Exam 4 lectures NERVES Flashcards
How did Abe Lincoln die?
the bullet passed through the occipital lobe of his cerebrum into the second ventricle (left lateral ventricle) causing his death
The bullet stopped near the back of the left orbit
How did Jon Wilkes Booth Die?
he died from a cavalry revolver severed his spinal cord between his 4th and 5th cervical vertebrae. He then suffocated two hours later
What is the Cerebellum responsible for?
controls balance
muscle movement
coordination
has two highly folded hemispheres connected by a thick band of nerves
referred to as ‘little brain’
chiari malformation
associated with inadequate room in the skull for the cerebellum.
this causes inferior projections of the cerebellum (cerebellar tonsils) to be be pushed out of the foramen magnum!
This leads to slowly developing symptoms of headache, nausea, muscle weakness, difficulty swallowing, impaired coordination and blockage of the normal flow of spinal fluid, particularly in the central canal of the spinal cord
1 per 1,000 births but likely higher
how is chiari malformation treated?
decompressive surgery
involves removing the lamina of the first and sometimes the second or third cervical vertebrae and part of the occipital bone of the skull to relieve the pressure
alternative way to treat chiari malformation
Cytoreduction of cerebellar tonsils using bipolar electrocautery
have the cerebellar tonsils burned off by electrocautery to releive pressure
reticular formation
loosely organized core of gray matter that projects vertically through the core of the midbrain, pons, and medulla.
It also extends slightly into the diencephalon and the spinal cord as well
*has a motor and sensory component
network of nerves that are involved and spread through different parts of your brain
reticular formation
motor component
communicates with the spinal cord and is responsible for regulating muscle tone (especially when the muscles are at rest)
also assists with the autonomic centers in the medulla and pons to help control respirations, blood pressure and heart rate
reticular formation
sensory component
*reticular activating system
RAS
responsible for alerting the cerebrum to incoming sensory information
contains sensory axons that project to the cerebral cortex
responsible for maintaining a state of awareness or conciousness
what wakes you up in the morning
what happens then the RAS (reticularing activating system) is traumatized by a blow to the head?
the person will become unconcious or perhaps go into a coma
limbic system
“emotional brain”
composed of structures that ring the diencephalon.
it exerts important influence upon the endocrine and autonomic motor systems
functions affect motivational and mood states (fear, happiness and sadness)
with odors, it can provoke certain emotions or memories
rostrocaudal brain deterioration
can occur whenever there is increased pressure in the brain
occurs when the cerebrum pushes down through the tentorial incisure (tentorial notch) becuase of head trauma
bleeding, tumors, infections etc
sequence of rostrocaudal brain deterioration
as pressure builds in the cranial cavity, about 50cc of CSF can be squeezed out of the cranium to allow more room
some blood can also be squeezed out, but this quickly leads to progressive loss of oxygen (hypoxia) which will then lead to increased brain swelling
Pressure on the RAS will soon lead to unconciousness
As the cerebrum pushes down on the midbrain, “decorticate posturing” (like holding a cord of wood) will occur
if not stopped, the crerbrum and midbrain will push down on the upper pons and “decerebrate posturing” (like a waiter with his arm at his side reaching for a tip) will occur, this is the last reversible phase
as everything continues to shift caudally and compresses the lower pons and medulla brain death will occur, the cerebellum may even begin to herniate out the foramen magnum!
how do you treat rostrocaudal brain deterioration
high flow oxygen
barbiturate-induced coma
diuretics
decompressive craniectomy
Le Fort classified different fracture trends
classified as
Le Fort I
Le Fort II
Le Fort III
Le Fort I
Transverse fracture through the maxilla = upper teeth move.
Le Fort II
Fracture of the maxilla, nasal bridge, lacrimal bones, orbital floor and rim = teeth and nose move.
Le Fort III
.
Craniofacial disjunction = whole face moves
another name for stoke
cerebrovascular accident
CVA
*two-thirds of stoke victims die within three years
another name for mini-stroke
Transient ischemic attack
TIA
how do
cerebrovascular accidents (stokes)
occur?
formation of a thrombus (clot) in a cerebral artery that can lead to a cerebral “infarc” (local area of dying or dead tissue)
an intracerebral hemorrhage
a bulge in the wall (aneurysm) of a cerebral artery that ruptures
build up of fatty plaques in a cerebral arterial wall (atherosclerosis) that disrupts blood flow
Peripheral Nervous System (PNS)
composed of cranial nerves and spinal nerves that relay information to and from the central nervous system (CNS)
Cranial nerve
0
may be related to the sensing of pheromones
involved in regulating sexual behavior in mammals
Cranial Nerve
I
responsible for our sense of smell
purely sensory and bypasses the thalamus
Cranial Nerve
II
relays visual nerve impulses to the occipital lobes
purely sensory
responsible for our temporal field of view
medial portion of the retina
funduscopic examination of the retina is being performed
