Humans can survive for a period of time without water thanks to the ability of the kidneys to produce concentrated urine. Briefly explain the factors that allow this to happen.
What will be an ideal response?
Facultative water reabsorption depends on the presence of antidiuretic hormone. In the presence of ADH, the pores of the collecting tubule enlarge and the filtrate loses water by osmosis as it passes through the medullary regions of increasing osmolarity. Consequently, water is conserved and urine becomes concentrated. The water that passes through these regions is reabsorbed by the body in order to prevent dehydration.
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When the inspiratory muscles contract,
A. thoracic volume increases. B. expiration occurs. C. the alveolar pressure increases. D. thoracic volume decreases. E. pleural pressure increases.
Answer the following statements true (T) or false (F)
1. The pericardium consists of two layers, the parietal pericardium and the epicardium. 2. Atrial and ventricular systole occur at the same time. 3. Both semilunar valves are attached to the heart wall by chordae tendineae. 4. A damaged chordae tendineae could affect the functioning of the tricuspid valve. 5. The term angioplasty refers to the medical procedure in which a vein from another part of the body is used to direct blood flow around a blocked artery in the heart.
Which substance decreases appetite?
a. Neuropeptide Y b. Orexin c. Ghrelin d. Melanocortin e. None of the above
The first paranasal sinuses to develop are the maxillary.
Answer the following statement true (T) or false (F)