters
Nissl bodies or Nissi substance
The soma forms a cone-shaped projection, or ____, as it projects to become the ____.
axon hillock
axon
The ___ is one of two types of neuron projections (fibers).
axon
The axon usually conducts action potentials ___ from the cell body.
away
The axon may be wrapped with a series of neuroglial cells called _____
Schwann cells
___ wrap like tape around the axons of some peripheral nerves, each spiraling around a fiber to form a multilayered coating.
Schwann cells
The inner layers of the Schwann cell are filled with the fatty white substance called ___.
Myelin
Because the Schwann cells are found in series, they form a segmented sheath of
Schwann, or ____
myelin sheath.
Myelin sheath is composed of?
Schwann cells
Myelin
Nodes of ranvier
The gaps between the Schwann cells are termed ___ (myelin sheath gaps).
nodes of Ranvier
The outer wrapping of each ___ is normal cytoplasm, with organelles and a nucleus.
Schwann cell
In the case described, the ___ is called a white fiber, or myelinated fiber.
axon
A group of white fibers together is called ____.
white matter