Explain how water-soluble nutrients are routed through the vascular system.
What will be an ideal response?
The routing of the blood leaving the digestive system has a special feature. The blood is carried to the digestive system (as to all organs) by way of an artery, which (as in all organs) branches into capillaries to reach every cell. Blood leaving the digestive system, however, goes by way of a vein. The hepatic portal vein directs blood not back to the heart but to another organ, the liver. This vein branches into a network of large capillaries so that every cell of the liver has access to the blood. Blood leaving the liver then collects into the hepatic vein, which returns blood to the heart.
The liver’s placement ensures that it will be first to receive the nutrients absorbed from the GI tract. In fact, the liver has many jobs to do in preparing the absorbed nutrients for use by the body. Of all the body’s organs, the liver is the most metabolically active. In addition, the liver defends the body by detoxifying substances that might cause harm and preparing waste products for excretion. This is why, when people ingest poisons that succeed in passing the first barrier (the intestinal cells), the liver quite often suffers the damage—from viruses such as hepatitis, from drugs such as barbiturates or alcohol, from toxins such as pesticide residues, and from contaminants such as mercury.
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During cardiorespiratory exercise, your body redistributes blood from your internal organs to maximize the volume of blood that is delivered to the muscles
Indicate whether the statement is true or false
The WHO estimates that about _______ percent of all childhood deaths in developing countries are associated with malnutrition, as noted in the "Health Connection" section.
Fill in the blank(s) with the appropriate word(s).
The four characteristics of a healthful diet are adequacy, balance, moderation, and
A) variety. B) value. C) Calories. D) color.
The four steps in the causation of cancer are:
a. stage I, stage II, stage III, and stage IV. b. primary, secondary, tertiary, and end-stage. c. initiation, promotion, development, and progression. d. mutation, differentiation, proliferation, and metastasis.