Hormones travel throughout the body, either in the blood stream or in the fluid around cells, looking for target cells. Once hormones find a target cell, they bind with specific protein receptors inside or on the surface of the
cell
and specifically change the cell’s activities.
How are hormones delivered to 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).
How do hormones travel in the body and communicate their message to the target cells?
Hormones are transported primarily
via the bloodstream
throughout the body, where they bind to receptors on target cells, inducing a characteristic response.
How hormones travel from an endocrine organ to a target cell?
Some hormones
bind to receptors
on the surface of target cells. Others enter the cells and bind to receptors in the cytoplasm or nucleus. The binding triggers a series of actions that change the physiologic behavior of the cell.
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.
Which organ does not have hormone production?
The pituitary glands are made of the anterior lobe and posterior lobe. The anterior lobe produces and releases hormones. The posterior lobe does not produce hormones per se—this is done by nerve cells in the
hypothalamus
—but it does release them into the circulation.
What are the 3 main hormones?
There are three basic types of hormones:
lipid-derived, amino acid-derived, and peptide
. Lipid-derived hormones are structurally similar to cholesterol and include steroid hormones such as estradiol and testosterone.
Which major hormones are released in a stressful situation?
Cortisol
, the primary stress hormone, increases sugars (glucose) in the bloodstream, enhances your brain’s use of glucose and increases the availability of substances that repair tissues. Cortisol also curbs functions that would be nonessential or harmful in a fight-or-flight situation.
What is a hormone How is it an example of long distance communication?
Endocrine signaling is an example of long distance communication between
hormone producing cells, tissues and glands and cells
that express hormone receptor molecules.
What are the target cells of progesterone?
PR expression has been described in tissues known to be progesterone responsive such as the uterus [mammalian endometrium (46–51) and myometrium (51, 52)];
the ovary
[luteinizing granulosa cells and corpus luteum (53), preovulatory granulosa cells (54)]; and the chick oviduct (24) and bursa of Fabricius (55).
What are the target organs of estrogen?
Estrogens have multiple effects on the growth and development of cells in their target tissues, including
the uterus, ovary, breast, bone marrow and brain
. The hormone regulates the transcription of diverse genes in these tissues via the estrogen receptor, a nuclear transcription factor.
What is the target organ for testosterone?
| Endocrine Gland Hormone Target organ | Pancreas Insulin All cells in the body | Gonads: Testes Testosterone Sex organs | Muscle | Ovaries Oestrogen Sex organs |
|---|
What affects the response of a target cell to a hormone?
A target cell responds to a hormone
because it bears receptors for the hormone
. In other words, a particular cell is a target cell for a hormone if it contains functional receptors for that hormone, and cells which do not have such a receptor cannot be influenced directly by that hormone.
How can a single hormone have different effects?
A hormone can have different effects depending on
the target cell’s location
, the gender of the individual and the species. … That is, hormones turn on certain genes that are preprogrammed to make specific proteins. These proteins cause a cell to respond in a new way (grow, secrete, metabolize, etc.).
What allows a cell to respond to a hormone?
Cells respond to a hormone when
they express a specific receptor for that hormone
. The hormone binds to the receptor protein, resulting in the activation of a signal transduction mechanism that ultimately leads to cell type-specific responses.
At what age are estrogen levels highest?
- Levels peak in a woman’s 20s and decline slowly thereafter. By menopause, level is at half of its peak.
- Ovaries continue to make testosterone even after estrogen production stops.
- Testosterone production from adrenal glands also declines with aging. but continues after menopause.
