Early Development, Devel. Physiol., Dr. D. Penney

EARLY DEVELOPMENT OF THE CV SYSTEM

Self-Assessment - Module 21:

1. With regard to cardiomyocytes:

A. each contains hundreds of nuclei, like skeletal muscle cells

B. they stop mitotic division about midway through fetal development

C. in the adult, each is associated with approximately 10 capillaries

D. in the human tetraploid, octaploid, etc. nuclei are common, and these increase in frequency with age

E. all are correct

2. In the transitional phase of heart growth, heart mass is increasing solely by an increase in heart muscle cell numbers (i.e. mitosis) ( T / F )

3. In the fetal human heart, muscle cells constitute 75% or more of the total cells by number, while in the adult heart muscle cells constitute about 25% of the total cells. ( T / F )

4. Muscle fiber to capillary ratio in the heart declines after birth, until in adulthood this ratio approaches 1.0. ( T / F )

5. The embryologic process by which the common atrium and ventricle are each divided into two chambers is known as? ( ) (ONE WORD)

6. Special features of the fetal circulation are the following EXCEPT:

A. pulmonary circulation has high vascular resistance

B. left and right side of heart pump blood in a parallel arrangement, therefore outputs may differ

C. circulation pattern insures higher P0₂ to brain

D. the pulmonary vasculature is sensitive to rising P0₂

E. cardiac output per g body weight is low, therefore conserving oxygen used by the fetal tissues

7. In the fetus the blood vessel below carrying blood with the lowest percent oxygen saturation is the:

A. thoracic inferior vena cava

B. pulmonary veins

C. descending aorta

D. ductus arteriosus

E. common carotid

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