A&P II - Nervous System

Define: Interneurons

Also called association neurons; always located in the CNS; situated between sensory and motor neurons; distribute sensory inputs and coordinate motor outputs

Neurons that are small and have no anatomical features; found in brain and special sense organs:

Anaxoic Neurons

Name the 4 structural classifications of neurons:

Anaxonic, Bipolar, Unipolar, and Multipolar

Neuroglia associated with forming the blood/brain barrier; largest and most numerous:

Astrocytes

Neurons that have two distinct processes; one dendritic process and one axon; rare; occur in special sense organs; relay information about sight, smell or hearing:

Bipolar Neuron

Function of a/an sensory (afferent) neuron:

Brings sensory information from the the receptors TO the CNS

Define nerves:

Bundles of axons (nerve fibers) in the PNS

What division of ANS is classified with: at rest, maintenance, and homeostasis?

Parasympathetic

Define: Cell Body

SOMA; contains large nucleus and a prominent nucleolus

Also called amphicytes; provide physical support to the neurons of the PNS:

Satellite cells

Form insulation around axons in the PNS -myelin sheath:

Schwann cells

Name the two types of PNS cells:

Schwann cells and satellite cells

PNS is divided into two categories; name them:

Sensory - afferent neuron Motor - efferent neuron

Name the 3 functional categories of neurons:

Sensory neurons, motor neurons, and interneurons

The efferent division of the PNS can be further divided into what:

Somatic Nervous System (SNS) Autonomic Nervous System (ANS)

Define: Synapse

Specialized site where the neuron communicates with another cell; Involves 2 cells: presynaptic (includes synaptic terminal and sends messages) and postsynaptic (receives the messages)

What division of ANS is classified as the Fight or Flight mode, all about energy (exercise/stress)?

Sympathetic

The ANS can be broken down into what two divisions?

Sympathetic Division Parasympathetic Division

CNS includes what:

The brain and spinal cord

What is perikaryon and what does it contain?

The cytoplasm surrounding the nucleus; contains organelles including neurofilaments, neurotubules, and neurofibrils

Descending tracts:

Travel down the cord - motor

Ascending tracts:

Travel up the cord - sensory

Neurons in which the dendrites and axons are continuous (fused); cell body lies off to side; most sensory neurons of the PNS; can carry sensations from tips of toes to spinal cord:

Unipolar Neuron

Describe the Somatic Nervous System (SNS):

Voluntary-conscious control; controls skeletal muscle contractions

Functon of a/an motor (efferent) neuron:

Carries/conducts impulses AWAY from the CNS to muscles and glands called effectors

Name the two anatomical divisions of the nervous system:

Central Nervous System (CNS) Peripheral Nervous System (PNS)

Define: Neurotransmitters

Chemicals released by the synaptic terminal involved with the communication between two cells; packaged in synaptic vesicles

Define: Axon Hillock

Connects the initial segment of the axon to the cell body (soma)

PNS includes what:

Cranial nerves and spinal nerves; all the neural tissue outside the CNS

Neuroglia associated with the movement and production of CSF; ciliated; lines ventricles of the brain and the central canal of the spinal cord:

Ependymal Cells

Name the four types of neuroglia (glial cells) found in the CNS:

Ependymal, astrocytes, oligodendrocytes, and microglia

Define: Tract

Group of nerve cell processes (dendrites and axons) in the CNS

Define: Plexus

Group of nerves; 4 types - cervical, brachial, lumbar, and sacral

Define: Nuclei

Groups of nerve cell bodies in the CNS

Define: Ganglia

Groups of nerve cell bodies in the PNS

Describe the Autonomic Nervous System (ANS):

Involuntarily; functions are automatic and occur subconsciously. Visceral Motor System regulates smooth muscle, cardiac muscle and glandular secretions

Describe a multipolar neuron:

Large cell body connected to a single, elongate axon and several short, branched dendrites

Phagocytic cells; engulfs foreign materials:

Microglia

Neurons that have two or more dendrites and a single axon; most common in the CNS; can carry motor commands from the spinal cord to the small muscles that move toes:

Multipolar Neuron

Define: Mixed Nerve

Nerves that carry both sensory (afferent) and motor (efferent) fibers; i.e. spinal nerves

The Nervous System includes all the neural tissue in the body; what is the basic functional unit?

Neuron

Neuroglia responsible for the myelination of CNS axons, which increases rate of signal conduction by 10x:

Oligodendrocyte