MDS PREP
What is the function of the middle piece in a sperm cell?
1) It produces the enzymes needed for sperm maturation
2) It contains the mitochondria for energy production
3) It is responsible for the sperm's ability to penetrate the egg
4) It is involved in the process of fertilization
Physiology
Answer: 2
The middle piece of the sperm cell is where the fibrous sheath is surrounded by spirally arranged mitochondria, which are the cell's powerhouses. They provide the energy required for the flagellum's movement during sperm motility.
In the presence of antidiuretic hormone (ADH), which part of the nephron becomes highly permeable to water?
1) Proximal Convoluted Tubule (PCT)
2) Loop of Henle
3) Collecting Duct
4) Afferent Arteriole
In the presence of antidiuretic hormone (ADH), the collecting duct becomes highly permeable to water, allowing for increased water reabsorption and concentrated urine.
What is the threshold for glucose excretion in the urine in a healthy individual?
1) 100 mg/100 ml
2) 180 mg/100 ml
3) 200 mg/100 ml
4) 250 mg/100 ml
Physiology
Answer: 3
The threshold for glucose excretion is when the plasma glucose reaches approximately 200 mg/100 ml, causing some glucose to be filtered into the urine.
Which of the following is NOT a hormone produced by the kidneys?
1) Renin
2) Erythropoietin
3) Aldosterone
4) 1,25 Dihydrocholecalciferol
Aldosterone is NOT a hormone produced by the kidneys; it is produced by the adrenal glands and acts on the kidneys to regulate sodium and potassium balance.
In which part of the nephron is bicarbonate primarily reabsorbed?
1) Loop of Henle
2) Distal convoluted tubule
3) Proximal convoluted tubule
4) Collecting duct
Bicarbonate is primarily reabsorbed in the proximal convoluted tubule, where it plays a crucial role in maintaining acid-base balance in the body.
The increased venous return to the heart causes:
1. End diastolic volume increase
2. End systolic volume decrease
3. Decrease stroke volume
4. Decreased isovolumetric ventricular contraction.
Physiology
Answer: 1
The increased venous return to the heart causes End diastolic volume increase
In the presence of which substance does vitamin B12 combine in the stomach to prevent its degradation by gastric acid?
1) Intrinsic factor
2) Pepsin
3) Gastric acid
4) Pancreatic amylase
Physiology
Answer: 1
Vitamin B12 combines with intrinsic factor to form a complex that is protected from degradation by gastric acid.
What is the effect of epinephrine on the bronchial smooth muscles during the fight-or-flight response?
1) Constriction (bronchoconstriction)
2) Dilatation (bronchodilatation)
3) No effect
4) Spasm
Answer: 2) Dilatation (bronchodilatation)Explanation: Epinephrine acts on beta-2 adrenergic receptors in the bronchial smooth muscles, leading to their relaxation and dilatation of the bronchioles. This allows for increased airflow and oxygenation of the lungs, which is essential during the fight-or-flight response.