Question

Please include as much detail as possible, thank you!

1. What is a surfactant and why is it important?

2.  Kate was involved in a ghastly motor accident. Autopsy reports indicated that her brain stem was transected rostral to the medulla oblongata. Can the Coroner rule out cessation of respiration as the cause of death? Why?

3. What is Respiratory Distress Syndrome?

4. Differentiate between type I and type II diabetes.

5. Both insulin and glucagon are released following the ingestion of a protein meal that raises plasma amino acid levels. Why is the secretion of both hormones necessary?

Answer 1

1: surfactant are surface acting agents which are responsible for lowering the surface tension of a fluid. These surfactant lines the epithelium of alveoli in lungs , and therefore are called pulmonary surfactant. These decreases surface tension on the alveolar membrane. Surfactant are secreted by type 2 alveolar epithelial cells in lungs and also by clara cells in bronchioles.

Surfactant reduces the surface tension in alveoli to provide stability and thus prevent collapsing tendency of lungs.

2- cessation of respiration cannot be ruled out as cause of death

Explanation- medulla oblangata contains two group of neurons which control respiration. These are-

1. Dorsal group of respiratory neuron- this group is responsible for basic rhythm of respiration and generate inspiratory ramp.

2. Ventral group of respiratory neuron- these are inactive during normal breathing but active during forced breathing.

Thus the medulla is a very important centre which regulate respiration. Any injury to this region which affect the respiration drastically and can even cause death.

3rd question-

Respiratory distress syndrome is a disorder which mainly affects newborn who are born prematurely.

It occurs because the lungs in premature babies don't develope well. It may be due to underdevelopment of alveolar parenchyma or due to the deficiency of surfactants.

Symptoms include difficult in breathing, sometimes baby is not able to breath at all in severe cases. Hypoxia occur due to less oxygen. The skin turns blue due to hypoxia.

4th question-

Type 1 diabetes

It is due to deficiency of insulin because of destruction of insulin froming beta cells in islet of Langerhans. It is called insulin dependent diabetes mellitus. The symptoms of disease appear very rapidly. The body weight reduces. Ketosis is present. This affects usually people before 40 years of age. The patient has to be given insulin from outside.

Type 2 diabetes-

It is due to insulin resistance, not deficiency. In this , the insulin receptors fails to give response to insulin. Therefore body is unable to use insulin. Usually occur after 40 years of age. It can be controlled by oral hypoglycemic drugs and therefore is called noninsulin dependent diabetes mellitus. These patients are usually overweight. Ketosis may or may not be present.