Ch 11: Nervous System Flashcards
Three essential roles of the nervous system
-Sensing (Sense organ and nerve endings)
-Integrating (Process information and determine response)
-Responding (Send commands to muscles)
Central nervous system
Involves the brain and spinal cord
Peripheral nervous system
-sensory (afferent)
-motor (efferent)
Sensory nervous system
-Somatic sensory (Signals from skin bones joints and muscle)
-Visceral sensory(Signals from viscera of heart lungs stomach and bladder)
Motor nervous system
-Somatic motor system (Signals from nerve to central nervous system)
-Autonomic motor system (Signals from the central nervous system to the body)
Autonomic motor system
-Sympathetic
-Parasympathetic
Four types of neuroglia in the CNS
-Oligodendrocytes
-Ependymal cells
-Microglia
-Astrocytes
Oligodendrocytes
Form myelin sheath in the brain and spinal cord to speed signal conduction
Ependymal cells
-glial cellls
-Line spinal cord and brain cavities
-Secrete and move cerebrospinal fluid
Microglia
-Perform phagocytosis of micro organisms and cellular debris
Astrocytes
Nourish neurons in the brain tissue
Neuroglia in PNS
-Schwann cells
-Satellite cells
Schwann cells
Form myelin sheath around nerves in the PNS (Same as oligodendrocytes)
Satellite cells
Nourishes the neurons in the PNS (Same as astrocytes)
Sensory neurons
Detect stimuli and transmit information to the CNS
Interneurons
Connect incoming sensory pathways with outgoing motor pathways
Motor neurons
Relay messages from the brain to the muscle or gland cells
Multipolar neurons
Have one axon and multiple dendrites. this is the most common type of neuron
Bipolar neurons
Have two processes an axon and a dendrite with the cell body in between the two processes
Unipolar neurons
Have one process: an axon that extends from the cell body before branching in a T shape.
-Exist mostly in the sensory nerves of the peripheral nervous system
Sodium potassium pump process
-Resting potential
-Depolarization
-Action potential
-Repolarization
-Refractory period
Electrical synapse
The neurons touch which allows an action potential to pass directly from one neuron to the next
Chemical synapse
The neurons do not touch so neurotransmitters are used to cross the synaptic cleft.
Cauda equina
Bundle of nerve roots that protrude from the end of the spinal cord
Ascending tract
Conveys sensory signals up the spinal cord
Descending tract
Conveys impulses down the spinal cord to the skeletal muscles
Gray matter
-Contains no myelin
-Contains motor neurons and interneurons
-H shaped mass in the middle of the spinal cord
White matter
-Contains myelin
-Contains bundles of axons that carry impulses away from one part of the nerve system to another
Epidural space
-Between the outer covering of the spinal cord and the vertebrae
-Contains blood vessels connective tissue and fat
Central canal of the spinal cord
-A small opening in the middle that carries cerebrospinal fluid
Three layers of the meninges from the inside out
-Pia Mater: Innermost layer that contains blood vessels
-Arachnoid Mater: Middle layer, very thin
-Dura mater: tough outer layer
Dorsal nerve roots
-Located posteriorly
-Carries information into the spinal cord
Ventral nerve roots
-Located anteriorly
-Carries motor information out of the spinal cord
Ganglion
Cell bodies of the dorsal neurons clustered in a knot like structure
Spinal nerve
-A single nerve resulting from the fusion of the dorsal and ventral nerve roots
-Called a mixed nerve
Ascending tracts
Convey sensory signals up the spinal cord to the brain
Descending tracts
Conduct motor impulses down the spinal cord to skeletal muscles
Subarachnoid space
-Between the pia Mater and the arachnoid Mater
-Contains cerebrospinal fluid
Cervical nerves
Eight pairs
-C1-C8
Thoracic nerves
12 pairs
-T1-T12
Lumbar nerves
Five pairs
-L1-L5
Sacral nerves
Five pairs
-S1-S5
Coccygeal nerve
Just one
-Co1
Dermatomes
Specific area of the skin innervated by each spinal nerve
Four major nerve plexus groups
-Cervical plexus
-Brachial plexus
-Lumbar plexus
-Sacral plexus
Cervical plexus Key nerve
Phrenic nerve-Stimulates the diaphragm for breathing
Brachial plexus key nerves
-axillary nerve
-Radial nerve
-Ulnar nerve
-Median nerve
Lumbar plexus key nerve
Femoral nerve
Sacral plexus key nerve
Sciatic nerve-Largest nerve in the body. Runs down the back of the thigh
