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Feralis BIO Chapter 9 Sec. 7
Terms in this set (88)
What does the endocrine system play an important role in?
As a communicator in our body
What is the difference between endocrine and exocrine?
Endocrine is secretion of hormones into the bloodstream while exocrine is secretion of hormones into ducts
What is paracrine?
Secreting hormones to neighboring cells
What is autocrine?
Secretion of hormones to itself
What are 4 characteristics of hormones?
- A small amount can have a large effect
- They bind to very specific receptors
- A single type of hormone can elicit multiple effects in the body
- They are slower acting than electrical signals
What are the 3 different types of hormones?
Peptide, steroid, and amino acid derived hormones
What is a peptide?
Short spans of amino acids chained together by peptide bonds
What are 3 hormones made by the hypothalamus (peptide hormones)?
- GnRH (gonadotropin releasing hormone)
- ADH (antidiuretic, aka vasopressin)
What are 6 hormones made by the anterior pituitary (peptide hormones)?
- TSH (thyroid stimulating hormone)
- ACTH (adrenocorticotropic hormone)
- LH (luteinizing hormone)
- FSH (follicle stimulating hormone)
- GH (growth hormone)
What are 4 more peptide hormones?
Glucagon, insulin, calcitonin, parathyroid hormone
What are secondary messengers?
Literally a second message with the hormone being the first
What are 4 common secondary messengers?
cAMP, IP3, DAG, calcium ions
Where are steroid hormones synthesized at?
What are 3 hormones made by the adrenal cortex (Steroid hormones)?
- Glucocorticoids (cortisol)
- Mineralocorticoids (aldosterone)
- Androgenic steroids
What are 3 hormones made by the reproductive organs (steroid hormones)?
What kind of property do steroid hormones have?
What kind of property do peptide hormones have?
How do peptide hormones travel in the bloodstream?
Via a carrier to help shield them from the water based blood
How do steroid hormones stimulate receptor cells?
They directly stimulate
What kind of action time do steroid hormones have compared to peptide hormones?
Have a slower action time
Where are amino-acid derived hormones synthesized?
Rough ER and cytosol
What are 2 hormones made by the adrenal medulla (amino-acid)?
Epinephrine (adrenaline), and Norepinephrine (noradrenaline) ; (polar, water soluble and through secondary messengers)
What are 2 hormones secreted by the thyroid (amino-acid)?
T3 and T4 (non-polar and lipid solube; go directly into cell)
What is the hypothalamus?
Body's master controller that serves to regulate out internal environment and maintain homeostasis
What does the posterior pituitary gland do?
Stores and releases ADH and oxytocin
What is the function of ADH?
A vasopressin that decreases urination
What does ADH target?
How does ADH work?
It inserts into small water channels called aquaporins in the collecting duct of our nephrons in our kidneys which facilitates the re-uptake of water from urine back into our body
What are the 2 targets of oxytocin?
Uterus and mammary gland
How does oxytocin work in child labor?
It causes uterine contraction through a positive feedback loop (the more the uterine contracts the more oxytocin is released)
How does oxytocin work in breastfeeding?
It triggers milk letdown when the baby begins suckling on the mothers nipple
How is the anterior pituitary gland connected to the hypothalamus?
Via a hypophyseal portal
What is a portal system?
Is when a capillary bed is connected to another capillary bed through a portal vein
Where are 2 other areas portal systems exist?
Liver and kidney
What are 4 key hypothalamic releasing hormones that instruct the anterior pituitary to release other hormones?
- GnRH (Gn stands for gonads)
- TRH (thyroid releasing)
- CRH (C stands for corticoids)
- GRH (G stands for growth hormone)
What does GnRH tell the anterior pituitary to release?
LH and FSH to the gonads
What does TRH tell the anterior pituitary to release?
TSH to our thyroid gland
What does CRH tell the anterior pituitary to release?
To release ACTH
What does GRH tell the anterior pituitary to release?
To release GH
The anterior pituitary releases both tropic and direct hormones. What is the difference between these 2?
Tropic target and act on other endocrine glands to release their own hormones and direct hormones will directly stimulate other organs
What are the 6 hormones produced by the anterior pituitary gland and the acronym to remember it?
- FLAT PiG (flat are all tropic and pig are all direct)
- Follicle stimulating hormone (FSH)
- Leutinizing hormone (LH)
- Adrenocorticotropic hormone (ACTH)
- Thyroid stimulating hormone (TSH)
- Growth hormone
What does FSH do?
Role in follicle hair growth in females and maturation of sperms in males
What does LH do?
Stimulates ovulation, the formation of corpus luteum in females and production of testosterone in males
What does ACTH do?
Stimulates the adrenal gland cortex to release glucocorticoids to combat stress
What does TSH do?
Stimulates the thyroid to produce T3 and T4 which ramps up metabolism in the body
What does Prolactin do?
Stimulates mammary gland development and increases milk production after childbirth
What does growth hormone do?
Stimulates the cells of the body to grow, reproduce and divide
What does the pineal gland secrete?
What is melatonin's function?
Functions to regulate our circadian rhythm
What 3 main hormones does the thyroid gland manufacture and release into the blood?
T3, T4, and calcitonin
What are 4 things that T3 and T4 have in common?
- Both derived from amino acid tyrosine
- Both release in response to TSH
- Both are responsible for increasing basal metabolic rate and tissue development for children
- Both provide a negative feedback force on TSH
What are 3 things that differ between T3 and T4?
- T4 has one more iodine atom than T3
- T3 is the active form of the hormone and more potent
- T4 is the main circulating hormone and is more stable which leads to a longer half life
What is hypothyroidism?
Under-secretion of T3 and T4 which results in reduced metabolic rate (lethargy, weight gain, low heart rate)
What is hyperthyroidism?
Over-secretion of T3 and T4 which results in increased metabolic rate (hyperactivity, anxiousness, weight loss)
Where is calcitonin secreted?
Parafollicular cells of the thyroid
What is the function of calcitonin?
Decreases blood calcium level
How does calcitonin work?
Stimulates osteoblasts to build more bone which uses up more calcium from the blood; inhibits osteoclasts form chewing up bone which means less calcium is released from bones to the blood and finally decreases calcium reabsorption from the kidney and intestines
What does the parathyroid gland secrete?
What is the function of PTH?
Increase blood calcium level
How does PTH work?
Stimulates osteoclasts to chew up more bone and increases calcium reabsorption from the kidney and intestines
What does the exocrine tissue secrete in the pancreas?
Digestive enzymes through the pancreatic duct into the stomach
What does the endocrine tissue secrete in the pancreas?
Called the islets of Langerhans and secretes insulin, glucagon and somatostatin into the bloodstream
What are the 3 main types of cells contained in each islet?
Alpha cells, beta cells, and delta cells
What does the endocrine gland of the pancreas mostly work to do?
Balance the level of glucose in our blood
How is the glucose that is not used for immediate energy stored in the body? (3)
- Liver stores it as glycogen
- Muscle cells store it as glycogen
- Adipose cells convert and store it as triglycerides
What do alpha cells secrete?
Glucagon when there is a low blood glucose level
What do beta cells secrete?
Insulin when there is a high blood glucose level
What do delta cells secrete?
Somatostatin and inhibits both secretion of both glucagon and insulin
What are the 2 main structures of the adrenal gland?
The outer cortex and the inner medulla
What is the adrenal cortex stimulated by?
Secretion of ACTH
Where is the primary site of androgen production in males since only a small amount is produced in the adrenal cortex?
How is the adrenal medulla controlled and what does it secrete?
Directly controlled by the sympathetic nervous system and secretes only amino-acid derived hormones
Overall though what is the adrenal medulla responsible for?
Helps in fighting against short term stresses
Overall though what is the adrenal cortex responsible for?
Helps us deal with long-term stress
What 2 hormones does the adrenal medulla produce and what are these 2 known as?
Catecholamines; epinephrine and norepinephrine which are the fight or flight hormones
What happens when the catecholamines bind to beta receptors vs when they bind to alpha receptors?
- When bound to beta receptors it causes vasodilation
- When bound to alpha receptors causes vasoconstriction
What hormone is produced in the adrenal cortex? (2 types)
Glucocorticoids (i.e cortisol) and mineralocorticoids (i.e. aldosterone)
What exactly do glucocorticoids do? (2)
- During periods of long-term stress it prevents tissue build-up and breaks down storage molecules to generate immediate fuel
- Also lowers the immune response suppressing inflammation
What is the function of mineralocorticoids?
Increase blood volume and blood pressure
What are both the testes and ovaries influenced by?
LH and FSH secreted from the anterior pituitary gland
What 2 things does the ovaries produce?
Progesteron and estrogen
In females what does LH do?
Triggers ovulation during the menstrual cycle
In females what does FSH do?
Stimulates the development of follicles in ovaries
In males what does LH do?
Triggers production of testosterone from leydig cells
In males what does FSH do?
Stimulates sperm maturation
What does a positive feedback loop do?
The loop ramps up and reinforces a stimulus
What are 2 examples of a positive feedback loop?
Infant nursing and labor
What does the negative feedback loop do?
Inhibits itself and prevent overproduction of certain hormones
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