Endocrine Physiology Smith 10/31/16 TEST #3 Flashcards
What four features do feedback mechanisms generally have?
- System variable
- Set point
- Detector
- Corrective mechanism
What is a hormone?
-Chemical messengers secreted into the blood or extracellular fluid by specialized cells
What do hormones generally act on?
-Remote organ sites
What controls long-term homeostatic processes?
Hormones
What are some examples of long-term homeostatic processes?
- Growth
- Development
- Metabolism
- Reproduction
- Internal environment regulation
How do hormones act?
By binding receptors on or in target cells
T/F
Hormones can help control gene expression and protein synthesis
True
T/F
Hormones can not control the movement of ions or molecules across membranes
False
It can control
T/F
Hormones can control the rates of enzymatic reactions
True
What are hormones produced by?
- Endocrine cells
- Organs
What are hormones released by?
-Endocrine glands
What hormone controls basal metabolism?
Thyroid hormone
Where is thyroid hormone made?
Thyroid
What hormone controls energy metabolism and stress responses?
Cortisol
Where is cortisol made?
-Adrenal cortex
What hormone regulates plasma volume via effects on serum electrolytes?
-Mineralcorticoids
Where are mineralocorticoids made?
-Adrenal cortex
What hormone regulates plasma osmolality via effects on water excretion?
-Vasopressin
Where is vasopressin made?
-Posterior pituitary
What hormone regulates calcium and phosphorous levels?
-Parathyroid hormone
Where is parathyroid hormone made?
-Parathyroid
Define neurocrine:
Secretion of hormones into the bloodstream by neurons
What type of hormonal communication is the secretion of hormones into the bloodstream by endocrine glands?
Endocrine
What type of hormonal communication is the secretion of hormones into the bloodstream by neurons?
-Neurocrine
What type of hormonal communication is: the hormone molecule secreted by one cell affects the adjacent cells?
-Paracrine
What type of hormonal communication is: hormone molecule secreted by a cell affects the secreting cell?
Autocrine
If you have a bound hormone to plasma carriers do you have an inactive or active hormone?
Inactive
What factors effect circulating hormone levels?
- Synthesis and secretion
- Rate of inactivation
- Receptor binding/ availability of receptor
- affinity of a given hormone for plasma carries
What are two hormone classification types?
- Chemical
- Solubility/polarity
What are three examples of hormones that are classified chemically?
- Amine hormones (tyrosine derivatives)
- Peptide hormones
- Steroid hormones
What are two examples of solubility/polarity hormones?
- Lipophilic
- Hydrophilic
Are lipophilic hormones polar or non-polar?
Non-polar
Are hydrophilic hormones polar or non-polar?
-Polar
Which type of solubility/polarity hormone is fat-soluble?
-Lipophilic
What type of receptors do lipophilic hormones bind to?
-Intracellular receptors (nuclear receptors)
What type of receptors do hydrophilic receptors bind to?
-Extracellular cell membrane receptors
What are two examples of lipophilic hormones?
- Steroid
- Thryoid
What are two examples of hydrophilic hormones?
- Peptide
- Catecholamines
What type of hormone is insulin?
-Peptide hormone
What type of hormone is cortisol?
-Steroid hormone
What type of hormone cannot diffuse through the cell membrane lipid bilayer?
-Hydrophilic hormones
What type of hormone does not directly affect the transcription of target genes?
-Water soluble hormones
What role do hormones play in signal transduction?
-Allows signal transduction to occur when hormones bind to receptors on the membrane coupled to a G-protein that activates a second messenger
What is the second messenger used by most water soluble hormones?
-cAMP
What is the first step for hormones that bind to cell membrane receptors?
-Bind to membrane receptors
What is the second step for water-soluble hormones?
-Activate G-protein by bound receptors
What is the third step for water soluble hormones?
–Activated G-protein activates adenylyl cyclase
What are two amine hormones derived from tyrosine?
- Thryoid hormone (long half life)
- Catecholamines (short half lives)
What type of receptor do thyroid hormones bind to?
-Nuclear receptors
What type of receptor do catecholamines bind to?
-Cell surface receptors
What is an example of a thyroid hormone?
-Thyroxine
What is an example of a catecholamine hormone?
-Epinephrine
Thyroid hormone: Lipophilic or hydrophilic
Lipophilic
Catecholamines: Lipophilic or hydrophilic
Hydrophilic
What type of hormone is the most numerous in the body?
-Peptide hormones
Peptide hormones: Lipophilic or hydrophilic
Hydrophilic
What is a peptide hormone called that is produced as a larger molecular weight precursor that is inactive?
-Preprohormones
How do peptide hormones have to be transported in the blood?
-Carrier proteins
What part of the peptide hormone binds to the cell surface receptors?
-Free (unbound portion) because the bound portion is inactive
How many steps are needed to produce peptide hormones?
Three
What is the first step needed to produce peptide hormones?
-Genes coding for mRNA, undergo translation into protein precursors
What is the second step needed to produce peptide hormones?
-Preprohormone formed in the ER that gets broken down into prohormone in Golgi apparatus
What is the third step needed to produce peptide hormones?
-After posttranslational modification in the golgi the peptide hormone gets secreted
What are all steroid hormones derived from?
-Cholesterol
Steroid hormones: Lipophilic or hydrophilic
Lipophilic
T/F
Steroid hormones are not packaged, but rather are synthesized and immediately released
True
How are steroid hormones carried in the plasma?
-Hormone-specific plasma binding globulins
What are some examples of hormone specific binding globulins?
- Albumin
- Testosterone binding globulin
What type of hormone uses the intracellular hormone receptor pathway?
-Lipid-soluble hormones
When the lipid-soluble hormone is bound what complex does it create?
-Hormone-receptor complexes
What does the hormone-receptor complex do?
-Act as a transcription factor to make mRNA to get translated
What is the main source of estrogens in postmenopausal women?
-Adipose tissue
What converts androgens to estrogens?
-Aromatase enzyme
What is a negative feedback loop?
-Hormone shuts down either the stimulating or the the releasing factors terminating the hormone action
What is a positive feedback loop?
-Hormones enhance releasing and stimulating factors thus perpetuating additional hormone action (Ovulation: LH and oxytocin)
Where can target organ hormones feedback inhibit their own production at?
- Level of anterior pituitary
- level of the hypothalamus
Other than target organ hormones, what other type of hormone can feedback inhibit the hypothalamus?
-Tropic
What general type of hormone is the hypothalamus responsible for releasing?
-Releasing hormone
What general type of hormone does the anterior pituitary release?
Tropic hormone
What part of the pituitary is adnohypophysis, a classical gland that secretes protein hormones that stimulate/inhibit target organs and may feedback to hypothalamus?
Anterior pituitary
What part of the pituitary is neurohypophysis, is not a separate organ, but an extension of the hypothalamus?
-Posterior pituitary
What feature connects the anterior gland to the hypothalamus?
Infundibular stalk
What acts as an extension of the hypothalamus?
-Posterior pituitary
What utilizes the hypophyseal portal system?
-Anterior pituitary
What is responsible for the adaptation component of the stress response?
-Hypothalamic-pituitary adrenal axis (HPA)
What type of regulatory implications does the HPA have?
- digestion
- immune system
- mood
- emotions
What is osmolality?
-Measure of how much of one substance has been dissolved in another substance
T/F
Serum osmolality is therefore a measure of how much dissolved blood urea nitrogen, glucose, and sodium are in your serum
True
What is vasopressin also known as?
-ADH
What is ADH or vasopressin produced by?
-Neurosecretory cells in the hypothalmus
Where is ADH or vasopressin secreted at?
-Neurohypophysis (Posterior pituitary)
What is the main control of vasopressin secretion?
-Hypothalamic osmoreceptors
How does vasopressin increase the water permeability of the renal collecting ducts?
-Inserting aquaporins
If your body needs to get rid of water what hormone will the pituitary release less of?
ADH
Adrenocortical hormones are all what type of compound?
-Steroid
Where are mineralcorticoids such as aldosterone secreted?
Zona glomerulosa
Where are glucocorticoids such as cortisol secreted?
-Zona fasciculata
Where are adrenal androgens such as dehydroepiandrosterone (DHEA) secreted?
-Zona reticularis
What does the adrenal medulla secrete?
-Catecholamines such as epinephrine and norepinephrine
What does aldosterone promote in the kidney?
-Sodium reabsorption and Potassium excretion by the renal tubular epithelial cells of the collecting and distal tubules
What is a persistently elevated extracellular fluid volume that causes pressure diuresis in the kidney known as?
-Aldosterone escape
If you have elevated levels of aldosterone what can occur?
-Hypokalemia and muscle weakness
If you have decreased levels of aldosterone what can occur?
-Hyperkalemia with cardiac toxicity
T/F
Cortisol stimulates gluconeogenesis in the liver while simultaneously decreasing glucose use by extrahepatic cells
True
What is the overall result of cortisol on the serum glucose and glycogen stores?
-Increases both
What does cortisol do to protein stores in the body?
-decreases them
What type of inflammatory effect does cortisol have?
-anti-inflammatory
What male hormones does the adrenal cortex continually secrete?
- DHEA
- Androstenedione
- 11-Hydroxyandrostenedione
- Progesterone
What does the hormones does the adrenal medulla release?
- Epinephrine
- Norepinephrine
What hormones are responsible for short term stress response?
- Epinephrine
- Norepinephrine
What type of stress does the adrenal medulla handle?
-Short term stress
What type of stress does the adrenal cortex handle?
-Long-term stress
What occurs in the body to long-term stress?
-Metabolic changes and immune supression
What occurs in the body during acute stress?
-Fight or flight response
How is cortisol regulated by the HPA axis?
- Hypothalamus signaled by circadian rhythm and stress
- Hypothalamus releases corticotropin releasing hormone (CRH)
- Anterior pituitary then increases release of ACTH
- The ACTH increases cortisol synthesis from the adrenal gland
What type of endocrine disorder deals with Type I Diabetes Myelitis?
-Endocrine gland hyposecretion (Hormone deficiency)
What type of endocrine disorder deals with Type II diabetes?
-Hormone resistance
What type of endocrine disorders deals with Acromegaly and Graves Disease?
-Hormone excess
What is it called that occurs in patients with adenoma derived from pituitary somatropes that secrete excess growth hormone?
-Acromegaly
What is a disease that is an example of a disorder mimicking hormone excess by antibodies binding to, and activating, hormone receptors?
-Graves Disease
What is the most common endocrine disorder diagnosed in the U.S?
-Diabetes
What is type I diabetes?
-Beta cells in the pancreas destroyed
What is Type II diabetes?
-Insulin is produced but the body is insulin resistant
What is Adrenal insufficiency?
-Adrenal gland releases to little of the hormone cortisol and aldosterone
What is a disease that has adrenal insufficiency?
–Addisons disease
What gland produces excessive growth hormone that leads to acromegaly/ gigantism?
-Pituitary gland
What is cushings syndrome?
-Excess of ACTH
What disorder is insufficient thyroid hormone that leads to fatigue constipation and dry skin?
-Hypothyroidism
If you produce to much thyroid hormone what is it called?
-Hyperthyroidism
