308+ quick-fire dental facts • tap a card to flip
The pyloric sphincter, also known as the pylorus, is a ring of smooth muscle that connects the stomach to the duodenum. It relaxes to allow small, controlled amounts of chyme to pass from the stomach into the duodenum. This regulation is important to prevent the rapid emptying of the stomach and the potential overwhelming of the small intestine with food and acid.
What is the primary function of the pyloric sphincter?
1) To regulate the flow of chyme into the small intestine
2) To mix and churn food in the stomach
3) To secrete intrinsic factor for vitamin B12 absorption
4) To secrete mucus for the protection of the gastric mucosa
E) To produce hydrochloric acid
Answer: 4) The ionic gradients involved in RMP generation are the same in both neurons and muscle cells
Explanation: 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 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
Pacinian corpuscles are rapidly adapting mechanoreceptors that are highly sensitive to high-frequency vibrations and are responsible for detecting rapid changes in pressure.
What is the primary mechanism of vibration detection in the musculoskeletal system?
1) Meissner's corpuscles
2) Pacinian corpuscles
3) Merkel's discs
4) Ruffini's endings
Which of the following is NOT a hormone secreted by the kidney?
1) 1,25 Dihydrocholecalciferol
2) Renin
3) Erythropoietin
4) Angiotensin I
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 vagus nerve, a part of the parasympathetic nervous system, has a negative chronotropic effect on the heart, meaning it decreases the heart rate. It does this by releasing acetylcholine onto the sinoatrial (S1) node, which slows the SA node's pacemaker activity.
What is the role of the vagus nerve in regulating heart rate?
1) Increases heart rate
2) Decreases heart rate
3) Has no effect on heart rate
4) Increases the force of heart contractions
E. Increases the conduction velocity of the cardiac impulse
Answer: 3) The sympathetic nervous system is regulated by the spinal cord through the sympathetic chain ganglia, which receive input from the hypothalamus and other higher centers.
Which of the following statements is true about the regulation of the sympathetic nervous system?
1) The sympathetic nervous system is primarily regulated by the parasympathetic nervous system.
2) The sympathetic nervous system is mainly controlled by the hypothalamus.
3) The sympathetic nervous system is regulated by the spinal cord through the sympathetic chain ganglia.
4) The sympathetic nervous system is primarily regulated by the sympathetic chain ganglia.
In which part of the nephron does the reabsorption of glucose and amino acids primarily occur?
1) Proximal Convoluted Tubule (PCT)
2) Loop of Henle
3) Distal Convoluted Tubule (DCT)
4) Collecting Duct
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