Exam 2 Review: Endocrine System Flashcards
What does the endocrine system do?
Allows communication among cells of the body.
What is different about the endocrine system when compared to the nervous system?
Unlike the nervous system, though, the endocrine system is slower to act and its actions generally last longer, so it tends to be used for long term regulation of growth, development, metabolism and reproduction.
Nervous system =
“system of wires” using action potentials and neurotransmitters
Endocrine system =
“wireless”, using hormones and receptors
A hormone is
Chemical messenger released by a cell or gland in one part of the body that affects cells in other parts of the body.(travels through blood)
3 classes of vertebrate hormones
1.peptide-derived from amino acid
2.monoamine-derived from amino acide
3.lipid-based-derived from steroid or eicosanoid
Hydrophilic hormones
Circulate in the bloodstream, then diffuse out to bind to target cells. These are active for a relatively short period of time before they’re metabolized by the liver and excreted through the kidneys.
Hydrophobic horomones
also travel in the bloodstream, but mostly bound to transport proteins (albumin, for example). This allows them to move more easily through the blood and slows their metabolic degradation and excretion so they’re able to stay active longer.
They are also bioavailable.
Hormone activated signaling pathways must have..
1.Permissive effects
2.Synergistic (additive) effects
3. Antagonist (opposing) effects
The pancreas has two sections
1.Exocrine
2.Endocrine
The endocrine pancreas has what type of cells? What does it do?
Acinar cells which release enzymes related to digestion
The endocrine pancreas contains what ? What does it do?
Contains islets and is responsible for controlling blood sugar
What do Alpha (A cells) do?
Secrete the hormone glucagon
What do beta (B cells) do?
Produce insulin
Islets of Langerhans does what (long name for islets)
Secrete hormones (insulin & glucagon) into the blood stream.
For people with insulin-
dependent diabetes mellitus,
exogenous insulin does what?
Makes up for lack of natural insulin
Define glucagon
hormone released from alpha cells in the pancreas
Define glycogen
the storage form of glucose
Insulin does what to cells?
Insulin signals cells to insert transporters into the membrane, greatly increasing glucose uptake.
What happens in the absence of insulin?
Little glucose enters the cell.
Type 1 diabetes is
Insulin dependent decreased or impaired production.
Type 2 diabetes is
non-insulin dependent insulin resistance.
Gestational diabetes is
insulin resistance secondary to hormones
produced by the placenta.
typically self-limiting and should resolve
post-partum
Hyperglycemia is
high glucose levels in blood
Hypoglycemia is
low glucose levels in blood
The hypothalamus is the major integrating link for
the nervous and endocrine systems
The hypothalamus controls ____ with what 2 things?
Controls the Anterior Pituitary with 2 different releasing hormones releasing & inhibiting.
Together the hypothalamus and pituitary gland do what?
Together, the hypothalamus and the pituitary gland regulate virtually all aspects of growth,
development, metabolism, and homeostasis.
The posterior pituitary releases what 2 hormones?
1.Antidiuretic hormone-regulates water balance and maintain blood pressure homeostasis.
2.Oxytocin-aids in childbirth, breastfeeding, and social bonding.
Antidiuretic hormone=
ADH=Vasopressin
Secretion from the anterior pituitary is controlled by
Hypothalamic regulating hormones( trophic hormones, tropic hormones, or tropins) AND negative feedback mechanisms.
Two classes of hypothalamic regulatory hormones are
1.Releasing hormone (RH)-stimulates synthesis and secretion of one or more hormones in the anterior lobe.
2.Inhibiting hormone (IH)-prevents synthesis and secretion of hormones form the anterior lobe
The hypothalamus produces what 6 hormones in response to hypothalamic hormones?
1.Prolactin
2.Thyroid SH
3.Adrenocorticotrophic hormone
4.growth hormone
5.follicle stimulating hormone
6.luteinizing hormone
Hypothalamic-
Pituitary-Prolactin
Axis consists of:
Hypothalamic
releasing
hormone: None (PRH)
Hypothalamic
inhibiting hormone: Dopamine Somatostatin
Hormones released
by anterior pituitary: Prolactin
Major target
organ:Mammary glands
Hormones released
by target: None
Hypothalamic-
Pituitary-Thyroid
Axis consists of:
Hypothalamic
releasing
hormone: TRH
Hypothalamic
inhibiting hormone: Somatostatin
Hormones released
by anterior pituitary: TSH
Major target
organ: Thyroid gland
Hormones released
by target: T3 & T4
Hypothalamic-
Pituitary-Adrenal
Axis consists of:
Hypothalamic
releasing
hormone: CRH
Hypothalamic
inhibiting hormone: None
Hormones released
by anterior pituitary: ACTH
Major target
organ:Adrenal cortex
Hormones released
by target: Cortisol, adrenal androgens
Two main parts of the adrenals are
1.The adrenal cortex- produces corticosteroids
2. The adrenal medulla-produces epi & nor-epi
The 3 main layers of the adrenal cortex are:
1.Zona glomerulosa- secretes mineralocorticoids (aldosterone)
2. Zona fasciculata- secretes glucocorticoids (cortisol)
3,Zona reticularis- secretes androgens
Mineralocorticoids are
steroid hormones that affect the electrolyte composition of body fluids
Glucocorticoids are
steroid hormones that affect glucose metabolism
What do ACE inhibitors do?
ACE inhibitors prevent an enzyme in the body from producing angiotensin II, a substance that narrows blood vessels.
95% of mineralocorticoid activity is due to what?
aldosterone
Mineralocorticoids also do what?
-increases reabsorption* of Na+ and Cl- in the kidneys
bicarbonate ions and water follow
-increases loss of K+ and H+ to the urine to help maintain pH balance
Renin-angiotensin-aldosterone system simple explanation
There are 3 main steps that occur to produce angiotensin II: renin release, conversion of angiotensinogen to angiotensin I using renin, and conversion of angiotensin I to angiotensin II using angiotensin converting enzyme (ACE). This is all due to low blood pressue.
What does glucocorticoid activity do other than produce cortisol?
- increases rate of protein catabolism
- stimulates conversion of amino acids
- to glucose (gluconeogenesis) in the liver
- stimulates glycogen breakdown in the liver
- stimulates lipolysis
has anti-inflammatory effects
What is Cushing’s syndrome?
– too much cortisol
What is Addison’s dz?
– too little corticosteroid
What would happen if you gave
exogenous ACTH to a person with
a normal HPA axis?
increase in circulating cortisol
Androgens are produced by
EX being steroids and testosterone are produced by the testes and some by the adrenal cortex.
Parts of the thyroid gland include:
Internal matrix of colloid- mostly composed of thyroglobulin
follicular cells-which secrete T3 & T4
parafollicular cells (clear cells)- secrete calcitonin
Calcitonin is released by
parafollicular cells of the thyroid gland
What is critical to T3 & T4 synthesis?
Iodine allows for the thyroid gland to keep producing t3 and t4
What do many of the effects of the thyroid hormones resemble
Sympathetic stimulation
Hypothyroidism
Thyroid gland does not make enough thyroid hormone.
Hyperthyroidim
Overproduction of thyroid hormone
The parathyroid gland secretes what hormone?
Parathyroid hormone or PTH
PTH does what to blood?
increases concentration of calcium in blood
What is the pineal gland responsible for?
Responsible for the production of melatonin, a hormone that that affects the
modulation of wake/sleep patterns and seasonal functions
3 main functions of the circulatory system
Transport, protection, and regulation
Cells are services by what two fluids?
Blood & intersitial fluid
Extracellular fluid=
interstitial fluid + plasma + lymph + CSF + synovial fluid
Blood plasma=
matrix
Formed elements=
blood cells, including red
blood cells (RBCs), white blood cells (WBCs), and
platelets (cell fragments)
