Introduction to Respiratory Anatomy and Smooth Muscle Function

This set of flashcards covers key concepts related to the structure and function of the respiratory system, focusing on the role of bronchi, bronchioles, and smooth muscle in gas exchange and airflow regulation.

What is the primary function of the alveoli in the lungs?

Gas exchange occurs in the alveoli, where oxygen diffuses into the blood and carbon dioxide is removed.

How do bronchioles contribute to increased surface area for gas exchange?

Bronchioles branch extensively, leading to millions of alveolar sacs, significantly increasing the surface area for gas exchange.

What type of epithelium is found in the alveolar sacs?

The alveolar sacs are lined with a single layer of epithelial cells.

What is the role of bronchial smooth muscle in respiratory function?

Bronchial smooth muscle regulates the diameter of the bronchi and bronchioles, affecting airflow and resistance.

Which neurotransmitter is released by postganglionic parasympathetic neurons to induce contraction of bronchial smooth muscle?

Acetylcholine is released by postganglionic parasympathetic neurons.

What receptor does acetylcholine bind to on bronchial smooth muscle?

Acetylcholine binds to M3 muscarinic receptors.

What is the effect of epinephrine on bronchial smooth muscle?

Epinephrine binds to beta-2 adrenergic receptors, causing relaxation of bronchial smooth muscle.

What physiological principle explains the relationship between the radius of a tube and airflow?

According to Poiseuille's law, airflow is proportional to the radius raised to the fourth power.

How does histamine influence smooth muscle in the bronchioles?

Histamine binding leads to contraction of smooth muscle, reducing the diameter of the bronchioles.

What happens during an asthma attack in terms of bronchial smooth muscle?

During an asthma attack, bronchial smooth muscle contracts excessively, narrowing the bronchioles and restricting airflow.

What is the purpose of using an EpiPen during anaphylaxis?

An EpiPen delivers epinephrine, which binds to beta-2 receptors, relaxing bronchial smooth muscle and reopening the airways.

What is the primary difference in response of smooth muscle to acetylcholine and histamine?

Acetylcholine causes contraction via parasympathetic activation, while histamine causes variable effects depending on the receptor type.

What is the role of the autonomic nervous system in regulating bronchial smooth muscle tone?

The autonomic nervous system controls bronchial smooth muscle tone through opposing actions of parasympathetic (contraction) and sympathetic (relaxation) pathways.

Describe the anatomical organization of the alveoli and their importance for gas exchange.

Alveoli are clusters surrounding capillaries that facilitate the diffusion of oxygen into blood and carbon dioxide out, allowing for efficient gas exchange.