Why is the blood-brain barrier important?

Why is the blood-brain barrier important? 
by

1 Answer

Answer :

The blood-brain barrier is formed by the contacts of special glial cells, called astrocytes, with blood vessels. It is essential for maintaining homeostasis in the brain. In general, only lipid-soluble molecules, such as carbon dioxide, oxygen, steroids, and alcohols, can pass through the blood-brain barrier easily. Water-soluble molecules, such as sodium, potassium, and chloride ions can pass through the blood-brain barrier only with the assistance of specific carrier molecules. Some substances cannot pass through the barrier at all. 
by

Related questions

Is brain size an indication of intelligence? How the size changes from birth to adulthood?

Description : Is brain size an indication of intelligence? How the size changes from birth to adulthood?

Last Answer : There is no correlation between brain size and intelligence. Individuals with the smallest brains (as small as 46 cubic inches [750 cubic centimeters]) and the largest brains (as large as 128 cubic inches [2,100 ... annual rate of shrinkage increases to 0.10 to 0.143 ounces (3 to 4 grams) per year.

How does blood circulate in the fetus?

Description : How does blood circulate in the fetus?

Last Answer : Fetal circulation differs from circulation after birth because the lungs of the fetus are nonfunctional. Therefore, blood circulation essentially bypasses the lungs in the fetus. The umbilical vein carries ... cava. Some blood stays in the pulmonary trunk to reach the developing lung tissues. 

What's meant by a diurnal rhythm ? And accordingly, How can I solve the following physiology MCQ?

Description : What's meant by a diurnal rhythm ? And accordingly, How can I solve the following physiology MCQ?

Last Answer : “Diurnal” is not a medical term. It’s just an English word. The opposite of “nocturnal.” https://www.dictionary.com/browse/diurnal

What is the nature of this sensation?

Description : What is the nature of this sensation?

Last Answer : Sounds like a cold sore.

Do you ever have days where you feel mentally high? (without intentional use of drugs)

Description : Do you ever have days where you feel mentally high? (without intentional use of drugs)

Last Answer : I am able to put myself there by working out in the morning, but not just any work out will do.. it has to be just the right kind of interval training of cardio and strength training at the same ... I give myself the greatest natural buzz.. I think clear, I have so much energy through out the day.

How many senses do humans have?

Description : How many senses do humans have?

Last Answer : I think there are many that have different abilities such as spiritual gifts that are not included in the 5 senses.

Is the ability to tiptoe designed for intimidation?

Description : Is the ability to tiptoe designed for intimidation?

Last Answer : No it is just part of what and who we are. We don’t use most of what we are capable of and if we knew how much we are able to really do we would be amazed. In Time. Smile

Why do our bodies do the wrong things so often?

Description : Why do our bodies do the wrong things so often?

Last Answer : Because life is messy. And we’re not the only things living on us. Not everything is symbiotic and beneficial.

Why does it feel so good to pop your knuckles?

Description : Why does it feel so good to pop your knuckles?

Last Answer : answer:Howstuffworks to the rescue: [The] Golgi tendon organs (a set of nerve endings involved in humans' motion sense) are stimulated and the muscles surrounding the joint are relaxed. This is ... crackers did experience soft tissue damage to the joint capsule and a decrease in grip strength.

Why don't we sneeze in our sleep?

Description : Why don't we sneeze in our sleep?

Last Answer : answer:i was just reading around, some guy asked how do you know you aren't sneezing when asleep? lol I also ready that a lot of our mucus membranes are .. in laymans terms, shut off , so ... one of my sisters burp while asleep (that was nothing short of hilarious), and we cough. Dunno really..

What are Killed (inactivated) vaccines?

Description : What are Killed (inactivated) vaccines?

Last Answer : When safe live vaccines are not available, either because attenuated strains have not been developed or else because reversion to wild type occurs too readily, it may be possible to use an ... site. However, the same disadvantages of poor immunogenicity and the need for multiple boosters apply. 

Are cells in the nervous system replaced during an individual’s lifetime?

Description : Are cells in the nervous system replaced during an individual’s lifetime?

Last Answer : Neurons have a very limited capacity for regeneration. In general, they neither replicate themselves nor repair themselves. Axons and dendrites in the peripheral nervous system may undergo repair if the cell ... stem cells that remain in adults that can produce a limited number of new neurons. 

Do creatine supplements improve muscular performance?

Description : Do creatine supplements improve muscular performance?

Last Answer : Creatine phosphate (CP) is a molecule stored in muscle that yields energy when the creatine splits from the attached phosphate. This energy is used to resynthesize the small amount of ATP (adenosine ... on aerobic metabolism. The long-term effect of such supplementation on the human body is unknown.

Which neurotransmitter is depleted in Parkinson’s disease?

Description : Which neurotransmitter is depleted in Parkinson’s disease?

Last Answer : Parkinson's disease results from a deficiency of the neurotransmitter dopamine in certain brain neurons that regulate motor activity. Parkinson's disease is characterized by stiff posture, tremors, slowness ... Nerve cells can use levodopa to make dopamine and replenish the brain's dwindling supply.

Are smooth muscle contractions the same as skeletal muscle contractions?

Description : Are smooth muscle contractions the same as skeletal muscle contractions?

Last Answer : There are similarities, as well as differences, in comparing smooth and skeletal muscle contractions. Both types of muscles include reactions involving actin and myosin, both are triggered by membrane impulses and ... (as when the stomach is full), while this does not occur in skeletal muscles.

Which is the only bone that does not touch another bone?

Description : Which is the only bone that does not touch another bone?

Last Answer : The hyoid bone is the only bone that does not touch another bone. Located above the larynx, it supports the tongue and provides attachment sites for the muscles of the neck and pharynx used in ... examined when there is a suspicion of strangulation, since it is often fractured from such trauma. 

How does the endocrine system differ from the nervous system?

Description : How does the endocrine system differ from the nervous system?

Last Answer : Both the endocrine and nervous are regulatory systems that permit communication between cells, tissues, and organs. A major difference between the endocrine system and nervous system is the ... endocrine system are longer lasting. Examples of endocrine control are growth and reproductive ability.

What is rigor mortis?

Description : What is rigor mortis? 

Last Answer : Dead bodies are at first limp. Several hours after death, the skeletal muscles undergo a partial contraction that fixes the joints. This condition, known as rigor mortis, may continue for 72 ... the muscle fibers to remain linked, stiffening the whole body until the muscles begin to decompose. 

How the Urinary tract infections are differentiating?

Description : How the Urinary tract infections are differentiating? 

Last Answer : Urinary tract infections may occur in the urethra, where they are called urethritis; if they occur in the bladder, they are referred to as cystitis; and if they develop in the ureters, ... of the immune system and type III hypersensitivity. Fever and high blood pressure accompany the disease.  

What are the effects of Ageing on respiratory system?

Description : What are the effects of Ageing on respiratory system? 

Last Answer : There is a decline in the efficiency of the respiratory system with ageing. There is a gradual loss of elastic tissue & the chest wall becomes less capable of expansion. These changes show up ... white blood cells. This leaves the system more prone to disease like pneumonia, bronchitis & emphysema. 

Which types of tissue have the greatest capacity to regenerate?

Description : Which types of tissue have the greatest capacity to regenerate?

Last Answer : Epithelial and connective tissues have the greatest capacity to regenerate. In small wounds and injuries, the epithelial and connective tissues often heal with normal tissue. The ability of muscle tissue to ... at a very slow pace, most brain and spinal cord injuries result in permanent damage.  

Is all the cartilage in the body the same?

Description : Is all the cartilage in the body the same? 

Last Answer : There are three types of cartilage in the human body: 1) hyaline cartilage; 2) elastic cartilage; and 3)fibrocartilage. Hyaline cartilage (from the Greek hyalos, meaning glass ) is the most ... , since there are no blood vessels in cartilage, the healing process is slower than for other tissues

How is the skin involved in the regulation of body temperature?

Description : How is the skin involved in the regulation of body temperature? 

Last Answer : The skin is one of several organ systems participating in maintaining a core temperature, meaning the temperature near the center of someone's body. Temperature sensors in the skin and internal organs monitor ... sweat evaporates off the skin surface it carries a large amount of body heat with it. 

Does your heart stop beating when you sneeze?

Description : Does your heart stop beating when you sneeze? 

Last Answer : The heart does not stop beating when you sneeze. Sneezing, however, does affect the cardiovascular system. It causes a change in pressure inside the chest. This change in pressure affects the blood ... a harmless delay between one heartbeat and the next, often misinterpreted as a skipped beat.

Why is a man’s voice usually lower than a woman’s voice?

Description : Why is a man’s voice usually lower than a woman’s voice?

Last Answer : The pitch of the voice-how high or low it sounds-depends on the length, tension, and thickness of the vocal cords. Because males have longer vocal cords of up to 1 inch (2.54 ... Testosterone is the hormone that is responsible for the increase of length of male vocal cords during puberty.

How are the neurotransmitter molecules inactivated after they are released at a synapse?

Description : How are the neurotransmitter molecules inactivated after they are released at a synapse?

Last Answer : After a chemical neurotransmitter has been released from the synaptic terminal, its action must be terminated in some way. Otherwise, the continued presence of the transmitter in the ... mechanism is used to inactivate Acetylcholine released from the synaptic terminals of the motor neurons.

What is Physiology?

Description : What is Physiology?

Last Answer : A. The study of the functions of living organisms and their parts.

Blood brain barrier can be crossed by (A) Epinephrine (B) Dopamine (C) Dopa (D) All of these

Description : Blood brain barrier can be crossed by (A) Epinephrine (B) Dopamine (C) Dopa (D) All of these

Last Answer : Answer : C

A hormone which cannot cross the blood brain barrier is (A) Epinephrine (B) Aldosterone (C) ACTH (D) TSH

Description : A hormone which cannot cross the blood brain barrier is (A) Epinephrine (B) Aldosterone (C) ACTH (D) TSH

Last Answer : Answer : A

At low blood glucose concentration, brain but not liver will take up glucose. It is due to the (A) Low Km of hexokinase (B) Low Km of glucokinase (C) Specificity of glucokinase (D) Blood brain barrier

Description : At low blood glucose concentration, brain but not liver will take up glucose. It is due to the (A) Low Km of hexokinase (B) Low Km of glucokinase (C) Specificity of glucokinase (D) Blood brain barrier

Last Answer : Answer : A

Ephedrine is similar to adrenaline in the following feature (a) Potency (b) Inability to penetrate blood-brain barrier (c) Duration of action (d) Producing both a and ß adrenergic effects

Description : Ephedrine is similar to adrenaline in the following feature (a) Potency (b) Inability to penetrate blood-brain barrier (c) Duration of action (d) Producing both a and ß adrenergic effects

Last Answer : Ans: D

Dobutamine differs from dopamine in that (a) It does not activate peripheral dopaminergic receptors (b) It does not activate adrenergic ß receptors (c) It causes pronounced tachycardia (d) It has good blood-brain barrier penetrability

Description : Dobutamine differs from dopamine in that (a) It does not activate peripheral dopaminergic receptors (b) It does not activate adrenergic ß receptors (c) It causes pronounced tachycardia (d) It has good blood-brain barrier penetrability

Last Answer : Ans: A

The capacity of an antihistaminic to produce sedation depends on the following except (a) Relative affinity for central versus peripheral H1 receptors (b) Ability to penetrate blood-brain barrier (c) Individual susceptibility (d) Ratio of H1 : H2 blockade produced by the drug

Description : The capacity of an antihistaminic to produce sedation depends on the following except (a) Relative affinity for central versus peripheral H1 receptors (b) Ability to penetrate blood-brain barrier (c) Individual susceptibility (d) Ratio of H1 : H2 blockade produced by the drug

Last Answer : Ans: D

Sulfamethoxypyridazine and other related long acting sulfonamides have now gone into disuse because (a) They have produced serious cutaneous reactions (b) They have produced high incidence of crystalluria (c) They interact with many drugs (d) They do not penetrate blood-brain barrier

Description : Sulfamethoxypyridazine and other related long acting sulfonamides have now gone into disuse because (a) They have produced serious cutaneous reactions (b) They have produced high incidence of crystalluria (c) They interact with many drugs (d) They do not penetrate blood-brain barrier

Last Answer : Ans: A

The following are true about blood-brain barrier: a. it is permeable at birth b. it involves tight junction between endothelial cells and end feet processes of astrocytes c. it is absent in the posterior pituitary d. all above

Description : The following are true about blood-brain barrier: a. it is permeable at birth b. it involves tight junction between endothelial cells and end feet processes of astrocytes c. it is absent in the posterior pituitary d. all above

Last Answer : all above

The blood-brain-barrier: a. contains the foot processes of astrocytes b. contains endothelial cells with tight junction c. allows transport in one direction only ie from the vascular system into the brain d. does not allow diffusion of water

Description : The blood-brain-barrier: a. contains the foot processes of astrocytes b. contains endothelial cells with tight junction c. allows transport in one direction only ie from the vascular system into the brain d. does not allow diffusion of water

Last Answer : does not allow diffusion of water

The blood - brain barrier: a. is permeable to bilirubin at birth b. is formed by the tight junctions between endothlial cells and the end feet processes of astrocytes c. is permeable to glucose d. all above

Description : The blood - brain barrier: a. is permeable to bilirubin at birth b. is formed by the tight junctions between endothlial cells and the end feet processes of astrocytes c. is permeable to glucose d. all above

Last Answer : all above

The blood - brain barrier: a. is permeable to bilirubin at birth b. is formed by the tight junctions between endothlial cells and the end feet processes of astrocytes c. is permeable to glucose d. all above

Description : The blood - brain barrier: a. is permeable to bilirubin at birth b. is formed by the tight junctions between endothlial cells and the end feet processes of astrocytes c. is permeable to glucose d. all above

Last Answer : all above

The following is not true of morphine: A. Its 2-glucuronide metabolite is an active analgesic B. Its active metabolite penetrates blood-brain barrier better than morphine C. Its oral: parenteral activity ratio is 1:4 D. It undergoes enterohepatic cycling

Description : The following is not true of morphine: A. Its 2-glucuronide metabolite is an active analgesic B. Its active metabolite penetrates blood-brain barrier better than morphine C. Its oral: parenteral activity ratio is 1:4 D. It undergoes enterohepatic cycling

Last Answer : B. Its active metabolite penetrates blood-brain barrier better than morphine

Neuromuscular blocking drugs do not produce central actions because: A. They do not cross the blood-brain barrier B. Nicotinic receptors are not present in the brain C. They are sequestrated in the periphery by tight binding to the skeletal muscles D. They do not ionise at the brain pH

Description : Neuromuscular blocking drugs do not produce central actions because: A. They do not cross the blood-brain barrier B. Nicotinic receptors are not present in the brain C. They are sequestrated in the periphery by tight binding to the skeletal muscles D. They do not ionise at the brain pH

Last Answer : A. They do not cross the blood-brain barrier

Compared to ****/beef insulins, the human insulins: A. Are more potent B. Have a faster kinetics of absorption and elimination C. Have longer biological action half life D. Penetrate blood-brain barrier more efficiently

Description : Compared to pork/beef insulins, the human insulins: A. Are more potent B. Have a faster kinetics of absorption and elimination C. Have longer biological action half life D. Penetrate blood-brain barrier more efficiently

Last Answer : B. Have a faster kinetics of absorption and elimination

The capacity of an antihistaminic to produce sedation depends on the following except: A. Relative affinity for central versus peripheral H1 receptors B. Ability to penetrate blood-brain barrier C. Individual susceptibility D. Ratio of H1:H2 blockade produced by the drug

Description : The capacity of an antihistaminic to produce sedation depends on the following except: A. Relative affinity for central versus peripheral H1 receptors B. Ability to penetrate blood-brain barrier C. Individual susceptibility D. Ratio of H1:H2 blockade produced by the drug

Last Answer : D. Ratio of H1:H2 blockade produced by the drug

Ephedrine is similar to adrenaline in the following feature: A. Potency B. Inability to penetrate blood-brain barrier C. Duration of action D. Producing both α and β adrenergic effects

Description : Ephedrine is similar to adrenaline in the following feature: A. Potency B. Inability to penetrate blood-brain barrier C. Duration of action D. Producing both α and β adrenergic effects

Last Answer : D. Producing both α and β adrenergic effects

Dobutamine differs from dopamine in that: A. It does not activate peripheral dopaminergic receptors B. It does not activate adrenergic β receptors C. It causes pronounced tachycardia D. It has good blood-brain barrier penetrability

Description : Dobutamine differs from dopamine in that: A. It does not activate peripheral dopaminergic receptors B. It does not activate adrenergic β receptors C. It causes pronounced tachycardia D. It has good blood-brain barrier penetrability

Last Answer : A. It does not activate peripheral dopaminergic receptors

Neostigmine is preferred over physostigmine for treating myasthenia gravis because: A. It is better absorbed orally B. It has longer duration of action C. It has additional direct agonistic action on nicotinic receptors at the muscle end plate D. It penetrates blood-brain barrier

Description : Neostigmine is preferred over physostigmine for treating myasthenia gravis because: A. It is better absorbed orally B. It has longer duration of action C. It has additional direct agonistic action on nicotinic receptors at the muscle end plate D. It penetrates blood-brain barrier

Last Answer : C. It has additional direct agonistic action on nicotinic receptors at the muscle end plate

Weakly acidic drugs: A. Are bound primarily to α1 acid glycoprotein in plasma B. Are excreted faster in alkaline urine C. Are highly ionized in the gastric juice D. Do not cross blood-brain barrier

Description : Weakly acidic drugs: A. Are bound primarily to α1 acid glycoprotein in plasma B. Are excreted faster in alkaline urine C. Are highly ionized in the gastric juice D. Do not cross blood-brain barrier

Last Answer : B. Are excreted faster in alkaline urine

Which of the following is not true of the blood-brain barrier: A. It is constituted by tight junctions between the endothelial cells of brain capillaries and the glial tissue B. It allows passage of lipid soluble drugs into the brain C. It limits entry of highly ionized drugs into the brain D. It regulates passage of substances from brain into blood

Description : Which of the following is not true of the blood-brain barrier: A. It is constituted by tight junctions between the endothelial cells of brain capillaries and the glial tissue B. It allows passage ... of highly ionized drugs into the brain D. It regulates passage of substances from brain into blood

Last Answer : D. It regulates passage of substances from brain into blood

6 The blood-brain barrier, which restricts entry of many drugs into brain, is constituted by: A. P-glycoprotein efflux carriers in brain capillary cells B. Tight junctions between endothelial cells of brain capillaries C. Enzymes present in brain capillary walls D. All of the above

Description : 6 The blood-brain barrier, which restricts entry of many drugs into brain, is constituted by: A. P-glycoprotein efflux carriers in brain capillary cells B. Tight junctions between endothelial cells of brain capillaries C. Enzymes present in brain capillary walls D. All of the above

Last Answer : D. All of the above

08. What does the term “bioavailability” mean? a) Plasma protein binding degree of substance b) Permeability through the brain-blood barrier c) Fraction of an uncharged drug reaching the systemic circulation following any route administration d) Amount of a substance in urine relative to the initial doze

Description : 08. What does the term bioavailability mean? a) Plasma protein binding degree of substance b) Permeability through the brain-blood barrier c) Fraction of an uncharged drug reaching the systemic ... following any route administration d) Amount of a substance in urine relative to the initial doze

Last Answer : C

06. A hydrophilic medicinal agent has the following property: a) Low ability to penetrate through the cell membrane lipids b) Penetrate through membranes by means of endocytosis c) Easy permeation through the blood-brain barrier d) High reabsorption in renal tubules

Description : 06. A hydrophilic medicinal agent has the following property: a) Low ability to penetrate through the cell membrane lipids b) Penetrate through membranes by means of endocytosis c) Easy permeation through the blood-brain barrier d) High reabsorption in renal tubules

Last Answer : a) Low ability to penetrate through the cell membrane lipids