MMSC 402 FINAL EXAM | QUESTIONS AND ANSWERS | 2026
UPDATE | WITH COMPLETE SOLUTION
cerebrospinal fluid (CSF) Answer - -mainly composed of secretion from the
choroid plexus the 4 ventricles of the brain
-is a selective secretion of plasma
-has higher Na, Cl and Mg than plasma does
-has lower K, Ca and protein than plasma
-adults have 85-150 mL
meninges Answer - 3 layered membrane that surrounds the brain and spinal
cord
-pia mater: inside layer touching neural tissue
-arachnoid mater: middle later that resembles spider web
-dura mater: outer layer that is next to bone
-CSF enters the space between arachnoid and pia mater to bathe and protect
neural tissue
CSF circulation Answer - CSF forms, circulates into the the areas surrounding
the neural tissues (brain and spinal cord) and is reabsorbed into blood
-20 mL are processed per hour
hydrocephalus Answer - when reabsorption of CSF is blocked and CSF builds up
,blood brain barrier Answer - the interface between blood and CSF
-accounts for differences in electrolytes, proteins and other solutes between
blood and CSF
CSF collection Answer - -collected by aseptic lumbar puncture between 3rd
and 4th lumbar interspace using local anesthesia
-initial/ opening pressure taken with manometer on the spinal needle (taken
while patient laying down, should be 50-180 mm Hg)
-closing pressure (taken after sample collection) is 10-30 mm Hg lower
-pressure values and volume of CSF collected (up to 20 mL) are recorded
-if pressure is too low or high only 1-2 mL should be taken
CSF collection tubes Answer - -1: chemistry (may contain skin contaminant)
-2: microbiology (likely contains no more skin contaminant)
-3: cell counts
CSF physical examination Answer - -should be clear and colorless and similar
thickness to water
-turbidity is related to number of cells in the sample
-cloudy appearance is associated with increased WBCs, RBCs or may be caused
by increased protein or microorganisms
pleocytosis Answer - increased number of cells in CSF
-increased neutrophils: bacterial meningitis, or viral, fungal, Tb or parasitic
infection
-lymphocytes: increased in viral, Tb, or fungal infections or late stages of
syphilitic meningitis
-plasma cells: make Ab's, typically only seen in multiple sclerosis, and acute
viral infection or chronic inflammatory conditions
, -monocytes: increased in Tb, fungal meningitis, chronic bacterial meningitis, or
rupture of cerebral abscess (typically present in infections that go on for a long
time)
-eosinophils: indicates parasitic, fungal or allergic reactions (reaction to
intracranial shunt)
-macrophage: found after hemorrhage to clean up
-other cells: check if malignant
-malignant cells: primary tumor in the CNS OR metastasis from leukemia or
lymphoma and chemotherapeutics will need to be injected directly into spinal
fluid (can't bass blood brain barrier)
blood in CSF Answer - -traumatic tap: greatest blood volume in tube 1, least
blood in tube 3, after centrifugation supernatant liquid is colorless
-hemorrhage: consistent amount of blood present in all sample tubes, after
centrifugation supernatant fluid is still xanthochromic (appears yellow/ orange
due to bilirubin)
-need to determine if hemorrhage is subarachnoid or intracerebral
CSF microscopic examination Answer - -normal cell count is 0-5 WBC/ul
-increased WBC count indicates disease of the CNS or other condition like
leukemia
-RBCs normally present
-cell counts need to be performed immediately to prevent lysing WBCs
protein in CSF Answer - -normal is 15-45 mg/dL
-protein naturally increased in infants and older adults
-increased protein can be due to contamination of blood during traumatic tap
(hemoglobin protein), change in blood brain barrier (allows more crossing of
plasma proteins into CSF), decreased reabsorption into venous blood (blood
not reabsorbing CSF)
UPDATE | WITH COMPLETE SOLUTION
cerebrospinal fluid (CSF) Answer - -mainly composed of secretion from the
choroid plexus the 4 ventricles of the brain
-is a selective secretion of plasma
-has higher Na, Cl and Mg than plasma does
-has lower K, Ca and protein than plasma
-adults have 85-150 mL
meninges Answer - 3 layered membrane that surrounds the brain and spinal
cord
-pia mater: inside layer touching neural tissue
-arachnoid mater: middle later that resembles spider web
-dura mater: outer layer that is next to bone
-CSF enters the space between arachnoid and pia mater to bathe and protect
neural tissue
CSF circulation Answer - CSF forms, circulates into the the areas surrounding
the neural tissues (brain and spinal cord) and is reabsorbed into blood
-20 mL are processed per hour
hydrocephalus Answer - when reabsorption of CSF is blocked and CSF builds up
,blood brain barrier Answer - the interface between blood and CSF
-accounts for differences in electrolytes, proteins and other solutes between
blood and CSF
CSF collection Answer - -collected by aseptic lumbar puncture between 3rd
and 4th lumbar interspace using local anesthesia
-initial/ opening pressure taken with manometer on the spinal needle (taken
while patient laying down, should be 50-180 mm Hg)
-closing pressure (taken after sample collection) is 10-30 mm Hg lower
-pressure values and volume of CSF collected (up to 20 mL) are recorded
-if pressure is too low or high only 1-2 mL should be taken
CSF collection tubes Answer - -1: chemistry (may contain skin contaminant)
-2: microbiology (likely contains no more skin contaminant)
-3: cell counts
CSF physical examination Answer - -should be clear and colorless and similar
thickness to water
-turbidity is related to number of cells in the sample
-cloudy appearance is associated with increased WBCs, RBCs or may be caused
by increased protein or microorganisms
pleocytosis Answer - increased number of cells in CSF
-increased neutrophils: bacterial meningitis, or viral, fungal, Tb or parasitic
infection
-lymphocytes: increased in viral, Tb, or fungal infections or late stages of
syphilitic meningitis
-plasma cells: make Ab's, typically only seen in multiple sclerosis, and acute
viral infection or chronic inflammatory conditions
, -monocytes: increased in Tb, fungal meningitis, chronic bacterial meningitis, or
rupture of cerebral abscess (typically present in infections that go on for a long
time)
-eosinophils: indicates parasitic, fungal or allergic reactions (reaction to
intracranial shunt)
-macrophage: found after hemorrhage to clean up
-other cells: check if malignant
-malignant cells: primary tumor in the CNS OR metastasis from leukemia or
lymphoma and chemotherapeutics will need to be injected directly into spinal
fluid (can't bass blood brain barrier)
blood in CSF Answer - -traumatic tap: greatest blood volume in tube 1, least
blood in tube 3, after centrifugation supernatant liquid is colorless
-hemorrhage: consistent amount of blood present in all sample tubes, after
centrifugation supernatant fluid is still xanthochromic (appears yellow/ orange
due to bilirubin)
-need to determine if hemorrhage is subarachnoid or intracerebral
CSF microscopic examination Answer - -normal cell count is 0-5 WBC/ul
-increased WBC count indicates disease of the CNS or other condition like
leukemia
-RBCs normally present
-cell counts need to be performed immediately to prevent lysing WBCs
protein in CSF Answer - -normal is 15-45 mg/dL
-protein naturally increased in infants and older adults
-increased protein can be due to contamination of blood during traumatic tap
(hemoglobin protein), change in blood brain barrier (allows more crossing of
plasma proteins into CSF), decreased reabsorption into venous blood (blood
not reabsorbing CSF)
