Nokea
Saliva contains the enzyme salivary amylase. Which food type does salivary amylase begin to break down?
- A. Proteins
- B. Starches
- C. Roughage
- D. Fats
Correct Answer: B
Rationale: Salivary amylase breaks down starches into simple sugars like maltose. Starch is a complex carbohydrate found in foods like bread, pasta, and rice. When you chew food, salivary amylase in saliva starts the digestion process by breaking down starch molecules. Proteins are broken down by stomach enzymes, roughage (fiber) is not digested by enzymes in the mouth, and fats are primarily digested in the small intestine by pancreatic lipase. Therefore, choice B, starches, is the correct answer as salivary amylase specifically targets this food type for initial breakdown.
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Which is not Na+ dependent for absorption?
- A. thiamin
- B. riboflavin
- C. niacin
- D. folate
Correct Answer: D
Rationale: The correct answer is D: folate. Folate absorption is not Na+ dependent as it is primarily absorbed in the small intestine through a carrier-mediated process that is independent of sodium. Thiamin, riboflavin, and niacin absorption, on the other hand, are Na+ dependent processes that rely on sodium co-transporters for uptake in the small intestine. Thiamin is absorbed through a sodium-dependent active transport system, riboflavin requires a sodium-dependent carrier protein for absorption, and niacin absorption involves a sodium-dependent transporter in the small intestine. Therefore, folate is the only option that is not Na+ dependent for absorption.
What describes the primary difference in treatment for diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic syndrome (HHS)?
- A. DKA requires administration of bicarbonate to correct acidosis.
- B. Potassium replacement is not necessary in management of HHS.
- C. HHS requires greater fluid replacement to correct the dehydration.
- D. Administration of glucose is withheld in HHS until the blood glucose reaches a normal level.
Correct Answer: C
Rationale: HHS requires more fluid replacement due to severe dehydration, while DKA management focuses more on correcting acidosis and insulin deficiency.
Which of the following is true about calcium homeostasis?
- A. Increased calcitonin levels will cause increased blood calcium levels.
- B. High calcium levels cause bone resorption.
- C. Parathyroid hormone causes an increase in osteoblast activity.
- D. Parathyroid hormone is the single most important regulator of calcium levels in the blood.
Correct Answer: D
Rationale: The correct answer is D: Parathyroid hormone is the single most important regulator of calcium levels in the blood. Parathyroid hormone plays a crucial role in maintaining calcium homeostasis by stimulating bone resorption, increasing calcium reabsorption in the kidneys, and activating vitamin D to enhance calcium absorption in the intestines. It acts to raise blood calcium levels when they are low.
Explanation for other choices:
A: Increased calcitonin levels actually lower blood calcium levels by promoting calcium deposition in bones.
B: High calcium levels do not cause bone resorption; it is actually the opposite as mentioned in choice D.
C: Parathyroid hormone does not increase osteoblast activity; it primarily affects osteoclasts to release calcium from bones.
The neurohypophysis:
- A. is the anterior pituitary gland.
- B. secretes ACTH, TSH, and the gonadotropins.
- C. secretes the releasing hormones.
- D. is the posterior pituitary gland.
Correct Answer: D
Rationale: Step-by-step rationale:
1. The neurohypophysis is the posterior pituitary gland.
2. It stores and releases hormones produced by the hypothalamus.
3. These hormones include oxytocin and vasopressin.
4. These hormones regulate water balance, blood pressure, and uterine contractions.
5. Choice D is correct as it accurately describes the neurohypophysis.
Summary:
A: Incorrect - Anterior pituitary gland is not the neurohypophysis.
B: Incorrect - These hormones are secreted by the anterior pituitary gland.
C: Incorrect - Releasing hormones are produced by the hypothalamus, not the neurohypophysis.
An example of a hormone that under certain circumstances is regulated by positive feedback is:
- A. calcitonin.
- B. histamine.
- C. oxytocin.
- D. melatonin.
Correct Answer: C
Rationale: Rationale:
1. Oxytocin is released during childbirth to stimulate uterine contractions.
2. As contractions increase, oxytocin secretion is further stimulated in a positive feedback loop.
3. This positive feedback mechanism amplifies the contractions until delivery.
4. Calcitonin regulates calcium levels, histamine is involved in allergic responses, and melatonin regulates sleep-wake cycles.
Summary:
- Calcitonin, histamine, and melatonin do not exhibit positive feedback regulation like oxytocin during childbirth.