Endocrine 2 Flashcards
(13 cards)
What is a hormone?
A signalling chemical molecule produced in small amounts by glands that can have relatively long lasting effects on target cells.
The term ‘Hormone’ derives from the Greek term ‘Hormona’ which means to ‘excite’.
Name two major endocrine glands.
- Pancreas
- Adrenal gland
- Thyroid gland
- Pineal gland
- Gonads (ovaries and testes)
The hypothalamus and pituitary gland are also considered neuroendocrine glands that link the nervous and endocrine systems.
What is the primary method of hormone transport in the body?
Hormones are primarily transported through the circulatory system via the bloodstream.
The lymphatic system plays a role in maintaining blood volume but is not the primary route for hormone transport.
How do hormones regulate cellular activity?
Hormones regulate the metabolism (activity, growth) of cells in animals and plants.
Hormones exist in all multicellular organisms.
What is the role of insulin in blood sugar regulation?
Insulin causes the uptake of sugar by cells, reducing concentration in blood.
This occurs when blood sugar levels increase and is part of a feedback mechanism for homeostasis.
Fill in the blank: A hormone can only act on _______ which has the hormone’s specific receptor proteins.
target cells
Where are hormone receptors located?
Inside the cell or within the cell membrane.
Some hormones cannot pass through the cell membrane, while others can.
True or False: Non-target cells will be affected by hormones even if they lack specific receptor proteins.
False
What is the effect of down-regulation on cells?
Cells become less reactive to excessive hormone levels by decreasing their number of receptors for that hormone.
This process helps maintain balance in hormone sensitivity.
What triggers up-regulation in target cells?
A reduction in hormone levels or the need for a stronger effect of the hormone.
This process increases the number of receptors and makes cells more sensitive to the hormone.
List some potential responses of a target cell upon receiving a hormone signal.
- Stimulation of protein synthesis
- Activation or deactivation of enzymes
- Alteration in the permeability of the cell membrane
- Altered rates of mitosis and cell growth
- Stimulation of the secretion of products
A single hormone may induce multiple responses in a given cell.
What is the relationship between receptor number and cell sensitivity to hormones?
Cell sensitivity to a hormone is directly linked to the number of receptors it possesses for that hormone.
What is the function of the endocrine system?
To provide slow and long-lasting control through the use of hormones.
