Peripheral Nervous System and the Spinal Cord Flashcards
Autonomic nervous system functions
Involuntary responses
Cranial nerve II
Optic. Sensory. Sight
How can the BBB potentially be opened or weakened?
high blood pressure, microwaves, ultrasonic waves, radiation, infection, injury (stroke, inflammation, pressure)
Blockage of CSF flow usually at narrow points in the passage
Hydrocephalus
How is blood supplied to the brain anteriorly?
Carotid arteries
Spinal nerve regions for sympathetic and parasympathetic
Sympathetic = thoracic/lumbar Parasympathetic = cranial/sacral
Cranial nerve VIII
Vestibulocochlear/auditory. sensory. inner ear
Same side of the midline
ipsilateral
What does the blood brain barrier do?
Excludes some molecules from passing easily
Far from the center
Distal
Opposite sides of the midline
contralateral
CSF path of flow
Ventricles down the spinal cord and up and around the cortex
What molecules are allowed through the BBB via passive diffusion?
water, some gasses like O2 and CO2, and lipid soluble molecules
What are the cerebral ventricles filled with?
CSF
Why is there left arm pain during a heart attack and who does it occur in?
Its linked to a spinal nerve and is pretty much only in males
How much CSF is replenished and how often?
100-150 mL at a time, replenished 3x a day
What are the 4 cerebral ventricles?
Lateral ventricles, third ventricle and fourth ventricle
What molecules are allowed through the BBB via active transport (protein channel)?
glucose and amino acids
Cranial nerve condition causing temporary paralysis of one side of face
Bell’s palsy
Where does CSF exit into the bloodstream?
Superior sagittal sinus
How is the BBB related to Alzheimer’s?
Research is showing that the BBB is leaky in Alzheimer’s
How is blood supplied to the brain posteriorly?
Vertebral arteries at base of skull
What do the sympathetic and parasympathetic pathways use at targets
Sympathetic uses NE and parasympathetic uses ACh
Functions of the somatic nervous system
Voluntary movement
Fight or flight response
Sympathetic division
What procedures are done on the meninges?
Spinal tap and epidural
Towards the midline
Medial
2nd synapse NT of sympathetic and parasympathetic
NE in sym and ACh in parasym
NTs of autonomic nervous system
ACh and NE
Cranial nerve VI
Abducens. Motor. external rectus muscle (eye)
Divides the brain into two relatively equal halves
Midsagittal section
Tight junction between endothelial cells and actroycyte end feet along capillaries
Blood brain barrier
Cranial nerve X
Vagus. both. motor heart, lungs, bronchi, GI tract. sensory heart lungs, bronchi, trachea, larynx, pharynx, GI tract, external ear
Ventral horn
motor output for voluntary movement or spinal reflexes
Examples of spinal reflexes
patellar reflex, flexor-withdrawal, Babinski reflex
Constricts pupils to baseline and stimulates digestion
Parasympathetic
Divisions of autonomic nervous system
Sympathetic and parasympathetic
Where is there a ganglion chain and what does it do?
sympathetic to improve timing
Cranial nerve III
Oculomotor. Motor. Eye muscles
Structures of somatic nervous system
Motor neurons, neuromuscular junctions
Why is the patellar reflex sort of monosynaptic?
While you only excite one muscle group, you must inhibit its counterpart
Maintains constant internal environment
BBB
How many peripheral spinal nerves?
31
NTs of the somatic nervous system
ACh
Posterior of body
Bottom
What is the gray matter?
Cell bodies
1st synapse of sympathetic and parasympathetic
sympathetic = short with light myelination parasympathetic = long with light myelination
Toward the back and higher in the brain
Superior or dorsal
Sun sneezing caused by overstimulation of trigeminal nerve
ACHOO syndrome
Close to the center
Proximal
Structures close to the midline
medial
How is Bells palsy caused
Usually following a sinus infection, inflammation/infection of facial nerve
Challenges of medicine and the BBB
how can we make a medicine that works and gets past the BBB
Structures to the side of the midline
lateral
Tail end of four legged animal and back of brain
Caudal or posterior
What does hydrocephalus cause?
Enlarged ventricles. The head can be so large they can’t be born vaginally
What does the meninges do?
Provides 3 layers of protection for the nervous system
Effectors (targets) of autonomic nervous system
Cardiac muscles, smooth muscles, glands (lungs, digestive system, internal organs, etc.)
How are spinal cord segments connected and what do they do?
They are interconnected and are involved with complex coordinated movements
Toward the belly and lower in the brain
Inferior or ventral
What areas have weak BBBs?
Secreting centers like the choroid plexus, pineal gland, and pituitary gland
Head end of legged animal and front of brain
Rostral or anterior
Anterior of brain
Front
How is the spinal ganglion formed?
Outside spinal cord nerves swell
Cranial nerve IV
Trochlear. Motor. Superior oblique muscle (eye)
Worst version of meningitis that is relatively rare, life threatening, and has antibiotics and vaccines available
Bacterial. Meningococcal
Ventral of body
Front
CNS to body
Motor
Parasympathetic division neurons path
Top of spinal cord and brain long to another neuron and short to organs
Cranial nerve XII
Hypoglossal. motor. muscles of the tongue
Would CSF help a concussion?
No
Dorsal and ventral horns
Gray matter
Sensory
afferent
Fever, headache, neck pain/stiffness, photophobia
Symptoms of meningitis
Sudden drop in HR and BP (fainting). Usually caused by seeing blood or needles
Vasovagal syncope
What happens in the cervical and lumbar regions?
Enlargement of horns
Cranial nerve V
Trigeminal. Both. Sensory in face, sinuses, teeth, etc. Motor in muscles of mastication (chewing)
Should we focus on the primary injury or secondary injury of the spinal cord?
Secondary bc we can’t do anything about the primary
How can the Babinski reflex be observed in adults?
Spinal cord damage
How does the CSF move?
In a pulsatile manner throughout the CSF system with a nearly zero net flow
Ascending and descending tracts
White matter
Cranial nerve VII
Facial. both. facial muscles
Cranial nerves
12 pairs, exit and enter directly from brain, sensory motor or both
Dorsal of brain
Top
Cranial nerve IX
Glossopharyngeal. both. motor food to pharynx. sensory posterior part of tongue, tonsil, pharynx
Cranial nerve I
Olfactory. Sensory. Smell
What are the three layers of the meninges?
Dura mater, arachnoid mater (only in CNS) and Pia mater
Regions of spine
cervical, thoracic, lumbar, sacral, coccygeal
Spinal nerves
31 left/right pairs that are afferent or efferent
Dilates pupils and inhibits digestive functions
Sympathetic
Ventral of brain
Bottom
How many cerebral ventricles are there?
4
Monitoring centers for the BBB
Area postrema (makes you vomit if too much of certain things like alcohol) and some hypothalamic nuclei
Increased heart rate, blood pressure and blood flow to skeletal muscles
Sympathetic
Protects the brain from foreign substances
BBB
What happens below the injury to the spinal cord?
loss of sensation (skin and internal organs), loss of voluntary movement (reflexive movement depends on location), loss of voluntary control of bladder and bowel (located in sacral portion)
Dorsal of body
Back
What does CSF do?
Mechanical and immunological protection, nutrition/excretion, regulation fo cerebral blood flow, buoyancy/cushioning
Cranial nerve XI
Spinal accessory. motor. sternocleidomastoid and trapezius muscles
Motor efferents (spine)
Ventral
Most common form of meningitis that affects younger individuals and is self resolving
Viral
Body to CNS
Sensory
Dorsal horn
sensory input
What cells form the BBB and how?
Astrocytes wrap around blood vessels in the brain
HSV1 (herpes simplex virus) caused by viral infection of facial nerve
Cold sores
Painful skin rash appearing in a band or strip on one side of body (dermatome)
Shingles
Rest and digest
Parasympathetic
Calms body to conserve and maintain energy
Parasympathetic
Releases ACh and NE
Sympathetic division
What is the white matter?
Axons
Mixed nerves that splits to dorsal and ventral
Spinal nerves
Area of the skin supplied with afferent nerve fibers by a single spinal cord dorsal root
Dermatome
What is the composition of CSF?
Similar to clear plasma of blood but without proteins
1st synapse NT of sympathetic and parasympathetic
ACh for both
Sensory afferents containing root ganglion (spine)
Dorsal
What makes CSF and where?
Ependymal cells make it in the choroid plexus (lines the walls of the cerebral ventricles) or cells in subarachnoid space
Sympathetic division neurons path
Spinal cord short to sympathetic chain ganglion and long to organs
Away from the midline
Lateral
How can hydrocephalus be treated?
Shunting procedure
Parallel to midline planes
Sagittal section
Decreases heart rate and blood pressure
Parasympathetic
Divides the brain from top to bottom
Horizontal (axial, transverse) section
Posterior of brain
Back
Why are the cerebral ventricles correlated with enlarged size in some neurodegenerative disorders?
If there’s empty space, fluid fills the space
What molecules are blocked by the BBB?
large molecules, non-lipid soluble molecules, highly charged molecules, potential neurotoxins, and many drugs including would be meds
Protects the brain from hormones and NTs in rest of body
BBB
Motor
efferent
Three forms of meningitis
Bacterial, fungal and viral
Where does the spinal cord extend from to?
Medulla to the first lumbar vertebra
2nd synapse of sympathetic and parasympathetic
sympathetic = long unmyelinated parasympathetic = short unmyelinated
Divides nervous system from front to back
Coronal (frontal) sections
Anterior of body
Top
Effectors (targets) of the somatic nervous system
Skeletal muscles
