STRUCTURAL AND FUNCTIONAL ORGANIZATION OF NERVOUS TISSUE Flashcards
CNS parts
Brain
Spinal cord
PNS parts
Cranial nerves Spinal nerves Ganglia Enteric Plexuses in small intestine Sensory receptors in the skin
how many pairs of spinal nerves are there
31
Sensory receptors
Monitor changes in the internal and external environment
Ganglia
Small masses of nervous tissue consisting of neuronal cell bodies that are located outside the brain and spinal cord
Example: Dorsal root
ganglion
Enteric Plexus
Extensive network of nerves that are located in the walls of the gastrointestinal tract that help regulate the digestive system.
Sensory function (afferent)
Detect internal and external stimuli and Convey impulses into CNS
Integrative function:
(Information processing)
1) Perception = awareness of sensory input
2) Analyzing and storing information to help lead to appropriate responses
Motor function (Efferent)
Once integration occurs the brain may elicit motor response to muscles or glands (effectors) via cranial and spinal nerves
Neurons vs neuroglia
Neurons: Provide most of the unique functions of the nervous system
Neuroglia: Function to provide support, nourishment, and protection
Parts of a Neuron
Cell body
Dendrites
Axon
Axon terminals
Parts of a Neuron
Axon terminals
Contain synaptic vesicles that can release neurotransmitters
Parts of a Neuron
Axon
Conducts away from cell body toward another neuron, muscle or gland
Emerges at cone-shaped axon hillock
Parts of a Neuron
Dendrites
Highly branched structures that carry impulses to the cell body
Parts of a Neuron
Cell body
Nucleus, cytoplasm with typical organelles
Structural Classes of Neurons
Multipolar
Have several or many dendrites and one axon
Most common type in brain and spinal cord
Structural Classes of Neurons
Bipolar
Have one dendrite and one axon
Example: In retina of eye and inner ear
Structural Classes of Neurons
Unipolar
1) Have fused dendrite and axon
2) Sensory neurons of spinal nerves
Function of the neuroglia
- Support, nourish, and protect neurons
- Critical for homeostasis of interstitial fluid around neurons
What makes up about half the volume of the CNS, supports nourishes and protects the neurons?
Neuroglia
Do neuroglia generate nerve impulses
no
In case of injury or disease, what can multiply to fill in space formerly occupied by neurons?
Neuroglia
what type of Neuroglia form blood brain barrier
Astrocytes
what type of Neuroglia produce myelin in CNS
Oligodendrocytes
what type of Neuroglia protects CNS cells from disease
Microglia
what type of Neuroglia form CSF in ventricles
Ependymal cells
what type of Neuroglia produce myelin around PNS neurons
Schwann cells
what type of Neuroglia support neurons in PNS ganglia
Satellite cells
Nodes of Ranvier
Gaps in myelin along the axon
Ganglion
Cluster of cell bodies in PNS
Nucleus
Cluster of cell bodies in CNS
what is a Bundle of axons in PNS
Nerve
what is a Bundle of axons in CNS
Tract
White matter is made up of?
Primarily myelinated axons
Gray matter is made up of
Cell bodies, dendrites, unmyelinated axons, axon terminals, neuroglia
Regeneration of PNS neurons
Axons and dendrites in the PNS can be repaired if
cell body is intact and Schwann cells functional. if scar tissue does not fill the tube
Regeneration of CNS neurons
Very limited even if cell body is intact
Action potentials, or nerve impulses, allow for_____
communication between neurons
Synaptic Transmission
allow neurons to communicate with other neurons or effectors
Components of synapse
Presynaptic neuron- sending
Synaptic cleft- Space between
Postsynaptic neuron- receiving
These are examples of what? Acetylcholine Amino acids Norepinephrine dopamine serotonin Neuropeptides such as endorphins Nitric oxide
Neurotransmitters
what includes all the nervous tissue outside the central nervous system
Peripheral Nervous System
What system Consists of the brain and spinal cord?
-Source of thoughts, emotions, and memories
Central Nervous System
Peripheral Nervous System subdivisions
)
1) Somatic nervous system (SNS)
2) Autonomic nervous system (ANS)
3) Enteric nervous system (ENS