Endocrine System (Practice Mode)

Estrogen is a hormone that plays various roles in the body, including causing breast growth, inhibiting FSH (follicle-stimulating hormone), and increasing follicle development. However, it does not have a function in decreasing overall transport proteins.

Vasopressin is not an anterior pituitary gland secretion. The anterior pituitary gland secretes TSH (thyroid-stimulating hormone), GH (growth hormone), and prolactin. Vasopressin, also known as antidiuretic hormone (ADH), is actually produced in the hypothalamus and stored in the posterior pituitary gland. It plays a role in regulating water balance and blood pressure by controlling the reabsorption of water in the kidneys.

Angiotensin I is changed into Angiotensin II by ACE (Angiotensin Converting Enzyme). ACE is an enzyme that plays a crucial role in the renin-angiotensin-aldosterone system, which regulates blood pressure and fluid balance in the body. ACE cleaves off a dipeptide from Angiotensin I, converting it into Angiotensin II. Angiotensin II is a potent vasoconstrictor and also stimulates the release of aldosterone, which increases sodium and water reabsorption in the kidneys, further contributing to the regulation of blood pressure.

During phase 3 of the myocardial action potential, the ion that is moving the most is K+. This is because phase 3 is the repolarization phase, where the cell membrane potential is returning to its resting state. K+ channels open, allowing K+ ions to move out of the cell, causing the cell to become more negative. This movement of K+ ions out of the cell is what leads to the repolarization of the myocardial cell.

The U wave is associated with hypokalemia during an electrocardiogram. Hypokalemia refers to low levels of potassium in the blood, which can cause changes in the heart's electrical activity. The U wave is a small waveform that follows the T wave and represents repolarization of the papillary muscles. In cases of hypokalemia, the U wave can become more prominent or even merge with the T wave, leading to an abnormal ECG pattern.

An S3 heart sound is often associated with congestive heart failure (CHF). In CHF, the heart muscle becomes weak and is unable to pump blood efficiently, leading to fluid buildup in the lungs and other parts of the body. The S3 sound is caused by the rapid filling of the ventricles during early diastole, when the blood is forced into an already stretched ventricle. This sound is commonly heard in patients with CHF and can be an important diagnostic clue in identifying the condition.

Angiotensin II is a hormone that plays a crucial role in regulating blood pressure and fluid balance in the body. It causes the release of aldosterone, which promotes sodium and water retention by the kidneys, leading to increased blood volume and blood pressure. It also stimulates the posterior pituitary gland to release antidiuretic hormone (ADH), which further promotes water reabsorption and raises blood pressure. However, angiotensin II does not cause vasodilation. Instead, it causes vasoconstriction, narrowing the blood vessels and increasing peripheral resistance, which contributes to elevated blood pressure.

Decreased capillary output is not a cause of peripheral edema because peripheral edema is the accumulation of fluid in the tissues due to increased capillary permeability or reduced levels of plasma proteins. In heart failure, the heart is unable to pump blood effectively, leading to fluid retention and edema. However, decreased capillary output would not cause fluid accumulation in the tissues.

PAH (para-aminohippuric acid) is a substance that is used to measure renal plasma flow. It is filtered at the glomerulus and then actively secreted into the proximal tubule. Therefore, the correct answer is the proximal tubule.

A 2nd degree (Mobitz Type 1) AV block is characterized by a nonsequential pattern, where there is a P wave that is not followed by a QRS complex. This condition is usually asymptomatic and is associated with an increased PR segment/interval. The statement "70% Fatal" is not generally associated with this type of AV block.

Pepsinogen is secreted by the chief cells. These cells are located in the gastric glands of the stomach. Pepsinogen is an inactive form of pepsin, which is an enzyme responsible for the digestion of proteins. The chief cells release pepsinogen into the stomach, and then it is activated by the acidic environment to become pepsin. Therefore, the correct source cell for the secretion of pepsinogen is the chief cell.

The ejection fraction is a measure of the percentage of blood pumped out of the heart with each heartbeat. It is calculated by dividing the stroke volume (the amount of blood pumped out of the heart with each contraction) by the end-diastolic volume (the amount of blood in the heart at the end of relaxation). Therefore, the correct answer is SV/EDV, as it represents the ratio of the blood ejected to the blood present in the heart at the end of diastole.

Thyroid Hormone T3 is known to have various functions in the body, including stimulating bone development and growth, creating beta-adrenergic responses, and causing brain development. However, it does not have the function of decreasing calcium re-absorption. This means that T3 does not play a role in reducing the amount of calcium that is reabsorbed by the body.

Hypercalcemia is a condition characterized by high levels of calcium in the blood. It can be caused by various factors, including Paget's disease, sarcoidosis, and malignancy. However, aldosterone, a hormone produced by the adrenal glands, is not directly linked to hypercalcemia. Aldosterone primarily regulates salt and water balance in the body, and its excess or deficiency can lead to conditions such as hypertension or electrolyte imbalances, but not hypercalcemia.

Bradykinin is a peptide that is involved in various physiological processes. It is known to cause elevated capillary permeability, which allows fluids and proteins to leak out of blood vessels. It also increases pain levels by sensitizing pain receptors. Additionally, bradykinin causes vasodilation, leading to the widening of blood vessels and increased blood flow. However, it does not have an effect on prothrombin secretion, which is the precursor to thrombin, a protein involved in blood clotting. Therefore, elevated prothrombin secretion is not a bradykinin effect.

ACTH (adrenocorticotropic hormone) does not require the pre-cursor progesterone. ACTH is produced by the pituitary gland and stimulates the production of cortisol in the adrenal glands. Progesterone is a hormone that is involved in the menstrual cycle and pregnancy, but it is not directly involved in the production of ACTH. Cortisol, testosterone, and aldosterone, on the other hand, do require progesterone as a pre-cursor hormone for their synthesis.

Acetylcholine is the primary activator of zymogen secretion. Zymogens are inactive enzymes that are converted into active enzymes when needed. Acetylcholine is a neurotransmitter that is released by the parasympathetic nerves and stimulates the release of digestive enzymes from the pancreas. It binds to specific receptors on pancreatic cells, triggering a signaling cascade that leads to the secretion of zymogens. This activation of zymogen secretion by acetylcholine is an important step in the digestive process, as it allows for the breakdown of food molecules in the intestine.

Progesterone is a hormone primarily involved in the regulation of the female reproductive system. It plays a crucial role in preparing the uterus for pregnancy and maintaining pregnancy. Progesterone causes increased body temperature by acting on the hypothalamus, which regulates body temperature. It also causes smooth muscle relaxation in the uterus, preparing it for implantation and preventing contractions. Additionally, progesterone promotes increased spiral artery growth in the uterus, ensuring proper blood supply to the developing fetus. However, it does not cause activation of FSH (follicle-stimulating hormone). FSH is primarily responsible for the development and maturation of ovarian follicles in the female reproductive system.

Atrial natriuretic peptide (ANP) is the correct answer. ANP is a hormone released by the atria of the heart in response to increased atrial pressure. It acts on the kidneys to decrease sodium reabsorption, which leads to increased excretion of sodium and water. This ultimately results in a decrease in blood volume and blood pressure.

Mean arterial pressure is the average pressure in the arteries during one cardiac cycle. It is determined by both the total peripheral resistance (TPR), which represents the resistance to blood flow in the systemic circulation, and the cardiac output (CO), which is the volume of blood pumped by the heart per minute. Therefore, the correct answer is TPR x CO, as both factors contribute to the calculation of mean arterial pressure.