Introduction to Endocrine System Flashcards
What are hormones?
Regulatory substances produced in a gland that stimulate specific cells into action
The term ‘hormone’ is derived from the Greek verb ‘hormao’, meaning ‘to set in motion’.
What are the major physiologic processes controlled by hormones?
- Growth and maturation
- Metabolism
- Reproduction
What distinguishes endocrine glands from exocrine glands?
Endocrine glands secrete hormones into the blood, while exocrine glands secrete through ducts onto surfaces.
Name two types of communication used by hormones.
- Communication between different endocrine glands
- Communication between an endocrine gland and a target organ
What is the role of hormone receptors?
Proteins located inside the cell or on the cell membrane that bind to hormones and initiate cellular responses.
What are the two main types of hormones?
- Peptide-derived hormones
- Steroid hormones
What is the function of second messengers in hormone signaling?
Activate intracellular enzymes and amplify hormonal signals.
True or False: Steroid hormones can be stored in secretory vesicles.
False
Fill in the blank: The term __________ was coined by Starling in 1905 to describe hormones secreted internally.
[endocrine]
List examples of hydrophilic hormones.
- Insulin
- Epinephrine
- Glucagon
What is a bound hormone?
A hormone that is attached to a transport protein.
What is the difference between free hormones and bound hormones?
Free hormones are unbound and biologically active; bound hormones are attached to transport proteins and inactive.
What are the effects of hormones on the body?
- Control growth
- Change sexual function
- Regulate metabolism
- Balance water and electrolytes
- Breastmilk production
- Uterine contraction
- Temperature regulation
- Sleep-wake cycle
What type of hormones are derived from cholesterol?
[steroid hormones]
What is the significance of the ‘free fraction’ of a hormone?
It refers to the percent of hormone that is unbound and biologically active.
Describe the structure of peptide hormones.
Made from chains of amino acids, and can be large proteins such as growth hormone.
What is the role of transport proteins in hormone circulation?
Protect hormones from degradation and increase their half-life in the bloodstream.
Name two examples of amino acid-derived hormones.
- Epinephrine
- Thyroxine
Fill in the blank: The interaction of a single hormone molecule with a receptor can lead to __________ signal-generating events within a cell.
[multiple]
What are the two types of feedback loops in hormone signaling?
- Positive feedback loops
- Negative feedback loops
True or False: Hydrophobic hormones can easily cross the cell’s plasma membrane.
True
What is the effect of increased blood binding protein during pregnancy on hormone concentration?
It can change the total amount of hormone but will not affect the concentration of free hormone.
What is the laboratory result for TSH in the presented clinical case?
0.6 (0.4 - 4.0 mU/L)
TSH stands for Thyroid-Stimulating Hormone.
What is the Total T4 level in the clinical case?
15 (5-12 ug/dl)
Total T4 refers to the total amount of thyroxine in the bloodstream.