Test 4 info Flashcards
endocrine system
slow, blood born mechanisms of action
nervous system
immediate, neuron-mediated mechanisms of action
signal transduction
ligand receptor interaction causes a response in the target cell called ____ ______
the nervous system uses ____ and the endocrine system uses
____ as chemical messengers (ligands) that bind to specific proteins (receptors)
nervous system uses neurotransmitters
endocrine system uses hormones
chemical messengers
ligand
the structure of a chemical messenger determines its mechanisms of ……
- synthesis
- release
- transport
- signal transduction
the most important chemical characteristic of a chemical messenger is….
is whether the messenger can dissolve in water or cross the plasma membrane (lipid bilayer)
lipophilic messengers
- lipid soluble
- crosses membrane easily, doesn’t dissolve in water
lipophobic messengers
- water-soluble
- does not cross membrane, does dissolve in water
endocrine glands
release hormones directly into the blood
hormones
alter the activity of tissues that posses receptors to which the hormone can bind
plasma hormone concentration
determines the magnitude of the effect at the tissue level
the effect a hormone exerts on a tissue is influence by:
- the number of receptors available for binding
2. blood hormone concentration
blood hormone concentration entails what four aspects
- the rate of secretion from the endocrine gland (whether its excitatory or inhibitory)
- rate of metabolism or excretion of hormone (hormone inactivation nor removal from the blood)
- quantity of transport protein
- changes in plasma volume
* ** during exercise plasma volume decreases which causes a slight increase in hormone concentration in plasma**
during exercise what happens to plasma volume?
during exercise, plasma volume decreases which causes a slight increase in hormone concentration in the plasma
rate of insulin secretion from the pancreas is dependent on :
- magnitude of input
2. stimulatory vs. inhibitory
true or false: most endocrine glands are under the direct influence of multiple inputs
true
the magnitude of effect of hormone receptor interactions is dependent on:
- concentration of the hormone
- number or receptors on the cell
- affinity of the receptor
hormones in the hormone receptor interactions bring about effects by:
- altering membrane transport
- stimulating DNA to increase protein synthesis
- activating second messengers (cyclic AMP and Calcium)
lipophobic hormones:
hormones that bind receptors located on the outer surface of the cell membrane activate ________ in or near the membrane to increase intracellular concentrations of some ion or substrate
carrier molecules
true or false: steroids are slow moving
true: steroids are slow moving
what are some examples of second messengers?
- cyclic AMP
- calcium
- second messengers are not independent, because changes in one can affect the other
what are the main endocrine systems we described in class?
- hypothalamus and pituitary gland
- thyroid and parathyroid glands
- adrenal glands
- pancreas
- testes and ovaries
- adipose tissue (secretes estrogen and testosterone)
- skeletal muscle
hypothalamus
“regulator of the pituitary”
- controls activity of the anterior and posterior pituitary glands
- influenced by positive and negative input
- typically the pituitary has a negative affect
a mammory gland secretes…
prolactin
where is growth hormone secreted from? What does it do?
- secreted from the anterior pituitary gland
- essential for normal growth
- it stimulates protein synthesis and long bone growth
- it increases during exercise to mobilize fatty acids from adipose tissue
- The MAIN OUTCOME IS THAT IT AIDS IN THE MAINTENENCE OF BLOOD GLUCOSE
what does the posterior pituitary gland secrete? what does it do?
ADH (antidiuretic hormone) (aka vasopressin) and oxytocin
-it also reduces water loss from the body to maintain plasma volume
what is the posterior pituitary gland stimulated by?
- high plasma osmolality and low plasma volume due to sweating
- exercise
how does the concentration of ADH change during exercise?
*most subjects show increased ADH ~60% of VO2 max
what is the thyroid gland important for?
- important in maintaining metabolic rate
2. the regulation of plasma calcium (calcitonin)
hypothyroid
linked to weight control problems
the thyroid gland secretes what
calcitonin
what is the ratio for T4:T3 secretion?
20:1
T3 is more potent
T4 can be converted to T3 (more potent form)