Endocrine System 1 Flashcards
Why do individuals still exhibit symptoms of a disorder even when hormones are within the population reference range?
Because it might be that they are moving outside their specific “normal range”.
Every individual has their own set point that is specific to their body. It’s different for everyone.
Consists of endocrine gland cells that secrete hormones which are released in the bloodstream to target cells upon which they act.
Endocrine system
These are cells that are mainly found in other distant tissues or organs and MUST have the appropriate receptors to receive/interact with hormones.
Target cells
This links the nervous system to the endocrine system and controls the secretion of many endocrine glands.
Hypothalamus
What are the major endocrine glands?
Pituitary gland, thyroid gland, adrenal gland, pancreas and parathyroid gland
These are chemical messengers produced in one location (eg., hypothalamus) and transported via the bloodstream to a target cell where they cause a response/effect in those cells.
Hormones/true hormones
What is the only way a hormone can affect cells?
If the cell has specific receptors for that hormones. If not, then it will not be able to bind to the receptor and cause a change in the system/effector organ
What are the 2 types of hormones? Give examples.
Water soluble hormones (peptides and catecholamines: adrenalin and noradrenalin)
Lipid soluble hormones (steroids and thyroid hormones)
These are hormones that can be made and stored until required.
- they are released via exocytosis
- can diffuse into the bloodstream and travel easily to the target cell
- receptors for this hormone are usually on the membrane (because they CANNOT cross the cell membrane)
Water soluble hormones
These are hormones that are made upon demand. Usually not stored.
- only exception to the rule is the thyroid hormone (thyroid hormones are able to be stored)
- travel in the blood bound to a carrier protein and diffuse in the lipid bilayer;
- because receptor for this hormone is usually an INTRACELLULAR receptor (found on nucleus/cytoplasm)
Lipid soluble hormones
This is the most common way of maintaining hormone levels. It maintains hormone levels by reducing the change until stimulus is removed.
Negative feedback system.
This maintains hormone levels by amplifying change until desired outcome is achieved.
Positive feedback system.
The amount of hormone secretion depends on:
- rate of hormone secretion
- rate of removal from blood (removal is controlled by enzymes in the blood or in target cells)
These cells secrete insulin (found in pancreas)
Beta cells
These cells secrete glucagon
Alpha cells
