The Spinal Cord And Spinal Nerves Flashcards
What does the spinal cord contain that controls some of your most rapid reaction to environmental change
Reflex circuits
The gray matter of the cord is a site for what
Integration of postsynaptic potentials
The white matter of the cord contains what
Major sensory and motor tracts to and from the brain
Two types of connective tissue coverings that protect the spinal cord and provide physical stability
- Vertebral column- provides backbone
- Spinal meninges
Spinal meninges
- Dura mater- outermost meninx, forms a sac that encloses the entire cord
- Arachnoid mater- middle meninx, forms the roof of the subarachnoid space in which CSF circulates
- Pia mater- pressed up against the cord, filled with blood vessels that supply nutrients to the cord
Epidural space
Runs between the dura mater and the more superficial ligamentum flavum (which lines the underside of the bony vertebral lamina)
Subdural space
Lies between the dura and the arachnoid, in the spinal column the dura and arachnoid membranes are held firmly together so the subdural space is often no more than a potential space
Pia mater
Has 21 pairs of denticulate ligaments which attach to the arachnoid and dura maters. The denticulate ligaments are known to provide stability for the spinal cord against sudden shock and displacement within the vertebral column
Filum Terminale
Extends inferiorly from the pia mater and blends with the arachnoid and dura to anchor the spinal cord to the coccyx
Cauda equina
Roots of the lower spinal nerves that angle down alongside the filum terminale
Enlargements in spinal cord
- Cervical area- correlates with the sensory input and and motor output to the upper extremities
- Lumbar area- handles sensory input and motor output to and from the legs
Posterior root ganglion
Contains cell bodies of sensory neurons
Anterior root and rootlets
Contain axons of motor neurons, which conduct nerve impulses from the CNS to effectors
Epidural anesthesia
Needle is placed between the bones of the posterior spine and it just penetrates the the ligamentum flavum yet remains superficial to the dura mater
Lumbar puncture
Needle is inserted into subarachnoid space for the purpose of withdrawing CSF
Neurotransmitter clearance
Removal is accomplished by diffusion out of the synaptic cleft, enzymatic degradation, and re-uptake by cells
A Fibers
Large, fast, myelinated neurons that carry touch and pressure sensations; many motor neurons are also of this type
B Fibers
Medium size and speed and compromise myelinated visceral sensory and autonomic preganglionic neurons
C Fibers
Smallest and slowest and compromise unmyelinated sensory and autonomic motor neurons
Cervical plexus
Formed by the anterior rami of C1-C5, serves the head, neck, and diaphragm.
The phrenic nerves arise from the cervical plexus to supply the major muscle of respiration (C3,4,5 keep the diaphragm “alive”)
Brachial plexus
Formed by the anterior rami of C5-C8 and T1. It is divided into roots —> trunks—> divisions —> cords —> nerves.
The nerves from the brachial plexus supply the shoulders and upper limbs
Lumbar plexus
Formed by the anterior rami of L1-L4 to supply the anterolateral abdominal wall, external genitalia, and part of the lower limbs.
The femoral and obturator nerves come from the lumbar plexus
Sacral plexus
Formed by the anterior rami of L4-L5 and S1-S4. It supplies the buttocks, perineum, and part of the lower limbs.
It gives rise to the largest nerve in the body, the sciatic nerve.
Coccygeal plexus
Formed by the anterior rami of S4-S5 and the coccygeal nerves. It is a small plexus from which the anococcygeal nerve exits to supply a small area of skin in the coccygeal region.
Internal carotid arteries
Supply blood to the brain anteriorly
Vertebral arteries
Supply blood to the brain posteriorly
The brainstem
Made up of the midbrain, pons, and medulla oblongata
