Endocrine Flashcards
Where does endocrine glade release hormones?
Directly into blood stream
What is a hormone?
Chemical messenger
What endocrine system is part of the CNS?
Central endocrine
Where is central endocrine system mostly located?
Brain
Name 3 main central endocrine glands in the brain
1) hypothalamus
2) pineal
3) pituitary
What does the pineal gland release?
Melatonin
What is the the peripheral endocrine system?
Any gland outside of the CNS
What are the 2 types of structures in the peripheral endocrine system?
1) dedicated
2) mixed function
What are 3 dedicated structures of peripheral endo system?
1) thyroid
2) parathyroid
3) adrenal glands
What does the thyroid control mostly?
Metabolism
What does the parathyroid do?
Controls calcium
What are the 2 parts of the adrenal gland?
1) medulla
3) cortex
What does the adrenal medulla produce?
Epinephrine and norepinephrine
What does the adrenal cortex produce?
Steroid hormones
What is an example of a mixed function peripheral endo structure?
Kidneys
What hormones does the kidney make?
EPO, renin and calcitriol
What does EPO do?
Helps make red blood cells in bone marrow
What does renin do?
Regulates blood pressure by maintaining Na and K in blood
What does calcitriol do?
Regulates calcium and phosphorus in body
True/false: hormones have a similar function in the body to taking a drug?
True
What is the relationship between a hormone and a receptor called?
An effect
Through what 3 ways can hormones cause a response?
1) ion channels
2) 2nd messenger system
3) gene activation
True/false: the same hormone can bind to multiple receptors and cause opposing reactions?
True
What happens when a hormone opens or closes an ion channel?
Depolarization or hyper polarization
What happens when a hormone acts through a 2nd messenger?
It alters an enzyme
What type of response is it when insulin increases enzyme activity to turn glucose into fat?
2nd messenger
What happens when a hormone activates specific genes?
A new protein is formed
Steroid hormones causing growth in puberty is an example of what type of hormone response?
Gene activation
Name 3 types of hormones
1) peptide
2) amino acid derived
3) steroid
What type of solubility are peptide hormones?
Water soluble
What are 2 types of peptide hormones?
1) short chain
2) long chain
Are long chain peptide hormones longer or shorter than average protein chains?
Shorter
What amino acid derived hormone is not water soluble?
Thyroid hormone
What are steroid hormones derived from?
Cholesterol
Are steroid hormones water or lipid soluble?
Lipid soluble
Where do water soluble hormones get stored?
In vesicles
Why do we not store many lipid soluble hormones?
Because they won’t stay in vesicles
Are lipid soluble hormones stored or made on demand?
Made on demand
How are hydrophilic/water soluble hormones transported?
Freely in the blood
How are lipid soluble/hydrophobic hormones transported?
By binding to a transporter protein
How does a water soluble hormone enter the cell?
Must bind to receptor on membrane
Which type of hormone is capable of affecting gene expression?
Lipid soluble
True/false: same hormone can affect 2 different receptors and produce different effects?
True
What are catecholamines derived from?
Tyrosine
What are examples of catecholamines?
Epinephrine and norepinephrine
What is thyroid hormone derived from?
Amino acid: thyronine
Which is the the active form of thyroid hormone?
T3
What does T4 have to do before it came become active?
Lose an iodine atom
How does T4 lose an iodine atom?
It is removed by liver or at the target cell
Do iodine atoms on thyroid hormone make the molecule polar or non-polar?
Non-polar (fat soluble)
Can thyroid hormone cross the cell membrane and affect genes?
Yes
Do the genes that thyroid hormones bind to code for proteins that consume a little or a lot of energy?
A lot of energy
What are thyroid hormones important for?
Metabolic rate
What are testosterone and estrogen examples of?
Steroid hormones
What are steroid hormones made from?
Cholesterol
Where do we get cholesterol?
Diet or liver
What is a package for of cholesterol?
Low density lipoprotein (LDL)
When LDL is broken down, what does cholesterol first get converted to before it becomes steroid hormone?
Pregnanalone
What does pregnanalone get converted to?
Steroid hormone
What is required at each step for cholesterol to become a steroid hormone?
Enzymes
What is hierarchical hormone control?
One hormone controls all other hormones
How are hierarchical hormones regulated?
Negative feedback loop
In hierarchical hormone control, what is typically endocrine gland #1?
Hypothalamus
In hierarchical hormone control, what is typically endocrine gland #2?
Pituitary
What portion of pituitary makes it an endo gland?
Anterior pituitary
What is posterior pituitary gland considered an extension of?
Hypothalamus
What is posterior pituitary connected to hypothalamus by?
Connecting stalk
What are 2 hormones released at posterior pituitary?
Oxytocin and vasopressin
What are examples of Endo #3 in the hierarchical hormones chain?
Ovaries/testes
Thyroid
Adrenal cortex
Mammary glands
What in the hypothalamus releases hormones?
Neuronal cells
What does GnRH from hypothalamus produce via anterior pituitary?
FSH/LH
What does FSH make?
Gametes (ova/sperm)
What does LH make?
Sex hormones
What does CRH produce in anterior pituitary?
ACTH
What does ACTH control?
Adrenal cortex; creates cortisol
What does TRH produce in anterior pituitary?
TSH
What does TSH affect?
Thyroid
What is produced in thyroid?
T3 and T4
What does PRH from hypothalamus stimulate in anterior pituitary?
Prolactin
What does prolactin do in mammary glands?
Produces milk
When is prolactin at its highest level?
At the time of giving birth
What does the hypothalamus release that inhibits milk production in mammary glands?
Dopamine (PIH)
What is released by hypothalamus that stimulates growth hormone (GH) in anterior pituitary?
GHRH
What does somatostatin released from hypothalamus do?
Inhibits release of GH
What does growth hormone do?
Causes cell repair and growth in body
What is the name of cell type in anterior pituitary that releases GH?
Somatotrophs
When is GH mostly released?
At night during stage 2 non-REM sleep
In liver, GH produces what?
IGF 1 and IGF 2
What does IGF stand for?
Insulin-like Growth Factor
What does GH & IGF do?
Increases organ size, bone density, lean muscle, bone growth in youth
Decreases adipose tissue
What does GH do to blood sugar?
Increases blood sugar; Stimulates liver to release glucose
What does IGF do to blood sugar?
Decreases blood sugar by bringing glucose into cells
True/false: GH blocks cells from taking up glucose
True
Where is thyroid gland located?
Over trachea
What connects left and right lobe of the thyroid?
Connecting band called “isthmus”
What are the two glands located in each lobe of the thyroid gland?
Parathyroid glands
What do parathyroid glands do?
Regulate calcium
What are the hollow structures in thyroid tissue?
Follicles
What is the a-cellular protein matrix inside each thyroid follicle called?
Colloid
Cuboidal follicular cells line the thyroid follicles and make what?
Thyroid hormone
Where is thyroid hormone made by follicular cells stored?
In the colloid
What is the water soluble protein inside the colloid that binds to the fat soluble thyroid hormone to store it?
Thyroglobulin
What are para-follicular cells in the thyroid called?
C-cells
What do c-cells make?
Calcitonin
What does calcitonin do?
Controls calcium in the body
What does the hypothalamus release to affect the thyroid?
TRH
TRH acts on the anterior pituitary to release what?
TSH
TSH acts on the thyroid to release what?
T3 & T4
What does T3/T4 use to control the thyroid system?
Negative feedback
Why is thyroid function connected to metabolic rate?
Because it it responsible for making other proteins and enzymes that consume energy.
Most energy in cellular metabolism goes toward the release of what?
Heat
How is metabolic rate measured?
By release of body heat
Where are adrenal glands found?
On top and slightly in front of kidneys
What does the adrenal medulla produce?
Catecholamines
What are the main catecholamines produced by the adrenal medulla?
Mostly epinephrine and some norepinephrine
What does the adrenal cortex produce?
All steroid hormones
How many layers to the adrenal cortex?
3
Which layer of the adrenal cortex produces aldosterone?
1st layer
Which part of the adrenal gland is considered an endocrine branch of the SNS?
Medulla
What is the 1st layer of the adrenal cortex called?
Glomerulosa
What are 3 categories of hormones produced by adrenal cortex?
1) glucocorticoids
2) mineral corticoids
3) sex hormones
What do glucocorticoids do to blood glucose?
Increase blood glucose
What are the 3 glucocorticoids?
1) corticosterone
2) cortisol
3) cortisone
What do mineral corticoids do?
Increase sodium
Decrease potassium
What are the sex hormones
-Androgens, testosterone
-Progesterone, estrogen, intermediates
What does the hypothalamus release to pituitary to stimulate glucocorticoids?
CRH
What does the pituitary release to adrenal cortex to stimulate glucocorticoids?
ACTH
When does cortisol get produced the most?
Daytime
When is cortisol production the lowest?
In evening
When the cortisol the highest (peak)?
Before waking up
Cortisol causes vasoconstriction t/f
True
Is cortisol action short or long lived in the body?
Short lived
What is main purpose of cortisol?
To mobilize
What does cortisol do to blood sugar?
Increases
What does cortisol do to bone?
Helps it release calcium for muscle contraction
Does cortisol suppress immune function?
Yes