Chapter 12 Flashcards
Three Functions of the Nervous System
Collects information (specialized nervous structures, receptors, monitor changes in external and internal environment); Processes and evaluates information then determines if response is required; initiates response to information via nerves to effectors which include muscle tissue and glands
Structural organization
CNS (Brain and Spinal Cord) and Peripheral nervous system (nerves and ganglia)
Functional Organization
Afferent and Efferent
Afferent
Sensory nervous system detects stimuli and transmits information from receptors to the CNS (somatic and visceral)
Somatic Sensory
sensory input that is consciously perceived from receptors
Visceral Sensory
Sensory input that is not consciously perceived from blood vessels and internal organs
Efferent
motor nervous system initiates and transmits information from the CNS to effectors (somatic motor and autonomic motor)
Somatic Motor
Motor output that is consciously or voluntarily controlled; skeletal muscle
Autonomic Motor
Motor Output that is not consciously or is involuntarily controlled; cardiac muscle, smooth muscle, and glands
Characteristics of Neurons
Excitability, Conductivity, Secretion (release ACh and Norepinephrine), Extreme Longevity; Amitotic (cannot reproduce)
Neurons
Basic structural unit of the nervous system; excitable cells that transmit electrical signals
Glial Cells
non-excitable cells that primarily support and protect neurons; capable of mitosis;
Unipolar Neurons
Single short cell process; fuses the two processes to one long axon; axons with peripheral process (dendrites to cell body) and central process (cell body to CNS)
Bipolar Neuron
Two nerve cell processes extend directly from the cell body; one axon and one dendrite (retina of the eye)
Multipolar Neuron
Multiple nerve processes extend directly from the cell body; typically many dendrites and one axon; most common type
Sensory Neurons
afferent neurons; conduct input from somatic and visceral receptors; most unipolar, few bipolar; cell bodies usually in posterior root ganglia, outside CNS
Motor Neurons
efferent neurons; conduct motor output to somatic and visceral effectors; all multipolar; most cell bodies in CNS
Interneurons
association neurons; entirely within the CNS; receive stimulation from many other neurons; receive, process, and store information; decide how body responds to stimuli; facilitate communication between sensory and motor neurons; generally multipolar
Epineurium
dense irregular connective tissue; encloses the entire nerve; provides support and protection
Perineurium
Layer of dense irregular connective tissue; wraps bundles of axons, fascicles, supports blood vessels
Endoneurium
delicate layer of areolar connective tissue; separates and electrically insulates each axon; has capillaries that supply the axon
Astrocytes
Processes touch capillary walls and neurons (perivascular feet); most abundant glial cell in CNS; help form the blood-brain barrier; Regulate tissue fluid composition; form a structural network; direct development of neurons in fetal brain;
Ependymal Cells
line internal cavities of brain and spinal cord; ciliated simple cuboidal or simple columnar epithelial cells; form choroid plexus with blood capillaries which help produce CSF
Microgilia
Small cells with slender branches; smallest percentage of CNS glial cells; phagocytic cells of the immune system; wander CNS and replicate in infection; engulf infectious agents; remove debris from dead or damaged tissue
Oligodendrocytes
processes ensheathing portions of axons of different neurons; insulate axons in a myelin sheath; prevent passage of ions through axonal membrane; allow for faster action potential propagation through CNS
Satellite Cells
arranged around neuronal cell bodies in a ganglion; physically separate cell bodies in ganglion from surrounding fluid; regulate the exchange of nutrients and waste products;
Neurolemmocytes
Ensheathe PNS axons to from myelin sheath; allows for faster action potential propagation
Collects information (specialized nervous structures, receptors, monitor changes in external and internal environment); Processes and evaluates information then determines if response is required; initiates response to information via nerves to effectors which include muscle tissue and glands
Three Functions of the Nervous System
CNS (Brain and Spinal Cord) and Peripheral nervous system (nerves and ganglia)
Structural organization
Afferent and Efferent
Functional Organization
Sensory nervous system detects stimuli and transmits information from receptors to the CNS (somatic and visceral)
Afferent
sensory input that is consciously perceived from receptors
Somatic Sensory
Sensory input that is not consciously perceived from blood vessels and internal organs
Visceral Sensory
motor nervous system initiates and transmits information from the CNS to effectors (somatic motor and autonomic motor)
Efferent
Motor output that is consciously or voluntarily controlled; skeletal muscle
Somatic Motor
Motor Output that is not consciously or is involuntarily controlled; cardiac muscle, smooth muscle, and glands
Autonomic Motor
Excitability, Conductivity, Secretion (release ACh and Norepinephrine), Extreme Longevity; Amitotic (cannot reproduce)
Characteristics of Neurons
Basic structural unit of the nervous system; excitable cells that transmit electrical signals
Neurons
non-excitable cells that primarily support and protect neurons; capable of mitosis;
Glial Cells
Single short cell process; fuses the two processes to one long axon; axons with peripheral process (dendrites to cell body) and central process (cell body to CNS)
Unipolar Neurons
Two nerve cell processes extend directly from the cell body; one axon and one dendrite (retina of the eye)
Bipolar Neuron
Multiple nerve processes extend directly from the cell body; typically many dendrites and one axon; most common type
Multipolar Neuron
afferent neurons; conduct input from somatic and visceral receptors; most unipolar, few bipolar; cell bodies usually in posterior root ganglia, outside CNS
Sensory Neurons
efferent neurons; conduct motor output to somatic and visceral effectors; all multipolar; most cell bodies in CNS
Motor Neurons
association neurons; entirely within the CNS; receive stimulation from many other neurons; receive, process, and store information; decide how body responds to stimuli; facilitate communication between sensory and motor neurons; generally multipolar
Interneurons
dense irregular connective tissue; encloses the entire nerve; provides support and protection
Epineurium
Layer of dense irregular connective tissue; wraps bundles of axons, fascicles, supports blood vessels
Perineurium
delicate layer of areolar connective tissue; separates and electrically insulates each axon; has capillaries that supply the axon
Endoneurium
Processes touch capillary walls and neurons (perivascular feet); most abundant glial cell in CNS; help form the blood-brain barrier; Regulate tissue fluid composition; form a structural network; direct development of neurons in fetal brain;
Astrocytes
line internal cavities of brain and spinal cord; ciliated simple cuboidal or simple columnar epithelial cells; form choroid plexus with blood capillaries which help produce CSF
Ependymal Cells
Small cells with slender branches; smallest percentage of CNS glial cells; phagocytic cells of the immune system; wander CNS and replicate in infection; engulf infectious agents; remove debris from dead or damaged tissue
Microgilia
processes ensheathing portions of axons of different neurons; insulate axons in a myelin sheath; prevent passage of ions through axonal membrane; allow for faster action potential propagation through CNS
Oligodendrocytes
arranged around neuronal cell bodies in a ganglion; physically separate cell bodies in ganglion from surrounding fluid; regulate the exchange of nutrients and waste products;
Satellite Cells
Ensheathe PNS axons to form myelin sheath; allows for faster action potential propagation
Neurolemmocytes
