Respiratory and Digestive System Study Guide

Respiratory Anatomy

Overview of the Respiratory Tract

The respiratory system is responsible for gas exchange, supplying oxygen to the body and removing carbon dioxide. It is divided into upper and lower respiratory tracts.

• Upper Respiratory Tract: Includes the nose, nasal cavity, pharynx, and larynx.

• Lower Respiratory Tract: Includes the trachea, bronchi, bronchioles, and lungs.

• Larynx: Also known as the voice box, it is involved in sound production and protects the lower airways.

Example: The trachea connects the larynx to the bronchi, allowing air to pass into the lungs.

Inspiration and Expiration

Inspiration and expiration are the two main phases of breathing. Models of the lung can demonstrate how changes in pressure and volume allow air to move in and out of the lungs.

• Inspiration: Diaphragm contracts, thoracic cavity expands, air flows into lungs.

• Expiration: Diaphragm relaxes, thoracic cavity decreases, air flows out of lungs.

Example: When the diaphragm contracts, the pressure in the thoracic cavity drops, causing air to enter the lungs.

Respiratory Physiology

Respiratory Terms and Processes

Understanding key terms is essential for describing how the respiratory system functions.

• Pulmonary Ventilation: Movement of air into and out of the lungs.

• Inspiration: Intake of air into the lungs.

• Expiration: Expulsion of air from the lungs.

Example: Pulmonary ventilation is measured as the volume of air exchanged per minute.

Respiratory Volumes and Capacities

Respiratory volumes and capacities are measured to assess lung function. These values are often represented on a spirographic record.

• Tidal Volume (TV): Volume of air inhaled or exhaled in a normal breath.

• Forced Expiratory Volume (FEV): Volume of air exhaled forcefully in a specific time period.

• Forced Vital Capacity (FVC): Maximum volume of air exhaled after a deep breath.

Example: FEV1 is the volume of air exhaled in the first second of a forced expiration.

Interpreting Lung Function Tests

Comparing measured FEV and FVC values to normal values helps identify possible obstructive lung diseases. If the FEV/FVC ratio is below 80%, it may indicate obstructive disease.

• Obstructive Lung Disease: Characterized by reduced airflow (e.g., asthma, COPD).

• Normal Values: FEV/FVC ratio typically above 80% in healthy individuals.

Example: A patient with asthma may have an FEV/FVC ratio below 80%.

Digestive System Lab

Swallowing and Tongue Function

The tongue plays a crucial role in the process of swallowing and in the initial stages of digestion.

• Swallowing: The tongue pushes food to the back of the mouth, initiating swallowing.

• Mechanical Digestion: The tongue helps mix food with saliva, forming a bolus.

Example: During swallowing, the tongue elevates to push the bolus into the pharynx.

Digestive System Anatomy

The digestive system consists of the alimentary canal and accessory organs, each with specific functions in digestion.

• Alimentary Canal: Continuous tube from mouth to anus, including esophagus, stomach, small intestine, and large intestine.

• Accessory Organs: Include salivary glands, liver, pancreas, and gallbladder.

Example: The pancreas secretes digestive enzymes into the small intestine.

Functions of Digestive Organs

Each organ in the digestive system contributes to the breakdown and absorption of nutrients.

• Stomach: Secretes acid and enzymes to digest proteins.

• Small Intestine: Main site for nutrient absorption.

• Liver: Produces bile to emulsify fats.

• Pancreas: Releases enzymes for digestion of carbohydrates, proteins, and fats.

Example: Bile produced by the liver is stored in the gallbladder and released into the small intestine.

Location and Contribution of Accessory Organs

Accessory organs are located adjacent to the alimentary canal and aid in digestion by producing enzymes and other substances.

• Salivary Glands: Located in the mouth, secrete saliva to begin carbohydrate digestion.

• Liver: Located in the upper right abdomen, produces bile.

• Pancreas: Located behind the stomach, secretes digestive enzymes.

Example: The liver and pancreas both release substances into the small intestine to aid digestion.