Hormone Synthesis, Regulation of Hormone Secretion, & Hormone Receptors Flashcards
The endocrine works in concert with the _______ to maintain homeostasis
nervous system
Most hormones are synthesized in, and secreted by, _______ (there are exceptions)
glands
Hormones are usually secreted by glands exit gastrointestinal hormones which are secreted by ________
clusters of endocrine cells, some made in hypothalamus, placenta, kidney
Both endocrine and neurons secrete substances into _______
the blood
T/F: Some molecules can be both hormones and neutrotransmitters
TRUE
Define homeostasis
ability of body to maintain a stable internal environment despite changes in external conditions
What are the 3 mechanisms of homeostasis?
receptor
control center
effector
What is the receptor in homeostasis?
receive information that something is changed
ex. thermometer
What is the control center in homeostasis?
integration
what receives and processes information (thermostat)
What is the effector in homeostatis?
respond to command of control center (furnace responding to thermostat)
T/F: Positive feedback results in homeostasis
FALSE!!!
it AMPLIFIES the change in variable
What are the hormone signaling pathways?
endocrine/telecrine
neurocrine
autocrine
paracrine
Define endocrine/telecrine
traveling long distance in blood to target tissue
Define neurocrine
secreted by neuron into blood
Define autocrine
exerts effects on itself or super identical cells
Define paracrine
travel just to intestinal within same tissue
- close to target cells
diffusion through interstitial fluid
What signaling pathways DO NOT go into the blood?
paracrine
autocrine
What are hormone classifications?
peptides & proteins
steroids
amines
eicosanoids
What is conserved across species?
Steroids
Amines are derived from _______
tyrosine
Eicosanoids are derived from ______
fatty acids
Peptides/protein hormones are derived from ______
amino acids
List some examples of peptide/protein hormones
insulin, growth factors, growth hormone, parathyroid hormone, thyroid-stimulating hormone, antidiuretic hormone
The structure of different peptide hormones may be very similar to each other and may only differ by a _______. This allows _________
side chain
allows similar hormones to act on multiple receptors
What can act on insulin receptors because their structure is very similar?
growth-factor hormones
Fill in the blanks
- nucleus
- mRNA
- preprohormone
- ER
- prohormone
- golgi
- secretory vesicles
What are the steps in synthesized peptide and protein hormones?
mRNA transcribed
message translated on ribosome = preprohormone
transported to ER = prohormone when signal peptide degraded
transported to Golgi - undergo more processing
package into secretory granules
granule contents release when endocrine cell is stimulated
T/F: A stimulus of peptide/protein secretion always results in immediate release
FALSE - transcription and translation is needed
Why are peptides/proteins not always released immediately? (What is required?)
transcription and translation is needed
body doesn’t have this in high amounts
How are catecholamines synthesized?
using tyrosine
Catecholamines are [fast/slow] release
fast
Thyroid hormones are synthesized from ________ and ________
tyrosine
iodide
Secretion of thyroid hormones require retrieval of ______ and release from __________, a storage protein
follicles
thyroglobulin
Steroid hormones are synthesized from _______
cholesterol
- there’s also cortisol and aldosterone
Steroid hormone secretion requires ______ because [it is/it is not] normally stored
synthesis
is not usually stored
Prostaglandins are synthesized from
arachidonic acid
What kind of hormone are prostaglandins?
paracrine - made locally and act within same tissues of nearby cells
What are the 2 mechanisms of hormone secretion?
neural mechanisms
feedback mechanisms
Neural mechanisms are [more/less] common than feedback mechanisms
less
What is an example of a neural mechanism?
stimulation of preganglionic nerve causes release of catecholamines from adrenal medulla
Feedback mechanisms use which kinds of loops?
long
short
ultra short
Define ultra short loops
hypothalamic hormone inhibiting its own secretion (autocrine)
Define short loops
negative feedback from pituitary to hypothalamus
Define long loops
hormone released from target tissue that feeds back to original release point (pituitary gland or hypothalamus)
all about distance travelled
What is negative feedback via a HORMONE?
when hormone levels are judged to be adequate or high, further secretion is inhibited
What is negative feed back via a SUBSTRATE?
when hormone/substrate levels are judged to be inadequate or low, secretion of hormone is stimulated
What is positive feedback?
a feature of hormone action causes MORE secretion of the hormone
