MDS PREP
What happens when the transport maximum for glucose is exceeded?
1) All excess glucose is reabsorbed
2) Some glucose is reabsorbed and some is excreted
3) All excess glucose is excreted in the urine
4) No glucose is excreted regardless of the amount
When the transport maximum for glucose is exceeded, some glucose is reabsorbed and some is excreted in the urine, leading to glucosuria.
What effect does sympathetic nervous system activation have on renal blood flow (RBF) and glomerular filtration rate (GFR)?
1) Increases RBF and GFR
2) Decreases RBF and increases GFR
3) Decreases RBF and decreases GFR
4) Increases RBF and decreases GFR
E) Has no effect on RBF and GFR
Sympathetic stimulation leads to the constriction of the afferent arterioles, decreasing RBF and GFR. This is part of the body's response to maintain blood pressure and blood volume during stress or hemorrhage.
The first heart sound relates to
1. Closure of the A-V valves
2. Opening of the A-V valves
3. Excitation of the auricles
4. Closure of the aortic valve
Physiology
Answer: 2
The first heart sound relates to Opening of the A-V valves
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 significance of the increased pulse rate and blood pressure during REM sleep?
1) It indicates the body is preparing for wakefulness
2) It is a byproduct of increased brain activity during dreaming
3) It is not significant and does not reflect any physiological changes
4) It indicates a pathological condition
The increased pulse rate and blood pressure during REM sleep are associated with the heightened brain activity and autonomic system arousal that occurs during this phase of sleep, despite the presence of muscular atonia.
What is the primary function of the pharyngeal stage of deglutition?
1) Voluntary contraction of the pharyngeal muscles to move food into the esophagus
2) Relaxation of the upper esophageal sphincter
3) Closure of the epiglottis to prevent aspiration of food into the trachea
4) Involuntary contraction of the pharyngeal muscles to propel the food bolus into the esophagus
E) Stimulation of salivary glands to secrete saliva
The pharyngeal stage of deglutition involves involuntary contraction of the pharyngeal muscles and is responsible for the rapid passage of the food bolus from the oral cavity to the upper esophagus. It is primarily a reflex act triggered by the voluntary movement of food into the back of the mouth.
What is the primary effect of insulin on the skeletal muscles?
1) Stimulation of protein synthesis
2) Increased glycolysis
3) Increased glucose uptake and glycogen synthesis
4) Stimulation of muscle contraction
Answer: 3) Increased glucose uptake and glycogen synthesisExplanation: Insulin stimulates glucose uptake by muscle cells and promotes glycogen synthesis. It does so by increasing the number of glucose transporters on the muscle cell membrane and facilitating the transport of glucose into the cells.
What is the primary site of vitamin B12 absorption in the intestine?
1) Stomach
2) Duodenum
3) Jejunum
4) Ileum
Physiology
Answer: 4
The ileum is the primary site of vitamin B12 absorption, facilitated by intrinsic factor binding to specific receptors.