Test 3 - Quiz 8 Endocrine (Smith) Flashcards
What is a hormone?
Chemical messenger secreted into the blood by specialized cells
What do hormones do?
Alter the rates of various metabolic processes in target cells
Act at very low concentrations
Control long-term homeostatic processes
Hormones control what?
Rates of enzymatic rxns
Movement of ions or molecules across membranes
Gene expression and protein synthesis
There are 4 methods of hormonal communication. Name and describe them.
Neurocrine - Secretion of hormones into the blood by NEURONS
Endocrine - Secretion of hormones into the blood by endocrine glands
Paracrine - Secretion of hormones into the ECF to affect another cell
Autocrine - Secretion of hormones that affect the secreting cell
Thyroid hormone is produced where and does what?
Thyroid
Controls basal metabolism
Cortisol is produced where and does what?
Adrenal cortex
Energy metabolism, stress responses
Mineralocorticoids are produced where and what is their action?
Adrenal cortex
Regulate plasma volume via effects on serum electrolytes
Vasopressin is produced where and what is the action?
Post pit
Plasma osmolality via effects on water excretion
Parathyroid hormone is produced where and what is their action?
Parathyroids
Regs CA2+ and phosphorous levels
Insulin is produced where and does what?
Pancreas
Regs plasma glucose concentration
Hormones are active in what form?
Free
The bound form of a hormone is ____________.
Inactive
*This allows us to have a reservoir of hormones in the body
What are the three chemical types of hormones?
Amine
Peptide
Steroid
Hormones can also be classified via solubility/polarity. What are the two types?
Lipophilic - BINDS INTRACELLULAR RECEPTORS**
Hydrophilic - BINDS EXTRACELLULAR CELL MEMBRANE RECEPTORS**
The second messenger used by most water soluble hormones is what?
cAMP
The hormone itself is called a _________ messenger.
First
It initiates a 2nd messenger response cascade
Amine hormones are derived from what AA?
Tyrosine
What are the two types of amine hormones?
Thyroid - Lipophilic - Nuclear receptors - T3, T4 - long 1/2 lives
Catecholamines - Hydrophilic - binds cell membrane receptors - Epi/Norepi - short 1/2 lives
Peptide hormones are what?
Water soluble - produced as preprohormones and then cleaved - bound to carrier proteins - only the free (unbound) part binds
*These need 2nd messenger systems to exert physiological actions
So to have a hormone what is the process for a large majority of them?
Preprohormone -> prohormone -> hormone
mRNA to preprohormone is formed where?
ER
Preprohormone to prohormone occurs where?
Golgi apparatus
Steroid hormones are all derived from what?
Cholesterol
All steroid hormones are _______ soluble?
Lipid
Steroid hormones are ___________ permeable on cell membranes.
Freely permeable
Steroid hormones are carried in the plasma by what?
Hormone-specific plasma binding globulins
*Like, albumin
**Bound hormones act as a reservoir for rapid release as needed
When intracellular horomone bind, what complex is formed?
Hormone-receptor complex that moves toward nuclear chromatin and binds a certain segment of the DNA.
*The complex acts as a transcription factor
When androgens go to estrogens, what does that conversion?
Aromatase enzymes
*This happens in trophoblastic tumors and normal adipose in fat, liver, and brain.
In postmenopausal women, adipose tissue is the _______ source of estrogens.
PRIMARY
There are two types of feedback loops. Name and describe them.
Negative - hormone shuts down the stimulating or releasing factors which terminates the hormone action
Positive (uncommon) - hormone enhance releasing and stimulating factors thus perpetuating add’l hormone action. EX: childbirth and lactation.
There are two types of negative feedback. Name and describe them.
Long-loop - Inhibits the pit and the hypothalamus (The organ above the one above the effected organ)
Short-loop - Inhibits the hypothalamus (The organ above the effected organ)
Peptide hormones?
Philic or phobic
Synthesis and storage
Release from parent cell
Half-life
Location of receptor
Philic
Made in advance - stored in secretory vesicles
Exocytosis
Short
Cell membrane
Steroid hormones
Philic or phobic
Synthesis and storage
Release of parent cell
Half life
Location of receptor
Phobic
Synthesized on demand from precursors
Simple diffusion
Long
Cytoplasm or nucleus (Some have membrane receptors, too)
Catecholamines
Philic or phobic
Synthesis and storage
Release from parent cell
Half life
Location of receptor
Philic
Made in advance, stored in secretory vesicles
Exocytosis
Short
Cell membrane
Thyroid hormones
Philic or phobic
Synthesis and storage
Release from parent cell
Half-life
Location of receptor
Phobic
Made in advance - precursor stored in secretory vesicles
Simple diffusion
Long
Nucleus
Catecholamines and thyroid hormones are considered what type of hormones?
Amine
The ant pit is called what?
Adenohypophysis
What connects the ant pit to the hypothalamus?
Infundibulum/infundibular stalk
The post pit is called?
Neurohypophysis
The post pit is considered a __________ of the hypothalamus.
Extension
Ant pit utilizes what system?
Hypophyseal portal system
*RAPID HORMONAL RESPONSES WITH LOW CONCENTRATIONS
The post pit uses what system?
Hypothalamic-hypophyseal tract
*Oxytocin and ADH into blood
ACTH is released by what to where to do what?
Ant pit
Adrenal cortex
Regs fluid balance, helps body cope with stress
Hypothalamic-Pit-Adrenal Axis is responsible for what?
Body’s adaptive stress response
Stress->Hypothalamus->Pit->Release of ACTH->Adrenal cortex->cortisol
What is serum osmolality?
How much dissolved blood urea nitrogen, glucose, and sodium in the serum
*275-299 mOsm for healthy serum osmolality
Vasopressin is aka what?
Produced where?
Released where?
Does what?
ADH
Hypothalamus
Secreted at post pit
Increases aquaporins in the renal collecting duct and distal tubules to increase H2O reabsorption from urine into blood
All adrenocortical hormones are _________ compounds.
STEROID
What are the three types of adrenocortical hormones, examples, and secreted by what in the adrenal cortex?
Mineralocorticoids - aldosterone - Zona glomerulosa
Glucocorticoids - cortisol - Zona fasciculata
Adrenal androgens - DHEA - Zona reticularis
What does aldosterone do?
Promotes sodium reabsorption and potassium excretion by the renal tubular epithelial cells.
**H2O follows, so aldosterone increases ECF volume with little change in the plasma concentration
When aldosterone escapes, what is the result and what happens to the kidney?
ECF fluid elevated
Severe dehydration b/c kidney loses excessive amts of sodium and water
Potassium is ________ whenever ________ is reabsorbed.
Excreted
Sodium
Hypokalemia and muscle weakness occurs when?
Aldosterone levels are increased
Hyperkalemia happens when?
Aldosterone levels are decreased.
The adrenal medulla secretes ________ 80% and ___________ 20%.
Epi
Norepi
What hormones are responsible for the short term stress response?
Epi/Norepi
*These increase cardiac output
For acute stress (fight/flight) what is released?
Epi/norepi
For long term stress (metabolic changes/immune suppression) what hormones are responsible?
Steroid hormones
Most endocrine disorders are in 3 groups. Name and describe them.
Hyposecretion - Type I diabetes - beta cells destroyed
Hormone resistance - Type II diabetes - cells insulin resist
Hormone excess - Graves’ disease - excess thyroid hormone
Hypothyroidism is from what and what is the common disease associated?
Insufficient thyroid stimulating hormone
Hashimoto’s disease
Hyperthyroidism is due to what and what is the common disease?
Too much thyroid stimulating hormone
Grave’s disease (bulging eyes)
Cushing’s syndrome is caused from what?
Elevated endogenous/exogenous glucocorticoids and excess ACTH which leads to overproduction of cortisol
Addison’s disease is caused by what?
Too little cortisol
Gigantism (acromegaly) is caused from what?
Too much growth hormone
What releases corticotropin releasing hormone?
Pro-inflammatory cytokines
Ant pit increases release of what to increase what synthesis from what gland?
ACTH
Cortisol
Adrenal gland
The adrenal cortex continually secretes several male sex hormones. Name the one important one.
DHEA
What does cortisol do?
Increases serum glucose and glycogen stores in the liver
- Anti-inflammatory effects
- Immune system is suppressed and lymphoid tissue may atrophy
- Eosinophil and lymphocyte counts in the blood decrease with atrophy of lymphoid tissue
The adrenal medulla secretes what type of hormones?
Catecholamines
I.e., Epi/Norepi
