7120 Lecture Notes - Lecture 4: Dorsal Root Ganglion, Somatic Nervous System, Ventral Root Of Spinal Nerve
21 Jun 2018
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LECTURE 4
Anatomy and research methods Chapter 3
Structure of the nervous system
- CNS: the brain and the spinal cord
- PNS: connects the brain and spinal cord to the rest of the body
oSomatic nervous system: consists of axons conveying messages from the sense
organs to the CNS and from the CNS to the muscles
oAutonomic nervous system: controls the heart. Intestine. And other organs
Sympathetic and parasympathetic
Anatomical directions
- Horizontal; top view (brain)
- Sagittal; side view (brain)
- Coronal; front or back (brain)
- Anterior; front
- Posterior; back
- Lateral; towards side
- Dorsal; towards the back away from the ventral (stomach side)
- Ventral; towards the stomach away from the dorsal side
- Superior; above
- Inferior; below
- Ipsilateral; same side
- Contralateral; opp side
The spinal cord
- Part of the CNS found in spinal column
oCommunicates with sense organs and muscles except those of the head
oEntering dorsal roots carry sensory info and exiting ventral roots carry motor info
oCell bodies of the sensory neurons outside the spinal cord – the dorsal root ganglia
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- Consists of two types of matter
oGrey matter: located in centre of spinal cord and is densely pack with cell bodies and
dendrites
oWhite matter; composed of myelinated axons that carry gray matter to the brain or
other areas of the spinal cord
- Sends sensory info and receive motor commands
The autonomic nervous system in PNS
- Sends and received messages to regulate autonomic matters of body
oSympathetic
Fight or flight
Vigorous activity preparation
Ganglia on right and left side of spinal cord; thoracic and lumbar regions
oParasympathetic
Vegetative and nonemergency responses
Digestion
Long preganglion axons from spinal cord, short post ganglion from fibers
themselves
Neurotransmitters in the ANS
- Postganglionic axons of the PNS mostly release acth as a neurotransmitter
- The SNS mostly uses norepinephrine
Divisions of the vertebrate Brain
- Forebrain:
oProsecephalon
Forward brain
contains diencephalon and telencephalon
odicephalon
between brain
thalamus. Hypothalamus
otelencephalon
end brain
cerebral cortex, hippocampus, basal gangli
- midbrain
omesencephalon
middle brain
tectum. Tegmentum, superior colliculus. Inferior colliculus, substantia nigra
- hindbrain
orhombencephalon
parallelogram brain
medulla, pons, cerebellum
the hindbrain
- consists of the
omedulla
opons
ocerebellum
- located at the posterior portion of the brain
- hindbrain structures, the midbrain and other central structures of the brain combine and
make up the brain stem
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human brainstem
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The hindbrain – medulla
- The medulla
oLocated just above the spinal cord; like an enlarged extension of spinal cord
oResponsible for vital reflexes such as breathing, HR, vomiting. Salivation, coughing
and sneezing
The hindbrain – cranial nerves
- The cranial nerves
oAllow the medulla to control sensations from the head, muscle movements in the
head and many parasympathetic outputs
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Document Summary
Dorsal; towards the back away from the ventral (stomach side) Ventral; towards the stomach away from the dorsal side. Sends and received messages to regulate autonomic matters of body: sympathetic. Ganglia on right and left side of spinal cord; thoracic and lumbar regions: parasympathetic. Long preganglion axons from spinal cord, short post ganglion from fibers themselves. Postganglionic axons of the pns mostly release acth as a neurotransmitter. Forward brain contains diencephalon and telencephalon: dicephalon between brain thalamus. Midbrain end brain cerebral cortex, hippocampus, basal gangli: mesencephalon. Inferior colliculus, substantia nigra hindbrain: rhombencephalon parallelogram brain. The medulla: located just above the spinal cord; like an enlarged extension of spinal cord, responsible for vital reflexes such as breathing, hr, vomiting. The cranial nerves: allow the medulla to control sensations from the head, muscle movements in the head and many parasympathetic outputs. Lies on each side of the medulla (ventral and anterior)
