Endocrine 1 Flashcards by Amanda S.

The major glands (pppta) (me at the pta)

The major glands: Pituitary, thyroid, parathyroid, adrenal and pancreas

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The endocrine system has five general functions: (me and children)

reproductive and CNS development in the fetus
Stimulation of growth and development during childhood and adolescence

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Hormones have specific rates and rhythms of secretion (circadian rhythm of cyclic pulsating hormones)

Circadian or diurnal pattern
Pulsatile and cyclic pattern

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A pattern that depends on circulating substrates (circle the milk - think)

Ca+, K+, Na+, glucose, etc.

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hormones

They operate on a feedback system: negative or positive
They affect only the cells with the appropriate receptors

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hormones are eliminated (2 main places)

by the kidneys or metabolized in the liver into water soluble compound ready for renal excretion

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HORMONE CLASSIFICATION

Water soluble
Lipid soluble

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Water soluble hormones - where are the receptors? (receptive water)

-circulate freely in blood to act on target tissues. Receptors on cell membrane

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Lipid soluble hormones - where is the receptor? Andhow does it cross membranes?

(fat is bound and diffues)

Lipid soluble
- bound by plasma proteins; cross membranes through diffusion
-receptor inside cell

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Hypothalamus – The Master Gland - what are the cells called? (hippo has a secretary)

Located superior and anterior to the brain stem
Responsible for the direct control of the endocrine system through the pituitary gland
Contains special cells called neurosecretory cells—neurons in the hypothalamus receive input from the CNS then coordinates release of hormones

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The Hypothalamus-pituitary Axis (HPA) - what 2 systems work together? (you know this)

Forms the structural and functional basis for the central
integration of the nervous and endocrine systems
The Neuro and Endocrine systems work together to maintain homeostasis in response to internal and external demands
In the HPA a number of releasing/inhibitory hormone as well as *tropic hormones are produced that affect body function:

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Corticotropic releasing hormone (CRH) (cort sneezes in the tropics)

→ anterior pituitary (ACTH- Adrenocorticotropic hormone)→ adrenal glands

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Prolactin releasing hormone (PRH) → (pro mammary)

Prolactin releasing hormone (PRH) → anterior pituitary (Prolactin) → mammary glands

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Thyrotropin releasing hormones (TRH)→ (TRH is tsh)

Thyrotropin releasing hormones (TRH)→ anterior pituitary (TSH) → thyroid gland (thyroxine)

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Gonadotropic releasing hormone →(fish for gonads)

Gonadotropic releasing hormone → anterior pituitary (gonadotropic hormones FSH and LH) → testes and ovaries

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Growth hormone releasing/inhibitory hormone (growth everywhere)

Growth hormone releasing/inhibitory hormone → anterior pituitary (GH or GIH) →all body tissue

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Prolactin releasing hormone →

Prolactin releasing hormone → anterior pituitary (PRL or PIH) →mammary glands

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Hormones secreted by the hypothalamus and stored in the Posterior Pituitary (just 2)

Antidiuretic hormone (ADH):
Oxytocin:

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ADH - what does it do to urine?

Regulates fluid volume by acting on collecting renal tubules to reabsorb water → concentrated urine

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oxytocin does 2 things (you know this)

Stimulates uterine contraction and milk production

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THE ADRENALS - do the medulla and cortex work together?

Located in the upper portion of both kidneys
Consists of the adrenal medulla and adrenal cortex both acting independently

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Adrenal MEDULLA “Fight or Flight response” (fight medusa)

Inner part of adrenal gland
Makes up 10 to 20 % of the mass of adrenal gland
Secretes catecholamines: Epinephrine (75%) and Norepinephrine (25 %) and dopamine

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Adrenal CORTEX - what does it secrete?

(cotex is on steroids)

Outer part of adrenal gland
Makes 80 to 90 % of the mass of adrenal gland
Secretes over 50 steroids (need cholesterol to make steroids)

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corticosteriods - 2 types

glucocorticoids
mineralcorticoids

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androgrens

convert testosterone in men and estrogen in women in the peripheral tissue

Cortisol released in response to (too much or too little sugar)

stressful situations: hypoglycemia, burns, infection, fever, anxiety, surgery

cortisol (cort is not inflammed when he eats sugar)

Anti-inflammatory properties Glucose metabolism

ADRENAL CORTEX HORMONE: MINERALOCORTICOID (Aldosterone) - when is it released - relationship btwn aldosterone and K+

Released in response to low plasma volume and high serum osmolarity, hyperkalemia (aldosterone releases K+ out of the body), angiotensin II

ADRENAL CORTEX HORMONE: (cotex is a man) Androgens

The adrenal cortex secrets small amounts of androgens Stimulates pubic and axillary hair growth and libido in females Androgens are converted into estrogen in the peripheral tissue After menopause, the adrenal cortex is the major source of endogenous estrogen In men, adrenal secretion of androgen is minimal compared to testicular production of testosterone

THE PINEAL GLAND (pictures of pineal)

Composed of photosensitive cells Secretes Melatonin Stimulated by exposure to dark and inhibited by light exposure

THE THYROID GLAND

- Two encapsulated lobes connected by the isthmus Regulated by TSH from the Anterior Pituitary Iodine is needed for the synthesis of these hormone

FUNCTION OF THYROID GLAND - just salt

To take in iodine found in many foods and converts it into thyroid hormones Release is controlled by a feedback mechanism

FUNCTIONS OF THE THYROID HORMONES (2 things) (fat and hot thyroid)

Metabolic rate Temperature regulation

PARAFOLLICULAR CELLS : CALCITONIN - produced by what? (c for calcitonin)

Produced by the C cells of the parafollicular cells of the thyroid gland It is a “ weak” regulator of calcium

thyroid assessment - Posterior approach

Stand behind the patient Place thumbs on the back of the neck (the sternocleidomastoid muscle) with fingers curved around the front of the neck on either side of the trachea Locate the isthmus and ask the patient to swallow to feel the thyroid rising

thyroid assessment - anterior approach

Stand in front of the pt with the pt’s neck flexed Place thumb on lower boarder of cricoid cartilage. Move thumb over isthmus while pt swallows Place fingers along sternocleidomastoid muscle and palpate each lobe as pt swallow Have pt turn head toward the lobe to be palpated

*Normal thyroid size often

not palpable. If thyroid enlarged, avoid pressing too aggressively as that will release more unnecessary thyroxine

parathyroid glands - located where? (para behind)

Located behind the thyroid glands (usually 4 but may range from 2-6 glands)

parathyroid glands - In the bones (parrot bones)

it acts on osteoclast to breakdown and release Ca into blood stream and inhibit bone formation (process called bone *resorption) * The process by which osteoclasts break down the tissue in bone and release Ca, resulting in increase circulating Ca in the blood

THE PANCREAS: As an exocrine gland: what does it break down? (everything)

Pancreas excretes enzymes through ducts to the gut to break down proteins, lipids, carbohydrates, and nucleic acids in food.

the pancreas - what is the active area?

The islet of Langerhans is the active area The islet accounts for < 2% of the gland:

PANCREATIC HORMONE: GLUCAGON - when is it released? (3 times)

Released in response to low blood glucose, exercise and protein ingestion Stimulates glycogenolysis; gluconeogenesis and ketogenesis in fasting states

PANCREATIC HORMONE: INSULIN - when is it stimulated?

Stimulated in response to high blood glucose

ATRIAL NATRIURETIC FACTOR - what does it do to the kidneys?

Produced by the right atrial myocytes in response to atrial wall stretch (high plasma volume) Acts on the kidneys to inhibit sodium reabsorption

endocrine - 5 general functions

Sexual reproduction Maintenance of internal homeostasis Adaptive responses to emergency demands

ex of water soluble hormones (PIG in the water)

-Insulin, growth hormone, prolactin

ex of lipid soluble hormones

-T3 and T4, steroids (Estrogen, Cortisol, Testosterone, Aldosterone)

ADH - Release is stimulated by

↑ plasma osmolality and hypovolemia

ADH - where do pressure changes occur? (4 places) (ADH CAAV)

Feedback from osmoreceptors in the hypothalamus and pressure changes in veins, arteries, atria and carotid arteries stimulates ADH release A potent vasoconstrictor

glucocorticoids - ex (cort has glue)

cortisol

mineralcorticoids - ex

aldosterone

cortisol - what happens when fasting? (stops glucose uptake)

Inhibits protein synthesis and decreases peripheral glucose uptake in fasting states

cortisol - contributes to the metabolism of what? (cort eats fat and acid)

lipid and nucleic acid metabolism

cortisol - liver? (does it release glucose?)

Stimulates hepatic glucose production (gluconeogenesis)

aldosterone

Decreased renal perfusion and hyponatremia stimulates RAAS (Rennin-angiotension system)

aldosterone - what makes it stop? (relationship btwn ANF and alden)

Inhibited by Atrial natriuretic factor (ANF) and hypokalemia Goal is to maintain extracellular fluid volume

pineal gland - melatonin (one surprising thing)

Melatonin is involved in regulating circadian rhythm and the reproduction system including puberty onset Therapeutically, melatonin is used to help with sleep disturbances and jet lag

thyroid gland - what does it secrete? (not T3 here) (calcium thyroid)

Secretes 2 forms of thyroxine and calcitonin:

thyroid gland - T4- what does it get converted to?

80-90% is in form of thyroxine (T4) which is precursor to T3. > 90 % of T4 bound to protein. Gets converted to T3 after its release into bloodstream

thyroid gland - T3 - is it potent?

20% Triiodothyronine (T3) is more potent and is the biologically active form

thyroid gland - Calcitonin - where is it secreted? (calcium parasailing)

Calcitonin is secreted in the parafollicular cells of the thyroid gland

thyroid gland - Low thyroxine levels stimulates

the hypothalamus (TRH) → anterior pituitary (TSH) → thyroid gland (thyroxine)

function of thyroid hormones

Caloric requirement O2 uptake and consumption Carbohydrates and lipid metabolism

function of thyroid hormones (mom's brain and nervous system)

Brain function and nervous system activity Growth and development

calcitonin - Released in response to (remember, calcitonin lowers ca)

Released in response to ↑ levels of serum calcium

calcitonin - where does it go? (2 places) - think, where is Ca+?

Its site of action is the osteoclasts and the kidneys:

calcitonin - what does it do? (reabsorb, stores, and excretes)

Inhibits bone resorption → lowers serum Ca Increases Ca storage in bone Increases renal excretion of Ca+ and phosphate

parathyroid glands - regulate what? (parrot)

Regulates serum calcium levels Stimulates renal conversion of vitamin D to its most active form

parathyroid glands - positive or negative feedback? (the usual)

Regulated by a negative feedback system

parathyroid glands - In the kidneys (Parrot loves vitamin D)

it promotes Ca reabsorption from renal tubules and excretion of phosphate. Stimulates renal conversion of Vit D to its most active form (1,25 –dihydroxyvitamin D) which promotes absorption of Ca and Phos from the GI tract

the pancreas - As an endocrine gland:

Pancreas secretes the hormones insulin and glucagon into blood stream to target cells in order to control blood sugar

pancreas - Alpha cells (glu the alpha's mouth shut)

synthesize glucagon

pancreas - Beta cells (beta has insulin, amy)

synthesize insulin and amylin

pancreas - Delta cells (delta loves somas)

secretes somatostatins

pancreas - PP cells (pp is full)

PP cells (Pancreatic Polypeptides), formerly F cells: Produced in response to food intake. Acts on satiety hormone, regulation of exocrine function and possibly in slowing gastric emptying

glucagon - in a fasting state when glucose is not available...

epinephrine, cortisol, and glucagon break down free fatty acids and glycerol

insulin - Inhibited by

Inhibited by ↓ blood glucose, glucagon, somatostatin, catecholamines and hypokalemia (insulin drives K+ back into cells → ↓K+ )

insulin - Facilitates transport of- what about amino acids?

Facilitates transport of glucose into cells, amino acids into muscles, and synthesis of amino acids into protein in peripheral tissue

Tissues that do not require insulin to transport glucose for energy

cells of intestinal mucosa, renal tubules, brain

The major effect of insulin is where? (just think where is glucose stored)

in the liver where insulin enhances glucose storage into glycogen and triglycerides

ANF - inhibits which hormone? (think bp)

Inhibits ADH, renin-angiotensin II pathway thereby suppressing aldosterone

ANF - vasodilate or constrict?

ANF also causes vasodilation GOAL is to decrease Blood Pressure!

aldosterone - what part of the kidneys does it work on? and what ions?

Acts on the renal distal tubules to reabsorb Na+ and secrete K+ and H+ (remember water follows Na+)

tissues that don't need insulin to get glucose (what about blood?)

lens of the eyes, hepatocytes, and RBCs

Endocrine 1 Flashcards

(84 cards)