Lecture 16: Autonomic Nervous System Flashcards
What layers make up the spinal meninges?
Outtermost:
- Vertebral canal
- Epidural Space- (fat and CT) NOT FOUND IN CRANIAL MENINGES
-
DURA MATER
- Subdural space- typically not present
-
ARACHNOID MATER
- Subarachnoid space (contains CSF
-
PIA MATER
- Spinal chord
-
PIA MATER
- Subarachnoid space (contains CSF
-
ARACHNOID MATER
- Subdural space- typically not present
-
DURA MATER
- Epidural Space- (fat and CT) NOT FOUND IN CRANIAL MENINGES
Describe the anatomical features of the spinal chord and its location.
- Flattened cylindrical shape extending to L2 Vertebrae.
- Terminates at **CONUS MEDULARIS**
- FILUM TERMINALE (non functioning extensions of pia mater anchor spinal chord) from coccygeal, lumbar and sacral region form CAUDA EQUINA
Contains enlargements at cervical and lumbar vertebrae which create a thickened spinal chord so nerves can be sent to peripheral limbs.
Label all important features
Label and Describe the anatomical features of the cross section of the spinal chord:
Grooves: Anterior median fissure AND posterior median sulcus
Grey Matter: H SHAPED: Grey commissure connects two sides of grey matter, central canal contains sensory and motor nuclei.
+ Anterior Grey Horn (Somatic Motor Nuclei)
+ Posterior Grey Horn (houses interneurons and and sensory neurons)
+Lateral Grey Horn (autonomic motor nuclei)
White matter: anterior, posterior and lateral columns, sensory ascending nuclei and motor descending nuclei
Anterior/posterior rootlets → Anterior root + Dorsal root ganglion → Spinal nerve
How many spinal nerves do you have and what are the main features of them.
31 pairs of spinal nerves ALL ARE MIXED (sensory + motor)
Exit from intervertebral foramina
- Cervical (8)
- Thoracic (12)
- Lumbar (5)
- Sacral (5)
- Coccyx (1)
What is the structure of a nerve?
Endoneurium - surrounds individual axons
perineurium- surround groups of axons into fascicles
epineurium - surrounds groups of fascicles ie ENTIRE NERVE contains blood vessels and lymphatics
Describe the process of nerves in the spinal chord innervating regions of the body.
Anterior rootlets(motor nuclei) → Anterior root →
dorsal rootlets (sensory nuclei) → Posterior root ganglion (collection of sensory neuron bodies)
- Converge to form spinal nerve trunk (mixed).
- Seperates into - anterior ramus ( limbs, skin and lateral and anterior trunk) , posterior ramus (deep muscles and posterior trunk) , meningeal branches (innervate the spinal chord) Rami communicates (make up autonomic visceral organ nerves)
Label the important features
What is a plexus?
Network of axons made by the anterior rami of spinal nerves:
- Cervical
- Lumbar
- Sacral
- Coccygeal
What is the cervical plexus composed of?
Cervical plexus is composed of C1 → C5 spinal nerves.
What is the brachial plexus composed of?
C5 C6 C7 C8 T1 T2
What is the Lumbar Plexus composed of?
L1- L5
What is the sacral plexus composed of?
L4- L5 → S5
What are your intercostal nerves?
→ Dont form plexuses
Arise from the anterior rami of T2 to T11
Somatic nervous system
muscle contraction of intercostal muscles, abdominal wall muscles, pleura and peritoneum.
What is a dermatome?
Area of the skin that porvides a sensory input to the CNS via one spinal/ cranial nerve.
What is the autonomic motor pathway for the sympathetic division?
Preganglionic nerves → exit anterior root of spinal nerve → White Rami Communicates → Sympathetic trunk ganglion where it will either synapse of continue to inferior or superior ganglion where it will synapse. OR continues to prevertebral ganglion. → sends post ganglionic motor signal to effector neurons.
What are the layers of the enteric organs and how are they supplied by the autonomic nervous system?
Lumen → Mucosa → Submucosa → Circular muscle layer → Myenteric Plexus → Longitudinal muscle layer → Serosa
SUBMUCOSAL PLEXUS AND MYENTERIC PLEXUS
