Endocrine System

the _____ system is a communicator system that monitors slower acting responses

the _____ system is a communicator system that monitors slower acting responses

endocrine

endocrine secretions involve cells secreting hormones into the _____

bloodstream

exocrine secretions involve cells secreting hormones into _____

ducts

_____ secretions involve cells secreting hormones to neighboring cells

paracrine

_____ secretions involve cells secreting hormones to themselves

autocrine

hormones bind to very specific _____

receptors

a single type of hormone can elicit _____ in the body

multiple/different effects

hormones are _____ (faster/slower) acting than electrical signals

slower

what are the three different types of hormones?

peptide; steroid; amino-acid derived

_____ hormones are made of short amino-acid chains

peptide

where are peptide hormones synthesized?

the rough ER

peptide hormones include

all hormones from the hypothalamus & anterior pituitary; glucagon & insulin; calcitonin & PTH

peptide hormones (are/are not) H2O soluble, so they (do/do not) need carriers to travel through the blood

are; do not

peptide hormones _____ (directly/indirectly) stimulate receptor cells - why?

indirectly; peptide hormones are not lipid soluble, so they can't pass through the phospholipid bilayer. They bind to a receptor on the cell surface to trigger changes/secondary messengers in a cell

secondary messengers are produced by _____ (direct/indirect) stimulation of receptor cells

indirect

(such as with peptides)

what are some common secondary messengers?

cAMP; IP3; DAG; Ca2+

what are the three main receptors peptide hormones will bind to indirectly stimulate target cells?

G protein-coupled receptors; receptor tyrosine kinases; ligand-gated ion channels

G protein-coupled receptors (GPCRs) are a type of _____ (location) receptor that can trigger _____

cell surface; 2nd messengers

GPCRs consists of _____ transmembrane domains that pass back and forth through the cell membrane

7

G proteins _____ (activate/deactivate) other substrates

activate

what are the G protein subunits?

alpha, beta and gamma subunits

insulin acts through _____ and 2nd messengers

receptor tyrosine kinases (RTKs)

RTKs will _____ & _____ when their hormone binds to them

dimerize, cross-phosphorylate

peptide hormones can also bind to _____-gated ion channels

ligand

what happens once a ligand binds a ligand-gated ion channel?

the channel changes its shape to allow certain ions to pass through

_____ hormones are 4-ring structures that belong in the same family as lipids

steroid

where are steroid hormones synthesized?

smooth ER

steroid hormones include

all adrenal cortex and reproductive organ hormones

steroid hormones are _____ (lipid-soluble/lipid-insoluble)

lipid-soluble (hydrophobic)

steroid hormones require a _____ to travel in the blood

carrier

steroid hormones _____ (can/cannot) pass directly through the cell membrane

can

steroid hormones _____ (directly/indirectly) stimulate receptor cells

directly

do peptide hormones or steroid hormones have a slower action time?

steroid hormones

steroids trigger changes from a _____ level

transcriptional

what is the main amino acid of amino acid derived hormones?

tyrosine

where are amino acid derived hormones synthesized

rough ER and cytosol

what are the main amino acid derived hormones?

all hormones made by the adrenal medulla; T3 and T4; melatonin

epinephrine and norepinephrine are amino acid derived hormones that act similarly to _____ hormones

peptide

(indirect stimulation)

T3 and T4 are amino acid derived hormones that act similarly to _____ hormones

steroid (direct stimulation)

the hypothalamus is involved with maintaining _____

homeostasis

what are the two lobes of the pituitary gland?

anterior and posterior

the _____ is an extension of neurons from the hypothalamus also known as the _____

posterior pituitary; neurohypophysis

which two hypothalamic hormones does the posterior pituitary store and release

ADH; oxytocin The posterior pituitary does not produce these hormones

antidiuretic hormone (_) targets _ of the kidney to reabsorb water and increase blood volume/pressure

ADH/vasopressin; nephrons

ADH/vasopressin is made by the _____ and stored in the _____

hypothalamus; posterior pituitary

oxytocin targets the _____ and _____

uterus; mammary glands

oxytocin provides positive feedback for _____ and _____

labor contractions; milk letdown

oxytocin is made by the _____ and is stored in the _____

hypothalamus; posterior pituitary gland

the anterior pituitary (adenohypophysis) is made of _____ tissue, so it _____ hormones

glandular; produces its own

the _____ connects the anterior pituitary and the hypothalamus

hypophyseal portal system

a _____ is when a capillary bed is connected to another capillary bed through a portal vein

portal system

what are some of the key hypothalamic-releasing hormones, which act on the anterior pituitary (telling it to release the hormones it makes)

GnRH; TRH; CRH; GRH Mnemonic

what are the effects of GnRH (gonadotropin-releasing hormone) from the hypothalamus?

tells the anterior pituitary to release LH and FSH to the gonads

what are the effects of TRH (thyrotropin-releasing hormone) from the hypothalamus?

tells the anterior pituitary to release TSH to our thyroid glands

(also stimulates the anterior pituitary to release prolactin)

what are the effects of CRH (corticotropin-releasing hormone) from the hypothalamus?

tells the anterior pituitary to release ACTH

what are the effects of GHRH (growth hormone-releasing hormone) from the hypothalamus?

tells the anterior pituitary to release GH

what are the two classes of hormones released by the anterior pituitary?

tropic and direct

_____ hormones target and act on other endocrine glands

tropic

_____ hormones stimulate/act on organs

direct

follicle stimulating hormone (FSH) is a _____ hormone from the _____

tropic; anterior pituitary

follicle stimulating hormone (FSH) stimulates _____ and _____

follicle growth (ovary); sperm maturation (testis)

luteinizing hormone (LH) is a _____ hormone from the _____

tropic; anterior pituitary

luteinizing hormone (LH) triggers _____ and the production of _____

ovulation; sex hormones

stress leads to the release of adrenocorticotropic hormone (ACTH), which is a _____ hormone from the _____

tropic; anterior pituitary

ACTH stimulates the adrenal _____ to release _____ to combat stress

cortex; glucocorticoids

thyroid stimulating hormone (TSH) is a _____ hormone from _____, which stimulates the thyroid to produce T3 & T4

tropic; anterior pituitary

T3 & T4 are regulated by _____ feedback

negative

prolactin is a _____ hormone from the _____

direct; anterior pituitary

what are the two phases of prolactin effects?

stimulates mammary gland development during pregnancy; increases milk production after birth

growth hormone (GH) is a _____ hormone from the _____, which stimulates cell growth, reproduction, division

direct; anterior pituitary

another name for GH is _____

somatotropin

what is an acronym to remember the hormones the anterior pituitary gland produces?

FLAT PiG

• Follicle Stimulating Hormone (FSH)

• Luteinizing Hormone (LH)

• Adrenocorticotropic Hormone (ACTH)

• Thyroid Stimulating Hormone (TSH)

• Prolactin

• ignore

• Growth Hormone (GH)

the _____ is a small gland in the brain that secretes melatonin

pineal gland

_____ regulates the circadian rhythm

melatonin

the largest endocrine organ in the body is the _____, which is located in front of the trachea

thyroid gland

what three hormones are manufactured/secreted by the thyroid gland?

T3, T4, and calcitonin

T4 has one more _____ atom than T3

iodine

T3 is the _____ form of the hormone

active (4x more potent than T4)

(T4 loses an iodine atom to become active T3)

which hormone (T4 or T3) is the main circulating form and why?

T4; it is more stable

under-secretion of T3 and T4 leads to _____ & a(n) _____ (increased/decreased) metabolic rate

hypothyroidism; decreased

over-secretion of T3 and T4 leads to _____ & a(n) _____ (increased/decreased) metabolic rate

hyperthyroidism; increased

hypothyroidism or hyperthyroidism can cause _____, which is the physical enlargement of the thyroid gland

goiter

where is calcitonin secreted?

parafollicular cells of the thyroid

what are the main functions of calcitonin?

decrease blood calcium

calcitonin stimulates _____ and inhibits _____ (cell types)

osteoblasts; osteoclasts

what is calcitonin's effect on the kidneys and intestines?

it decreases Ca2+ reabsorption in these areas

what hormone does the opposite function of calcitonin?

parathyroid hormone (PTH)

from where is PTH secreted?

parathyroid gland

what is the primary function of PTH/the parathyroid gland?

increase blood calcium level

PTH stimulates _____ and _____ (increases/decreases) Ca2+ reabsorption in the kidneys and intestines

osteoclasts; increases

the pancreas has _____ and _____ functions

exocrine; endocrine

the _____ tissue of the pancreas secretes digestive enzymes through the pancreatic duct

exocrine

where does the pancreatic duct connect to?

duodenum of the small intestine

the _____ are endocrine pancreatic tissue

islets of Langerhans

what are the three key islet of Langerhans hormones?

insulin, glucagon, and somatostatin

(somatostatin =/= somatotropin (GH))

The ____ releases insulin and glucagon to help maintain glucose concentration in the blood.

pancreas

what are the three key islet of Langerhans cell types?

alpha (α); beta (β); delta cells (δ)

alpha (α) cells of islets secrete _____

glucagon

when is glucagon secreted from the alpha (α) cells of the islets?

during a low blood glucose level (typically during fasting or between meals)

what is the function of glucagon secreted from the alpha (α) cells of the islets?

increase blood glucose levels