The Respiratory System

Question 1

Describe the position and structure of the upper and lower respirator tracts

Answer 1

The upper respiratory tract contains the: nasal cavity, pharynx, nasopharynx, oropharynx, laryngopharynx and larynx
The lower respiratory tract contains the: trachea, bronchi, bronchioles, alveolar sacs, alveoli

Question 2

Identify the roles played by each of the following: nose, nasopharynx, mouth, oropharynx, larynx, trachea, bronchi and alveoli

Answer 2

Nose: air is warmed, moistened and filtered. Large SA maximised this. Very vascular, rapidly warming air. Hairs trap large particles. Smaller particles adhere to the mucus. Sense of smell.

The pharynx involves the nasopharynx, oropharynx and laryngopharynx, which warm and humidify the arm, and protect from infection

Larynx: produce sound and speech. Ensures food passes into the oesophagus not the trachea as the epiglottis is hinged

The tracheal cartilages hold the trachea permanently open, proving support and flexibility. The cilia waft mucus up.

The bronchi control air entry

The alveoli provide large SA:VOL allowing efficient gas exchange

Question 3

Describe the structure and position of the lungs

Answer 3

There are 2 cone shaped lungs, one lying each side of the midline in the thoracic cavity
The space between the lungs is called the mediastinum, and contains the heart, great vessels ect
The lungs are not symmetrical
Left is slightly smaller, because the heart occupies space
The right sits slightly higher than the left due to the liver
Each lung is divided into subunits called lobes, which are separated by fissures
The right lung has three lobes
The left has two

Question 4

Describe the mechanics of ventilation

Answer 4

The movement of the rib cage and the flattening of the diaphragm cause an increase in lung volume
This causes a drop in airway pressure
Air rushes in to fill the vacuum
This causes the lungs to expand
Once the maximum amount of air has filled the lungs this is called lung volume

Question 5

Describe the chemical and neural aspects of breathing

Answer 5

Peripheral chemoreceptors detect if oxygen levels are too low, carbon dioxide levels are too high, and if hydrogen levels are too high
Respiratory centres in the brain stem receive inputs from these receptors
They respond appropriately to the situation, sending modding signals to the effectors (muscles)

Question 6

Describe gaseous exchange and discuss how gases are transported around the body

Answer 6

Gas exchange takes place in the alveoli in the lungs and the capillaries that surround them
Inhaled oxygen moves form the alveoli to the blood in the capillaries and carbon dioxide moves from the blood in the capillaries to the air in the alveoli