Endocrine System Flashcards
ductLESS and secrete directly into the blood
endocrine glands
CONTAIN DUCTS and carry substances directly to a specific target
exocrine glands
major endocrine organs
thyroid organs
adipose tissues
hypothalamus
two categories of hormones
steroid derived hormones
amine and polypeptide hormones
what are amine and polypeptide hormones synthesized from?
amino acids
Hormones alter cellular rxns by altering plasma membrane transport via what?
second messenger system
Hormones alter cellular reactions of specific target cells by what 4 things:
1] MODIFYING rate of intracellular protein synthesis
2] CHANGING rate of enzyme activity
3] ALTERING plasma membrane transport
4] INDUCING secretory activity
Hormones increase enzyme activity by:
stimulating production and combining with the enzyme to change its shape and action
Over the course of exercise, some enzymes increase in #, causing what?
increases ability to produce oxygen and VO2 max
Cyclic AMP: cyclic 3’5’-adenosine monophosphate
important 2nd messenger to amp up cellular response
How do you create a cellular response?
nonsteroid circulating hormone (1st messenger) binds to a receptor in plasma membrane…cyclic amp (2nd messenger) and this activates protein kinase –> target enzyme –> cellular response
4 factors that determine plasma concentration of a hormone:
- amount synthesized in host gland
- rate of either catabolism or secretion into blood
- amount of transport protein present
- changes in plasma volume
patterns of hormone release
as needed; in intervals during 24 hours or monthly cycles, etc
promotes cell division and cellular proliferation throughout the body
growth hormone (GH)
GH facilitates protein synthesis by:
increasing amino acid transport and stimulating RNA formation
slows carbohydrate breakdown and initiates mobilization and use of fat for energy
GH (growth hormone)
indirect actions of GH does what?
promote anabolism and goes to liver and other organs
direct actions of GH does what?
anti-insulin effect; reduces glucose uptake to maintain blood sugar level and goes to adipose tissue
What does ACTH regulate?
adrenal cortex output
- helps maximize fuel source for exercise
enhances FFA mobilization from adipose tissue
increases gluconeogenesis
stimulates protein catabolism
how ACTH regulates
What does prolactin do?
initiates and supports milk secretion from mammary glands in females
PRL levels _________ with intense exercise and return toward baseline within 45 min in recovery
increase
Repeated exercise-induced PRL for women release may ? and contribute to menstrual cycle alterations with intense training for women who do competitions
inhibit ovarian function
Stores antidiuretic hormone ADH: aka vasopressin and oxytocin
posterior pituitary hormone
ADH does what by the kidneys?
inhibits water excretion
Thyroxine
T4
Triiodothyronine
T3
secretion raises metabolism except in brain, spleen, testes, uterus, and thyroid gland
T4
release facilitates neural reflex activity
T3
low T4 levels cause
sluggishness
Exercise increases levels of T3 and T4 doing what
speeding up metabolism
Regular physical activity ? reproductive hormone responses in women and men
depresses
Women with history of intense physical activity
have ? FSH and LH levels which may contribute to menstrual dysfunction
altered
two main structures of adrenal glands
medulla and cortex
Enhances sympathetic effects by secreting epinephrine + norepinephrine
medulla
secretes adrenocortical hormones
mineralocorticoids, glucocorticoids, androgens
cortex
stimulates glycogenolysis and lipolysis so this increases glucose availability and helps with fat breakdown
epinephrine
provides powerful lipolytic stimulation in adipose tissue
norepinephrine
norepinephrine goes where?
liver for glucose
epinephrine goes where?
adipose tissue for fatty acids and muscle to block glucose entry
Increased sympathetic activity during physical activity ? kidney blood flow and this is known as?
constricts; renin-angiotensin mechanism
? blood flow stimulates kidney release of ?
reduced; renin
Increased renin stimulates production of ?
angiotensin II and III
causes kidneys to retain sodium and excrete potassium to conserve water
aldosterone
What does angiotensin II and III do?
constricts arteries and secretes aldosterone
angiotensins are powerful ?
vasoconstrictors!!!!!!!!
a major glucocorticoid
cortisol
Promotes breakdown of protein to amino acids
cortisol
inhibits glucose uptake
cortisol
promotes fat breakdown to glycerol and acids in fat tissue to optimize fuel mix
cortisol
normally released in response to a stress like exercise
cortisol
this is immunosuppresive
cortisol
what do opioids do?
“exercise high”
what does endorphin secretion do?
increases pain tolerance
improves appetite control
reduces depression, anger, anxiety, tension
With ?, ingesting 1 L/hr of a carbohydrate-rich drink reduces negative changes in immune function
prolonged intense activity
ADH helps you retain more what? Why is this important?
salt and fluids; since you have more water now, this increases SV and CO
endurance raining improves ?
target tissue sensitivity
efficient response
Risk of URTI with different levels of intensity?
sedentary= average risk of URTI
moderate intensity= below average
very high intensity= above average
