Respiratory System Anatomy and Physiology

Comprehensive practice flashcards covering respiratory processes, chemical formulas, airway anatomy, tracheal histology, bronchial tree transitions, and alveolar cell types.

What are the four distinct processes included under the term respiration?

1. Pulmonary ventilation (breathing): air moves in and out of the lungs
2. External respiration: $O_2$ moves from alveoli into the blood, and $CO_2$ moves from blood to alveoli
3. Transport of respiratory gases: blood carries $O_2$ from lungs to tissues, and $CO_2$ from tissues to lungs
4. Internal respiration: $O_2$ moves from the blood into body tissues, and $CO_2$ moves from body tissues into the blood

What is the memory trick for remembering the four processes of respiration?

Breathe, Exchange, Transport, Exchange (Pulmonary: air moving; External: lungs and blood; Transport: blood carrying gases; Internal: blood and body cells).

What is the molecular equation for the bicarbonate buffer system in respiration?

$$CO_2 + H_2O \rightleftharpoons H_2CO_3 \rightleftharpoons H^+ + HCO_3^-$$

What is the molecular equation for cellular respiration?

$$C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP}$$

What is the complete anatomical pathway air follows from inhalation until gas exchange occurs with the blood?

Nose/nasal cavity $\rightarrow$ pharynx (throat) $\rightarrow$ larynx (voice box) $\rightarrow$ trachea (windpipe) $\rightarrow$ primary, secondary, and tertiary bronchi $\rightarrow$ bronchioles, terminal bronchioles, and respiratory bronchioles $\rightarrow$ alveolar ducts, alveolar sacs, and alveoli $\rightarrow$ respiratory membrane, pulmonary capillary blood.

What mnemonic is used to remember the sequence of anatomical structures air passes through?

"Naughty people love to bring big red apples" (Nose, Pharynx, Larynx, Trachea, Bronchi, Bronchioles, Alveoli).

What type of epithelium and specialized cells compose the mucosal lining of the trachea?

The trachea is lined with pseudostratified ciliated columnar epithelium and goblet cells.

What roles do goblet cells and cilia play in the trachea?

Goblet cells produce mucus to trap dust and germs, while cilia move the trapped mucus upward toward the throat via the mucociliary escalator.

What is the structural role of the C-shaped hyaline cartilage rings in the trachea, and what occupies their open posterior side?

The C-shaped hyaline cartilage rings prevent the trachea from collapsing. The open back faces the esophagus and contains the trachealis smooth muscle.

How do structural features change from the primary bronchi down to the bronchioles?

• Primary bronchi: Cartilage rings and ciliated epithelium
• Secondary bronchi: Cartilage plates (less cartilage than larger airways)
• Tertiary bronchi: Smaller branches where cartilage plates become less prominent
• Bronchioles: No cartilage, with an increased proportion of smooth muscle relative to airway size

Which airway structure represents the end of the conducting zone, and which represents the first site of gas exchange?

Terminal bronchioles are the last part of the conducting zone, whereas respiratory bronchioles are the first airways involved in gas exchange.

What four changes occur in the male larynx during puberty?

1. The larynx enlarges
2. The thyroid cartilage becomes more prominent ("Adam's apple")
3. The vocal cords lengthen and thicken
4. The voice becomes deeper

What are the paranasal sinuses and what functions do they serve?

They are air-filled spaces within the skull bones that lighten the skull, produce mucus, warm and humidify incoming air, and add resonance to the voice.

What is the function of the pleurae and the pleural cavity?

The pleurae form a double-layered membrane (visceral and parietal) that cushions the lungs, reduces friction during respiration, and couples lung expansion to chest wall movements. The pleural cavity is the fluid-filled potential space between the two pleural layers.

What is the respiratory membrane, and how are gases exchanged across it?

The respiratory membrane is a thin tissue wall in the lungs across which gases are exchanged between the air in the alveoli and the blood in the pulmonary capillaries via simple diffusion.

What are the structural features and primary function of Type I alveolar cells?

• Shape: Thin, flat, squamous, and scale-like
• Surface coverage: Approximately $95\%$ of the alveolar surface area
• Main function: Gas exchange; their extreme thinness allows $O_2$ and $CO_2$ to pass easily between the lungs and blood

What are the characteristics and two primary functions of Type II alveolar cells?

• Shape and coverage: Smaller, cuboidal cells that cover about $5\%$ of the alveolar surface but are numerous
• Main functions:
  1. Produce surfactant, which lowers surface tension and prevents the air sacs from collapsing
  2. Repair and regeneration: Act as caretakers that can divide and differentiate into Type I cells if lung tissue is damaged

Why is the respiratory membrane wall extremely thin?

To allow for rapid, efficient gas exchange between the alveoli and pulmonary capillaries.