[L3 Anatomy and Physiology] Section 5: The endocrine system Flashcards
The endocrine system helps maintain what?
Homeostasis
The endocrine system exerts its influence using?
Hormones
How are hormones produce and where do they secrete to?
Hormones are produced by glands and secreted into the bloodstream
What are hormones and what is their purpose?
Hormones are chemicals that are released into the bloodstream to help control and manage the internal environment of the body.
Describe the general steps of how hormones work.
- Endocrine gland receives stimulus.
- Gland releases chemical hormone.
- Hormone travels in bloodstream.
- Hormone received by target cell receptors.
- Cell stimulated to cause desired response.
- Feedback to the originating gland.
Name the 6 major endocrine glands
PITUITARY GLAND THYROID GLAND ADRENAL GLANDS PANCREAS OVARIES TESTES
What is the purpose of the Pituitary gland?
The ‘master gland’ - Many of the early endocrine outputs originate from here.
What is the purpose of the Thyroid?
The master regulator of metabolism.
What is the purpose of the Adrenal?
Named after their location on top of the renals (or kidneys).
These small glands primarily help to control and manage the stress response in the body.
What is the purpose of the Pancreas?
Helps to control carbohydrate metabolism (blood-sugar levels).
What are the two hormones released by the pancreas and what is their primary goal?
Insulin and Glucagon - Primary goal is to regulate glucose levels in the blood.
What are the steps involved in reducing glucose levels?
- Glucose enters the bloodstream
- Pancreas detects increased levels of blood
glucose - Pancreas secretes insulin into bloodstream
- Insulin increases permeability of cells (esp. muscle
and liver) and membranes to glucose - Blood glucose levels begin to drop
- Pancreas detects drop in levels of blood glucose
- Pancreas reduces insulin secretion
- Cells become less permeable to insulin
What are the steps involved in increasing glucose levels?
- Glucose levels begin to drop
- Pancreas detects decreased levels of blood
glucose - Pancreas secretes glucagon into bloodstream
- Glucagon stimulates the release of glucose from
the liver - Blood glucose levels begin to rise
- Pancreas detects rise in levels of blood glucose
- Pancreas reduces glucagon secretion
- Liver reduces release of glucose
Where are the adrenal glands located?
The adrenals are small glands that sit on top of the kidneys.
What is the name of the inner layer of the adrenal glands, and what category of hormones does it produce?
The inner layer (or adrenal medulla) produces a category of hormones called the ‘catecholamines’.
What is the name of the outer layer of the adrenal glands, and what category of hormones does it produce?
The outer layer (the adrenal cortex) produces a category of hormones called the ‘corticosteroids’
Why are the adrenals well located?
they have a direct link to the major blood vessels of
the body. This allows their valuable hormones to get out into circulation and have an effect very quickly.
What is the most well-known hormone in the catecholamine category?
Adrenaline
What is the primary hormone in the catecholamine category?
Cortisol
What effect does adrenaline have on the body?
Increases heart rate, blood flow, and breathing and alertness levels, rapidly preparing the body for action.
What effect does cortisol have on the body?
helps to provide reserves in the body for managing stress, whether mental, physical, or emotional, by breaking down carbohydrates and fats to provide energy for the body during stressful periods.
Which category does aldosterone belong to and what effect does it have on the body?
Corticosteroid - It helps to regulate the balance of the minerals sodium and potassium in the blood, which play a major role in maintaining the water balance in the bloodstream.
Growth hormone is released directly from which gland?
The pituitary gland
Growth hormone is responsible for what effects on the body?
- Drives bone growth during puberty
- Stimulates protein synthesis in muscle tissue
- Helps to break down and release fat tissue from storage sites around the body for oxidation
