Anatomy 1 Flashcards
What is decussation?
- Axons crossing the midline
- Important example: The corpus callosum is the major fiber tract connecting the L & R hemispheres of the brain.
Lateral vs. medial
- Lateral = away from midline
- Medial = towards midline
Contralateral
Opposite side of body or brain as another structure
Ipsilateral
Same side of body or brain as another structure
Directional terms with mouse
Rostral
Sounds like nostril!
Towards the nose/front in a quadruped
Dorsal
Towards back (dos in French)
Directional terms & neuraxis
Directional terms ending with -ior vs. -al
- Ends with -ior: Directions are perpendicular or parallel to the ground
- Ends with -al: Directions are relative to the neuraxis
Planes of section
Transverse sections
Starts coronal rostrally –> becomes horizontal caudally
Transverse sections are always ___ to the neuraxis
Perpendicular
Examples of directional terms (separate into flashcards)
White vs. grey matter
- White matter is mostly axons
- Grey matter is mostly cell bodies
Afferent vs. efferent
- Afferent fibers arrive into the central nervous system (ex. sensory axon
carrying information from fingertips into the dorsal root of the spine). - Efferent fibers exit the central nervous system (ex. motor axon exiting the
ventral root of the spine to control fingertips). - We will be using these terms to describes fibers as they arrive in or exit the
central nervous system (brain and spine), but you will encounter these terms
in the future to refer to specific regions (ex. afferent fibers arriving into the
thalamus)
Divisions of the NS - flow chart
What does the central nervous system include?
Brain and spinal chord
What does the peripheral nervous system include?
Everything except the brain and spine, e.g. spine nerves
What are the two divisions of the peripheral NS?
- Somatic (voluntary)
- Visceral/autonomic (involunary)
Somatic nervous system
- Voluntary
- Motor axons control muscle contractions (soma in CNS vs. axons in PNS)
- Sensory nerves entering spine containing info from skin, muscles, and joints
Visceral/autonomic nervous system
- Involuntary
- Innervates internal organs, blood vessels, and glands
- Motor axons control relaxation or contraction of walls of blood vessels and intestines i.e. smooth muscles
- Sensory axons carry info on visceral function (e.g. pressure in blood vessels)
- Divided into sympathetic (fight or flight) and parasympathetic (rest and digest)
Diagram of spinal cord
Components of spinal nerve (look at pink box in diagram)
- Afferent dorsal root (going into spine)
- Efferent ventral root (going out of spine)
- There is one spinal nerve for each level of the spinal cord
- The dorsal root ganglia contain the cell bodies of sensory neurons BUT there are no ventral root ganglia
How many spinal nerves are there for each level of the spinal cord?
1
Dorsal root ganglia
- Contain the cell bodies of sensory neurons
- No ventral root ganglia