What Is Brain Blood Barrier?

If you are regular reader of our blog then you already know about the four stages of medication, routes for medicine administration, and what happens to the medicine in digestive system, circulatory system, and tissues and cells.

Medication and the Brain

As you know, medication we take enters into the blood stream and circulated throughout the body. It travels to various organs including brain. Some medications can affect the functionality of chemical called neurotransmitters. These chemicals control signal being sent and received between brain cells called neurons. There are specialized neurotransmitters that are responsible for your feelings and moods.

Brain Blood Barrier

There is a blood-brain barrier in place that prevents medicines from getting the access to the brain. This barrier also blocks toxins, bacteria and other unwanted molecules to protect the brain from potential damages. However, sometimes infections can infiltrate this line of defense. The molecules of anti-biotic are larger in size and are blocked by BBB. Therefore, these antibiotics cannot fight bacteria. However, the infection causes inflammation which further weakens the barrier and allows anti-biotic molecules to filter through.

Medicines with Fat Soluble Properties           

There is another way for getting through the blood brain barrier. There are some medications that require the direct access to the brain. These medicines are fat soluble medicines and can easily get through the defense of the BBB. The brain blood barrier is deliberately weak in some areas of the brain. In these areas, the brain monitors the composition of blood and makes necessary adjustments in the blood. There are some diseases and conditions that weaken this barrier to a dangerous level. This allows harmful chemicals and toxins to pass though the brain blood barrier.

Disease and Conditions That Weaken the Brain Blood Barrier  

• Hypertension  
• Infections
• Inflammation
•  Ischaemia
• Head trauma
•  Meningitis
• Epilepsy
• Alzheimer’s disease
• Multiple sclerosis
• Viruses
• HIV Encephalitis
•  Abnormal pressure around the brain
• Very high and prolonged exposure to radiation and microwaves

When you are preparing or appearing for a medical entrance exam, you can find multiple choice questions about medicines. You can search and practice MCQ questions for medical students online or you can download Synap for creating, sharing and practicing medical quizzes on your Smartphone. This application allows students to create quizzes and study circles for sharing their knowledge with their classmates. Teachers can use this application to create private classrooms for their students.

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What Happens To The Medicine We Eat? Learn About the Four Stages of the Lifecycle of Medicine

You popped pills prescribed by the doctor to get relief from pain in some part of your body, what’s next? What happens to the medicine after it enters in our body? How does it make a way to identify and treat a particular site in the body?

Pharmacology is the branch of medicine that is concerned with the modes of action, uses and effects of the drugs.

Pharmacokinetics is one of the aspects of Pharmacology that deals with the study of the entire lifecycle of medicine inside our body.

Whether you are a medical student preparing for medical entrance exam or just a curious person, you are going to learn about the voyage of pills, potions and syrups in our body.

Four Stages of Pharmacokinetics

The lifecycle of medicine in our body is completed in following four phases. These stages are known as four stages of pharmacokinetics.

Absorption  Þ Distribution ÞMetabolism Þ Excretion  

There is an easy way to remember these four stages. You can collectively refer to these stages as ADME (Absorption, Distribution, Metabolism and Excretion).

The understanding of the lifecycle of medicine helps in designing medicines that can treat a disease, injury or condition completely, effectively and with minimum side effects.  

The Absorption Stage

This stage starts with the administration of the medicine. Oral, intramuscular, intravenous, transdermal and subcutaneous are the most common ways to administer a medicine. When a medicine is administrated orally, it makes its way via special blood vessels. These blood vessels lead from the digestive tract to the liver. This is where the medicine is broken down. Directly administrating drug/medicine to the bloodstream, bypassing the liver and there are a few other ways for administrating medicine in the body.

The Distribution Stage

The bloodstream serves the purpose of a vehicle that carries medicines or drugs throughout the body. In this stage, sometimes the medicine targets the wrong site. This is the cause of side effects. For example, if you are experiencing pain in the leg, the medicine is designed to target a sore muscle in the leg. However, the pain reliever can cause irritation in the stomach as a side effect. Fat and protein molecules present in blood have an influence on the distribution of the medicine or drug. These molecules latch onto the drug/medicine and put it out of the commission.

The Metabolism stage 

Once the distribution is done, the drug is metabolized or broken down. Everything entering the bloodstream is taken to the liver, the chemical processing plant of our body. In this plant, proteins called enzymes pummel, twist, cut down, stuck together and transform these chemicals. Many products obtained after enzymatic breakdown are chemically less active. Genetics also have an effect on the way enzymes work.

The Excretion stage 

In this final stage, the removal of non-active drugs takes place via the feces or urine. A pharmacologist can actually calculate how the body of a person is processing drug or medicine. This can be done by measuring the percentage of the drug in urine. For example, if the amount of drug in urine is more than the expected, there is a need of giving higher doses or changes in the medicine.

Students preparing for medical entrance exams need to have the knowledge of the way medicines work inside our body. The best, easiest and quickest way of learning is practicing the maximum number of MCQs. You can visit a website providing medicine MCQs for practice. Smartphone applications like Synap allow students and teachers to create, share and practice medicine MCQs online. Download this app and learn more in less time.