Intro to Central nervous system Flashcards
Name the two divisions of the structural nervous system.
- CNS (brain and spinal cord)
- PNS (everything else … spinal nerves, cranial nerves, ganglia, plexuses)
Name the 2 functional divisions of the nervous system. Explain what they mean.
- Afferent (= sensory) : bring back sensory information back to the CNS.
- Efferent (= motor) : stimulate muscles to contract & gland to secrete.
What do the terms somatic and visceral refer to :
Somatic : motor innervation of voluntary muscles (think skeletal muscle and skin)
Visceral : motor innervation of involuntary muscles (think smooth muscles such as viscera, cardiac muscle and glands).
The efferent (motor) division can act on the _____ nervous system or the ______ nervous system.
Somatic nervous system
Autonomic nervous system
Parasympathetic ‘’rest & digest’’ and sympathetic ‘’fight or flight’’ are branches of the ____ nervous system.
Autonomic nervous system.
Define the neuron.
The neuron is the structural & functional unit of the nervous system.
It is composed of a cell body and nerve cell processes (dendrites & axons).
Dendrites receive _____.
Axon produce ______.
Incoming signals
Outgoing outputs
What are collection of axons called in the PNS ?
What are they called in the CNS ?
Nerve & tracts respectively.
Compare nucleus and ganglion.
Nucleus is a collection of nerve cell bodies in the CNS .
Ganglia is a collection of nerve cell bodies in the PNS.
Compare unipolar, bipolar and multipolar types of neurons.
Unipolar (pseudounipolar) : relate to sensory function = afferent.
Bipolar : associated with special senses (retina, inner ear).
Multipolar : relate to motor function = efferent
Unipolar / sensory neurons have their cell bodies in the _____.
Dorsal root ganglion.
The DRG is a cluster of neurons in the dorsal root of the ganglion
ALL sensory nerve cell bodies are located in the dorsal root ganglia.
Differentiate white matter from gray matter.
Gray matter is mainly composed of neuron cell bodies.
White matter is mainly composed of neuron axons.
Remember that axons are covered with myelin which is white!
Sensory nerve cell bodies are located in the DRG.
Motor ones are located in the _____.
Sympathetic chain ganglia.
Define glial cells and gives 4 examples.
Glial cells are supporting cells of the nervous system (greatly outnumber neural cells)
E.g.
- Astrocytes*
- Microglia*
- Schwann cells*
- Oligodendrocytes*
Schwann cells (neurolemmocytes) are _____ forming cells in the ___.
Myelin
PNS
Oligodendrocytes are ____ forming cells in the ____.
Myelin
CNS
What are Astrocytes ?
Astrocytes are specialized glial cells that outnumber neurons by over fivefold. They contiguously tile the entire central nervous system (CNS) and exert many essential complex functions in the healthy CNS.
They form the blood/brain barrier.
What are microglia?
Microglia are the resident innate immune cells of the CNS and are responsible for normal maintenance of CNS tissue as well as the local response to injury or infection.
They act as phagocytes within the CNS.
They act as the ‘‘glue”“
Nerves can convey several types of axons. Name the 4 different general components of a nerve.
General Somatic Afferent (GSA)
General Somatic Efferent (GSE)
General Visceral Afferent (GVA)
General Visceral Efferent (GVE)
Describe GSA nerves.
General Somatic Afferent nerves transmits pain, touch, temperature & proprioception from the body to the CNS.
Describe General Somatic Efferent nerve (GSE)
General Somatic Efferent : motor impulses to skeletal muscles.
Describe General Visceral Afferent (GVE) neurones.
GVA : sensory info from visceral organs to CNS.
General Visceral Efferent (GVE) :
Motor to cardiac, smooth muscles & gland cells.
Name the 3 SPECIAL functional components of a nerve:
- Special Somatic Afferent (SSA)
- Special Visceral Afferents (SVA)
- SpecialVisceral Efferents (SVE)
Define SSA neurones.
Sensations of vision, hearing and equilibrium to the CNS.
Define SVA :
Special Visceral Afferent : taste and smell to CNS.
Define SVE neurons.
Special Visceral Efferent : Motor to certain muscles of the head & neck (mastication, facial expression, some muscles of the pharynx/larynx)
The peripheral system consists of _____ pairs of cranial nerves which exit the skull through a foramina AND ___ pairs of spinal nerves which exit through intervertebral foramina.
12 pairs of cranial nerves
31 pairs of spinal nerves
What is a spinal cord segment ?
A portion of the spinal cord that gives rise to a pair of spinal nerves (left and right).
There are 31 pairs of spinal nerves.