Opening and closing of the heart valves is caused by ________.
A. osmotic gradients
B. pressure gradients
C. gravity
D. valves contracting and relaxing
E. breathing
Answer: B
You might also like to view...
In the fetus, the blood from the umbilical vein is shunted away from the liver and sent to the inferior vena cava through the ductus ________.
Fill in the blank(s) with the appropriate word(s).
The study of disease states in the body is called
A. differentiation. B. pathophysiology. C. anatomy. D. homeostasis. E. histology.
The medial and lateral condyles of the tibia articulate with the
A. apex of the patella. B. medial and lateral condyles of the femur. C. medial and lateral epicondyles of the femur. D. head of the fibula. E. greater and lesser trochanters of the femur.
Why doesn’t semen enter the urinary bladder during ejaculation?
A) There is no common duct between the reproductive system and the urinary system. B) There is no urge to urinate during sexual intercourse because of the suppression of LH by testosterone buildup in the blood. C) The smooth muscle sphincter at the base of the urinary bladder closes. D) Ejaculation is a parasympathetic reflex resulting in no response by urinary contraction muscles.