In cardiac muscle,
A) calcium ions are not released from the sarcoplasmic reticulum.
B) calcium ions do not bind to troponin molecules.
C) calcium ions play no role in the process of contraction.
D) about 20 percent of the calcium ion required for contraction comes from outside the cell.
E) calcium ions play an important role in repolarizing the membrane after the depolarization phase.
D
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Development of the heart commences in the ________ week.
A. eighth B. first C. tenth D. third E. fifth
Describe the location and position of the heart
A) The heart is located near the anterior chest wall, directly behind the sternum. B) The heart is located near the posterior chest wall, directly beside the vertebral column. C) The heart is located near the anterior chest wall, below the diaphragm. D) The heart is located near the right lateral chest wall. E) The heart is located near the stomach in the abdominopelvic cavity.
Lipid droplets and pleomorphic mitochondria containing tubular cristae are found in:
a. Leydig cells b. Sertoli cells c. Spermatocytes d. Spermatogonia e. Spermatozoa
What type of epithelium is found in the urethra near the junction with the urinary bladder?
A) transitional epithelium B) simple cuboidal epithelium C) stratified squamous epithelium D) pseudostratified columnar epithelium