Endocrine System Flashcards
Nervous System
Neurotransmitters released by neurons relay signals from one part of the body to another part of the body.
how is the endocrine system similar to the nervous system?
Like the nervous system, the endocrine system acts to coordinate the functions of various body systems.
Endocrine System
Chemical mediators called hormones are released from one part of the body and travel (usually via the blood) to another part of the body.
What are the chemical mediators released by the nervous system?
Neurotransmitters.
How do neurotransmitters relay signals in the nervous system?
They are released by neurons and relay signals from one part of the body to another.
What are the chemical mediators released by the endocrine system?
Hormones.
How do hormones travel in the body in the endocrine system?
They travel through the bloodstream to target cells.
How do the endocrine and nervous systems work together to coordinate body functions?
They work together using chemical mediators to coordinate the functions of organs and systems in the body.
What form do mediators take in the nervous system?
Neurotransmitters.
What form do mediators take in the endocrine system?
Hormones
How do neurotransmitters released by a neuron differ from hormones released by a gland cell in terms of target cells?
Neurotransmitters released by a neuron target specific types of cells located close to the neuron, whereas hormones released by a gland cell typically target many different types of cells located in different regions of the body.
What is the difference in the duration of effects between neurotransmitters and hormones?
Neurotransmitters have relatively quick effects and a short duration because they only need to travel across the synapse to their target cell and are quickly inactivated. Hormones, on the other hand, have much slower effects and a longer duration because they must travel through the bloodstream to reach their target cells and remain active for a period.
What are cells or groups of cells in the body that release substances called?
Glands
What distinguishes endocrine glands from exocrine glands in terms of secretion?
Endocrine glands secrete hormones into the blood, while exocrine glands secrete substances into ducts that transport them to the external environment.
What is the primary mode of secretion for endocrine glands?
Endocrine glands primarily secrete hormones into the bloodstream.
Give an example of a substance secreted by exocrine glands.
Examples include sweat, saliva, and digestive enzymes.
Why are glands that release substances into the gastrointestinal tract classified as exocrine glands?
Because the space within the gastrointestinal tract is continuous with the external environment.
What determines whether an organ contains only endocrine glands, only exocrine glands, or both?
It depends on the specific function of the organ. Some organs contain only endocrine glands, some contain only exocrine glands, while others contain both types.
What is the significance of the digestive tract being considered part of the “external environment”?
It explains why glands that release substances into the gastrointestinal tract are classified as exocrine glands, as the tract is continuous with the external environment.
How do hormones reach their target cells?
Hormones travel through the bloodstream until they reach their target cell, which has a receptor specific to that hormone.
What are artificial hormone analogues, and how do they interact with receptors?
Artificial hormone analogues are molecules designed to mimic natural hormones. They can bind to hormone receptors, either mimicking the hormone’s effects (agonist) or blocking the hormone from binding (antagonist).
What is the function of tamoxifen, and how does it interact with estrogen receptors?
Tamoxifen is an artificial analogue of estrogen. It acts as an antagonist when it binds to estrogen receptors in breast tissue, fighting breast cancer. However, it acts as an agonist when it binds to estrogen receptors in uterine tissue, potentially increasing the risk of uterine cancer.
Why is it important to consider the relative benefits and risks of using tamoxifen?
It is important because tamoxifen’s effects can vary depending on the tissue it interacts with. While it can be beneficial in treating breast cancer, it may also carry risks, such as increasing the risk of uterine cancer.
How do water-soluble hormones differ from lipid-soluble hormones in terms of administration?
Water-soluble hormones must be injected directly into the bloodstream, whereas lipid-soluble hormones can be taken orally.