Questions & Answers

Work Book Questions & Answers

Complete the following table. Give two of the key normal changes that take place over the lifespan (from 5 years to older age) for the body systems below and provide details of their effects on the anatomy or physiology. Extend the table as required (10 marks).

System

Characteristics of the system when a child

Characteristics of the system as an older adult

Implication of the changes with ageing

Respiratory

Till the age of 2 to 8 years the lungs and chest wall development takes place. The process of alveolization continues and becomes 300 million by the time child is 8 years old. An increase is alveoli cause an increase in alveolar surface area that is from 2.8m2 at birth to 32m2 at the age of 8 years.

Collateral ventilation which takes place through the pores as Kohn and Lamberts canal is not well developed in the early age.

The elastin to collagen ration also changes as the age increases and lung stiffness also become more potential. Lung recoil increases and elastin increases in children over the age of 6 years.

The orientation of the ribs in infants is horizontal and by the age of 10 years it becomes downward.

The main site of airway resistance in children younger than 5 years is medium sized bronchi.

(Elsevier, 2005, p. 165)

The diaphragm becomes weak. The number of air sacs (alveoli) and capillaries decreases as a result of which the alveolar membranes involved in the exchange of gases decreases. The lungs elasticity decreases.

Chest wall becomes stiff and shows reduced compliance.

Dried mucus membrane and decreased ciliary and macrophage activity, therefore the cough reflexes also decreases.

Hypoxia and hypercapnia becomes difficult to manage.

(Smith, 2012)

Decreased pulmonary functional reserve when at rest will not change but with physical exertion it causes Dyspnea and decreased exercise tolerance.

Decrease in lung expansion and the exhalation and inhalation becomes less effective.

Respiratory rates ranges from 12-24 breathe per minute.

Decreased mucus and clearance of foreign particles

Increased risk of airway obstruction, increased chances of infections and bronchospam

Cardiovascular

Soon after birth the detachment of placenta triggers a sudden change in the fetal heart and blood pressure. The heart becomes functioning and starts pumping blood to the lungs so that the baby can breathe on its own. A newborn heart beats at a faster rate because of increased demand of oxygenated blood by the developing tissues.

Till late teens the heart rate slows down. During the initial months of baby's life the heart has ventricles walls of similar thickness and right ventricular function is more dominant. With increasing age the left ventricular becomes sounder in function and the thickness of left ventricular wall increases.

The position of the apex also changes as the child's rib cage increases in size. Children below seven years of age the heart is more horizontaly placed making the apex higher and in the fourth intercostals space which is medial to the left midclavicular line. When the child is seven years old the apex moves in the fifth intercostal space ...