Respiratory Anatomy & Functions
What is pulmonary ventilation?
This respiratory process moves air into and out of the lungs.
This muscle contracts and moves downward during quiet inspiration.
Answer: diaphragm
Q1 : What is hemoglobin?
Q2: What is bicarbonate (HCO₃⁻)?
Q1: A small amount is dissolved in plasma.Most oxygen travels through the blood attached to this protein.
Q2: Most carbon dioxide is transported through the blood in this form.
Name the major digestive functions and distinguish the alimentary canal from accessory organs.
Answer: Ingestion, propulsion, mechanical digestion, chemical digestion, absorption, and defecation. Food passes through the alimentary canal; accessory organs, such as the salivary glands, liver, and pancreas, help digestion.
Which pharyngeal regions carry food, and how does the esophagus move food toward the stomach?
Answer: Food passes through the oropharynx and laryngopharynx; the nasopharynx normally carries only air. The esophagus uses peristalsis. Its upper third contains skeletal muscle, middle third contains both skeletal and smooth muscle, and lower third contains smooth muscle.
What is the difference between the conducting zone and the respiratory zone?
The conducting zone transports, warms, humidifies, and filters air. The respiratory zone exchanges gases and includes respiratory bronchioles, alveolar ducts, and alveoli.
During inspiration, what happens to thoracic volume, intrapulmonary pressure, and airflow?
Answer: Thoracic volume increases, intrapulmonary pressure falls below atmospheric pressure, and air flows into the lungs. Intrapleural pressure becomes more negative.
Compare how hyperventilation and hypoventilation affect blood carbon dioxide and pH.
Answer: Hyperventilation decreases CO₂ and raises pH. Hypoventilation increases CO₂ and lowers pH.
Explain how the different types of teeth and the tongue prepare food for swallowing.
Answer: Incisors cut, canines tear, and premolars and molars crush and grind. The tongue mixes food with saliva, forms a bolus, and pushes it toward the pharynx.
Name the three phases of swallowing and explain how the airway is protected.
Answer: Oral, pharyngeal, and esophageal phases. The oral phase is voluntary; the others are mainly involuntary. During the pharyngeal phase, the soft palate rises, the larynx moves upward and forward, the vocal folds close the glottis, and the epiglottis folds over the laryngeal entrance.
Trace the pathway of inhaled air from the nasal cavity to the alveoli.
Answer: Nasal cavity → pharynx → larynx → trachea → primary bronchi → secondary bronchi → tertiary bronchi → bronchioles → terminal bronchioles → respiratory bronchioles → alveolar ducts → alveoli.
Explain how narrowed airways, decreased lung compliance, and surfactant affect breathing.
Answer: Narrowed airways increase resistance, making airflow harder. Decreased compliance makes lungs harder to expand. Surfactant reduces surface tension, helping alveoli stay open and expand.
Name the three regions of the small intestine in order.
Answer: What are the duodenum, jejunum, and ileum?
Name the three major pairs of salivary glands, where their ducts open, and two important components of saliva.
Serous cells produce watery secretions containing salivary amylase, which begins starch digestion. Mucous cells produce mucus for lubrication.
Name the four major stomach regions and describe how the stomach stores, mixes, and releases food.
Answer: Cardia, fundus, body, and pyloric region. The cardia receives food; the fundus and body accommodate and process it. Rugae allow expansion, and three muscle layers churn food into chyme. The pyloric region grinds chyme, and the pyloric sphincter controls its release into the duodenum.
Identify the alveolar cells that allow gas exchange, produce surfactant, and remove debris. Explain why the respiratory membrane is thin.
Answer: Type I cells allow gas exchange; type II cells produce surfactant; alveolar macrophages remove debris. A thin respiratory membrane provides a short diffusion distance, allowing rapid gas exchange.
A person breathes normally, then inhales as deeply as possible. Identify the volume of a normal breath, the extra air inhaled, and the air remaining after maximal exhalation.
Answer: Tidal volume, inspiratory reserve volume, and residual volume, respectively.
Bonus: Vital capacity = tidal volume + inspiratory reserve volume + expiratory reserve volume.
What is increasing surface area?
Circular folds, villi, and microvilli improve nutrient absorption by doing this.
Explain how the enteric nervous system, autonomic nervous system, and hormones regulate digestion.
Answer: The enteric nervous system controls local digestive activity: the myenteric plexus mainly controls motility, and the submucosal plexus mainly controls secretion and local blood flow. Parasympathetic activity generally increases digestion, while sympathetic activity generally decreases it. Hormones such as gastrin, secretin, and CCK coordinate secretion and motility.
Identify the major gastric gland cells and explain how stomach acid is produced, stimulated, and controlled.
Answer: Parietal cells secrete HCl and intrinsic factor; chief cells secrete pepsinogen and gastric lipase; mucous cells provide protective mucus; G cells release gastrin; ECL cells release histamine; and D cells release somatostatin. Parietal cells pump H⁺ into the stomach lumen, where it combines with chloride. Acetylcholine, gastrin, and histamine stimulate acid secretion; somatostatin inhibits it. Acid activates pepsin, denatures proteins, and kills many microbes.
This structure contains the vocal cords and helps prevent food from entering the lower respiratory tract during swallowing.
Answer: the larynx?
Explain where oxygen and carbon dioxide move during pulmonary and tissue gas exchange, and what drives their movement.
Answer: In the lungs, oxygen moves from alveoli into blood, while carbon dioxide moves from blood into alveoli. In the tissues, oxygen moves from blood into tissues, while carbon dioxide moves from tissues into blood. Each gas diffuses from higher to lower partial pressure.
What are the liver and gallbladder, respectively?
This organ produces bile, while this other organ stores and concentrates it.
Name the four layers of the digestive tract wall, from inner to outer, and give each layer’s main function.
Mucosa: epithelium, lamina propria, and muscularis mucosae; protects, secretes, and absorbs.
Compare the cephalic, gastric, and intestinal phases, including how chyme affects stomach emptying.
Answer: