Endocrine System Flashcards
Crine
Having to do with secretion
Pure endocrine organs (4)
Pituitary
Pineal gland
Thyroid and parathyroid glands
Adrenal glands (Adrenal cortex and adrenal medulla)
Organs containing large proportion of endocrine cells (4)
Pancreas
Thymus
Gonads
Hypothalamus (a neuroendocrine organ)
Organs containing some endocrine cells
Heart
Digestive tract
Kidneys
Skin
Endocrine cells are of _____ origin?
epithelial
Action-Reach: Endocrine versus Neural signaling
Neural signaling is very localized
Endocrine signaling is a long distance action
Action-Path:Endocrine versus Neural signaling
Neural signals travel along defined routes between specific cells (neural networks)
Endocrine signals broadcast through bloodstream to almost all cells
The pituitary gland sits in the ____
Sella turcica of the sphenoid bone
Action-Speed:Endocrine versus Neural signaling
Neural signals are very rapid (milliseconds)
Endocrine signals are slow (seconds, minutes, hours, days)
Action-Control:Endocrine versus Neural signaling
Release of neural signal may have some conscious control
Release of endocrine system has no conscious control
neurotransmission is highly targeted (NTs only affect the _____) and occurs over tiny distances (the ____)
- Postsynaptic cell
2. Synaptic Cleft
endocrine signaling is completely -1. targeted or untargeted- (hormones in circulation affect all cells with receptors for them) and occurs over -2. small or large- distances (whole body)
- untargeted
2. large
A signaling molecule released into the bloodstream
Hormones
Neurons sometimes release their signaling molecules into circulation instead of at synapses
in these cases the molecules are called?
neurohormones or just hormones
Dopamine is regarded as a (1) when secreted by the adrenal gland and a (2) when secreted by a neuron.
- Hormone
2. Neurotransmitter
Neurons that blend characteristics of the nervous and endocrine systems
Neurosecretory (or neuroendocrine) cells
Hormones can ONLY act on _____?
organs/tissues that have the receptor for them
Hormones that stimulate other glands to make & release hormones
Tropic hormones
Three broad structural classes of hormones:
proteins (peptide hormones) amine hormones (modified amino acids) steroid hormones (modified cholesterol)
The three broad structural classes of hormones are hydro(1) and can (2)
- Hydrophobic
2. Directly cross cell membranes
What can hormones do?
Standard actions of a biological signaling molecule. They can:
alter membrane permeability
activate second messenger pathways
alter gene expression
Endocrine cell types and tissues (2)
Nonneural (epithelial) endocrine cells
Neuroendocrine cells
Endocrine cells (either nonneural or neuroendocrine) organized into their own organs specialized for hormone secretion
Endocrine glands
Endocrine glands can be stimulated to release a hormone in 3 ways:
Humoral stimulus
Neural stimulus
Hormonal stimulus
Glands monitor the blood and release the hormone in response to change
Humoral stimulus
A neuron stimulates the gland to release hormone
Neural stimulus
Glands controlled by a tropic hormone
Hormonal stimulus
Medulla of the adrenal gland is a ______
Sympathetic ganglion
The adrenal gland secretes?
catecholamines
Catecholamines are?
epinephrine and norepinephrine
The hypothalamus secretes hormones that stimulate the (1) to secrete hormones that stimulate other endocrine glands (such as 2, 3, 4)to secrete hormones
- Anterior pituitary gland
2. Thyroid gland, Adrenal cortex, gonad
The adrenal gland is a type of ____stimulus
Neural
The hypothalamus is a type of ____stimulus
Hormonal
A_____ is a type of pathway that is regulated by the presence of the hormone itself, or of the product of hormone release
Feedback loop
Hormone levels are controlled by _______
Feedback loops
There are positive and negative loops. _____ loops are far more common.
Negative
A negative feedback loop is where the product of the pathway, turns the pathway (on or off)
Off
In a positive feedback loop, the output ____ the original stimulus
Enhances or amplifies
The key difference between positive and negative feedback is their response to change: positive feedback (1) change while negative feedback (2) change.
- amplifies
2. Reduces
Blood clotting is an example of a (positive or negative) feedback loop
Positive
The _____ oversees the endocrine system and responds to feedback.
Hypothalamus
hypothalamic releasing/inhibiting hormones -> carried by portal vessels -> detected by anterior pituitary cells -> release/inhibit of pituitary hormones into general circulation
The anterior pituitary
The anterior pituitary has ____ tissue
Non-neural
terminals of hypothalamic neurosecretory cells -> release of hormones into general circulation
Posterior pituitary
The posterior pituitary has ____tissue
neuroendocrine tissue
The anterior pituitary can be subdivided into 3 parts (pars)
Pars tuberalis
Pars intermedia
Pars distalis
a region of the anterior pituitary that wraps around the infundibular stalk
Pars tuberalis
A part of the anterior pituitary that is the boundary between anterior and posterior pituitary
Pars intermedia
The part of the anterior pituitary that is the anterior bulge
Pars distalis
The posterior pituitary can be subdivided into 2 parts:
Infundibular stalk
Pars nervosa
connects posterior pituitary and hypothalamus
Infundibular stalk
the posterior bulge pf the pituitary gland, consists of nervous (not glandular) tissue that includes axons of hypothalamic neurons from hypothalamo-hypophyseal tract
Pars nervosa
Hypothalamus makes_____ that regulate anterior pituitary
tropic hormones
Hypothalamus connected to the anterior pituitary through a special blood vessel network
Hypophyseal portal system
A _____ is network that connects 2 capillary beds before returning to heart
“Portal System”
Hormones of the Anterior Pituitary
Thyroid-stimulating hormone (TSH)
Prolactin (PRL)
Adrenocorticotropic hormone (ACTH)
Growth hormone (GH)
Causes growth of bones, muscles and most body cells
Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH)
Stimulates release of thyroid hormone from thyroid gland
Thyroid-stimulating hormone (TSH)
Regulates breast milk production & secretion of other hormones
Prolactin (PRL)
Stimulates adrenal cortex to produce hormones
Adrenocorticotropic hormone (ACTH)
Causes growth of bones, muscles and most body cells
Growth hormone (GH)
Influence reproductive activities by regulating hormone synthesis by the male and female gonads
Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH)
Involute
Decreases in size (i.e. when discussing the thymus when one turns 14)
Follicular cells make _____.
Thyroid hormone (TH)
Thyroid production is an example of a ____ feedback loop. Why?
Negative
The production of Thyroid hormone (TH) by the thyroid gland stops the production of Thyrotopin releasing hormone (TRH) in the hypothalmus
The posterior pituitary does or does not make hormones?
Does not
Posterior pituitary is a storage vessel for two hormones produced by the hypothalamus:
Antidiuretic hormone (ADH) Oxytocin
_____regulates blood pressure by controlling water output
Antidiuretic hormone (ADH)
_____ regulates uterine contractions and milk production in the mammary glands.
Also involved in social bonding
Oxytocin
Influences parental/partner bonding
Has receptors in many organs throughout the body with unknown function
Males and females express receptors
Oxytocin lowers heart rate and is thought to modulate stress & anxiety
Oxytocin
The thymus is a _lobed gland
Bilobed
Where is the thymus located?
In the mediastinum, superior to the heart
The thymus is large in_____ and _____
Fetus and infants
Maturation of certain white blood cells (T cells)
Releases hormones that stimulate development of lymphatic organs and T cells
Thymus
Butterfly-shaped gland found in the neck, just inferior to the adam’s apple
Thyroid gland
The thyroid gland produces 2 hormones:
Thyroid hormone (TH) Calcitonin
______: maintains our metabolism/body temperature
Thyroid hormone (TH)
_____: regulates the amount of calcium in our blood by encouraging deposition into bone
Calcitonin
_____: jelly-like precursor to thyroid hormone
Colloid
Cells that make TH and are filled will colloid
Follicular cells
Cells that make calcitonin in the thyroid
Parafollicular cells
Steps of thyroid production
- Thyrotropin releasing hormone (TRH)-hypothalamus
- Thyroid stimulating hormone(TSH)-anterior pituitary
- Thyroid hormone(TH)-thyroid gland
Cells that secrete parathyroid hormone. Whole cell taken up by nucleus
Parathyroid cells
_____cells have much more cytoplasm than the parathyroid cell in the parathyroid gland. Function?
Oxyphil
Unknown
Calcium regulation
______secretes Calcitonin, bones take up Ca2+, blood Ca2+ levels lower
_____secretes PTH, bones release Ca2+, blood Ca2+ levels rise
Thyroid Gland
Parathyroid glands
The adrenal gland is comprised of the
adrenal medulla and adrenal cortex
The adrenal medulla is actually a modified_____
sympathetic nerve ganglion.
The adrenal medulla has no ____ on cell bodies. Release secretions into the blood
Axons
The adrenal medulla secretes
epinephrine, norepinephrine, and dopamine
Functions of the adrenal medulla:
Raises metabolic rate, mobilizes glucose and fat release for energy, vasoconstriction
The _____ directly innervates the adrenal medulla where it triggers the release of epinephrine into the bloodstream
sympathetic nervous system
The ____hormones help the body cope with danger, terror or stress
adrenal
The adrenal medulla is ____ of the adrenal gland while the adrenal cortex is ____ of the adrenal gland
10-20%
80-90%
The three zones of the adrenal cortex (superficial to deep) are:
Zona glomerulosa: Most superficial layer
Zona fasciculata: Intermediate, thick layer
Zona reticularis: Deepest cortical layer
Name and function of the lipid hormones of the glomerulosa
mineralocorticoids (regulate minerals/electrolytes)
Name and function of the lipid hormones of the fasciculata
glucocorticoids inc. cortisol (regulate glucose levels in blood)
Name and function of the lipid hormones of the reticularis
gonadocorticoids (androgens and estrogens)
The adrenal cortex makes more than 25 different lipid-based hormones! Whole group of them =
corticosteroids
Regulate blood volume by controlling amount of sodium in urine
Main mineralocorticoid = Aldosterone
A stress hormone that responds to fasting, anxiety and trauma
Insures high blood glucose levels for brain, forces other areas to get energy from fat
Decreases inflammatory response
Main glucocorticoids = cortisol
Converted to estrogen and testosterone in peripheral tissues
Main gonadocorticoid = DHEA (dehydroepianderosterone)
In the adrenal medulla, clusters of neuroendocrine cells called ____ secrete epinephrine, norepinephrine and dopamine
All are involved in the sympathetic nervous response: Fear, pain, stress, raise metabolic rate, increase heart rate, mobilize glucose release
chromaffin cells
Is the pancreas an exocrine or endocrine gland?
both, it is a heterocrine
exocrine secretions aid (1)
Endocrine functions are in groups of cells called pancreatic islets that (2)
- digestion (pancreatic juice)
2. regulate blood sugar
Each pancreatic islet contains 3 types of cells:
Alpha cells
Beta cells
Delta cells
Secrete glucagon-a hormone that tells the liver to break down energy stores and get glucose (sugar) into the bloodstream
Alpha cells
Secrete insulin-a hormone that tells cells to take glucose out of the bloodstream
Beta cells
Secrete somatostatin that regulates the rate of digestion
Delta cells
Attached to the roof of the third ventricle
Synthesizes and secretes melatonin
The pineal gland
The pineal gland secretes more melatonin at (1), less during the (2)
Establishes a 24-hour clock (circadian rhythm)
- Night
2. Day
In the ovaries,____ and ____ regulate menstrual cycle, pregnancy
Estrogen, progesterone
______regulates sex drive, sperm production
Testosterone
_____in both male and female gonads inhibits FSH secretion from the pituitary (disrupts egg and sperm production)
Inhibin
In the kidneys, ____increases red blood cell production
Erythropoietin
In the kidneys,___ is released in response to falling blood pressure.
Renin
In the heart, ______stretching in the wall of the heart triggers release. Causes water loss (by urination) so that blood volume/pressure decreases.
Atrial Natriuretic Peptide (ANP):
Many of the gastrointestinal tract organs have ______ cells associated with digestion. Hormones secreted by the hypothalamus also play a role.
enteroendocrine
Adipose Tissue secretes ____ which regulates our appetite
leptin