What can cause down regulation of a target cell?
What can cause down regulation of a target cell?
For example, the presence of a significant level of a hormone circulating in the bloodstream can cause its target cells to decrease their number of receptors for that hormone. This process is called downregulation, and it allows cells to become less reactive to the excessive hormone levels.
What factors determine the responsiveness of a target cell to a hormone?
Three factors influence the responsiveness of a target cell to a hormone: The hormone’s concentration, abundance of target cell receptors, and influences exerted by other hormones.
How do hormones Recognise their target cells?
Hormones activate target cells by diffusing through the plasma membrane of the target cells (lipid-soluble hormones) to bind a receptor protein within the cytoplasm of the cell, or by binding a specific receptor protein in the cell membrane of the target cell (water-soluble proteins).
Which of the following hormones plays key regulatory roles in the body’s long term response to stress?
Stressful stimuli cause the hypothalamus to signal the adrenal medulla (which mediates short-term stress responses) via nerve impulses, and the adrenal cortex, which mediates long-term stress responses, via the hormone adrenocorticotropic hormone (ACTH), which is produced by the anterior pituitary.
What is down-regulation hormones?
Downregulation: An decrease in the number of receptors on the surface of target cells, making the cells less sensitive to a hormone or another agent. For example, insulin receptors may be downregulated in type 2 diabetes.
What causes down-regulation of hormone receptors?
Elevated levels of the hormone insulin in the blood trigger downregulation of the associated receptors. When insulin binds to its receptors on the surface of a cell, the hormone receptor complex undergoes endocytosis and is subsequently attacked by intracellular lysosomal enzymes.
How do target tissues regulate their sensitivity to a hormone?
For example, after receptor stimulation the signaling target cell often sends feedback to the hormone-secreting tissue to down-regulate hormone expression. Additionally, the target cell can up or down-regulate receptor expression to make it more or less sensitive to the same hormone.
What does not affect the response of a target cell to a hormone?
Lipid insoluble hormones bind to receptors on the outer surface of the plasma membrane, via plasma membrane hormone receptors. Unlike steroid hormones, lipid insoluble hormones do not directly affect the target cell because they cannot enter the cell and act directly on DNA.
What do hormones control and regulate?
Hormones are found in all organisms with more than one cell, and so they are found in plants and animals. They influence or control a wide range of physiological activities such as growth, development, puberty, regulating sugar levels, bone growth and appetite.
Which statement is false regarding how a target tissue regulates its sensitivity to a hormone?
which statement is false regarding how a target regulates its sensitivity to a hormone? target tissues tend to up-regulate when exposed to large amounts of a hormone over time. identify the endocrine glands and the hormones each gland secretes. Which of the following is NOT an endocrine gland?
What is the target of ACTH?
Adrenal cortex
| Endocrine gland/ source of hormone | Hormone | Target organ or tissue |
|---|---|---|
| Anterior pituitary (adenohypophysis) | ACTH (adrenocorticotrophic hormone) | Adrenal cortex |
| FSH (follicle stimulating hormone) | Ovaries / testes (tubules) | |
| LH (luteinizing hormone) | Ovaries / testes (Leydig cells) | |
| GH (growth hormone) | All tissues |
What is down-regulation?
Downregulation: An decrease in the number of receptors on the surface of target cells, making the cells less sensitive to a hormone or another agent.
What is the difference between down regulation and up regulation of hormones?
Down-regulation makes a target cell less sensitive to a hormone. In contrast, when a hormone is deficient, the number of receptors may increase. This phenomenon, known as up-regulation, makes a target cell more sensitive to a hormone. Identify the chemical classes of hormones, and give an example of each.
What makes a cell more sensitive to a hormone?
This phenomenon, known as up-regulation, makes a target cell more sensitive to a hormone. Identify the chemical classes of hormones, and give an example of each. (Chemically, hormones can be divided into two broad classes: those that are soluble in lipids, and those that are soluble in water.
How do hormones enter the target cell?
T or F: In the direct genera activation method of hormone action, the hormone enters the target cell and binds to an intracellular receptor.. The activated receptor-hormone complex then alters gene expression to produce the protein that causes the physiological responses that are characteristics of the hormone.
What is the direct gene activation method of hormone action?
True or False: In the direct gene activation method of hormone action, the hormone enters the target cell and binds to an intracellular receptor. The activated receptor-hormone complex then alters gene expression to produce the protein that causes the physiological responses that are characteristic of the hormone.
