Biology Questions

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BIO 169 Ch. 20 S.G.

Name: __________________________ Date: _____________
1. The anatomical region found between the lungs that extends from the sternum to the vertebral column and from the first rib to the diaphragm.
A) Epicardium
B) Abdominal cavity
C) Pericardium
D) Mediastinum
E) Thoracic cavity
2. The membrane that surrounds and protects the heart is called the
A) pericardium.
B) pleura.
C) myocardium.
D) mediastinum.
E) endocardium.
3. The apex of the heart is normally pointed
A) at the midline.
B) to the left of the midline.
C) to the right of the midline.
D) is different for males and females
E) posteriorly.
4. The outermost layer of the pericardium, which consists of inelastic dense irregular
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Cardiac muscle fibers are electrically connected to neighboring fibers by
A) desmosomes.
B) tight junctions.
C) gap junctions.
D) interneurons.
E) chordae tendinae.
22. Which of the following types of muscle contains the largest number of mitochondria per cell? A) Smooth muscle
B) Skeletal muscle
C) Cardiac muscle
D) All the muscle types contain approximately the same number.
E) Mitochondria are not found in muscle cells.
23. This is a network of specialized cardiac muscle fibers that provide a path for each cycle of cardiac excitation to progress through the heart.
A) Systemic circuit
B) Intercalated discs
C) Cardiovascular center
D) Cardiac conduction system
E) Pulmonary circuit
24. Which of the following correctly lists the sequence of structures that a cardiac action potential follows in order to excite normal contraction of the heart?
A) Bundle of His, Purkinje fibers, Atrioventricular (AV) node
B) Sinoatrial (SA) node, Purkinje fibers, AV node, Bundle of His
C) Purkinje fibers, AV node, SA node, Bundle of His
D) SA node, AV node, Bundle of His, Purkinje fibers
E) Bundle of His, SA node, AV node, Purkinje fibers

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BIO 169 Ch. 20 S.G.

25. In comparison to skeletal muscle fibers, the contractile fibers of the heart are depolarized for ____ period of time.
A) a shorter
B) a longer
C) the same
26. The volume of blood ejected from the left
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