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)
actual percent of hypothyroidism***
3-4%***
true or false: the thyroid gland is very slow***
True: the thyroid gland is very slow***
parathyroid hormone
primary hormone involved in plasma Ca++ regulation- intense and prolonged exercise
what does the adrenal medulla secrete?
epinephrine(80%) and norepinephrine
what does the adrenal cortex secrete?
steroids
- mineralcorticoids (aldosterone)
- glucocorticoids (cortisol)
- sex steroids (androgens and estrogens)
what does the adrenal medulla secrete and what does it do?
secretes: epinephrine (80%) and norepinephrine
- it increases HR, Glycogenolysis, lipolysis, and BP
pheochromocytomas
tumor of the adrenal gland
true or false: norepinephrine is a hormone and a neurotransmitter
true
the catecholamine epinephrine and norepinephrine do what?
bind androgenic receptors
-the magnitude and direction (inhibitory and excitatory) of the response depends on ____?
the precursor for all steroid hormones
cholesterol
adrenal cortex secretes _____ hormones.
steroid hormones
true or false. predrisome and dexamethasome are used in cancer treatments
true
in the adrenal cortex what do mineral corticoids (aldosterone) do?
mineralcorticoids (aldosterone)
- maintain plasma Na+ and K+
- and regulate blood pressure
what is the release of aldosterone controlled directly by _____.
plasma k+ and ang II
- the increase in plasma k+ induces the secretion of aldosterone
aldosterone
helps maintain plasma Na+ and k+
helps maintain plasma volume
what happens to mineral corticoids during exercise?
light exercise: little change in aldosterone and renin but if exercise during heat both increase
heavy exercise (>50% max): parallel increases in aldosterone, renin, and ang II
aldosterone and ADH work together to regulate body fluids during exercise
what are glucocorticoids stimulated by?
exercise and long term fasting (to maintain plasma glucose)
what do glucocorticoids (cortisol) do?
- promote the use of free fatty acids as fuel
- stimulates glucose synthesis
- promotes protein breakdown for gluconeogenesis and tissue repair (start to lose muscle mass in disease state ex: cancer)
true or false: endurance training largely prevents atrophy associated with glucocorticoids
FALSE: RESISTANCE TRAINING largely prevents atrophy associated with glucocorticoids
what does the pancreas secrete?
digestive enzymes and bicarbonate into the small intestine
- insulin
- glucagon
- somatostatin
insulin
promotes the storage of glucose, amino acids, and fats
glucagon
promotes the mobilization of fatty acids and glucose
somatostatin
modifies GI tract to controls rate of entry of nutrients into the circulation
what do the testes release? and what does it do?
testosterone (an anabolic steroid)
- promotes tissue (muscle building)
- performance enhancement
testosterone (androgenic steroid)
- promotes secondary masculine characteristics
follicle stimulating hormone helps with
the production of sperm
luteinizing hormone from the anterior pituitary helps with
testosterone production
Endurance training _____ testosterone levels significantly
endurance training reduces testosterone levels significantly**
resistance training ____ testosterone levels
resistance training does not change testosterone levels
what is the female triad?
- eating disorders
- loss of menstrual cycles
- bone mineral declines
tumor necrosis factor alpha is significant for what?
significant for inflammation
skeletal muscle produces____ when it contracts
myokines
what do myokines do?
- stimulate glucose uptake and fatty acid oxidation
- promote blood vessel growth in muscle
- promote liver glucose production and triglyceride breakdown
interleukin 6 does what
- has both proinflammatory and anti-inflammatory effects**
- produced during exercise is has an ANTIINFLAMATORY effect*****
the breakdown of muscle glycogen is under dual control. what two things control it
- epinephrine -cyclic AMP
2. Ca++ - calmodulin
glycogenolysis
breakdown of glycogen
glycogenolysis is related to exercise intensity
- high intensity exercise results in a more rapid glycogen depletion (not necessarily greater glycogen depletion than lower intensity exercise)
- duration plays a key role
plasma epinephrine is a powerful stimulator of glycogneolysis with calcium. what does high intensity exercise result in?
results in greater increases in plasma epinephrine thus contracting muscle will break down glycogen
glycogen depletion during exercise:***
- glycogen depletion is greater for 90 minutes***
- heavier the exercise= the faster glycogen is broken down***
overall aim of the maintenance of plasma glucose during exercise is to :
- provide fuel for work while maintaining plasma glucose for the CNS
- * the liver = 80g of glycogen/glucose before exercise, blood glucose oxidation ~1g/minute for heavy exercise***
cortisol
- stimulates FFA mobilization from adipose tissue
- mobilizes amino acids for gluconeogenesis
- block entry of glucose into the cell
what are the permissive facilitators and slow acting hormones?
TSH
cortisol
growth hormone
- they act in a permissive manner to support actions of other hormones
-***for example, without T3, epinephrine has little effect on FFA mobilization from adipose tissue
plasma cortisol during exercise ***
- ** at low intensity: plasma cortisol decreases***
* ** at high intensity: plasma cortisol increases***
what was the main point of the pubmed article on growth hormone?
basal growth hormone was only elevated in the 2 hour aerobic exercise group
fast acting hormones
norepinephrine and epinephrine
-insulin and glucagon
epinephrine and norepinephrine during exercise
- increases linearly during exercise
- favor the mobilization of FFA and maintenance of plasma glucose
epinephrine and norepinephrine following training
- decreased plasma levels in response to exercise bout
- parallels reduction in glucose mobilization
plasma catecholamines during exercise following training
***** endurance training causes a rapid decrease in plasma NE and E to a fixed workload
insulin during exercise
plasma insulin decreases during exercise
** throughout exercise insulin is lower than measured at rest*
true or false: insulin does not decrease as much with training
true
endurance training in healthy individuals. what happens to glucagon and insulin
glucagon and insulin response to fixed exercise (absolute submaximal workload) is diminished (meaning there are smaller changes in either hormone) after training
endurance training:
- decreased epinephrine
- decreased stimulation of a and b cells
- decreases secretion of insulin and glucagon
