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Which region of the pharynx connects directly to the oral cavity?
What is the role of the glottis in the respiratory system?
Which of the following is NOT a paired cartilage found in the larynx?
Which part of the pharynx is located inferiorly between the hyoid bone and the entrance to the larynx?
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Which of the following structures is NOT found in the nasopharynx?
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What do bronchioles primarily contain that allows them to regulate airflow?
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What is the result of sympathetic activation in the bronchioles?
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What occurs during bronchoconstriction?
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What connects pulmonary bronchioles to alveoli?
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What structural feature surrounds each alveolus?
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How many terminal bronchioles are formed from each segmental bronchus?
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What structure forms at the end of the alveolar ducts?
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What primarily causes the reduction of luminal diameter in the bronchioles?
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What is a pulmonary embolism?
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Which layer of the pleura covers the outer surfaces of the lungs?
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Which process is involved in external respiration?
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What role does pleural fluid play?
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Which of the following describes internal respiration?
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What separates the two pleural cavities in the thoracic cavity?
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What is the first step in the process of external respiration?
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What characterizes the blood pressure in the pulmonary circuit compared to the systemic circuit?
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What is the primary role of the diaphragm during inhalation?
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Which muscles are primarily responsible for active exhalation?
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During normal breathing, which muscles contribute to the largest percentage of air movement?
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Which of the following statements accurately describes the mechanics of breathing?
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Which accessory muscle would assist in elevating the ribs during intense inhalation?
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What is the primary factor that influences the Bohr effect on hemoglobin saturation?
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What is produced when carbon dioxide reacts with water in red blood cells?
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How does a decrease in pH affect hemoglobin's affinity for oxygen?
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What happens to hydrogen ions produced in the red blood cells?
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At what partial pressure of oxygen (PO2) does hemoglobin exhibit 75% saturation?
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How does temperature affect hemoglobin's saturation curve?
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What role does carbonic anhydrase play in the carbon dioxide transport process?
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During which physiological condition is hemoglobin's oxygen binding most affected by CO2 levels?
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Study Notes
Upper Respiratory System
- The pharynx is a chamber shared by the digestive and respiratory systems.
- It extends between the choanae and the entrances to the larynx and esophagus.
- It is divided into three regions:
- Nasopharynx: The superior portion of the pharynx, containing the pharyngeal tonsil and the pharyngeal openings of the auditory tubes.
- Oropharynx: Connects directly to the oral cavity.
- Laryngopharynx: The inferior portion of the pharynx, located between the hyoid bone and the entrance to the larynx and esophagus.
Lower Respiratory System
- Air flows from the pharynx to the larynx through the glottis, a slit-like opening between the vocal cords.
- The larynx is formed by three large unpaired cartilages:
- Thyroid cartilage
- Cricoid cartilage
- Epiglottis
- There are also three pairs of smaller paired hyaline cartilages in the larynx:
- Arytenoid cartilage
- Corniculate cartilage
- Cuneiform cartilage
- Each segmental bronchus branches into multiple bronchioles, which further branch into terminal bronchioles.
- Each segmental bronchus forms about 6500 terminal bronchioles.
- Bronchioles do not have cartilage and are dominated by smooth muscle.
- The autonomic nervous system controls the luminal diameter of bronchioles by regulating smooth muscle.
- Bronchodilation: Enlarges the luminal diameter of the airway, caused by sympathetic activation, reducing resistance to airflow.
- Bronchoconstriction: Reduces the luminal diameter of the airway, caused by parasympathetic activation and histamine release during allergic reactions.
Gas Exchange Structures
- Each terminal bronchiole branches to form several respiratory bronchioles.
- Respiratory bronchioles are connected to alveoli along alveolar ducts.
- Alveolar ducts end at alveolar sacs, common chambers connected to many individual alveoli.
- Each alveolus has an extensive network of capillaries surrounded by elastic fibers.
The Lungs
- Blood pressure in the pulmonary circuit is lower than in the systemic circuit.
- Pulmonary vessels are easily blocked by blood clots, fat, or air bubbles.
- Pulmonary embolism is a blocked branch of the pulmonary artery that stops blood flow to lobules or alveoli.
- There are two pleural cavities separated by the mediastinum.
- Each pleural cavity contains a lung lined with a serous membrane called the pleura.
- The pleura consists of two layers:
- Parietal pleura: Lines the inner surface of the thoracic wall.
- Visceral pleura: Covers the outer surfaces of the lungs.
- Pleural fluid lubricates the space between the two layers.
External and Internal Respiration
- Respiration involves two integrated processes:
- External respiration: All processes involved in the exchange of oxygen and carbon dioxide with the external environment.
- Internal respiration: Uptake of oxygen and release of carbon dioxide by cells, resulting from cellular respiration.
- External respiration includes the following steps:
- Pulmonary ventilation (breathing).
- Gas diffusion across the blood-air barrier in the lungs and across capillary walls in other tissues.
- Transport of oxygen and carbon dioxide between alveolar capillaries and capillary beds in other tissues.
Pulmonary Ventilation
- The primary respiratory muscles are the diaphragm and external intercostal muscles.
- Accessory respiratory muscles are activated when respiration increases significantly.
- Inhalation is always active, while exhalation can be active or passive.
- Muscles involved in inhalation:
- Diaphragm: Contraction draws air into the lungs, contributing 75% of normal air movement.
- External intercostal muscles: Assist inhalation, contributing 25% of normal air movement.
- Accessory muscles: Assist in elevating the ribs, including the sternocleidomastoid, scalenes, pectoralis minor, and serratus anterior.
- Muscles involved in exhalation:
- Internal intercostal muscle and transversus thoracis: Depress the ribs.
- Abdominal muscles: Compress the abdomen, forcing the diaphragm upward.
Gas Transport
- The Bohr effect describes the effect of pH on the hemoglobin saturation curve, caused by CO2.
- CO2 diffuses into red blood cells, where carbonic anhydrase catalyzes its reaction with H2O, producing carbonic acid (H2CO3).
- Carbonic acid dissociates into hydrogen ion (H+) and bicarbonate ion (HCO3–).
- Hydrogen ions diffuse out of red blood cells, lowering pH.
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Description
Test your knowledge on the anatomy of the upper and lower respiratory systems, including the pharynx and larynx. This quiz covers the regions of the pharynx and the cartilages that form the larynx. Perfect for students studying human anatomy or respiratory biology.
