endocrine system Flashcards
neural versus endocrine
neural sends signals through neurons and impulses and endocrine is through blood secretion and hormones.
what are the four types of cell to cell communication?
Gap junctions/direct, neurotransmitters, autocrine/ paracrine (diffuse), blood to target organs with specific receptors
endocrine
into/secrete
hormone
excite/set in motion
What are steroid hormones derived from?
derived from cholesterol. They are hydrophobic and require a transport protein.
Where are peptide hormones synthesized?
synthesized in the endoplasmic reticulum
What are amine hormones synthesized from?
one or two amino acids (melatonin and thyroid hormone
Do most peptide and amine hormones require transport proteins? Why or why not?
no because they are water soluble
What are the three ways that a hormone might be secreted?
neural, hormonal or humoral stimuli
What is the function of a transport or binding protein? How is it beneficial to a hormone? How might it inhibit hormone action?
carry steroid hormones through the blood because they are hydrophobic and provide protection from degradation which increases hormones half life. (thyroid)
Describe the relationship between a hormone and its receptor.
key and lock
bound hormone
has a transport protein
free hormone
does not have a transport protein
What is a second messenger system? What types of hormones require one? Why?
small ions the relay signals received by cell surface receptors to effector proteins. Hydrophilic peptide and amine hormones require it because they cannot readily pass through the phospholipid bailer and require a cell surface receptor
What are some examples of second messenger systems?
cAMP, calcium, kinase
How do second messenger systems amplify the signal from a hormone?
activate multiple target enzymes
What factors determine the degree of hormone action?
hormone concentration (secreted vs degraded), receptor number and location, carrier protein concentration
What stimulates insulin secretion? Is this a humoral, neural or hormonal stimulus?
response to increased blood glucose. humoral stimulus
What type of hormones are insulin and glucagon?
pancreatic endocrine hormones
What are the actions of insulin on the cell? What are its target organs?
insulin acts to stimulate muscle and adipose tissue to store excess potential energy and also surpasses the use of energy that is already stored. Insulin stimulates the reactions of glycogen and fatty acid synthesis and inhibits enzymes involved in catabolic reactions. It’s target organs are muscle, adipose and the liver
How does blood glucose stimulate the release of insulin?
when it is too high insulin is released
What would happen to blood glucose levels if the beta cells were destroyed?
the body would no longer be able to produce enough insulin
What are the actions of glucagon on the cell? What are its target organs?
stimulated when blood glucose levels fall below normal it stimulates the release of stored energy and its target organ is the liver
What are the counter-regulatory hormones?
glucagon, growth hormone cortisol, and epinephrine
