How does the brain affect the heart rate and strength of contraction? Describe the specific nerve, hormones, locations on the heart that are affected, and the effect on the heart.
What will be an ideal response?
Answer: The brain controls the heart via the autonomic nervous system. The parasympathetic nervous system reaches the heart via the vagus nerve, which releases acetylcholine onto the pacemaker cells of the sinoatrial node, slowing heart rate. The sympathetic nervous system reaches the heart via sympathetic nerves which secrete norepinephrine onto the sinoatrial node and ventricle. The SNS can also secrete epinephrine into the blood. Both norepinephrine and epinephrine can, speed up heart rate. Both can also increase the strength of the ventricular contraction.
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Biofilms are likely to be found in environments
A. that are nutrient rich. B. that are relatively warm. C. with rapidly flowing water. D. with low nutrients.
Red algae
a. are primarily marine organisms. b. are thought to have developed from green algae. c. contain xanthophylls as their main accessory pigments. d. are mostly unicellular. e. are all of these.
Simberloff and Wilson conducted a well-known experiment in which they fumigated small mangrove islands and observed the recovery through time of arthropod communities on these islands. They found that mangrove islands tended to recover to about the same number of species present pre-fumigation. Which proposition of the equilibrium theory of island biogeography did this observation support?
A) Islands distant from the mainland have fewer species than islands close to the mainland. B) Small islands have fewer species than large islands. C) Each island has an equilibrium number of species.
Answer the following questions true (T) or false (F)
1. Streak plates are a useful way to obtain CFUs. 2. Agar is a useful compound in the microbiology lab because it is an excellent nutrient for bacteria. 3. Enrichment culturing may require use of controlled environmental conditions.