Endocrine System Flashcards
(170 cards)
The second controlling system of the body
Endocrine system
First controlling system and the fast-control system
nervous system
Uses chemical messengers (hormones) that are released into the blood. These hormones control several processes including reproduction, growth and development, mobilization of body defenses, maintenance of homeostasis, and regulation of metabolism
Endocrine system
They are ductless. Instead, hormones are secreted directly into capillaries and circulate in the blood throughout the body
Endocrine glands
Produced by specialized cells
hormones
Cells that secrete hormones into extracellular fluids while the blood transfers hormones to target sites
specialized cells
In general they help regulate growth, the use of foods to produce energy, resistance to stress, the pH of body fluid and fluid balance, and reproduction
Endocrine system and its hormones
Simple hormones that are structural variations of the amino acids tyrosine
Amines
This group includes thyroxine from the thyroid gland and epinephrine and norepinephrine from the adrenal medulla
Amines
These hormones are chains of amino acids
proteins
Short chains of amino acid
peptides
Antidiuretic hormone and oxytocin, synthesized by hypothalamus are ____
peptide hormones
The precursor of steroid hormones
cholesterol
include cortisol and aldosterone from the adrenal cortex, estrogen and progesterone from the ovaries, and testosterone from the testes
Steroids
Secreted by endocrine glands when there is a need for them, that is, for their effects on their target organs
hormones
Secretes insulin when the blood glucose is high
pancreas
Th stimulus for secretion of insulin
hyperglycemia
Enables cells to remove glucose from the blood so that it can be used for energy production and enables the liver to store glucose as glycogen
insulin
Information about the effects of the hormone is “fed back” to the gland, which then decrease its secretion of the hormone. The effects of the hormone reverse the stimulus and decrease the secretion of then hormone
hormonal negative feedback mechanism
Hormones of the anterior pituitary gland are secreted in response to ____ secreted by the hypothalamus
releasing hormone (also called releasing factor)
Is secreted in response to growth hormone-releasing hormone (GHRH) from the hypothalamus
Growth hormone
Cells where hormones exert their action, must have specific protein receptors for the hormones to bind
Target cells
The hormone diffuse through the plasma membrane of the target cells and enter the nucleus. Once the hormone is inside the nucleus of the cell, it binds to a specific protein within the nucleus then binds into specific sites on cell’s DNA
This activate genes that will result in the synthesis of new proteins
Direct gene activation
The hormone binds to a membrane receptor and does not enter the cell however; it sets off a series of reactions that activates an enzyme
Then the enzyme catalyzes a reaction that produces a second-messenger molecule (such as cAMP) to oversee additional intracellular changes to promote a specific response
second-messenger system