Respiratory System Quiz

Respiratory System Overview

• The respiratory system is a network of tubes that filters, transports, and exchanges gases.
• The system aims to bring oxygen into the body and remove carbon dioxide.
• The respiratory system is split into the upper respiratory tract (URT) and the lower respiratory tract (LRT).

Respiratory System Objectives

• Define external, internal, and cellular respiration.
• Name the organs of the respiratory system and describe their functions.
• Explain the role of respiratory muscles in inspiration and expiration.

Respiratory Definitions

• External respiration: Gas exchange between blood capillaries and air sacs in the lungs.
• Internal respiration: Gas exchange between blood capillaries and body cells.
• Cellular respiration: The breakdown of organic molecules (usually glucose) in cells to produce energy.

Atmospheric Gases

• Rank gases in the atmosphere by concentration: Nitrogen, Oxygen, Others, Carbon Dioxide

Respiratory System Structures

• Nose and Mouth: Supported by bone and cartilage, lined with mucous membranes containing hairs. Hairs filter and the mucosa warms and moistens the incoming air. Air and food are separated by the hard and soft palates. The pharynx is a common passageway for both air and food.
• Air Passages: Include the larynx, trachea, bronchi, and bronchioles. The larynx contains vocal cords. The trachea is supported by cartilages. Bronchi branch into smaller bronchioles.
• Lungs: Spongy cone-shaped organs that occupy most of the thoracic cavity. The lungs are separated by the mediastinum. Visceral and parietal pleura surround the lungs and create a fluid-filled space between them.
• Diaphragm, Ribs & Intercostal Muscles: The diaphragm is a large sheet of muscle, ribs protect the internal organs, and intercostal muscles move the ribs during breathing.

Lung Structure

• The bronchi divide into progressively smaller bronchioles which lead to alveolar ducts.
• Alveolar ducts open up into tiny air sacs called alveoli.
• Alveoli have thin walls with a rich supply of blood capillaries.
• Gases are exchanged across the thin alveolar walls.

Gas Transport and Diffusion

• Gas exchange rates are determined according to the partial pressure differences of each gas across the alveolar-capillary membrane.
• Oxygen and carbon dioxide move according to the concentration gradient, from high to low. This is diffusion.
• Oxygen is primarily carried by hemoglobin.

Breathing Mechanics

• Inspiration: The process of breathing in. The diaphragm contracts and moves downward, the intercostal muscles contract, the thoracic cavity expands, and the air pressure in the alveoli decreases, so air flows in.
• Expiration: The process of breathing out. The diaphragm relaxes, moves upward, the intercostal muscles relax, the thoracic cavity shrinks, and the air pressure in the alveoli increases, so air flows out.

Respiratory System Control

• Neural control: The breathing rhythm is controlled by respiratory centers in the brainstem (medulla and pons).
• Chemical control: Chemical receptors in the bloodstream sense changes in blood carbon dioxide (CO₂) levels or pH, which influence the breathing rate.
• Intrapulmonary receptors: Receptors in the lungs respond to factors such as lung inflation and send signals to regulate breathing.

Summary of Factors Affecting Breathing Rate

• Breathing rate changes with age.
• Breathing rate increases during and after exercise.
• Control of breathing is mostly automatic (involuntary).

Important aspects of the Respiratory System

• The respiratory system is essential for gas exchange which is the primary function.
• A range of different structures and mechanisms work together to ensure efficient gas exchange.
• Airflow within the system is regulated via various nerves and muscles as well as other signals.
• The respiratory system is affected by smoking as tar in cigarettes coats the air passages.

Test your knowledge of the respiratory system with this quiz. Explore the functions of various structures, including the trachea, bronchi, alveoli, and diaphragm. Understand the roles these components play in breathing and gas exchange.