1. Where is oxygen produced, and what is its function in the human body?

Question

2. What causes a breath to be taken?
3. Trace the pathway of oxygen to an internal cell.
4. How is voice sound produced?
5. Explain the difference between external and internal respiration.
6. What is surfactant and how does it affect inflation of the lungs?
7. List five instances when a breathing pattern is altered normally.
a.
b.
c
d.
e.
8. Describe the pleural coverings of the lungs and explain their purpose.

Answer 1

1. Where is oxygen produced, and what is its function in the human body?
   Oxygen is primarily produced through the process of photosynthesis in plants, algae, and some bacteria. In the human body, oxygen plays a crucial role in cellular respiration, which occurs in the mitochondria of cells. Its primary function is to help convert glucose into adenosine triphosphate (ATP), the energy currency of the cell, and to support various metabolic processes.

2. What causes a breath to be taken?
   Breathing is initiated by the rhythmic contraction of the diaphragm and intercostal muscles. This contraction creates a negative pressure in the thoracic cavity, allowing air to flow into the lungs. The process is regulated by the respiratory center in the brainstem, which responds to levels of carbon dioxide, oxygen, and pH in the blood.

3. Trace the pathway of oxygen to an internal cell.

• Air is inhaled through the nose or mouth, traveling down the trachea.
• It then passes through the bronchi and into the bronchioles, reaching the alveoli in the lungs.
• In the alveoli, oxygen diffuses across the alveolar membrane into the bloodstream, binding to hemoglobin in red blood cells.
• The red blood cells transport oxygen through the pulmonary veins to the left atrium of the heart, then to the left ventricle, and finally out to the systemic circulation through the aorta.
• Oxygen-rich blood is delivered to tissues and organs, where it is transported across capillary walls to individual cells.
• Inside the cells, oxygen is utilized in the mitochondria for aerobic respiration.

4. How is voice sound produced?
   Voice sound is produced when air from the lungs passes through the vocal cords located in the larynx (voice box). The vocal cords vibrate as air flows between them, and this vibration creates sound waves. The pitch and volume of the sound can be altered by changing the tension and length of the vocal cords, as well as adjusting the shape of the vocal tract and mouth.

5. Explain the difference between external and internal respiration.

• External respiration refers to the exchange of gases (oxygen and carbon dioxide) between the atmosphere and the alveoli in the lungs, occurring during breathing. It involves inhalation of oxygen into the lungs and exhalation of carbon dioxide out of the body.
• Internal respiration is the exchange of gases between the blood and the body's tissues. It involves the delivery of oxygen from the blood to the cells and the uptake of carbon dioxide from the cells into the blood.

6. What is surfactant and how does it affect inflation of the lungs?
   Surfactant is a lipoprotein substance produced by type II alveolar cells in the lungs. It reduces surface tension in the alveoli, preventing their collapse and making the lungs more compliant (easier to inflate). Surfactant allows for more efficient gas exchange by ensuring that the alveoli remain open and can expand with each breath.

7. List five instances when a breathing pattern is altered normally.
   a. Exercise – Increased demand for oxygen leads to deeper and faster breaths.
   b. Sleep – Breathing may become shallower and slower during certain stages of sleep.
   c. Emotional responses – Stress, anxiety, or excitement can lead to rapid or irregular breathing patterns (hyperventilation).
   d. Altitude – Breathing may become deeper as the body compensates for lower oxygen availability at high altitudes.
   e. Singing or speaking – Controlled breathing patterns are used to manage breath support and produce sound.

8. Describe the pleural coverings of the lungs and explain their purpose.
   The pleural coverings consist of two layers: the visceral pleura, which tightly adheres to the surface of the lungs, and the parietal pleura, which lines the thoracic cavity. The pleural space in between these layers contains pleural fluid, which serves several purposes: it reduces friction during breathing movements, provides lubrication, and helps maintain pressure differences that facilitate lung inflation. The negative pressure in the pleural cavity also helps keep the lungs expanded against the thoracic wall.