Endocrine System Flashcards
What are the two types of mechanisms used to maintain homeostasis?
Positive feedback and negative feedback
Which type of feedback is the most common?
Negative feedback
What does the endocrine system do?
It regulates long term processes
What are some examples of what the endocrine system regulates?
It regulates growth, development, and reproduction
What is the endocrine system unable to do?
It’s unable to handle split-second responses
What does the endocrine system use chemical messengers for?
They use them to relay information and instruction to cells
What makes up the endocrine system?
All endocrine cells and body tissues that produce hormones
What do endocrine cells release?
They release chemicals (hormones) into the blood stream
What releases hormones/chemicals into the blood stream?
Endocrine cells
What do hormones do?
They alter metabolic activities of many tissues and organs simultaneously, they stimulate synthesis of enzymes or structural proteins in the cell, they activate and deactivate enzymes, they stimulate mitosis, and they induce secretory activity
What alters metabolic activities of many tissues and organs simultaneously?
Hormones
What stimulates the synthesis of enzymes + structural proteins in the cell?
Hormones
What activates and deactivates enzymes?
Hormones
What stimulates mitosis?
Hormones
What induces secretory activity?
Hormones
What are small molecules that are structurally related to amino acids?
Amino acid derivatives
Are AAs water soluble?
Yes
What are AAs synthesized from?
Amino acids tyrosine and tryptophan
What are steroid-based hormones derived from?
Cholesterol (lipids)
Where are steroid-based hormones released from?
The reproductive organs, adrenal glands, and kidneys
What is unique about water-soluble hormones?
They can’t enter the cell and instead act on the receptor in the plasma membrane
What can most amino acid hormones be described as?
Water-soluble
What do water soluble hormones act on ?
They act on the receptor in the plasma membrane
What type of hormone can’t enter the cell, and instead acts on the receptor in the plasma membrane?
Water-soluble hormones
What types of hormones can cross the membrane?
Steroid and thyroid hormones
What can steroid and thyroid hormones do?
Cross the cell membrane
What are the two types of hormone travel?
Circulating freely or being bound to transport proteins
Which type of hormone travel causes the hormone to only remain functional for an hour?
Free hormones / free circulation
What are some characteristics of free hormones/ free circulation?
They only remain functional for an hour and they diffuse out of the blood and bind to receptors
What type of hormones diffuse out of the blood and bind to receptors? (Travel)
Free hormones
What types of hormones remain in blood longer?
Thyroid and steroid
What types of hormones cross cell membranes?
Thyroid hormones and steroid hormones
What is amplification?
When a small number of hormones bind to membrane receptors, which leads to thousands of second messengers in the cell.
What is the effect of amplification?
The effect of the hormone on the target cell is amplified
What is down regulation?
The presence of a hormone decreases in the number of hormone receptors.
What happens when hormone levels are high in down regulation?
When levels are high, the cells become less sensitive
What is up regulation?
When the absence of a hormone triggered an increase in the number of hormone receptors
What happens when hormone levels are low in up regulation?
When levels are low, the cells become more sensitive
What does the hypothalamus do?
It integrates the nervous and endocrine systems
What three things does the hypothalamus do?
It decreases regulatory hormones, acts as an endocrine organ, and contains autonomic***
What controls the endocrine cells of the pituitary gland?
Special hormones secreted by the hypothalamus
What is the master gland?
The pituitary gland
What is the pituitary gland also called?
The master gland
Where is the pituitary gland?
It hangs inferior to the hypothalamus
What connects the pituitary gland?
It’s connected by the infundibulum
What does the pituitary gland do?
It releases important peptide hormones, which bind to the membrane receptors
What do blood vessels do? What is this called?
Blood vessels in the pituitary link two capillary networks, called the portal system
What doesn’t he hypophyseal portal system ensure?
It ensures that hormones/ regulatory factors reach the intended target cells before entering general circulation
What ensures that hormones reach the intended target before they enter general circulation?
The hypophyseal portal system
What are the two types of hypothalamic regulatory hormones?
Releasing and inhibiting hormones
What are releasing and inhibiting hormones?
They’re the two types of hypothalamic regulatory hormones
When is ADH released?
When you’re dehydrated
What is released when you’re dehydrated?
ADH
What does ADH cause?
Vasoconstriction and your kidneys to not produce much urine
What does oxytocin affect and what inhibits it?
It stimulates the mammary gland + uterine wall and it’s inhibited by stress
What surrounds the thyroid follicles?
The thyroid capillaries
What determines the amount of thyroid hormones released?
The blood TSH concentration
What does calcitonin regulate? What does this prevent?
It regulates calcitonin concentration, and it decreases/ prevents bone breakdown by osteoclasts
What does calcitonin increase?
It increases the excretion in the kidneys
What can’t be stored?
Calcitonin
What do the parathyroid glands control?
They control osteoclasts
Where are the adrenal glands and what do they make?
They’re along the top of the kidneys and they create steroid hormones
What does glucocorticoids secrete and what does it regulate and increase?
It secretes cortisol and it regulates blood glucose and increases glucose synthesis
What stimulates glucocorticoids?
It’s stimulated by stress or ACTH
What does glucocorticoids affect?
The liver
What produces androgens?
ACTH stimuli
What do androgens produce?
A small amount of testosterone and a very small amount of estrogen
What is required for female sex drive?
Estrogen
What controls the flight or fight instinct?
The adrenal medullae
What does the adrenal medulla do?
It controls the fight or flight instinct
What does the adrenal medullae produce?
80% E, 20% NE
What does adrenal medullae cause?
Metabolic change due to to the fight or flight response
What does the adrenal medullae affect?
Most cells
What does the pineal gland control?
Sleep (melatonin) and puberty
