The endocrine system Flashcards
What is hormone?
A hormone is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior.
What does the endocrine system do?
help control mood, growth and development, the way our organs work, metabolism , and reproduction.
How many chemical classes are there?
3
What are the chemical classes?
Which hormones belong in these chemical classes?
lipid-derived, amino acid-derived, and peptide hormones
describe how hormones are synthesized and transported to their target organs;
describe how hormones stimulate their target cells;
name several organs of the endocrine system;
hypothalamus.
pituitary gland.
thyroid.
parathyroids.
adrenal glands.
pineal body.
reproductive glands (which include the ovaries and testes)
pancreas.
recognize the standard abbreviations for many hormones;
Thyroid-releasing hormone (TRH)
Corticotropin-releasing hormone (CRH)
Gonadotropin-releasing hormone (GnRH)
Growth hormone releasing hormone (GHRH)
Prolactin-inhibiting hormone (PIH)
Follicle-stimulating hormone (FSH)
Luteinizing hormone (LH)
Thyroid-stimulating hormone (TSH)
Thyroid hormone (TH)
Oxytocin (OT)
Antidiuretic hormone (ADH)
Adrenocorticotropic hormone (ACTH)
Prolactin (PRL) (the only non tropic hormone bc only milk produced not another hormone is being affected by prl)
Growth hormone (GH)
describe similarities and differences between the nervous and endocrine systems.
Both systems serve for internal communication:
*Speed and persistence of response
-Nervous: reacts quickly (ms timescale), stops quickly
-Endocrine: reacts slowly (seconds or days), effect may continue for days or longer
*Adaptation to long-term stimuli
-Nervous: response declines (adapts quickly)
-Endocrine: response persists (adapts slowly)
*Area of effect
-Nervous: targeted and specific (one organ)
-Endocrine: general, widespread effects (many organs)
*Several chemicals function as both hormones and neurotransmitters:
-Norepinephrine, dopamine, and antidiuretic hormone
*Both systems can have similar effects on target cells
-Norepinephrine and glucagon both cause glycogen hydrolysis in liver
*The two systems can regulate each other
-Neurotransmitters can affect glands, and hormones can affect neurons
*Neuroendocrine cells share characteristics with both systems
-Neuron-like cells that secrete oxytocin into blood
*Target organs or cells—those organs or cells that have receptors for a hormone and can respond to it
-Some target cells possess enzymes that convert a circulating hormone to its more active form
describe the anatomical relationships between the hypothalamus and pituitary gland;
*Pituitary gland is suspended from hypothalamus by a stalk—infundibulum
*Housed in sella turcica of sphenoid bone
*Size and shape of kidney bean
*Composed of two structures with independent origins and separate functions
-Adenohypophysis (anterior pituitary)
-Neurohypophysis (posterior pituitary)
distinguish between the anterior and posterior lobes of the pituitary;
*Adenohypophysis (anterior lobe) constitutes anterior three-quarters of pituitary
-Linked to hypothalamus by hypophysealportal system
*Primary capillaries in hypothalamus connected to secondary capillaries in adenohypophysis by portal venules
*Hypothalamic hormones regulate adenohypophysis cells
-Hypothalamic-releasing and -inhibiting hormones travel in hypophysealportal system from hypothalamus to anterior pituitary
-Different hormones are secreted by anterior pituitary
*Neurohypophysis (posterior lobe) constitutes the posterior one-quarter of the pituitary
-Nerve tissue, not a true gland
*Nerve cell bodies in hypothalamus pass down the stalk as hypothalamo-hypophyseal tract and end in posterior lobe
*Hypothalamic neurons secrete hormones that are stored in neurohypophysis until released into blood
describe the structure, location, and function of the thyroid and parathyroid glands;
*Pineal gland—attached to roof of third ventricle beneath the posterior end of corpus callosum.
*Thymus- bilobedgland in the mediastinum superior to the heart.
*Thyroid- is the largest gland that is purely endocrine. It is composed of two lobes and an isthmus below the larynx.
*Parathyroid Glands- usually four glands partially embedded in the posterior surface of the thyroid gland. Can be found from as high as hyoid bone to as low as aortic arch.
*Adrenal Glands- a gland located on the top of both kidneys. Adrenal medulla is the inner core (about 10% to 20% of gland) and adrenal cortex surrounds the medulla.
*Pancreatic Islets- located inside the pancreas, an elongated , spongy gland located below and being the stomach.
*Gonads- In women these are the ovaries and in men they are the testicles.
describe the structure, location, and function of the adrenal glands;
Adrenal glands, also known as suprarenal glands, are small, triangular-shaped glands located on top of both kidneys. Adrenal glands produce hormones that help regulate your metabolism, immune system, blood pressure, response to stress and other essential functions.
describe the structure, location, and function of the pancreas;
The pancreas is an organ located in the abdomen. It plays an essential role in converting the food we eat into fuel for the body’s cells. The pancreas has two main functions: an exocrine function that helps in digestion and an endocrine function that regulates blood sugar.
describe the structure, location, and function of the gonads;
The gonads, the primary reproductive organs, are the testes in the male and the ovaries in the female. These organs are responsible for producing the sperm and ova, but they also secrete hormones and are considered to be endocrine glands.
Lipid soluble MOA
hydrophobic. need proteins to carry them through the plasma.
ex. albumin, thyroid binding protein, sex hormone binding protein.
Water soluble MOA
Protein based. insulin example. can travel in plasma easily. cannot get through plasma membrane. is hydrophilic and lipophobic.
Water soluble: second messenger activates various proteins inside cell.
What are target cells
A cell whose activity is affected by a particular hormone
What type of tissue is endocrine glands made of
epithelial
What are the classes of chemical messengers
Endocrine, paracrine, and autocrine
Endocrine messengers
Humoral hormone release
Change of chemistry in the blood.
A humoral stimulus refers to the control of hormone release in response to changes in extracellular fluids such as blood or the ion concentration in the blood.
Chemoreceptors detect change.
Neural hormone release
the nervous system directly stimulates endocrine glands to release hormones, which is referred to as neural stimuli.
hormonal hormone release
A change in hormone A can have an effect on hormone B called a tropic effect
