Chapter 21

All vertebrates have _________. a. an open circulatory system b. a closed circulatory system c. a four-chambered heart d. both b and

The SA node _________. a. prevents backflow of blood b. is the cardiac pacemaker c. is located in the brain d. regulates breathing rate

Blood pressure is highest in the _________ and lowest in the __________. a. arteries, veins b. arterioles, venules c. veins, arteries d. capillaries, arterioles

Contraction of _________ is the main force driving the flow of blood away from the heart. a. the atria b. arterioles c. the ventricles d. skeletal muscle

At rest, the largest volume of blood is in the __________. a. arteries b. capillaries c. veins d. arterioles

In the blood, most oxygen is transported ________. a. in red blood cells b. in white blood cells c. bound to hemoglobin d. both a and c

The ________ circuit carries blood from the heart to the lungs, then back to the heart.

The heart chamber with the thickest wall pumps blood into the _________. a. aorta b. pulmonary artery c. pulmonary vein d. superior vena cava

In human lungs, gas exchange occurs at the __________. a. bronchi b. pericardium c. alveoli d. epiglottis

When you breathe quietly, inhalation is _________ and exhalation is _______. a. passive; passive b. active; active c. passive; active d. active; passive

During inhalation ___________ . a. the thoracic cavity expands b. the glottis closes c. the diaphragm relaxes d. all of the above

The diaphragm is ______________ muscle. a. \(\operatorname{smooth}\) b. skeletal c. cardiac

Arrange these structure in the order through which air flows inward when inhaled. ___________larynx ___________pharynx ___________trachea ___________bronchus ___________bronchiole

Match the words with their descriptions. $$ \text {________plasma} \quad \quad\quad\quad\quad \text {a. receives blood from veins} $$ $$ \text {________alveolus} \quad \quad\quad\quad\quad \text {b. fluid component of blood} $$ $$ \text {________hemoglobin} \quad \quad\quad\quad\quad \text {c. cardiac pacemaker} $$ $$ \text {________veins} \quad \quad\quad\quad\quad \text {d. gap between vocal cords} $$ $$ \text {________SA node} \quad \quad\quad\quad\quad \text {e. site of gas exchange} $$ $$ \text {________trachea} \quad \quad\quad\quad\quad \text {f. drives blood flow from heart} $$ $$ \text {________glottis} \quad \quad\quad\quad\quad \text {g. windpipe} $$ $$ \text {________ventricle} \quad \quad\quad\quad\quad \text {h.blood volume reservoir} $$ $$ \text {________atrium} \quad \quad\quad\quad\quad \text {i. reversibly binds oxygen} $$