Ch 13 Flashcards
Cauda Equina
(Spinal)Nerve extensions from the spinal cord that serve the lumbar, sacral, and coccygeal regions. *How the spinal cord extends down to lower parts of body
Dura Mater
Multiple layers of Dense irregular tissue loosely wrapped around spinal cord.
Acts as a stabilizer
Most outer layer
Epidural Space
Space just above/superficial to dura mater that contains adipose tissue, blood vessels, and nerves.
-Anesthetics are often delivered here
Potential Space (Subdural)
Beneath/deep to dura mater. Place where space can (POTENTIALLY) develop under certain circumstances
Arachnoid Mater
2nd connective tissue layer deep to Dura Mater
-Collagen
Sub- Arachnoid space
Space where cerebral spinal fluid circulating around the spinal cord
Pia Mater
(Deepest layer) Thin CT cover connected to/ on top of spinal cord
-cover extends past conus medularis/end of spinal cord to form filum terminale
Filum Terminale -“Terminal Thread”, Terminal Filument
Dura and Arachnoid maters extend to S2
Lumbar cistern
Container that contains CSF and is where Spinal taps are performed to check for pathologies.
Central Canal
Ependymal cells that produce and circulate CSF are found here
Open canal for kids-Closed canal for adults
Grey Commisure
Central division that Divides Left and right grey Matter
-important structure for interneurons that help propagate action potentials from one side of spinal cord to the other.
Dorsal Gray Horns
-For sensory Action Potentials that are coming into the spinal cord.
-(Input region of spinal cord)
-found here are Unmylinated portions of sensory neurons
Lateral Gray Horns
Found here are neurosoma and initial segments of autonomic neurons
Ventral Gray Horns
Contain nuerosoma and axon hillock’s initial segment of Motor neurons exiting spinal cord to their effector signals(Cells/Tissue/Organs)
White Matter
Contains myelinated axons of neurons of spinal cord
Dorsal/Posterior Root
Contains axons that delivers sensory information into spinal cord
-For Sensory neurons’ Action Potential being sent towards grey matter of spinal cord
Root Ganglion
Enlargement due to buildup of Neurosoma of unipolar neurons
Ventral/Anterior Root
Contains axons of either autonomic or motor neurons that leave the spinal cord to deliver Action potential to effector: cell/tissue/organ
31 Pairs (Total)
Spinal Nerves
Mismatch Between Cervical Vertebra and Cervical Spinal Nerves?
Because Spinal nerve c1 is above cervical vertebrae c1
Ramus
Branch off of spinal nerve that provides both sensory and Motor output to the trunk
Posterior/Dorsal Ramus
Contains axons of Sensory &Motor Neurons that activate/innervate limb muscles and skin in the back region
8
Pairs of Cervical Nerves
12
Thoracic Nerve Pairs
5
Lumbar nerve pairs - includes cuada equina
5
Sacral Nerve Pairs
1
Coccygeal pair
Anterior Ramus
Contains axons of Sensory &Motor Neurons that activate/innervate limb muscles and skin in the ventro-lateral(front-side) region.
Plexus
Result of Anterior Rami that anastomose/merge together to form a network/web
Cervical Plexus(head/kneck
Phrenic Nerve- motor axons that serve the diaphragm. Provide contraction & relaxation of muscle for breathing
Brachial Plexus( arms, neck, shoulders)
Musculocutaneous Nerve( provides motor innervation to biceps brachii)
Lumbar Plexus( lower ab, gluteal, genital, and legs)
Femoral Nerve( provides motor innervation to Recuts Femoris)
Sacral Plexus( Motor & Sensory for gluteal, genital, & legs)
Inferior Gluteal Nerve- Contains Alpha Motor neurons that innervate the Gluteus Maximus
Coccygeal Plexus (genital)
Pudenal Nerve- alpha motor neurons that innervate sex organs( penis, clitoris)
Spinal Tracts
Myelinated axons/White Matter within spinal cord
Cuneate & Gracile Fasciculus (Proprioception Sensory Tract 1)
(Ascending) Spinal Tracts that are responsible for proprioception. Myelinated axons deliver sensory information up to brain
Spinoreticular Tract (nociception Sensory Tract 2)
(Ascending) Spinal Tracts that are responsible for nociception. Myelinated axons of neurons that deliver/conduct action potentials, that integrates pain into the brain.
Spinothalamic Tract
(Ascending Tract) Neurons synapse in Thalamus. Tickle, itch, light touch
Corticospinal Tract
(Descending Tract frm Motor Cortex) Major tract that synapses with Alpha Motor Neurons to generate Muscle contraction
Cerebral Cortex- GreyMatter of Brain
Receives action potential from Third order neuron which enables awareness of sensory information.
Reflex
[Quick-Involuntary-Stereotyped] reaction to stimuli
Somatic Reflex
Skeletal Muscle reflexes
Spinal (cord) reflexes
Spinal cord is the integrating center and brain isn’t needed for reflex to happen
Cranial (nerve) reflex
Blinking, gagging, pupil dilation/constriction
Visceral Reflex
Involuntary neural reflexes of organs( heart, stomach, etc)
Somatic Reflex
Skeletal Muscle reflex/reaction to harmful stimuli
Reflex Arc
1.Receptor
2. Afferent Neurons- generate Action Potential(afferent signal)
3. Integrating Center- Spinal Cord, brainstem(Medulla Oblongata & Pons)
4. Efferent Neurons - Action Potential(Efferent Signal)
5. Effector organ/tissue/cells
Muscle Spindle
Modified skeletal muscle cell that plays a sensory function in reflexes and proprioception.
Muscle Spindle(2)
Allows brain to maintain ongoing knowledge/awareness of muscle’s contractile state and muscle position, as sensory neuron is wound around fibers.
Gamma Motor Neurons
(Adjust sensitivity) Contracts muscle spindle when muscle is shortened, relax spindle when stretched
Mechanoreceptor
Muscle Spindle
Reciprical Inhibition
Activation of one muscle group while simultaneously inhibiting the other
