Brain 2: brain blood flow, CFS brainstem Flashcards Preview

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Flashcards in Brain 2: brain blood flow, CFS brainstem Deck (43):

how many % is the brain's weight (out of total body) and how many % of energy/oxygen does it consume

Brain is 2% of total body weight but consumes 20% of all the oxygen and glucose


How are glucose and oxygen used in the brain

Neurons use glucose and oxygen to make ATP in the brain


How long does it take for neuronal function to be impaired or permanently damaged

interruption in blood flow for 1-2 minutes to be impaired and total deprivation of oxygen for about 4 minutes causes permanent injury


how does brain store glucose

No glucose is stored in the brain so the supply of glucose must be continous


what does a low level of glucose in the blood to the brain cause

mental confusion
loss of consciousness


how many % of cardio output goes to brain



what is blood brain barrier

Tight junctions that seal together endothelial cells of capillaries in the brain and thick basement layer that surrounds the capillaries


What type of neuroglia at blood brain barrier and what does it do?

Astrocytes - their processes press up against the capillaries and secrete chemicals that maintain the permeability characteristics of tight junctions


What can cross the blood brain barrier

-Some water-soluble substances cross by active transport (ie glucose)
-Creatinine, urea, ions cross slowly
-lipid-soluble substances (O2, Carbon dioxide, alcohol, most anesthetic agents)


What can not cross the blood brain barrier

Proteins and most antibiotic drugs do not cross


What can break down the blood brain barrier

Trauma, certain toxins and inflammation


What is Cerebral spinal fluid

Clear colourless lipids, mainly water and protects brain and spinal cord from chemical and physical injuries


what does cerebral spinal fluid carry

carries small amount of O2, glucose, proteins, lactic acid, urea, cations, anions and some WBCs needed to neurons and neuroglia


Where does cerebral fluid circulate through

The cavities in the brain and spinal cord and around the brain and spinal cord in the subarachoid space


What is the total volume of cerebral spinal fluid?

80-150 ml in adult


what are ventricles in the brain

cavities within the brain filled with CSF
2 lateral ventricles (1 in each hemisphere of the cerebrum, Septum pellucidum)
Third ventricle
Fourth ventricle


What is a thin membrane that separates that the lateral ventricles

Septum pelluciadum


Functions of ventricles

1. Mechanical protection
-shock absorbing medium that protects brain and spinal cord from jolts
-fluid also keeps brain floating in the cranial cavity
2. Homeostatic function - the pH of CSF affects pulmonary ventilation and cerebral blood flow
3. Circulation - minor exchange of nutrients and waste products between blood and nervous tissue


Where is CSF formed

In the Choroid plexuses, networks of blood capillaries in the walls of the ventricles


what is difference between Blood brain barrier and blood-CSF barrier

BBB=tight junctions of brain capillary endothelial cells
Blood-CSF barrier=tight junctions of ependymal cells


What does Blood CSF barrier do

to protect brain and spinal cord from harmful blood borne substances


Circulation of CSF

CSF formed in Choroid plexus ->lateral ventricles ->Interventricular foramina ->Third ventricle ->Cerebral aquaduct -> Forth ventricle -> 2 lateral apertures and 1 median aperture -> central canal subarachoid space ->Arachoid villi ->superior sagittal sinus ->Straight sinus ->Sigmoid sinus -> internal jugular


brain stem contains

Medulla Oblongata


Where and what is in Medulla Oblongata

Starts at the foremen magnum and goes to pons
Mede up of sensory (ascending) tracts and motor/(descending) tract


what is pyramids

bulges of white matter of the anterior part of the medulla
formed by the corticospinal tracts


What is dicussation of pyramids

Crossing of axons in pyramids
90% of axons cross here
explains why each side of brain controls the opposite side of body


nuclei in medulla

- Cardiovascular center (regulates the heart beats and the diameter of BVs)
- Medullary rhythmicity area of the respiratory center (adjusts the basic rhythm of breathing along with areas in the pons)
- vomiting center (causes vomiting)
- deglutition center (causes swallowing)
Others causes sneezing, coughing, hiccupping


what and where is olive

just lateral to each pyramid


inferior olivary nucleus

- within the olive, receives input from cerebral cortex, red nucleus (midbrain), spinal cord
- it provides instructions that the cerebellum uses to make adjustments to mm activity as you learn new motor skills


gracile nucleus and cuneate nucleus

are associated with sensations of touch, pressure, vibration and conscious proprioception.
Gracile (leg), Cuneate (arm)


gustatory nucleus

from tongue to brain, receives gustatory input from taste buds of tongue


cochlear nuclei

part of the auditory pathway from inner ear to brain
receives auditory input from cochlea of the inner ear


Vestibular nuclei

equilibrium pathway from inner ear to brain


Cranial nerves in medulla

VIII vestibular cochlear nerves
IX glossopharyngral nerves
X vagus nerves
XI accessory nerves
XII hypoglossal nerves


Injury to Medulla

hard blow to the back of head/upper neck
can be fatal
damage to medullary rhythmicity area is really bad
alcohol overdose also suppresses the medullary rhythmicity area and may result in death


Where and what is pons

consists of nuclei and tracts
is a bridge that connects parts of brain with each other


relays signals for voluntary movements from cerebral cortex to cerebellum

pontine nucleus


pons' nuclei

pneumotaxic area: Rhythm of breathing
apneustic area: inhale/exhale
These 2 areas along with the medullary rhythmicity area help control breathing


pons'nuclei associated with cranial nerves

V trigeminal nerves
VI abducens nerves
VII facial nerves
VIII vestibulocochlear nerves (balance and equilibrium)


associated with sensations of touch, pressure, vibration and conscious proprioception

gracile nucleus and cuneate nucleus


from tongue to brain

gustatory nucleus


part of the auditory pathway from inner ear to brain

cochlear nuclei


equilibrium pathway from inner ear to brain

vestibular nuclei