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
The middle piece of a sperm cell contains mitochondria, which provide the energy needed for sperm motility and movement towards the egg.
What is the primary mechanism of sodium reabsorption in the distal convoluted tubule and collecting ducts?
1) Passive diffusion
2) Active transport with sodium-potassium ATPase pump
3) Facilitated diffusion
4) Countercurrent exchange with hydrogen ions
The primary mechanism of sodium reabsorption in the distal convoluted tubule and collecting ducts is active transport with the sodium-potassium ATPase pump.
What is the primary function of the parasympathetic nervous system?
1) Control of sympathetic nervous system
2) Control of visceral functions during rest and digestion
3) Control of musculoskeletal system during rest
4) Control of sensory systems during stress
The parasympathetic nervous system is primarily responsible for the "rest and digest" functions, which include the regulation of the gastrointestinal system, cardiovascular system, and other visceral activities that are not directly involved in movement or emergency response.
What is the function of cholecystokinin (CCK) in the digestive system?
1) Stimulates the release of bile from the liver
2) Increases the secretion of water in the collecting tubules of the kidney
3) Relaxes the lower esophageal sphincter
4) Decreases the motility of the small intestine
Physiology
Answer: 3
Cholecystokinin is a hormone secreted by the mucosa of the upper intestine in response to the presence of food, particularly proteins and fats. One of its key functions is to stimulate the contraction of the gallbladder and relax the sphincter of Oddi, facilitating the release of bile and pancreatic enzymes into the duodenum to aid in digestion.
What is the difference in the generation of the Resting Membrane Potential (RMP) in neurons and muscle cells?
1) Neurons have a higher RMP than muscle cells
2) Muscle cells have a higher RMP than neurons
3) The mechanism of RMP generation is different in neurons and muscle cells
4) The ionic gradients involved in RMP generation are the same in both neurons and muscle cells
Answer: 4) The ionic gradients involved in RMP generation are the same in both neurons and muscle cellsExplanation: The RMP in both neurons and muscle cells is generated primarily by the difference in potassium ion concentration across the cell membrane. The concentration gradient of K+ is maintained by the sodium-potassium ATPase pump, which pumps 3 Na+ ions out and 2 K+ ions into the cell, contributing to the negative resting membrane potential.
What is the primary function of the myenteric plexus in the gastrointestinal tract?
1) Control of gastrointestinal motility
2) Regulation of intestinal secretion
3) Blood flow regulation in the gut wall
4) Nutrient absorption from the intestinal lumen
E) Maintenance of the mucosal barrier function
The myenteric plexus, or Auerbach's plexus, is located between the longitudinal and circular muscle layers of the gut wall. Its primary function is to regulate the motility of the gastrointestinal tract. It does so by coordinating the contractions of the smooth muscles, which are responsible for peristalsis and the propulsion of food through the digestive system. The myenteric plexus works in conjunction with the submucosal plexus and can be influenced by both the sympathetic and parasympathetic nervous systems.
The main stimulation for production of A.D.H. is
1. Increase in plasma potassium.
2. Decrease in blood volume
3. Increase in extracellular fluid
4. Decrease inextracellularosmotic pressure
Physiology
Answer: 2
The main stimulation for production of A.D.H. is Decrease in blood volume
- A.D.H. secretion increases during osmotic diuresis
What is the function of calcidiol in the body?
1) It is the active form of vitamin D
2) It is the precursor to calcitriol (active vitamin D)
3) It has no known function
4) It inhibits calcium absorption
Calcidiol is the precursor to calcitriol (active vitamin D) and plays a role in calcium absorption and bone health.