A student is learning about the different breathing patterns and breadth depth. Which term describes the true breathing that a resting individual may have?

A. Primary bronchus: The primary (main) bronchus is the first large airway branch that arises at the carina from the trachea and conducts air into each lung.
B. Respiratory bronchiole: Respiratory bronchioles are very small distal airways that contain alveoli and are deep within the lung parenchyma; they are much smaller than the structure shown near the main branch.
C. Trachea: The trachea is the central airway above the bifurcation (a vertical tube with cartilage rings); a label on the long central tube would indicate the trachea, not the branching airway.
D. Secondary bronchus: Secondary (lobar) bronchi are branches of the primary bronchus that lead to lung lobes; they are a generation distal to the main bronchus and are smaller than the primary bronchus.

A. Protects against heart disease: Estrogen has several effects on the cardiovascular system (improving lipid profile and vascular function) that are thought to reduce cardiovascular risk prior to menopause.
B. Helps regulate the menstrual cycle: Estrogen is a key ovarian hormone that helps regulate the growth of the endometrium and the timing of the menstrual cycle .
C. Promotes bone growth: Estrogen is essential for bone homeostasis, inhibiting bone resorption and helping maintain bone density .
D. Increases testosterone production: Estrogen does not increase testosterone production; testosterone is produced by Leydig cells in males (and ovaries/adrenals in females) and is not a primary product increased by estrogen .