MDS PREP
What is the main function of the cephalic phase of gastric secretion?
1) To secrete digestive enzymes
2) To increase gastric motility
3) To increase gastric acidity
4) To initiate the secretion of gastrin
E) To prepare the stomach for food intake
The cephalic phase of gastric secretion is initiated by the sight, smell, thought, or taste of food and prepares the stomach for the arrival of food by increasing gastric secretion, gastric motility, and salivation. It does not directly increase gastric acidity but does contribute to the overall digestive process.
Diabetic insipidus is due to the lack of
1 Insulin
2 Angiotensin.
3 Aldosterone.
4 A.D.H.
Physiology
Answer: 4
Diabetic insipidus is due to the lack of 4. A.D.H. (Antidiuretic hormone).
Explanation:
Diabetic insipidus (DI) is a condition characterized by the production of large
volumes of dilute urine due to the lack of the antidiuretic hormone (ADH) or the
body's inability to respond to it. It is different from diabetes mellitus, which
involves problems with insulin and blood sugar regulation.
1. Insulin: Insulin is a hormone produced by the pancreas that plays a critical
role in regulating blood sugar levels. A deficiency or resistance to insulin
leads to diabetes mellitus, not diabetic insipidus. Diabetes mellitus is
characterized by hyperglycemia (high blood sugar) and increased thirst and urine
production due to the inability of the kidneys to reabsorb glucose properly.
2. Angiotensin: Angiotensin is a hormone system that plays a role in the
regulation of blood pressure and fluid balance. It is involved in the
renin-angiotensin-aldosterone system (RAAS). While it is crucial for maintaining
blood pressure, it is not directly related to the pathophysiology of diabetic
insipidus.
3. Aldosterone: Aldosterone is a mineralocorticoid hormone produced by the
adrenal glands. It helps regulate sodium and potassium levels in the body, which
in turn affects fluid and blood volume. While it is essential for electrolyte
and fluid balance, it does not cause diabetic insipidus when lacking.
4. Antidiuretic hormone (ADH): ADH is a hormone produced by the hypothalamus and
stored in the posterior pituitary gland. It acts on the kidneys to increase
water reabsorption, which leads to the production of concentrated urine. In
diabetic insipidus, there is either a deficiency of ADH or the kidneys fail to
respond to it adequately. This results in the kidneys being unable to reabsorb
enough water, leading to the production of large volumes of dilute urine and
increased thirst.
There are two main types of diabetic insipidus: central and nephrogenic. Central
DI occurs when the pituitary gland does not produce enough ADH, while
nephrogenic DI results from the kidneys' inability to respond to ADH. Both types
lead to an imbalance in water regulation and can cause symptoms such as polyuria
(excessive urine production), polydipsia (excessive thirst), and dehydration if
not managed properly.
To treat diabetic insipidus, the underlying cause must be addressed. If it is
central DI, synthetic ADH (desmopressin) is administered to replace the missing
hormone. If it is nephrogenic DI, the treatment focuses on addressing the
kidney's response to ADH and managing symptoms such as maintaining fluid intake
and sometimes medications to reduce urine output.
What is the role of the corpus luteum in the second half of the menstrual cycle?
1) It secretes FSH
2) It secretes LH
3) It secretes estrogen and progesterone
4) It secretes inhibin
Physiology
Answer: 3
The corpus luteum, which forms after ovulation, secretes estrogen and progesterone. These hormones are essential for preparing the endometrium for potential implantation and supporting early pregnancy.
What happens when the corpus luteum regresses during the menstrual cycle?
1) It secrets more estrogen and progesterone
2) It stops secreting estrogen and progesterone
3) It starts secreting FSH and LH
4) It causes an increase in the thickness of the endometrium
When the corpus luteum regresses during the menstrual cycle, it stops secreting estrogen and progesterone, leading to the shedding of the uterine lining.
MCQ: The gastrocolic reflex is:
1) The contraction of the stomach triggered by the presence of food in the duodenum
2) The contraction of the small intestine triggered by the presence of food in the stomach
3) The contraction of the rectum triggered by the presence of food in the stomach
4) The contraction of the gallbladder triggered by the presence of food in the small intestine
The gastrocolic reflex is the contraction of the colon triggered by the presence of food in the stomach, facilitating bowel movements.
What is the primary role of sleep spindles during sleep?
1 ) To facilitate memory consolidation
2) To maintain muscle tone
3) To regulate body temperature
4) To initiate REM sleep
Sleep spindles are associated with the transition from stage 1 to stage 2 NREM sleep and are thought to play a role in memory consolidation and the integration of new information.
Which of the following statements about Secretin is true?
1) It is structurally similar to insulin.
2) It is structurally similar to glucagon.
3) It stimulates the release of hydrochloric acid by the stomach.
4) It is secreted in response to high blood glucose levels.
Secretin is structurally similar to glucagon, which is involved in glucose metabolism and regulation.
What is the role of ghrelin in the control of food intake?
1) It stimulates the release of growth hormone
2) It suppresses the secretion of gastric acid
3) It inhibits food intake
4) It increases the sensation of hunger
Ghrelin increases the sensation of hunger, stimulating appetite and food intake, particularly before meals.