Endocrine System Flashcards
Glands that secrete substances through openings (ducts) onto your body surfaces
exocrine glands
i.e sweat glands, skin oil glands, earwax glands, breast milk glands
Name at least two examples of endocrine glands that end in “gland”
- pituitary gland
- thyroid gland
- parathyroid glands
Name three endocrine glands that don’t end in “gland”
- Hypothalamus
- adrenal cortex
- medulla
- pancreas
- gonads
Name 2 organs that have both exocrine and endocrine functions
- Pancreas (releases digestive enzymes via ducts & hormones i.e insulin and glucagon)
- Liver (releases bile via ducts & secretes angiotensin hormone)
When a cell secretes a signaling moleculethat acts on a nearby cell
paracrine signaling
heavily invlved in differentiation in embryonic development
para = next to
when a cell releases a molecule that acts on itself
autocrine signaling
auto = Self
Signaling that requires cells to be in close contact with each other
juxtacrine signaling
juxta - think just next to
A cell that releases secretions via exocytosis
merocrine cells
Cells that release secretions via membrane-bound vesicles
apocrine cell
Results from rupture of the plasma membrae, destroying the cell and relesing its product from the cytoplasm into the lumen
i.e sebaceous glands of the skin
holocrine secretion
Hormones can be classified according to their chemical structure as ____ hormones, ____ hormones, or ____ derivatives
Peptide hormones, steroid hormones, or amino acid derivatices
True or False
Peptide hormones can diffuse freely in the blood, but cannot cross the lipid bilayer membrane of their target cells
True
due to their hydrophillic nature
Thus, they have to exert their effects via receptors embedded on the plasma membrane surfce
Peptide or Steroid Hormone?
Which type of hormone is associated with signal cascades, amplificiaction, and rapid, intense, short-term impacts on cellular functions?
Peptide hormones
due to second messenger systems (i.e cAMP) resulting in signal cascades
The image below describes what process?
Second-messenger systems
in peptide hormones
Steroid or Peptide hormones?
Which hormone category requires transport proteins to reach their targets?
Steroid hormones
their hydrophobic nature prevents them from being soluble in bloodstream
Albumin and sex-hormone binding globulin are examples of …
transport proteins
Peptide or Steroid?
____ hormones can diffuse directly through the lipid bilayer membrane and enter their target cells
Steroid hormones
due to their hydrophobicity and small size
Peptide or Steroid hormone?
Works by modulating gene transcription
receptor-hormone complex binds directly to DNA to affect transcription
Steroid hormones
associated with a slower-onset and longer-lasting physiological response
Name at least 4 steroid hormones
- Estradiol
- Testosterone
- Aldosterone
- Cortisol
Note: steroid hormones have 4-ring structure!!!
peptide or steroid
____ are first translated as preprohormones, then (in the rough ER) modified into prohormones. Prohormones are processed in the Golgi apparatus, then are cleaved by endo____ases and may be modified by the addition of carbohydrates to generate the final, active form of the hormone. The hormones are then packaged into vescicels to be releasex via exocytosis
Peptide hormones
Peptide or Steroid?
Synthezides from cholesterol in the smooth ER and *diffuse directly through the cell membrane *
Steroid
Peptide or Steroid (function)
Regulation of other hormones
Peptide
+ short term responses
Peptide or Steroid (function)
Sex, sugar, and salt
The 3 S’s!
Steroid
salt = mineralocorticoids
sugar = glucocorticoids
steroid hormoes affects the 3 S’s
Which amino acid derived hormones are lipid soluble and behave much like steroid hormones?
T3 and T4
Which amino acid derived hormones are water-soluble and act similar to peptide hormones, exerting powerful, short term responses?
Epinephrine and norephinephrine
True or False
Water-soluble amino acid derived hormones are either water soluble or lipid-soluble
False
Some are both! i.e Melatonin
Name the hormone category
any of a class of hormones from the anterior pituitary gland that affect the secretion of other endocrine glands
Tropic hormones
tropic hormones –> target cells –> other hormones
hormones that directly stimulate target cells to induce effects
nontropic hormones
nontropc hormones –> target cells –> physiological effects
the hypothalamus-anterior pituitary-adrenal cortex (HPA) axis is an example of a ____ loop
Negative feedback loop
What is the tropic hormone that the hypothalamus releases in the HPA axis?
Corticotropin-releasing hormone (CRH)
Which hormone acts on the anterior pituitary gland and stimulates the release of adrenocorticotropic hormone (ACTH)
Corticotropin-releasing hormone (CRH)
This hormone is tropic and acts on the adrenal cortex, causing the release of cortisol
adrenocorticotropic hormone (ACTH)
What is the physiological function of the negative feedback loop of the HPA axis?
The negative feedback exerted by cortisol on CRH and ACTH inhibits further cortisol production, which prevents levels of cortisol from getting out of control and inducing an overly intense long-term stress response
Name one hormone involved in the positive feedback loop of labor?
oxytocin
uterine contactions stimulate the release of more oxytocin, which stimulates stronger contractions, and the process continues to amplify itself until childbirth
Which type of feedback loops have a distinct physiological endpoint?
Positive feedbak loops
without an endpoint, these loops would spiral out of control
the branch of biology (specifically of physiology) which studies the interaction between the nervous system and the endocrine system; i.e. how the brain regulates the hormonal activity in the body.
Neuroendocrinology
In general, when thinking about endocrine regulation or the regulation of any biochemical pathway, you should (probably) be thinking about ____ feedback
Negative
You should hesitate choosing positive feedback on the MCAT! Positive feedback loops are rare.
The two main hormones associated with glucose regulation are
Insulin and glucagon
growth hormone (GH), epinephrine, and cortisol also affect glucose levels
____ is a peptide hormone released by the pancreas in response to high glucose levels
Insulin
function: reduce blood glucose levels by promoting the transport
function: reduce blood glucose levels by promoting the transport of glucose into the cells via insulin receptors
promotes the transport glucose into the cells
insulin receptors
these receptors then activate glucose transporters and increases the transport of glucose into the cell
What can 3 options do cells have with increased glucose uptake?
- use glucose immediately via glycolysis
- storage as glycogen in muscle and liver
- adiptocytes can store downstream byproducts of glucose metabolism as triglycerides
insulin upregualtes all of these proceses, as well as protein synthesis
the technical term for a fat cell
adiptocytes
what hormone reduces the rate of glyconeogenesis, lipolysis, and fatty acid oxidation, and protein breakdown
Insulin
What hormone is released by the pancreas when there are suboptimal levels of glucose?
glucagon
glucose is gone
Which hormone promotes glycogenolysis and gluconeogenesis in liver cells?
glucagon
the biochemical pathway in which glycogen breaks down into glucose-1-phosphate and glucose when blood glucose levels drop
glycogenolysis
the synthesis of glucose from non-carbohydrate sources like lactic acid, glycerol, amino acids and occurs in liver and kidneys.
gluconeogenesis