Endo Exam 1

What is a hormone?

organic chemical which is released by living cells, it then travels through the bloodstream to trigger physiological changes in other living cells

Receptors located on the surface of the cell are called___

transmembrane

Receptors located on the inside of the cell are called ____

intracellular receptors

Up-regulation means the number of receptors is ___

increased= sensitivity is increased/stronger response

Down-regulation ___ the number of receptors

reduces; cells are less sensitive/diminished response

T/F all cells within endocrine glands or organs are able to secrete hormones

FALSE

What are the endocrine glands? (9)

1. Hypothalamus

2. Pituitary gland

3. Pineal gland

4. Thyroid gland

5. Parathyroid gland

6. Thymus

7. Pancreas

8. Adrenal glands

9. Gonads

Are peptide hormones water or fat soluble?

water soluble

Peptide hormones are packaged in vesicles and released by ___

exocytosis

Peptide hormones use ____ receptors

transmembrane

Are peptide hormones fast or slow acting?

fast

What are peptide hormones made of?

chains of amino acids

What are steroid hormones made of ?

lipids- mainly cholestrol

are steroid hormones water or lipid soluble?

lipid

What type of receptor do steroid hormones use?

intercellular receptor

Are steroid hormones fast or slow acting?

slow acting- because they need to use a transport protein

T/F endocrine system is ductless? (closed)

True

Steroid hormones hate water and love fat and therefore could be classified as____ and ____

hydrophobic and lipophilic

Peptide hormones love water and hate fat and therefore would be classified as___ and ___

hydrophilic and lipophobic

What do autocrine hormones affect?

affect the cell that secreted it (self)

What does a paracrine hormone affect?

cells close to the secreting cell (neighbor)

What doe endocrine hormones affect?

travel through bloodstream/lymph to affect a cell far away

What is a hormonal pathway?

chemical in nature

What is a humoral pathway?

“sensor” associated with the gland itself

What is a neural pathway?

generates rapid release of hormone

T/F hormones wait to build hormones until they receive stimulus

False- DO NOT WAIT

What is the ongoing process which cells constantly construct different useful molecules called?

biosynthesis

55% of our blood is plasma and how much of plasma is water?

90%

What does the amount of hormone secreted into the bloodstream depend on?

strength and duration

What is the purpose of a direct transport route?

ensure some of the more important hormones reach their targets

What are two examples of direct transport routes?

1. hypothalamus and anterior pituitary

2. hepatic portal circulation

What is a half life?

how long it takes to have a drug be half diluted in your system and cleared out

What is metabolic clearance?

removal of hormones from circulation

What is the difference between a primary and secondary messanger?

primary messenger- hormone itself travels directly into a cell

secondary messenger- bind to a receptor on target cell’s surface, causing cell to release proteins

Are steroid or peptide hormones primary messengers?

steroid hormones- cross the lipid membrane to enter cell

Are peptide or steroid hormones need a secondary messengers?

peptide hormones- need secondary messenger to get into cell since they are lipophobic

How is changes within the cell made?

activating or deactivating specific genes within the cell’s DNA

What physiologic action is associated with movement such as contraction of a muscle cell, movement of products like enzymes within a cell so they can be secreted?

Kinetic effect

What effect is associated with changing the speed of cellular processes?

Metabolic effect

What effect involves a cells growth or changes to its form?

Morphogenetic effects

What is the secondary messenger for adenylyl cyclase?

cAMP

What is the secondary messenger for phospholipase C?

IP3, DAG, Ca+

What is the goal of peptide hormones?

make new proteins

What is the goal of steroid hormones?

initiate DNA transcription and synthesis of new proteins

What receptor does Insulin and GF use?

tyrosine kinases

T/F Tyrosine kinases have both extracellular and intracellular domains

TRUE

What are the target receptors for tyrosine kinase?

JAK and STAT

What hormones act through the guanylate cyclase mechanism?

1. Atrial netriuretic peptide (ANP)

2. Nitric oxide (NO)

What is a negative feedback loop?

hormone secretion of hormone inhibits its own production (NO MORE NEEDED)

What is a positive feedback loop?

secretion of hormone stimulates further production of that hormone (MORE NEEDED)

What is a physiological response-driven feedback loop?

secretion of a hormone is stimulated or inhibited by a change in the level of a specific extracellular parameter (CIRCULATING COMPONENT) Ex: Insulin

What is a endocrine axis-driven feedback loop?

3 tier configuration

1. Hypothalamic neuroendocrine neurons

2. Tropic hormones from pituitary gland

3. Peripheral endocrine glands

What is the nervous systems involvement with the endocrine system?

3 endocrine glands are in the brain

some endocrine glands are stimulated directly by the nervous system (adrenal medulla)

What is the immune systems involvement with the endocrine system?

lines between the two systems intertwine and blur

immune cells carry receptors for many different hormones

Immune cells secrete GH and cytokines

What is the digestive system’s involvement with the endocrine system?

stomach and pancreas are both organs that are included in the digestive system and endocrine system

T/F Gut microbes are endocrine organs

TRUE

What hormone is stress managing?

cortisol

What hormone stimulates growth and repair?

Thyroxine

What hormones are released in response to food?

Ghrelin and Leptin

What is an agonist?

molecule binds to a receptor

What is an antagonist?

molecules bind to receptor and block binding of the agonist

What is a primary hyposecretion?

too little hormone secretion by endocrine gland

What is a secondary hyposecretion?

endocrine gland receiving too little of tropic hormone

What is a primary hypersecretion?

too much hormone secretion by endocrine gland

What is a secondary hypersecretion?

endocrine gland is receiving too much of its tropic hormone

What is hyporesponsiveness?

target cell do not respond normally to hormone

What is hyperresponsiveness?

excessive response to hormone

What is another name for the posterior lobe?

neurohypophysis

What’s another name for anterior lobe?

adenhypophysis

What is the infundibulum?

stalk between the hypothalamus and pituitary

Posterior lobe is derived from _____

neuroectoderm

A collection of axonal projections from the hypothalamus ( Rathke’s pouch) creates ____ ____

anterior pituitary

What is the process from hypothalamus to secretion of hormones into blood?

1. Hormones synthesized in the cell bodies of the hypothalamus

2. 2 non-myelinated axons pass down the infundibulum and end the posterior pituitary

3. Stored int eh nerve terminals of the posterior pituitary

4. Cell body is stimulated

5. Neurosecretory vesicles are released and secreted into blood

Where is ADH primarily produced/released? stored?

Produced/released by supraoptic nuclei

Stored in posterior pituitary

What causes the release ADH?

1. decrease in blood volume or low blood pressure (baroreceptor)

2. increase in blood osmolarity (dehydration) (osmoreceptors)

Where does ADH act?

principle cells of the collecting ducts

What is the primary effect of ADH?

increase water reabsorption

What is the secondary effect of ADH?

in high concentrations, it causes constriction of blood vessels→ increases blood pressure by increasing peripheral resistance

Adenylyl cyclase uses what receptor?

V2 (kidneys)

What receptor does phospholipase C?

V1 (vascular smooth muscle)

T/F ADH limits amount of water being lost in urine by resorbing water back into plasma thus concentrating sodium and waste products in the urine

TRUE

What population uses VRA’s?

people with conditions like congestive heart failure, hyponatremia, liver cirrhosis and SIADH

What are VRA and what do they do?

Vasopressin receptor antagonist

blocks action of ADH/vasopressin

What occurs during central diabetes insipidus? What is it caused by?

decreased output of antidiuretic hormone

insufficient release of ADH by hypothalamus

What are the physical characteristics of central diabetes insipidus?

1. Polyuria

2. Dilute urine

3. Hypotension

4. Increased plasma concentration

In CDI, what is one way that the body tries to compensate for lack of ADH?

increased aldosterone

In CDI compensation, aldosterone is produced by the ___ ___ and functions to ____ by reabsorption of ___

adrenal gland

act on distal tubules and collecting ducts of the kidney

sodium

How is aldosterone synthesized?

1. Kidney senses low BP and secretes RENIN

2. Renin converts angiotensinogen to angiotensin I

3. The lungs secrete ACE (angiotensin converting enzyme) and converts angiotensin I to angiotensin II

4. Angiotensin II stimulates the zona glomerulosa (outer layer of adrenal cortex)

5. Zona glomerulosa makes and secretes aldosterone to act on principal cells of the collecting duct in the kidney.

what cells in the kidney respond to low BP and produce Renin?

What does renin then activate?

granular cells and juxtaglomerular cells

-renin converts angiotensinogen from the liver to angiotensin I.

When aldosterone is released, what three things change with urine?

1. postassium secretion

2. decreased urine output

3. increased urine concentration

What occurs when a patient has nephrogenic diabetes insipidus?

decreased sensitivity to ADH in principle cells of the collecting ducts which causes ADH secretion to increase since the kidney is not responding

T/F In nephrogenic diabetes insipidus, kidneys concentrate urine

False- CAN NOT

How is nephrogenic diabetes insipidus treated?

treated with thiazide diuretics

What’s the difference between CDI and NDI?

In NDI, ADH is not low, its high with a low response from the kidney

What are the physical characteristics of Nephrogenic diabetes insipidus?

1. Polyuria

2. Dilute urine

3. Hypotension

4. Increased plasma concentration

   ADH levels are elevated in blood

What is happening in syndrome of inappropriate antidiuretic hormone secretion? (SIADH)

excessive release of antidiuretic hormone

fluid overload in patients due to excess water reabsorption by collecting ducts

T/F In SIADH, blood volume is increased and the plasma sodium is diluted

TRUE

How is SIADH treated?

treated with ADH antagonist: Demeclocycline or water restriction

What can cause SIADH?

1. Strokes

2. Head trauma

3. Brain tumors

4. Cancer

What is a major concern in someone with SIADH?

edema developing in dangerous places (Cerebral edema)