Introduction to Anatomy & Physiology

Respiratory Functions and Breathing Mechanics

• Breathing is a mechanical process that provides oxygen, which is essential to all living things.
• The respiratory system supplies oxygen to the body with inhalation and removes carbon dioxide via exhalation.
• The respiratory system can be functionally divided into the air-conducting portion and gas exchange portion.
• When a person inhales, oxygen enters the body by way of the larynx, trachea, bronchi, and bronchioles.
• Gas exchange occurs in the alveolar region, or in the tiny air sacs within the lung called alveoli.
• External respiration is a gas exchange that happens between blood and the lungs.
• Internal respiration involves gas exchange between blood and body tissues.

The Digestive System and Path of Food

• The digestive system consists of the digestive tract, which is a tube extending from the mouth to the anus, accessory organs, and various enzymes.
• Digestion is the breakdown of food into molecules that are small enough to be absorbed into the bloodstream.

• Food is digested into biomolecules and then into monomers for the body’s usage.
• The two types of digestion are mechanical and chemical.

• The mouth chews and moistens food into a bolus with help of the tongue, an accessory organ. The bolus travels through the pharynx into the esophagus.
• The epiglottis covers the trachea to prevent food from going into the windpipe and causing choking.
• Food is continually broken down for nutrients that are absorbed by rugae in the stomach and villi of the small intestines.
• Food does not pass through the accessory organs. Other accessory organs include the pancreas, liver, gallbladder, and salivary glands which contribute to the process of digestion by secreting enzymes.
• Waste is compressed by the large intestines and bowels are expelled by the rectum.

Basic Nutrition

• Humans are consumers that must obtain their energy by eating food.
• Food is mainly categorized by the biomolecule groups carbohydrates, proteins, and lipids. These biomolecules will contain micronutrients such as vitamins and minerals.
• Fruits and vegetables are mainly composed of natural carbohydrates with high values in micronutrients, including fiber.
• Fiber is a carbohydrate that does not break down into sugar molecules, but passes through the intestinal tract. It is a nutrient that supports healthy bowel movement.
• Foods such as fish, poultry, eggs, beans, and nuts are good sources of protein. Lean protein is a protein source that has a higher amount of protein without excessive fats. Higher fat protein sources include processed meats, usually from beef and pork.
• A person’s daily intake of each biomolecule class will be dependent upon their age and individual bodily needs. Nutrition labels represent daily values based upon a 2,000 calorie diet.
• Sufficient water intake is necessary for proper hydration levels which affect almost all bodily systems.