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Brain
The center of our nervous system and daily thoughts, the brain is a complex, magnificent organ. Ask questions about parts of the brain and their functions here.
2,537 Questions
What is the brains most startling accomplishment?
self-awareness of it's own different capabilities and knowledge
What happen to the organs and brain after an autopsy?
donated
No, not necessarily. Organs are usually useless for transplant donation after such a time has elapsed, and can only be donated to medical schools for students to study and dissect as part of their training. In any case, such donation can only happen if the deceased has especially stipulated that they are happy for this to happen. Normally, they are returned to the body for burial or cremation by the next of kin.
In cases where the autopsy is investigating an unknown cause of death as oppose to a routine confirmation of a suspected cause, or in cases where the dead person has been murdered and further investigation is needed to determine what they died of, how a bullet or knife wound entered and exited an organ etc., then the organ(s) may be retained for a longer period to be examined by forensic pathologists. If poisoning is suspected, then chemical tests may be done to confirm that this was the cause of death. During such time, the body is kept in cold storage in case any other part of it needs examination- finally, when a conclusion is reached and agreed upon, then the organs are placed back in the cadaver which is handed over to the next of kin for disposal.
parallel processing
How can subarachnoid hemorrhages be prevented?
Traumatic brain injury is the leading cause of subarachnoid hemorrhages, so it follows that efforts to prevent head injury would prevent these hemorrhages.
The sense of smell is directed through the limbic system without passing through the thalamus first.
What is the function of the sylvian fissure?
a sylvian fissure is one of the parts of the brain and we spell it s y l v i a n f i s s u r e i thank you =)
List of all drugs which cross blood brain barrier?
Drug Class
Generic Name
(Trade Name)
Absorption
Distribution
Elimination Alkylating Agents
melphalon
(Alkeran)
oral - variably and incompletely absorbed from the GI tract, decreased in presence of food
moderately high protein binding, Vz 0.5 l/kg
deactivated in plasma by hydrolysis
cyclophosphamide
(Cytoxan)
oral - high bioavailability; intravenous
crosses blood-brain barrier (limited)
hepatic biotransformation (includes activation); 5 - 25% eliminated unchanged (renal); parent and metabolites eliminated in urine are toxic to bladder
ifosfamide
(Ifex)
intravenous infusion only
active metabolites cross blood-brain barrier (limited)
hepatic biotransformation (includes activation); 10 - 60% eliminated unchanged (increases with increasing dose - renal); parent and metabolites eliminated in urine are toxic to bladder
busolfan
(Myleran)
oral - completely absorbed from GI tract
rapid hepatic biotransformation
procarbazine
(Matulane)
oral - Rapidly and completely absorbed from the gastrointestinal tract.
Crosses blood-brain barrier.
Hepatic biotransformation, very short elimination half-life. 70% renal elimination as metabolites.
dacarbazine
(Otic-Dome)
Intravenous only
limited access to CNS; low protein binding
Extensive hepatic biotransformation; 50% renal elimination (1/2 unchanged).
Antibiotics
daunorubicin
(Cerubidine)
intravenous only
body water, excluded by blood-brain barrier
hepatic metabolism produces both active and inactive metabolites.
daunorubicin or doxorubicin liposomes
(Daunoxome or Doxil)
intravenous infusion only
limited to vascular fluid, animal studies indicate delivery to CNS; tissues selectively "acquire" liposomes.
greatly reduced hepatic metabolism compared to un-encapsulated drug
doxorubicin
(Adriamycin)
intravenous only
high protein binding; extensive uptake into many tissues, does not cross blood-brain barrier
hepatic metabolism produces both active and inactive metabolites; tissue metabolism results in production of free radicals.
idarubicin
(Idamycin)
intravenous infusion only
extensive tissue binding of both native drug and metabolite; very high plasma protein binding
hepatic and extrahepatic metabolism to equipotent metabolite; elimination primarily biliary as active metabolite.
plicamycin
(Mithracin)
intravenous infusion only
crosses blood-brain barrier, concentrated in Kupffer cells, renal tubular cells and bone surfaces
elimination is renal
mitomycin (Mutamycin)
intravenous only
does not cross blood brain barrier
hepatic biotransformation, 10% eliminated in urine unchanged (% increases as dose increases)
pentostatin
(Nipent)
intravenous only
crosses blood-brain barrier (CSF concentrations ~10% of plasma concentrations within 24 hours). Low plasma protein binding
hepatic biotransformation, 30% - 70% eliminated in urine as unchanged drug
mitoxantrone
(Novantrone)
intravenous infusion only
rapid extensive distribution to tissues; high protein binding
hepatic; long half-life (due to tissue binding & slow metabolism); small fraction eliminated unchanged.
dactinomycin
(Cosmegen)
intravenous only
does not cross blood brain barrier
Minimal biotransformation; Elimination primarily biliary/fecal 50% unchanged (24 hours), another 10% unchanged in urine (24 hour); remainder of the drug is recovered within 1 week.
Antimetabolites
fluorouracil
(Adrucil)
intravenous only
good tissue penetration, crosses blood brain barrier
hepatic metabolism produces 2 active metabolites and catabolism; respiratory elimination as carbon dioxide; 7 - 20% unchanged in urine
capecitabine
(Xeloda)
oral (pro drug)
as for fluorouracil
hepatic activation by conversion to 5 fluorouracil; elimination pattern as for 5 flurouracil
fludarabine
(Fludara)
intravenous only
distributed to whole body water
RAPIDLY dephosphylated in serum to 2-fluoro-Ara-A, then phosphorylated intracellularly to active compound. Elimination is renal, approximately 20% unchanged 2-fluoro-Ara-A
mercaptopurine
(Purinethol)
oral - variably and incompletely absorbed from the GI tract (up to 50%)
Crosses blood-brain barrier but poorly; low protein binding
Hepatic metabolism for both activation and catabolism; degraded by xanthine oxidase; 7 - 40% eliminated unchanged.
gemcitabine
(Gemzar)
intravenous infusion only
distribution of active metabolite is limited by saturable process. Giving gemcitabine at an excess rate WASTES drug (eliminated intact before conversion).
Intracellular metabolism (saturable) to active metabolites. Hepatic deamination to inactive uracil metabolite.
Hormonal Oncologics
topotecan
(Hycamtin)
intravenous infusion only
good tissue penetration, volumes approximately 2x body water, crosses blood brain barrier
reversible pH-dependent hydrolysis to inactive moeity (low pH favors active compound), hepatic metabolism insignificant; 30% eliminated unchanged in urine
leuprolide
(Lupron)
IM injection - 90% bioavailability; 1 month, 3 month and 4 month release formulations
distributed to extracellular fluid volume; moderate (50%) protein binding.
Metabolized to several inactive peptides. Less than 5% recovered as parent or pentapeptide metabolite.
tamoxifen
(Nolvadex)
oral administration, bioavailability?
?
Hepatic biotransformation with enterohepatic circulation. Prolonged elimination; Elimination primarily biliary/fecal, mostly as metabolites
Mitosis inhibitors
etopside
(VP16)
oral - variable dose-dependent oral bioavailability (F decreases as dose increases); intravenous
Low and variable into CSF, concentration differentials between normal and cancerous tissues. Very high protein binding (97%). Protein displacement interactions and hypoalbuminemia are concerns.
Hepatic biotransformation; up to 50 - 60% renal elimination (2/3 as unchanged drug); remainder fecal.
Others
hydroxyurea
(Hydrea)
Well absorbed following oral administration.
Crosses the blood-brain barrier (very small molecular weight).
Hepatic metabolism (inactivation), 80% renal elimination within 12 hours (50% unchanged); balance eliminated from lungs as CO2
paclitaxel
(Taxol)
intravenous only
extensive extravascular distribution and/or tissue binding. Very high plasma protein binding.
Hepatic p450 metabolism. Elimination primarily biliary / fecal. Variable renal elimination of unchanged drug.
docetaxel
(Taxotere)
intravenous only
widely distributed in tissues; slightly larger than body water; poor CNS penetration.
Hepatic p450 metabolism. Elimination primarily biliary / fecal.
cisplatin
(Platinol)
intravenous only
does not penetrate CNS
rapid non-enzymatic conversion to inactive metabolites. Elimination usually expressed as recovered platinum (only 50% after 5 days), platinum detected in tissues for months.
aspariginase
(Elspar)
intravenous
intramuscular
slow sequestration by reticuloendothelial system; poor CNS penetration
unknown pathway, only trace amounts appear in the urine following IV administration.
Anti-toxicity
amifostine
(Ethyol)
intravenous infusion only
wide rapid distribution
metabolised by alkaline phosphatase to active free thiol metabolite (binds cisplatin metabolites and alkylating agents and scavanges free radicals. Reaction favored in normal tissues (higher AP)
dexrazoxane
(Zinecard)
intravenous only
distributed to whole body water, low protein binding
several hepatic metabolites, intracellular metabolite may be responsible for action though this is speculative at this time
mesna
(Mesnex)
intravenous only
volume of distribution approximates body water.
rapid hepatic biotransformation to mesna disulfide; mesna disulfide is reduced to mesna by renal tubular epithelium, mesna binds and detoxifies metabolites of oxazophosphorines.
I think it maybe useful for You :)
A, acetylcholine.
Acetylcholine is commonly secreted at neuromuscular junctions, the gaps between motor neurons and muscle cells, where it stimulates muscules to contract. At other kinds of junctions, it typically produces and inhibitory post-synaptic potential.
What is the major organ of a peripheral nervous system?
The brain, spinal cord, retina, sensory neurons, ganglia, and the nerves are the organs of the nervous system.
What part of the brain is affected from epilspy?
Surprisingly and fortunately the brain does not seem to get affected by epilepsy.
Do people think they are right all the time?
There are a group of people who think they are right all the time. Which clearly says they aren't because no one is right 'all the time'. Those people have just enough knowledge on any given subject to always have an opinion on everything and when the conversation reaches to a point where they don't know....they feel attacked. They should just humbly accept the fact that they don't know everything and just make comments to contribute to the conversation and allow for different opinions.
brain injury is more serious at the back of the brain. this is because the cerebellum is located in this area. the cerebellum controls coordination and balance :D btw i just guessed this
Does the hypothalamus produce antidiuretic hormone?
Yes. It is secreted in the posterior pituitary though.
What do it mean when you smell coffee and there is none around?
If I understand you're question correctly you are reffering to the term "wake up and smell the coffee". it basically means except reality, or stop pretending or thinking things are going to be one way when their not. also kinda of like get you're head out of the clouds. if someone wants to live their life without having to work someone might say wake up and smeel the coffee or something like that.
When you are depressed what happens to the levels of serotonin?
You have it backward I believe. When serotonin is lower, people have more risk to experience depression.
Which are the regions of the brain occupied by Left MCA?
That is called the left middle cerebral artery (MCA)
