IV. The Structure and Function of the Digestive System.

1. Where is the largest cavity of the body situated?

2. What organs does the abdominal cavity contain?

3. Why is the liver so important?

4. What does the gall-bladder serve for?

5. What are the characteristics of the stomach?

6. How do we distinguish «small» and «large» intestines?

7. What is digestion?

8. What types of digestion do you know?

The abdomen is the largest cavity of the body. It is surrounded by the thorax, two pelvic bones, lower ribs and the abdominal muscles, and it is also supported by the spinal column. The organs of the abdominal cavity are the liver, the gall-bladder, the stomach, the intestines, the pancreas, the spleen, the kidneys and the bladder.

The liver is a large organ that weighs about 1.5 kg and lies under the right ribs. The liver is important, because it secretes bile which participates in the digestive process and has a defensive function, i.e. some toxic substances are detoxified in the liver.

The gall-bladder lies beneath the right lobe of the liver and serves as a bile reservoir.

The stomach lies under the left ribs. It serves as a container of food, which is partly digested in it. The size and shape of the stomach vary with amount of consumed food, and its capacity is some 1-2 litres.

The intestines, in which food undergoes chemical and mechanical changes, occupy the central portions of the abdominal cavity. The small intestine is only 1.5 to 2 inches, the large intestine is up to 2.5 inches wide.

Digestion is the breakdown of food into smaller components that can be absorbed into the bloodstream. The process of digestion is due to the activity of many enzymes, chemicals, and physical processes within the digestive tract. Digestive processes may be classified as salivary digestion, when occurring in the mouth; gastric digestion in the stomach; and intestinal digestion in the small intestine. With normal digestion, between 95 and 100 per cent of all carbohydrates, fats, and animal proteins are absorbed.

 

V. The Urinary System.

1. What is the urinary system?

2. What are the parts of the urinary system?

3. Where are the kidneys placed?

4. What are the functions of the parenchyma of the kidney?

5. What does the bladder serve for?

6. Where is urine formed?

7. What does urine consist of?

Various harmful and unnecessary substances are continually being formed in the human body.The urinary system is the system which excretes the largest part of the waste products of the body. The urinary system consists of the kidneys, ureters, urinary bladder and urethra.

The kidneys are placed one on each side in the lumbar region of the spine, on the posterior abdominal wall. A kidney is a bean-shaped organ, which weighs about 150 grams and is covered by membranes. The kidneys contain one million small tubes, which have to excrete products of metabolism and control the concentrations of most body fluids. These small and various tubules make up the parenchyma of the kidney.

The bladder is a reservoir for urine, which is situated in the cavity of the pelvis. The capacity of the bladder of an adult is about 350-500 ml.

The urine is being formed in the kidneys from many waste and harmful substances contained in the blood. Then it passes through the ureters into the urinary bladder. The bladder is emptied through the urethra, which leads to the exterior of the body. The wastes are excreted as urine, which is normally composed of approximately 96 per cent water, plus urea and various salts. The healthy adult seems to excrete an average of about 1.5 litres of urine from the body daily. Through this system blood is being continuously depleted of water and the loss must be made up by the ingestion of new water.

 

                                          VI. Congenital Heart Defects

1. What are congenital heart defects?

2. How many newborns have congenital heart defects?

3. Why do congenital heart defects happen?

4.  Are there many treatments for the congenital heart defects?

5.  When does the human heart begin to form?

6.  What can increase the risk of congenital heart malformations during   pregnancy?

7. An extra chromosome is associated with congenital heart disease, isn’t it?

Congenital Heart Defects

 

Congenital heart defects are abnormalities in the heart's structure that are present at birth. Approximately 8 out of every 1,000 newborns have congenital heart defects, which can range from mild to severe.

Congenital heart defects happen because of incomplete or abnormal development of the fetus' heart during the very early weeks of pregnancy. Some are known to be associated with genetic disorders, such as Down syndrome, but the cause of most congenital heart defects is unknown. While they can't be prevented, there are many treatments for the defects and any related health problems.

Congenital defects usually are treated with surgery, catheter procedures, and sometimes medication.

Cardiac surgery and cardiac catheterizations are now performed on younger children — in fact, it's common for them to be done during infancy or even the newborn period, which has many long-term advantages.

Although nothing can be guaranteed with 100% certainty, most kids with heart problems can enjoy happy and healthy futures.

The human heart begins to form as a single tubular structure at about the fourth week of pregnancy. By the eighth week, this tube will gradually increase in length, eventually twisting upon itself. A wall, or septum, grows to divide the upper (atrial) and lower (ventricular) chambers into left and right sides. Four valves made of tissue develop, which keep blood moving forward through the cardiac chambers, lungs, and body as the heart pumps.

Multiple genetic and environmental factors interact to alter the development of the heart during the early stages of a fetus' development (the first 8 to 9 weeks during pregnancy).

Uncontrolled diabetes, alcohol or drug abuse, or exposure to industrial chemicals during pregnancy also can increase the risk of congenital heart malformations. Some chromosome abnormalities, in which there is an extra or missing chromosome (or part of a chromosome) are associated with congenital heart disease.

                           

 

                                  

                     VII. Infectious diseases

1. What are the symptoms of chickenpox?

2. What are the symptoms of measles?

3. What are the symptoms of rotavirus?

4. What infection diseases do you know?

5. What infection disease is also called rubeola?

6. Is rotavirus or measles the leading cause of severe, dehydrating diarrhea      in infants?

7. Can children be protected from chickenpox?