Nervous System Flashcards
Anatomic division:
CNS
PNS
Anatomic division:
brain and spinal cord
CNS
Anatomic division:
nerves outside CNS and associated ganglia
PNS
Functional division:
Sensory
Motor (somatic and autonomic)
Two types of cell:
Nerve cells (neurons)
Glial (neuroglial) cells
Two types of cell:
conduct impulses
Nerve cells (neurons)
Two types of cell:
support, nurture, protect neurons
Glial (neuroglial) cells
Connective tissue investments:
Epineurium
Perineurium
Endoneurium
the layer of fibrous dense connective tissue (fascia) that forms the external coat of the nerves.
Epineurium
surrounds each bundle of nerve fibers (fascicle).
Perineurium
is a thin layer of reticular fibers, produced mainly by Schwann cells, that surrounds individual nerve fibers.
Endoneurium
CELLS:
NEURONS
NEUROGLIAL CELLS
Cell body, multiple dendrites, single axon
NEURONS
Morphologic classification of Neurons
Unipolar, bipolar, multipolar, pseudounipolar
Functional classification of Neurons
Sensory, interneurons, Motor
Astrocytes, oligodendrocytes, Schwann cells, microglia, ependymal cells
NEUROGLIAL CELLS
large, spherical, and pale staining and is centrally located, abundant euchromatin and a large nucleolus (owl-eye nucleus)
nucleus
nucleus, cytoplasmic organelles and inclusions, cytoskeletal components
Neuronal cell body (soma, perikaryon)
_____ receive stimuli from sensory cells, axons, or other neurons and convert these signals into small electrical impulses (action potentials) that are transmitted toward the soma
Dendrites
arborized terminals (except in bipolar neurons)
Dendrites
Lack golgi complex in cytoplasm
Dendrites
Organelles are reduced in number or absent near the terminals except for mitochondria which are abundant
Dendrites
_____ conduct impulses away from the soma to the axon terminals without any diminution in their strength.
AXONS
Some axons are as long as _____ cm.
100
originate from the axon hillock,( lacks RER, ribosomes, Golgi cisternae, and Nissl bodies but contains many microtubules and neurofilaments)
AXONS
______ lacks a Golgi complex but contains SER, RER, and elongated mitochondria
Axoplasm
______ terminate in many small branches (axon terminals) from which impulses are passed to another neuron or other types of cells
Axons
some neurons in the CNS; dorsal root and sympathetic ganglia.
Melanin-containing granules
increase in number with age.
Lipofuscin-containing granules
occasionally are present
Lipid droplets
(10 nm in diameter) are abundant and run throughout the soma cytoplasm; intermediate filaments
Neurofilaments
(24 nm in diameter) are also present in the soma cytoplasm
Microtubules
(actin filaments 6 nm in diameter) are associated with the plasma membrane.
Microfilaments
Protect and support the neurons
NEUROGLIAL CELLS
largest of the neuroglial cells
Astrocytes
scavenge ions and debris from neuron metabolism and supply energy for metabolism
Astrocytes
Types of Astrocytes
Protoplasmic astrocytes (gray mater)
Fibrous astrocytes (white mater)
Needed for the survival of neurons in the CNS
OLIGODENDROCYTES
produce myelin sheath for CNS
OLIGODENDROCYTES
both gray matter and white matter.
OLIGODENDROCYTES
possess a small, round, condensed nucleus and only a few short processes
OLIGODENDROCYTES
flat cells with only a few mitochondria and a small Golgi region
Schwann cells
they protect and insulate neurons by providing myelin sheath for PNS
Schwann cells
a single ______ can only insulate a single axon, whereas a single _______ may insulate several axons.
Schwann cell, oligodendrocyte
small, phagocytic neuroglial cells that are derived from the mononuclear phagocytic cell population in the bone marrow
Microglia
condensed, elongated nucleus and many short, branching processes
Microglia
epithelial cells that line the neural tube and ventricles of the brain
Ependymal cells
May possess cilia, which aid in moving the cerebrospinal fluid (CSF)
Ependymal cells
distributed throughout the body as an integrated communications network
NERVOUS TISSUE
highly irritable and conducts waves of excitation as nerve impulses
NERVOUS TISSUE
Transmits nerve impulses to the CNS from sensory receptors
SENSORY [AFFERENT]
Transmits impulses from the CNS to effector organs (muscle and gands)
MOTOR (SOMATIC AND AUTONOMIC)[EFFERENT]
voluntary nervous system
Somatic
involuntary system
Automatic
numerous long processes and conducts impulses
NERVE CELLS (NEURONS)
support, nurture, protect neurons
GLIAL (NEUROGLIAL) CELLS
has single process
Ex. spinal ganglia
UNIPOLAR NEURONS
- possess 1 axon
- 1 dendrite
- present in several sense organs
BIPOLAR NEURONS
- possess a single axon and more than one dendrite
- most common type
Ex. neuron of vertebrates
MULTIPOLAR NEURON