Intro To Hormone Synthesis, And Organization Of Endocrine Flashcards
What does the endocrine system maintain
Homeostasis, assisted with the neurvous system
Which is longer lasting? Nervous system or endocrine system
Endocrine
Which is slower, nervous system or endocrine system
Endocrine
What does the endocrine system consist of
Hypothalamus anterior and posterior pituitary gland thyroid parathyroid adrenals gonads Placenta Pancreas
What are some organs with endocrine functions but are not considered endocrine organs
Kidney
Heart
Gut
Adipose tissue
How does the endocrine system work
Controls through release of hormones into the body. Bind to receptors on target cells and elicit a function
Autocrine
Hormone can directly affect the secreting cell
Paracrine
Hormone can affect a nearby cell (cells)
Endocrine
Hormone can affect distance cells by secretion in the blood stream
How are hormones characterized
Peptides and proteins
Steroids
Amines
Depends on receptor and mechanism of action
Which of the following differentiates the nervous from the endocrine system
Nervous responses are generally short acting
What is the largest class of hormones
Peptide and protein hormones
What are peptide and proteins hormones produced by
Endocrine cells and stores in the secretory vesicles until needed
What is peptide and proline hormone secretion in response to
Stimulus
- sensed by endocrine cells
- causes release of pre-made hormones
What must peptide and protein hormones do to have an effect
They must bind to a cell surface receptor on target cell
What are the peptide hormones of the hypothalamus
- thyrotropin-releasing hormone (TRH)
- corticotropin-releasing hormone (CRH)
- gonadotropin releasing hormone (GnRH)
- somatostatin
- growth hormone-releasing hormone (GHRH)
What are the peptide hormones of f hte anteiror pituitary gland
- thyroid stimulating hormone (TSH)
- follicle-stimulating hormone (FSH)
- lutenizing hormone (LH)
- growth hormone
- prolactin
- adrenocorticotropic hormone (ACTH)
What are the peptide hormones of the posteiror pituitary gland
Oxytocin
Vasopressin (ADH)
What is the peptide hormone of the thyroid
Calcitonin
What is the peptide hormone of the parathyroid
Parathyroid hormone
What are the peptide hormones of the placenta
- human chorionic gonadotropin (HCG)
- human placental lactogen (HPL), or human chorionic somatomammotropin
What are the peptide hormones of the pancreas
- insulin (B cells)
- glucagon (a cells )
What is the peptide hormone of the kidney
Renin
Thyrotropin-releasing hormone (TRH)
- peptide hormone
- from hypothalamus
- stimulates secretion of TSH and prolactin
Corticotropin-releasing hormone (CRH)
- peptide hormone
- hypothalamus
- stimulates secretion of ACTH
Gonadotropin-releasing hormone
- peptide
- hypothalamus
- stimulates the secretion if LH and FH
Somatostatin
- peptide
- hypothalamus
- inhibits secretion of growth hormone
Growth hormone releasing hormone (GHRH)
- peptide
- hypothalamus
- stimulates secretion of growth hormone
Thyroid stimulating hormone (TSH)
- peptide
- anterior pituitary
- stimulates synthesis and secretion of thyroid hormones
Follicle stimulating hormone (FSH)
- peptide
- anterior pituitary
- stimulates testosterone synthesis in Leydig cells of testes
- stimulates ovulation, formation of corpus luteum, estrogen and progesterone synthesis in ovaries
Growth hormone
- peptide
- anteiror pituitary
- stimulates proline synthesis and overall growth
Prolactin
- peptide
- anterior pituitary
- stimulates milk production and secretion in breasts
Adrenocorticotropic hormone (ACTH)
- peptide
- anterior pituitary
- stimulates synthesis and secretion of adrenal cortical hormones (cortisol, androgens, and aldosterone)
Oxytocin
- peptide
- posterior pituitary
- stimulates milk ejection from breasts and uterine contractions
Vasopressin (ADH)
- peptide
- posterior pituitary
- stimulates water reabsorption in principal cells of collecting ducts and constriction of arterioles
Calcitonin
- peptide
- thyroid
- decreases serum calcium
Parathyroid hormone (PTH)
- peptide
- parathyroid
- increases serum Ca
Human chorionic gonadotropin (HCG)
- peptide
- placenta
- stimulates estrogen and progesterone synthesis in corpus Luteum of early pregnancy
Human placental lactogen (HPL) or human chorionic somatomammotropin
- peptide
- placenta
- has growth hormone like and prolactin like actions during pregnancy
Insulin (B-cells)
- peptide
- pancreas
- decreases blood sugar
Glucagon (a cells)
- peptide
- pancreas
- increases blood sugar
Renin
- peptide
- kidney
- catalyzes conversion of angiotensinogen to angiotensin I
What kind of hormones are derivatives of cholesterol
Steroid hormones
What kind of receptors do steroid hormones deal with
- NO EXTRACELLULAR RECEPTORS
- diffuse across the cell membrane and bind intrcellular receptors either in the nucleus or the cytosol
How do steroid receptors work
They bind intracellularly and initiate changes in transcription and translation
-direct production of new proteins
What is the speed of steroid hormones compared to the other classes of hormones
Slower
What are the steroid hormones of the adrenal cortex
- cortisol (glucocorticoids)
- aldosterone (mineralocorticoid)
- dehydroepiandrosterone (DHEA) and androstenedione (adrenal androgens)
What are the steroid hormones of the testes
Testosterone
What are the steroid hormones of the ovaries
- estradiol
- progesterone
What are the steroid hormones of the corpus luteum
Estradiol
Progesterone
What are the steroid hormones of the placenta
Estradiol
Progesterone
What are the steroid hormones of the kidney
1,25-dihydroxycholecalciferol
Cortisol (glucocorticoid)
- steroid
- adrenal cortex
- stimulates gluconeogensis; inhibits inflammatory response; suppresses immune response; enhances vascular responsiveness to catecholamines
Aldosterone (mineralocorticoids)
- steroid
- adrenal cortex
- increases renal Na reabsorption, K+ secretion, and H+ secretion
DHEA and androstenedione (adrenal androgen)
- steroid
- adrenal cortex
- stimulates spermatogensis; stimulates male secondary sex characteristics
Testosterone
- steroid
- testes
- stimulates spermatogenesis; stimulates secondary male sex characteristics
Estradiol
- steroid
- ovaries, corpus luteum, placenta
- stimulates growth and development of female reproductive system, follicular phase of mentrsual cylce, development of breasts, prolactin secretion; maintains pregnancy
Progesterone
- steroid
- ovaries, corpus luteum, placenta
- stimulates luteal phase of menstrual cycle; maintains pregnancy
1,25-dihydroxycholecalciferol
- steroid
- kidney
- increases intestinal absorption of Ca; bone mineralization
What is the smallest class of hormones
Amine hormones
How are amine hormones produced
By metabolism of the amino acid tyrosine
What must amine hormones do
Must bind to a cell surface receptor on target cell to have an effect
-target cell can upregulate or down regulate receptor expression to modify response
What is weird about thyroid hormone
An amine hormone that signals like a steroid
-binds an intracellular receptor
What is the amine hormone for the hypothalamus
Dopamine or prolactin-inhibiting factor (PIF)
What is the amine hormone from the thyroid
T3 and T4
What is the amine hormone from the adrenal medulla
Norepinephrine, epinephrine
Dopamine or prolactin-inhibiting factor (PIF)
- amine
- hypothalamus
- inhibits secretion of prolactin
T3 and T4
- amine
- thyroid
- stimulates skeletal growth; oxygen consumption; heat production; protein, fat, and carb utilization; perinatal maturation of the central nervous system
Norepinephrine, epinephrine
- amine
- adrenal medulla
- SNS function
Which of the following is both a hormone and NT
Epinephrine
How do target cells regulate hormone response
They can alter the number or affinity of receptors to modulate response
How well the receptor binds the hormone
Affinity
This gets a response at a lower hormone concentration
High affinity
This gets a response only at high hormone concentrations
Low affinity
Less receptors available
Less of a response
Insulin in DM2
High affinity normally
Cells stop paying attention, decreased affinity
How are most hormones released
In response to another hormone
What is the axis of hormones
Most hormones are released in response to another hormone
TRH causes release of TSH which causes release of T3/4
Multiple layers of control on hormone release
What kind of control are most hormone axes
Negative feed back
TSH inhibits TRH
T3/4 inhibits TSH and TRH
What is the main area where there is a positive feedback
In female reproductive system
-leads to ovulation
What is the steroid hormone mechanism
Binds an intracellular receptor and generates a second messenger
Hormones that bind extracellular receptors
Immediate action and long term affect
Hormones that bind intracellular receptors
Long term affect, slower
What are the second messengers used
cAMP/cGMP
IP3 and Ca2+
Receptor tyrosine kinase
What do the second messengers that were activated by the hormones do
Activate downstream kinases and phosphatases
Add/remove phosphate from protein to alter function
Which of the following hormones has to bind an intracellular receptor to cause an affect
Progesterone
Which of the following hormones has to bind an extracellular receptor to cause an effect
Growth hormone
What pathway do growth hormone and insulin use
Tyrosine kinase receptors
What connects the nervous system to the endocrine system
Hypothalamus
What are the two divisions of the pituitary
Posterior (neural tissue)
Anterior (glandular tissue)
Posterior pituitary
Is the axons and nerve endings of neurons in the hypothalamus
- release hormones made in the cell bodies
- doesn’t directly make any hormones
- ADH, oxytocin
Anterior pituitary
- glandular tissue
- receives blood supply after it has passed through hypothalamus
- hypothalamus releases hormones into the primary plexus caps
- stimulates anterior pituitary to release hormones into the blood stream
- directly produces and releases hormones
What part of the pituitary gland directly produces and releases hormones
Anterior
What controls the anteiror pituitary
Hypothalamus via blood supply
What is the endocrine axis
Hypothalamus controls the pituitary which controls the actually gland
How is dysfunction of the endocrine axis determined
From the secreting gland and the secreted hormone
Primary dysfunction
Secreting gland is to blame, the rest is fine
Secondary dysfunction
The pituitary is to blame, the rest is fine
Tertiary dysfunction
Hypothalamus is the blame, the rest is fine
Hypothalamic-pituitary-adrenal axis
Adrenals make cortisol
Hypothtlamic -pituitary-thyroid axis
Thyroid makes T3/T4
Hypothtlamic-pituitary-gland axis
- gonads make sex hormones
- testosterone (males)
- estrogens (females)
A disease in which the T3/T4 levels are low, while TSH and TRH levels are very high would be characterized as a
Primary hypothyroidism
