Describe the events that result in a beating heart
What will be an ideal response?
The SA node sends out a nervous impulse over both atria. The intercalated discs connecting adjacent cardiac muscle cells facilitate this transmission. This results in atrial contraction or atrial systole. In this part of the cycle, blood flows to the ventricles, which are relaxed (they are in diastole). The nervous impulse travels to the AV node, is briefly delayed, and then an impulse is conducted over the ventricles (from the bottom or apex) towards the top, as the great vessels of the heart are oriented at the "top of the heart" (the base). In this part of the cycle, both of the ventricles are in systole, and the blood is pumped through the semilunar valves to the aorta and the pulmonary artery.
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Questions of ____ and development are ____ explanations of behavior
Fill in the blank with the appropriate word.
An individual is exposed to a pathogen and takes five days to recover. When exposed a year later they again take five
days to recover. Would you suspect that adaptive immunity was involved? Why or why not? What will be an ideal response?
The total living component of an ecosystem is its
A) niche. B) biotic potential. C) carrying capacity. D) biomass. E) geographic range.
Which of the following statements about fungi is FALSE?
A) fungi are eukaryotes. B) molds are multicellular. C) fungi have a cell wall. D) fungi are photosynthetic. E) yeasts are unicellular.