MDS PREP
What is the primary mechanism responsible for the reclamation of bile acids in the enterohepatic circulation?
1) Active transport in the ileum
2) Facilitated diffusion in the colon
3) Passive diffusion in the small intestine
4) Bacterial synthesis in the liver
Physiology
Answer: 1
Bile acids are actively reabsorbed in the ileum, primarily by the sodium-dependent bile acid transporter (ASBT), and returned to the liver.
What is the significance of the intestinal phase of gastric acid secretion?
1) It is responsible for the majority of acid secretion
2) It is primarily responsible for the inhibition of acid secretion
3) It is only triggered by the thought of food
4) It is not a significant phase of gastric acid secretion
The intestinal phase of gastric acid secretion is primarily responsible for the inhibition of acid secretion, helping to regulate the digestive process after food enters the intestine.
What is the primary role of the cephalic phase of gastric acid secretion?
1) Stimulation of gastrin release in the stomach
2) Secretion of gastric juices in response to the thought or smell of food
3) Increase in gastric motility
4) Secretion of gastric juices in response to food entering the duodenum
Physiology
Answer: 2
The cephalic phase of gastric acid secretion is initiated by the parasympathetic system and is triggered by the sight, smell, or thought of food. It accounts for approximately 20% of total acid secretion and prepares the stomach for digestion even before food arrives.
MEAN CIRCULATING FILLING PRESSURE IS?
1. DIFFERENCE BETWEEN CENTRAL VENOUS PRESSURE AND CENTRAL ARTERIAL PRESSURE
2. MEAN ATRIAL PRESSURE
3. ARTERIALPRESSURE TAKEN JUST AT THE POINT WHEN HEART STOPS BEATING
4. DIFFERENCE BETWEEN SYSTEMIC AND PULMONARY ARTERIAL PRESSURE
Physiology
Answer: 3
Mean Circulating Filling Pressure (MCFP) is a concept used in cardiovascular physiology to describe the average pressure in the large veins and the right atrium when the heart is not actively pumping (i.e., during diastole or when the heart is stopped). It reflects the pressure that fills the heart and is influenced by the volume of blood in the circulatory system and the compliance of the vascular system.
What is the primary function of the epididymis in the male reproductive system?
1) Storage and maturation of sperm
2) Secretion of androgens
3) Formation of the spermatozoa
4) Fusion of gametes during fertilization
Physiology
Answer: 1
The epididymis is a coiled tubular structure located behind the testis. Its primary function is to store and mature sperm cells, making them fully motile and capable of fertilization.
What is the primary function of the neck in a sperm cell?
1) It connects the head and tail of the sperm
2) It produces the sperm's energy for movement
3) It is responsible for the fertilization process
4) It contains the cell's genetic material
The primary function of the neck in a sperm cell is to connect the head and tail of the sperm, facilitating movement and energy transfer.
What is the role of the acrosome in sperm penetration of the egg during fertilization?
1) It produces energy for the sperm's movement
2) It contains enzymes that help dissolve the egg's outer layers
3) It transfers genetic material to the egg
4) It has no role in the penetration process
Physiology
Answer: 2
The acrosome contains enzymes such as hyaluronidase and acrosin that are essential for breaking down the zona pellucida, the egg's outermost layer, allowing the sperm to penetrate and fertilize the egg.
What is the primary neurotransmitter responsible for the contraction of the pupillary sphincter muscle?
1) Acetylcholine
2) Norepinephrine
3) Epinephrine
4) GABA
Answer: 1) AcetylcholineExplanation: The pupillary sphincter muscle is innervated by the parasympathetic nervous system, which uses acetylcholine as its primary neurotransmitter. Contraction of this muscle leads to pupil constriction, or miosis, which occurs in low-light conditions or when focusing on near objects.