Describe the events allowing monospermy
What will be an ideal response
A sperm entering the secondary oocyte causes ionic calcium to be released into the oocyte cytoplasm, activating the oocyte and preparing it for the second meiotic division. This also causes the cortical granules to spill their contents into the extracellular space beneath the zona pellucida. Enzymes from the cortical granules destroy sperm receptors, preventing further sperm entry. This spilled material binds with water, and as it swells, detaches all sperm still in contact with the oocyte membrane.
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What prevents food from entering the nasal passages during swallowing?
a. elevation of the uvula b. contraction of the pharyngeal muscles c. positioning of the tongue d. tight apposition of the vocal cords over the glottis e. elevation of the epiglottis over the nasopharynx
The galea aponeurotica is:
A) the dense fibrous membrane covering the surface of the cranium. B) a loose connective tissue that is easily damaged during "scalping" injuries. C) the subcutaneous layer of the scalp that contains easily damaged major veins. D) a tendon expansion that connects the frontal and occipital muscles of the cranium.
The respiratory system alone can return the pH only __________% of the way toward normal
Fill in the blank(s) with correct word
When a person rises quickly from a lying position, there is
A. an increase in vasomotor sympathetic stimulation to the blood vessels causing vasoconstriction. B. reflexive slowing of the heart. C. an increase of parasympathetic stimulation of the heart. D. a decrease in heart rate and stroke volume. E. an increase in the frequency of action potentials produced by the baroreceptors.