What does a closed venous valve prevent?
a. escape of blood from the vessel
b. muscle contraction
c. hypertension
d. backflow of lymph
e. backflow of blood
e
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Which is true of Golgi tendon organs?
A) They are located in the epidermis. B) They are located in the dermis. C) They function as light-touch receptors. D) They are classified as proprioceptors.
A man was in an accident and severed his spinal cord between C6 and C7. Which of the following would NOT occur?
A. loss of sensation in the trunk below the shoulders, the lower limbs and portions of the arms B. loss of use of the phrenic nerves and paralysis of the diaphragm C. loss of movement in the lower limbs D. loss of the use of the intercostals nerves, and breathing would be affected because the intercostals muscles would be paralyzed E. loss of sensation and movement in the jaw
The forerunner of modern sex research is:
A. Richard von Krafft-Ebing B. Henry Havelock Ellis C. Magnus Hirschfeld D. Sigmund Freud
Nutrients are delivered and waste products are carried away from the cells of the posterior segment of the eye by blood vessels. However, the cells in the cornea and lens (in the anterior segment) are avascular. Which is the best explanation for how these cells are maintained?
A) These cells, like the cells of the corneal layer of the integument are not living cells. B) The nutrients and waste products of the anterior segment diffuse into and through the vitreous humor of the posterior segment. C) The aqueous humor is continuously replenished and flows from the ciliary process to drain in the scleral venous sinus. D) The metabolic activity of these cells is very low. They produce little waste and need few nutrients.