Brain 2: brain blood flow, CFS brainstem Flashcards

0
Q

How are glucose and oxygen used in the brain

A

Neurons use glucose and oxygen to make ATP in the brain

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1
Q

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

A

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

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2
Q

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

A

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

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3
Q

how does brain store glucose

A

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

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4
Q

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

A

mental confusion
dizziness
convulsions
loss of consciousness

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5
Q

how many % of cardio output goes to brain

A

15%

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6
Q

what is blood brain barrier

A

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

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7
Q

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

A

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

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8
Q

What can cross the blood brain barrier

A
  • 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)
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9
Q

What can not cross the blood brain barrier

A

Proteins and most antibiotic drugs do not cross

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10
Q

What can break down the blood brain barrier

A

Trauma, certain toxins and inflammation

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11
Q

What is Cerebral spinal fluid

A

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

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12
Q

what does cerebral spinal fluid carry

A

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

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13
Q

Where does cerebral fluid circulate through

A

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

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14
Q

What is the total volume of cerebral spinal fluid?

A

80-150 ml in adult

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15
Q

what are ventricles in the brain

A

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

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16
Q

What is a thin membrane that separates that the lateral ventricles

A

Septum pelluciadum

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17
Q

Functions of ventricles

A
  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
18
Q

Where is CSF formed

A

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

19
Q

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

A

BBB=tight junctions of brain capillary endothelial cells

Blood-CSF barrier=tight junctions of ependymal cells

20
Q

What does Blood CSF barrier do

A

to protect brain and spinal cord from harmful blood borne substances

21
Q

Circulation of CSF

A

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

22
Q

brain stem contains

A

Medulla Oblongata
Pons
Midbrain

23
Q

Where and what is in Medulla Oblongata

A

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

24
Q

what is pyramids

A

bulges of white matter of the anterior part of the medulla

formed by the corticospinal tracts

25
Q

What is dicussation of pyramids

A

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

26
Q

nuclei in medulla

A
  • 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
27
Q

what and where is olive

A

just lateral to each pyramid

28
Q

inferior olivary nucleus

A
  • 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
29
Q

gracile nucleus and cuneate nucleus

A

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

30
Q

gustatory nucleus

A

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

31
Q

cochlear nuclei

A

part of the auditory pathway from inner ear to brain

receives auditory input from cochlea of the inner ear

32
Q

Vestibular nuclei

A

equilibrium pathway from inner ear to brain

33
Q

Cranial nerves in medulla

A
VIII vestibular cochlear nerves
IX glossopharyngral nerves
X vagus nerves
XI accessory nerves
XII hypoglossal nerves
34
Q

Injury to Medulla

A

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

35
Q

Where and what is pons

A

consists of nuclei and tracts

is a bridge that connects parts of brain with each other

36
Q

relays signals for voluntary movements from cerebral cortex to cerebellum

A

pontine nucleus

37
Q

pons’ nuclei

A

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

38
Q

pons’nuclei associated with cranial nerves

A

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

39
Q

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

A

gracile nucleus and cuneate nucleus

40
Q

from tongue to brain

A

gustatory nucleus

41
Q

part of the auditory pathway from inner ear to brain

A

cochlear nuclei

42
Q

equilibrium pathway from inner ear to brain

A

vestibular nuclei