18 Questions
Where are steroid hormones mainly conjugated?
Liver
How are peptide hormones and catecholamines degraded?
By enzymes in the blood and tissues
What is the typical half-life of angiotensin II in the blood?
Less than a minute
Where are hormones that are bound to plasma proteins cleared from?
Liver
Which type of hormones remain in the blood for only a short time?
Peptide hormones
What causes endocytosis of the cell membrane hormone-receptor complex?
Degradation in target cells
What is the main difference in how water-soluble hormones and steroid/thyroid hormones are transported in the blood?
Water-soluble hormones are mainly free in solution, while steroid/thyroid hormones circulate bound to plasma proteins.
How do protein-bound hormones differ in their ability to interact with target cells compared to free hormones?
Protein-bound hormones dissociate from plasma proteins easily to access target cells, whereas free hormones have difficulty interacting with target cells.
Why do relatively large amounts of hormones being bound to proteins serve as reservoirs?
To maintain a constant concentration of free hormones when they are lost from the circulation or bound to target receptors.
What is the primary role of metabolic clearance rate in determining hormone concentration in the blood?
To maintain a constant concentration of the hormone in the plasma.
Why do water-soluble hormones diffuse out of capillaries into interstitial fluid before reaching target cells?
To replenish the concentration of free hormones in the plasma
How does binding of hormones to plasma proteins affect their clearance from the bloodstream?
Binding to plasma proteins slows down hormone clearance by preventing easy diffusion across capillaries.
What is the primary purpose of measuring the metabolic clearance rate of a hormone?
To assess the various ways in which the hormone is cleared from the plasma
What is the formula used to calculate the metabolic clearance rate of a hormone?
Metabolic clearance rate = Rate of disappearance of hormone from the plasma / Concentration of hormone
Which of the following is NOT one of the ways in which hormones are cleared from the plasma?
Excretion by the lungs into the air
What is the purpose of infusing a radioactive solution of the hormone into the bloodstream during the measurement of metabolic clearance rate?
All of the above
How does a decreased metabolic clearance rate of a hormone affect its concentration in the circulating body fluids?
It increases the concentration of the hormone in the circulating body fluids
What is the primary reason for measuring the plasma concentration of the radioactive hormone during the metabolic clearance rate procedure?
To calculate the metabolic clearance rate using the formula
Learn about the different ways water-soluble hormones and lipid-soluble hormones are transported in the blood to reach target tissues and cells. This quiz covers the mechanisms of transport for peptides, catecholamines, steroids, and thyroid hormones.
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