MDS PREP
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 significance of the blood-brain barrier being absent in the circumventricular organs?
1) Allows free passage of hormones and neurotransmitters to the cerebrospinal fluid (CSF)
2) Enables direct interaction with the hypothalamus for osmoregulation
3) Facilitates the entry of pathogens and drugs into the brain
4) Necessary for the synthesis of neurotransmitters in these areas
The absence of the blood-brain barrier in circumventricular organs allows for the unimpeded movement of substances between the blood and the CSF, which is crucial for the regulation of various physiological processes, including osmoregulation.
What is the role of the corpus luteum in the second half of the menstrual cycle?
1) It secrets FSH
2) It secrets LH
3) It secrets estrogen and progesterone
4) It secrets inhibin
The corpus luteum secretes estrogen and progesterone during the second half of the menstrual cycle, which are essential for maintaining the uterine lining.
What is the primary stimulus for the secretion of Secretin?
1) High blood glucose levels
2) Low pH in the duodenal lumen
3) The presence of fatty acids and amino acids in the duodenal lumen
4) Stretching of the duodenal wall
The primary stimulus for the secretion of Secretin is low pH in the duodenal lumen, which indicates the presence of acidic chyme.
What is the function of the reticular formation in the regulation of sleep and wakefulness?
1) It initiates sleep
2) It maintains wakefulness
3) It is not involved in sleep-wake regulation
4) It initiates REM sleep
The reticular formation plays a crucial role in maintaining wakefulness by sending activating signals to the thalamus and cortex.
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 role of leptin in the regulation of food intake?
1) It stimulates food intake
2) It inhibits food intake
3) It has no effect on food intake
4) It increases the absorption of nutrients in the intestine
Leptin plays a role in the regulation of food intake by inhibiting hunger, signaling to the brain that the body has enough energy stored.
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
The primary mechanism responsible for the reclamation of bile acids in the enterohepatic circulation is active transport in the ileum, allowing for recycling of bile acids.