Bio2 Lesson 3.1: Endocrinology Flashcards
Where are peptide hormones made?
On the rough endoplasmic reticulum
Are peptide hormones polar/nonpolar?
Polar
How do peptide hormones enter a cell?
They bind to a membrane bound/cell surface receptor because they cannot diffuse through the membrane
What do peptide hormones do?
They act on effector cell membrane receptors and initiate internal secondary messenger cascades (cAMP, Ca2+, etc…)
What type of change results from a peptide hormone?
Change in proteins (phosphorylation)
Peptide hormones have a slow/fast effect on the cell?
Fast
Do peptide hormones produce a long-term/short-lived signal?
Short-lived
What are the pancreatic peptide hormones?
Insulin, glucagon
Where are steroid hormones made?
On the smooth endoplasmic reticulum or mitochondria
Are steroid hormones polar/nonpolar?
Nonpolar; they need a carrier protein to travel in blood
How do steroid hormones enter a cell?
They diffuse into the cell through the membrane and then bind to a cytosol or nuclear receptor
What type of change results from a steroid hormone?
Change in gene expression; changed transcription factors
Steroid hormones have a slow/fast effect on the cell?
Slow
Do steroid hormones produce long-term/short-lived signals?
Long-term
What are the gonadal steroid hormones?
Progesterone, estrogen, testosterone
What is an example of a mineralocorticoid (steroid hormone)?
Aldosterone
What is an example of a glucocorticoid (steroid hormone)?
Cortisol
What are tyrosine derivative hormones derived from?
The amino acid tyrosine
What are the two groups of tyrosine derivative hormones?
Catecholamines and the thyroid hormones
Do catecholamines behave like peptide/steroid hormones?
Peptide hormones
Do thyroid hormones act as peptide/steroid hormones?
Steroid hormones
Are catecholamines polar/nonpolar?
Polar
Are thyroid hormones polar/nonpolar?
Nonpolar
What are catecholamines used for?
They are used in the fight/flight system
What are thyroid hormones used for?
They are used to change metabolism (fast or slow)
Where are catecholamines released from?
The adrenal medulla
Where are tyrosine derived hormones made?
In the cytosol or RER
How do peptide hormones exit a cell?
The Golgi packages the hormone into secretory vesicles and releases the vesicles via exocytosis
The hypothalamus is located below the ___________ and above the _____________
Thalamus, pituitary gland
The hypothalamus is considered the _____________ of the endocrine system
Master gland
The hypothalamus _________ and _________ both direct and tropic __________ hormones
Synthesizes, releases, peptide
What is a direct hormone?
A hormone that targets an organ/organ system
What is a tropic hormone?
A hormone that targets and activates another endocrine gland
How is the hypothalamus connected to the anterior pituitary?
By the hypothalamic-hypophyseal portal system
What is a portal system?
A capilary bed that drains into another capillary bed through a vein, without first going through the heart
How is the hypothalamus connected to the posterior pituitary?
By a special group of nerve cells called neurosecretory cells
Hormones travel from the hypothalamus to the anterior pituitary via ___________. Hormones travel from the hypothalamus to the posterior pituitary via ____________
The bloodstream (hypothalamic-hypophyseal portal system), nerve axons (neurosecretory cells)
The hypothalamus secretes _______ hormones that activate the ________ pituitary to ______ and ______ new hormones
Tropic, anterior, make, release
The posterior pituitary is regulated by the __________ via ___________
Hypothalamus, nerve axons
Does the posterior pituitary make hormones?
No. It releases them
Neurosecretory cells of the hypothalamus synthesize ____ direct peptide hormones. These hormones are ___________ and _________
2, vasopressin (anti-diuretic hormone or ADH), oxytocin
Vasopressin is synthesized by the ____________ and stored in the ____________
Hypothalamus, posterior pituitary
Oxytocin is synthesized by the ____________ and stored in the _____________
Hypothalamus, posterior pituitary
How are hormones in the hypothalamus made?
By neurosecretory cells
How many sets of neurosecretory cells does the hypothalamus have?
2
What are the 7 peptide hormones synthesized/released by the anterior pituitary?
Mneumonic: FLAT PEG
1) Follicle-Stimulating Hormone (FSH)
2) Luteinizing Hormone (LH)
3) Adrenocorticotropic Hormone (ACTH)
4) Thyroid-Stimulating Hormone (TSH)
5) Prolactin (PRL)
6) Endorphins/Enkephalins
7) Growth Hormone (hGH, GH, somatotropin)
Name the 7 peptide hormones synthesized/released by the anterior pituitary and describe whether they are direct or tropic hormones
1) FSH: Tropic
2) LH: Tropic
3) ACTH: Tropic
4) TSH: Tropic
5) PRL: Direct
6) Endorphins/Enkephalins: Direct
7) GH: Direct
Describe the following for FSH (Follicle-Stimulating Hormone):
1) Is it a direct or tropic hormone?
2) What stimulates its release?
3) If applicable, what inhibits its release?
4) What is its function?
1) Tropic
2) GnRH (hypothalamus)
3) Combination of estrogen and progesterone
4) In females: causes maturation of ovarian follicles; In males: stimulates maturation of seminiferous tubules for sperm production
Describe the following for LH (Luteinizing Hormone):
1) Is it a direct or tropic hormone?
2) What stimulates its release?
3) If applicable, what inhibits its release?
4) What is its function?
1) Tropic
2) GnRH (hypothalamus)
3) Combination of estrogen and progesterone
4) In females: stimulates ovulation and formation of corpus luteum; In males: stimulates interstitial cells of testes to synthesize testosterone
Describe the following for ACTH (Adrenocorticotropic Hormone):
1) Is it a direct or tropic hormone?
2) What stimulates its release?
3) If applicable, what inhibits its release?
4) What is its function?
1) Tropic
2) CRF: Corticotropin-Releasing Hormone (hypothalamus)
3) Cortisol
4) Stimulates adrenal cortex to synthesize and secrete glucocorticoids or cortical hormones during stress
Describe the following for TSH (Thyroid-Stimulating Hormone):
1) Is it a direct or tropic hormone?
2) What stimulates its release?
3) If applicable, what inhibits its release?
4) What is its function?
1) Tropic
2) TRH: Thyrotorpin-Releasing Hormone (hypothalamus)
3) A negative feedback loop from T3 and T4 to the anterior pituitary and hypothalamus
4) Synthesize/release Thyroid Hormone (T3 and T4)
Describe the following for PRL (Prolactin):
1) Is it a direct or tropic hormone?
2) What stimulates its release?
3) If applicable, what inhibits its release?
4) What is its function?
1) Direct
2) TRH: Thyrotropin-Releasing Hormone
3) N/A
4) Stimulation of lactation in breasts
Describe the following for Endorphins/Enkephalins:
1) Is it a direct or tropic hormone?
2) What stimulates its release?
3) If applicable, what inhibits its release?
4) What is its function?
1) Direct
2) Comes directly from the hypothalamus
3) N/A
4) Inhibit pain perception
Describe the following for GH (Growth Hormone):
1) Is it a direct or tropic hormone?
2) What stimulates its release?
3) If applicable, what inhibits its release?
4) What is its function?
1) Direct
2) GHRH: Growth Hormone-Releasing Hormone (hypothalamus)
3) N/A
4) Stimulate all cells for growth
What is the luteal surge and what does it result in?
During ovulation (around day 14 of the menstrual cycle), the luteal surge is an increased release of LH. This promotes ovulation
Normally, what kind of feedback loop does estrogen perform for LH, FSH, and GnRH?
Negative feedback loop
When does estrogen perform a positive feedback loop for LH, FSH, and GnRH?
During the luteal surge to promote ovulation, estrogen activates the hypothalamus to release GnRH and the anterior pituitary to release LH/FSH
What are the two parts of the adrenal glands?
1) Adrenal cortex
2) Adrenal medulla
The adrenal cortex responds to _______ and synthesizes/secretes _______________
ACTH, corticosteroids
What are the three corticosteroids of the adrenal cortex?
Mneumonic: SUGAR, SALT, and SEX
1) Glucocorticoids (e.g., cortisol) ——- SUGAR
2) Mineralocorticoids (e.g., aldosterone) ——- SALT
3) Cortical sex hormones (e.g., androgens) ——- SEX
What does the adrenal medulla secrete?
Epinephrine and norepinephrine in response to the sympathetic nervous system (fight/flight)
Glucocorticoids are released in response to ________ from the adrenal __________
Stress, cortex
What is the function of cortical sex hormones?
Secondary sexual characteristics; can produce masculinizing effects in women
What is the function of mineralocorticoids?
To regulate plasma levels of electrolytes and therefore, total extracellular water volume
What type of corticosteroid is aldosterone?
Mineralocorticoid
Where does the renin-angiotensin system act and to do what?
It acts in the distal convoluted tubules and collecting ducts of the kidney to increase Na+ and Cl- reabsportion and K+ and H+ secretion
The renin-angiotensin system _________ the osmolarity of the solution
Increases
The renin-angiotensin system _______ blood volume and blood pressure
Increases
When does the renin-angiotensin system come into play?
When there is low blood volume/pressure
What is the active form of angiotensinogen?
Angiotensin II
What does the kidney do when there is low blood volume/pressure?
Juxtaglomelular cells of the kidney produce renin and release it into the blood system
What releases angiotensinogen into the blood?
The liver
How is angiotensinogen converted to angiotensin II?
In the blood system, renin converts angiotensinogen to angiotensin I. Then angiotensin I is converted into angiotensin II by Angiotensin Converting Enzyme (ACE)
What covnerts angiotensin I to angiotensin II
Angiotensin Converting Enzyme (ACE)
What does angiotensin II do?
1) Stimulates the adrenal cortex to release aldosterone – which increaes reabsorption of Na+ (this causes more water retention)
2) Vasoconstriction of our arteries, increasing blood pressure
3) Secretion of vasopression (anti-diuretic) hormone that causes water reabsorption
What does aldosterone do in the renin-angiotensin system?
Increases Na+ reabsorption and increase K+ secretion
What type of feedback system is the renin-angiotensin system?
Negative feedback
What are the steroids of the adrenal medulla?
Epipnephrine/adrenaline and norepinephrine/noradrenaline
What are the functions of the steroids of the adrenal meddula?
- Increase the conversion of glycogen to glucose in the liver (raising blood glucose levels)
- Increase the rate and strength of the heartbeat
- Vasoconstrict blood vessels to internal organs
- Vasodilate blood vessels of skeletal muscle
The steroids of the adrenal medulla are involved in what system?
Sympathetic nervous system
What type of hormones are epinephrine and norepinephrine?
Tyrosine derivative hormones; catecholamines
Endocrine release of catecholamines causes a ___________ response than the nervous system
Longer
Where is the thyroid located?
On the ventral surface of the trachea
What does the thyroid gland produce and secrete?
Thyroxine (T4), Triiodothyronine (T3), and Calcitonin
What is the difference between T3 and T4?
T3 has 3 iodine atoms and T4 has 4 iodine atoms
What type of hormones are T3 and T4?
Tyrosine derviatime hormones: thyroid hormones
T3 and T4 act to increase the ____________
Basal metabolic rate
High plasma levels of T3 and T4 inhibit _________ and ________ in a negative feedback system
TSH, TRH
What kind of hormone is calcitonin and what is released by?
A peptide hormone released by the thyroid gland
What does calcitonin do?
It decreases blood calcium by inhibiting calcium release from osteoclasts
The parathyroid consists of ______ small glands attached to the _______ of the thyroid
4, back
What does the parathyroid secrete?
Parathyroid Hormone (PTH)
What kind of hormone is PTH (parathyroid hormone)?
Peptide hormone
What does PTH do?
Increase blood calcium by stimulating calcium release from bone by osteoclasts
PTH and Calcitonin are ________ systems that maintain ________
Antagonistic; homeostasis
When there are high levels of blood calcium, which hormone comes into play?
Calcitonin
When there are low levels of blood calcium, what hormone comes into play?
PTH (parathyroid hormone)
The pancreas is both an ________ gland and an _________ gland
Endocrine, exocrine
Where do endocrine glands secrete their hormone products?
Directly into the blood
Where do exocrine glands secrete their products?
Into ducts that lead directly into the external environment
What hormones does the endocrine gland of the pancreas secrete?
Insulin and glucagon
What are the Islets of Langerhans?
Glandular structures in the pancreas that perform its endocrine function. They are composed of alpha, beta, and delta cells
What are the Islets of Langerhans composed of?
Alpha, beta, and delta cells
What do the alpha cells of the Islets of Langerhans do?
Secrete glucagon (when blood sugar is low)
What do the beta cells of the Islets of Langerhans do?
Secrete insulin (when blood sugar is high)
What do the delta cells of the Islets of Langerhans do?
Secrete somatostatin, which inhibits alpha and beta cells
What type of hormone is glucagon?
Peptide hormone
What type of hormone is insulin?
Peptide hormone
What type of hormone is somatostatin?
Peptide hormone
