The first heart sound (the "lub" of the "lub-dup") is caused by __________.

opening of the atrioventricular valves
closure of the atrioventricular valves
opening of the semilunar valves
closure of the semilunar valves


closure of the atrioventricular valves

Anatomy & Physiology

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What is the direct source of the heart sounds in a heart beat?

A) Contraction of ventricles B) Rush of blood through the chambers C) Blood turbulence resulting from valve closure D) Electrical impulse between the SA and AV nodes

Anatomy & Physiology

Living keratinocytes exfoliate from the epidermis as tiny specks called dander

Indicate whether the statement is true or false

Anatomy & Physiology

Which of the following is true regarding systemic versus regional anatomy?

A. Systemic anatomy focuses on only one system at a time. B. Regional anatomy focuses on only one system at a time. C. Systemic anatomy focuses on several organ systems. D. Systemic anatomy focuses on several regions of the body.

Anatomy & Physiology

The epiphyseal plates in long bones are examples of synchondroses.

Answer the following statement true (T) or false (F)

Anatomy & Physiology