Digestive System

Every time I teach the digestive system as part of the medical terminology module, the students are confusing and making mistakes into two things. The first one is the correct order of the alimentary canal organs, and the second one is the confusion between the alimentary canal organs and the digestive system organs. That is why I will try to explain this question in this post.

 

Q. A digestive organ that is not part of the alimentary canal is the.

a.      Stomach.

b.      Liver.

c.      Small intestine.

d.     Large intestine.

e.      Pharynx.

 

 

Correct answer;

So may questions we can create related to this topic. If you know the answer, so that means you know many things about the digestive system. Let start with the meaning of alimentary? According to Mosby’s dictionary, alimentary means something to nourish or to feeds, and the canal is the passage or channel, so together, the meaning of the alimentary canal is the passage that feeds or nourishes the body.  How is it related to the digestive system? What is the function of the digestive system? The digestive system functions are ingesting, digesting, absorbing, and excreting. The body needs to have a continuous, coiled, hollow muscular tube that winds through the ventricle body cavity and is open at both ends to do the job of the digestive system. This coiled, hollow muscular tube is called the alimentary canal. The alimentary canal also called the gastrointestinal tract (GI), starting from the mouth as the canal opening.

We can follow the correct order of the alimentary canal as below;

 

1. The mouth

2. The pharynx

3. The esophagus

4. The stomach

5. The small intestine, (duodenum, jejunum, and ileum)

6. The large intestine, (cecum, ascending colon, transverse colon, descending colon, sigmoid colon)

7. The rectum

8. The anus

 

Try to look at the image to understand the correct order of the alimentary canal.

Now, back to your question and the choices you have. One choice is not part of the alimentary canal, which is the liver. The liver is part of the accessory digestive organs, which they are working along with the alimentary canal to do the digestive system job. They are; teeth, salivary glands, pancreas, liver, and gallbladder are; together with the alimentary canal, they are make up the digestive system.

One thing left to explain it about the digestive system. Every time I taught this system to my students, they are struggling in the small intestine correct order. Every time there is a test in the digestive system, there is a question about the correct order of the small intestine, and unfortunately, the students answer the wrong answer. To make things easy to remember, the correct order of the small intestine, which they are (duodenum, jejunum, and ileum). I asked the students to take the first letters from the term duodenum, which is D, and the first letter from the term jejunum is J; if we are binding them together, we will have (DJ). (DJ) is something trendy, no one would forget it. These two letters will present the duodenum as the first part of the small intestine, then the jejunum the second part and the last part is the ileum. After that, believe or not, no one made any mistake about the order of the small intestine.

 white blood cells (WBC)

Q; Which type of leukocyte that surrounds and kills invading cells. Also, remove dead cells and stimulates the action of other immune cells?

a.      B lymphocytes

b.      T lymphocytes

c.      Natural killer

d.     Macrophage

 

Correct answer

         Another interesting question. The reason why this question is an interesting one, it is because of the leukocytes. What is the meaning of leukocytes? Leuko is the word root, and it would be prefix as well. leuko means white, and the meaning of cyte is a cell. Together leuko and cyte represent the white cell. Which white cell? Of course, the white blood cells in which its abbreviation is WBC. There are two types of WDC in our body classified according to the granules in their cytoplasm. They are the granulocyte WBC and nongranulocyte or agranulocyte WBC; also, some books called these WBCs a mononuclear WBC because they have one single unlobed nuclear.

The granulocyte cells are;

Neutrophile cells, also called the polymorphonuclear cell (PMN), because of its segmented nucleus. These cells the most numerous cells among all WBCs as their percentage would be more than 60%, and their job is to do the phagocytosis to foreign bacteria.

Basophile cells, they are also polymorphonuclear cells, but their cytoplasm contain very dark granules, and their percentage normally would be from 0 to 1%. They are able to secret heparin and histamine.

Eosinophils cells, also they are polymorphonuclear, but their granules stain by eosin stain. Their job is to respond to the allergy reaction and their percentage between 1 to 3%.

The agranulocyte cells are;

Lymphocyte cells, there are no granules in their cytoplasm. They have round or oval nucleus shape. Play an essential job in the immune response that protects the body against infection. Depends on their specific job and place where they become mature, their name will be. T lymphocyte will become mature in the thymus gland. B lymphocyte will become mature in the bone marrow like the natural killer cells. They are the only WBC will not contribute to the phagocytosis. The percentage of lymphocyte cells in average differential WBCs count ranges between 20% to 35%. It would increase more than this range in viral infection.

Monocyte cells, the giant cell among all WBCs, but their percentage would not be more than 9%. They have a segmented nucleus its shape like a horseshoe. The main job of these cells is phagocytosis, as they can surround the dead or foreign microorganisms and engulf them.

The term macrophage means the large cell that can engulf or eat; also, it is called the phagocytosis. I believe you will choose the letter d as a correct answer.

From (Medical Terminology, Human Anatomy and Physiology Certification Pretest volume 1) by oday Alubaidi 

The pathway of blood flow through the heart 

Q:  Freshly oxygenated blood transported from the lungs is first received by the

a.      Right ventricle

b.      Left ventricle

c.      Right atrium

d.     Left atrium

This question is about heart anatomy and physiology. You would expect such a question every time you write a test related to the cardiovascular system. The question mentioned the oxygenated blood. You should focus on this part. You should know which part of the heart it has oxygenated blood and which part it has the deoxygenated. The anatomy of the heart is about a hollow, cone-shaped structure. Has four champers or cavities, two small champers in the upper side called atria, divided into right and left atria, and two large champers in the lower side called ventricles, also divided into right and left ventricles.  The two right chambers (right atrium and right ventricle) will have blood that should not mix with the blood of left side chambers (left atrium and left ventricle). An interventricular septum separates them. From that, we can understand the blood on the right side of the heart is different from the left side by the component of gases. If you look at the image, you will find the arrows on the right side of the heart is in blue.

In contrast, the arrows on the left side are colored by the red color. That will tell us the blood flow on the right side have a low level of oxygen, which is called deoxygenated blood, while the blood flow on the left side has a high level of oxygen when the blood exchanges the gases in the lungs which are called oxygenated blood. Try to follow the arrows in the image as they will guide you to understand the heart anatomy and blood flow. Start from number 1; the deoxygenated blood enters the right atrium coming from the superior and inferior vena cava vein. 2 is the right atrium, which will push the blood to the right ventricle through the tricuspid valve. 3 the right ventricle will contract to push the blood to the pulmonary arteries through the semilunar valve. 4 and 5, the deoxygenated blood will flow to the lungs through the pulmonary arteries for gas exchange. Till this number or point, the journey of deoxygenated blood will end. The journey of oxygenated blood will start from number 6. At this point, the blood will enter the left atrium comes from the lung by the pulmonary veins. 7 the blood will push by the contraction of the left atrium to the left ventricle through the bicuspid valve. 8, once the left ventricle received the oxygenated blood, it will contract to empty its chamber by sending the blood to the aorta through the semilunar aortic valve. 9 and 10 present the oxygenated blood in the aorta moving towered the entire body cells.

Back to the question, which heart chamber should first receive oxygenated blood? I believe you would love to answer it by yourself.

Some essential things left you should know;

The pulmonary arteries, the only arteries, carry deoxygenated blood.

The pulmonary veins the only veins carry oxygenated blood.

The term semilunar for the valves between the ventricles and pulmonary arteries and veins.

A tricuspid valve is between the right atrium and the right ventricle.

A tricuspid valve is between the left atrium and left ventricle, and it is called the mitral valve.

from ( Medical Terminology, Human Anatomy, and Physiology Certification Pretest volume 1) book by Oday Alubaidi 

 urine analysis

Last week while we were practicing some lab procedures in the college lab as a regular lab day, a student was practicing the procedure of urine analysis, while she is doing that she jumped with this question.

Q; What would happen to the urine sample that is left standing on the bench at room temperature for more than one hour? Is sugar in urine will turn to ketone? Or will the protein become creatinine? Or alkaline urine will become acid urine reaction? Or, maybe the bilirubin will no longer react? Or maybe the specific gravity will become lower? Which one is the correct answer?

I know the student who asked the question she is a smart student; she tried to figure the correct answer from me as this question was one of the review exam questions.

I don’t mind; I would be so happy to answer any question to any student.

When we work in the clinical laboratory, the integrity of the sample is very critical. Any change in the sample property will lead to the wrong result, either false positive or false negative, wrong lab result will mislead the provider to reach the correct diagnosis.

If the urine sample left at room temperature for longer the required time, then some biochemical and microbiological changes would happen.

Like;

RBCs will reduce in the sample and become crenated cells. Difficult to recognize them in the urine sample.

WBCs will crumble or crash because of the hypotonic solution. Difficult to recognize them in the urine sample.

PH will turn from acid PH to alkaline PH due to the production of ammonia by the growth of bacteria.

Cast will disintegrate, and they will dissolve.

Bacteria will grow in the sample, lead to confusing the other sample components.

Color will become darker because of  oxidation or reduction of metabolites

Turbidity will increase duo bacterial growth.

Glucose will decrease due to glycolysis

Bilirubin will decrease as will be oxidized to biliverdin.

Ketones will decrease due to the evaporation of acetone.

Nitrite  will increase due to bacterial production.

Now, let back to the question.

Some times you have to use your knowledge in addition to your skills of analytic, creative, and practical intelligence. The knowledge you gain from studying the subject of urine analysis, but in this question, you need to look out of the box. Why? If you back to the tone of the question, you will find there are two specific conditions, temperature and time. How would these two conditions help you to find the correct answer? Look at the answers which one related to the temperature and time? All of them but one is need another condition to consider it, which is ( maybe the bilirubin will no longer react). Bilirubin needs exposure to light for a certain period to oxidized to biliverdin. Which is correct, but leave it now, try to analyze the other answers or choices.

The other choices are;

Is the sugar will turn to ketone?

Or will the protein become creatinine?

Or alkaline urine will become acid urine reaction?

Or, maybe the specific gravity will become lower?

First one; is the sugar will turn to ketone? Can sugar turn to ketone? The answer is no. There is no way. The sugar in the urine sample will reduce due to glycolysis.  Ketone will reduce (if there is)because of the evaporation. So this answer is wrong.

The second one is, will protein become creatinine? When the body breaks, the protein will have amino acid and urea, not creatinine. It is wrong, as well.

The third one is, alkaline urine will become acid urine reaction? The change in the urine PH should be from acid to alkaline, not from alkaline to acid. Also, it is the wrong answer.

The fourth one is, the specific gravity will become lower? The specific gravity will increase, not decrease.

All of them are the wrong answer. Only one answer would make sense, which is the bilirubin will no longer react because there is no bilirubin any more. Still, we isolate this answer away because the question doesn’t mention anything about light.

This is what I meant by thinking out of the box.

Good luck.

you have a question, would be more than happy to help you to analyze the correct answer.