Lesson 7: Endocrine System Flashcards
What are the 6 major endocrine organs?
Pineal
Pituitary
Thyroid
Parathyroid
Thymus
Adrenal glands
What are 4 non-endocrine hormone-producing tissues?
Pancreas
Gonads
Hypothalamus
Adipose Tissue
What is the “master” endocrine gland?
Pituitary gland
Endocrine System Organization
Host organ (gland)
Chemical messengers (hormones)
Target (receptor) organ
Chemical substances synthesized by specific host glands that enter the bloodstream for transport throughout the body
Hormones
Two categories of hormones:
Steroid derived hormones
Amine & Polypeptide hormones
Amine and polypeptide hormones are synthesized from ______
amino acids
In contrast to steroid derived hormones, anime and polypeptide hormones are soluble in _____
plasma
What is a benefit for hormones to be soluble in plasma?
allows for easy uptake at target sites
Half-life
The time it takes a hormone’s blood concentration to reduce by one-half
The half-life of a hormone provides an indication of _______
how long a hormone’s effect persists
What are the two types of amine hormones?
Catecholamines
Thyroid hormones
Examples of peptide hormones
Insulin, glucagon, letptin, etc
Examples of steroid hormones
Androgens, DHEA, cortisol
Examples of catecholamines
epinephrine; norepinephrine
Example of thyroid hormone
Thyroxine
Peptide hormones have a short/long half-life
short
Steroid hormones have a short/long half-life
Long
Catecholamines have a short/long half-life
Short
Thyroid hormones have a short/long half-life
Long
Hormones alter cellular reactions in 4 ways:
- Modify rate of intracellular protein synthesis by stimulating nuclear DNA
- Change the rate of enzyme activity
- Alter plasma membrane transport via a second-messenger system
- Induce secretory activity
What is the first step in initiating hormone action?
Hormone-receptor binding
The extent of the target cell’s activation depends on three things:
- Hormone concentration in the blood
- Number of target cell receptors for the hormone
- Sensitivity of the union between the hormone and receptor
Which type of diabetes causes trouble with the hormone concentration in the blood?
1
Which type of diabetes causes trouble with number of target receptors and sensitivity of the union between the hormone and the receptor?
2
What happens during up-regulation?
Target cells form more receptors in response to increasing hormone levels to increase the hormone’s effect
What happens during down-regulation?
A loss of receptors to prevent target cells from over responding to chronically high hormone levels to decrease the hormone’s effect
How do hormones alter enzyme activity and transport?
- stimulate enzyme production
- combine with enzymes to alter its shape and decrease/increase its effectiveness
- activates inactive enzyme forms to increase the total amount of active enzymes
_____ facilitates glucose transport into the cell
insulin
_________ inhibits insulin release
Epinephrine
True or false: Hormone secretion adjusts rapidly to meet the demands of changing body conditions
True
Four factors determine hormone concentration:
- amount synthesized by the host gland
- rate of secretion into the blood
- quantity of transport proteins present
- plasma volume changes
Most hormones respond to stimuli on as _________ in response to stimuli
as needed basis
Some hormones release at _______ during a ________
regular intervals; 24 hour cycle
True or false: each category of hormones follows a uniform release pattern
FALSE; will vary based on the individual hormone
Some hormones follow cycling patterns that span ________ or the course of a ____
several weeks; day
Testosterone promotes __ release and ___ synthesis
GH; IGF
Which 6 hormones are produced by the pituitary gland?
Lactogen
Gonadotropic hormones (FSH/LH)
ACTH
Thyrotropin
GH
Endorphins
What three things are achieved by GH?
Increased amino acid transport
Increased protein synthesis
Slows CHO breakdown and increased use of fat as energy
Acute aerobic exercise leads to an increased amount of ___ secreted
GH
Acute aerobic exercise leads to an increased release of GH with extended _____
half-lives
Acute aerobic exercise leads to an increased preservation of ______ _______ concentrations, which leads to enhanced prolonged exercise performance
plasma glucose
IGF stands for
Insulin-like growth factor
___ mediates many of GH’s effects, acting as an intermediary messenger
IGF
IGH provides for potent peripheral effects on _______ ____ and other tissues
motor units
IGF is synthesized by _____ ____ in response to GH stimulation
liver cells
ACTH stands for
Adrenocorticotropic hormone
ACTH enhances _____ mobilization, increases ________, and stimulates protein synthesis/breakdown
fatty-acid; gluconeogenesis; breakdown
ACTH is difficult to measure, but increases/decreases with exercise intensity or duration
increases
ADH stands for
anti-diuretic hormone
___ influences water excretion by the kidneys
ADH
ADH action limites production of large volumes of _____
urine
ADH leads to reabsorption of _____ in the kidney tubules
water
True or false: Acute aerobic exercise is a potent stimulus for ADH secretion
True
During acute aerobic exercise, what does ADH do?
conserves body fluids during exercise in hot environments (stimulated by sweating)
T4
Thyroxine
T3
Triiodothyronine
The “major metabolic hormones” are stimulated by _____
thyroid-stimulating hormone production of the anterior pituitary
True or false: Thyroid hormones are soluble in plasma
False
Because thyroid hormones are insoluble in plasma, they must be bound to _____ _______
carrier proteins
T4 release has a significant impact on ___
Resting metabolic rate (RMR)
Abnormally low secretion of T4 leads to _______
weight gain
During aerobic exercise, free T4 increases by __%
35
Symptoms of hypothyroidism
Increased VO2 and metabolic heat production at rest
Increased protein catabolism and weakness/weight loss
Heightened reflex activity and psychological disturbances
Tachycardia
Symptoms of Hyperthyroidism
Reduced metabolic rate
Cole intolerance
Decreased protein synthesis (brittle nails, thinning hair, dry skin)
Fatigued, depressed reflex activity
Slow speech
Bradycardia
PTH stands for
Parathyroid hormone
___ controls blood calcium balance
PTH
A decrease in _____ _____ stimulates the release of PTH
blood calcium
PTH activates bone reabsorbing cells called ________
osteoclasts
True or false: Exercise may increase PTH release
True
Where are the adrenal glands located?
Above each kidney
Adrenal glands are composed of two parts:
Medulla
Cortex
The _____ of the adrenal glands makes up part of the sympathetic nervous system
Medulla
The medulla of the adrenal gland acts to prolong and augment _________ nervous system effects
Sympathetic
Which hormones does the medulla of the adrenal gland secrete?
Epinepherine
Norepinepherine
Within the adrenal medulla, norepinepherine increases exponentially at ____ VO2 max
50% or greater
Within the adrenal medulla, epinepherine is unchanged until it intensities at ____ VO2max
75% or greater
Within the adrenal medulla, the catecholamines aid in mobilizing ____ from the liver and fatty acids from adipose tissue
glucose
The adrenal cortex produces which four hormones?
Cortisol
Aldosterone
Androgens
Estrogen
The release of adrenal cortex hormones leads to an increase in _______ and _____
Blood volumes; BP
The effect of aldosterone will typically occur during aerobic exercise of at least ___ minutes
45
The “stress” hormone
Cortisol
The secretion of cortisol increases with _____
stress
Cortisol promotes the breakdown of proteins into amino acids for gluconeogenesis in the _____
liver
Cortisol supports other hormones in the _______ process
gluconeogenesis
Cortisol serves as an _____ ______, which halts glucose from entering the cell
insulin antagonist
Cortisol promotes _______ breakdown in adipose tissue to glycerol/fatty acids
triacyglycerol
______ suppresses immune system function
Cortisol (‘cause now we’re stressed out)
Cortisol produces a negative/positive calcium balance
negative
Cortisol production will increase/decrease with activity intensity
increase
Cortisol levels may remain elevated up to _ hours post exercise, suggesting a potential role in tissue repair/recovery
2
True or false: Distinct male or female hormones exist
False
Hormones vary in their type/concentration between the sexes
concentration
______ is the most important secretion from the male testes
Testosterone
_____ are the primary hormones secreted by the female ovaries
Estrogens
Testosterone initiates _____ production
sperm
______ stimulates male secondary sex characteristics
Testosterone
Testosterone will convert to ______ in peripheral tissue to maintain bone structure
estrogen
How does testosterone affect neurotransmitter release and the neuromuscular junction?
Increase NT release
Increase NMJ size
There is an increased ______ concentration in untrained males after 15-20min of moderate aerobic exercise or resistance exercise
plasma
True or false: Plasma concentration also increases in females with exercise, but only 1/10 the concentration of that in males.
True
What are the primary estrogen hormones?
Estradiol
Progesterone
What is the purpose of estrogen?
Regulate ovulation, menstruation, and pregnancy adjustments
Will exercise increase estradiol and progesterone levels?
Yep. Shocker.
Estrogens may even affect metabolism in these two ways:
increase free fatty acid metabolism
Inhibition of muscular glucose uptake
______ regulates glucose entry into all tissues
Insulin
Insulin will be released in response to elevated or decreased ________ levels
blood glucose
With prolonged steady-state aerobic exercise, the concentration of insulin below resting concentration increases/decreases
decreases
What in the huh is a GLUT?
Glucose Transport Protein
GLUT-1 will provide for most glucose transport with exercise/at rest
at rest
GLUT-4 will provide for most glucose transport with exercise/at rest
with exercise
Diabetes
Subgroup of disorders characterized by elevated blood glucose levels due to an insulin abnormality
Symptoms of diabetes mellitus
Glucose in urine
Frequent urination
Excessive thirst
Extreme hunger
Unexplained weight loss
Increased fatigue
Irritability
Blurry vision
Numbness or tingling in the extremities
Slow-healing wounds or sores
Abnormally high frequency of infection
Type 1 Diabetes
Absolute deficiency of insulin that develops early in life
Type II diabetes
relative insulin resistance and deficiency that develops later in life and relates to obesity, diet, and sedentary living
What is the purpose of prolactin?
Initiates and supports milk secretion from mammary glands
Levels of prolactin increase with what type of activity?
High intensity
PRL stands for…
Prolactin
Repeated release of PRL may inhibit ________ and lead to alterations in ____ ______ with intense training in females
ovarian function; menstrual cycle
As blood glucose goes up, release of insulin goes up/down
up
As blood glucose levels go down, release of insulin goes up/down
down
As exercise duration increases, plasma and insulin levels go down and ___ is used for energy instead
fat
If the intensity increases by 75% or more of our VO2 max, insulin levels will increase/decrease
increase (spike back up)
What is the test used to find diabetes?
Hemoglobin A1c Test
When blood glucose becomes uncontrolled, the excess glucose enters RBCs and links to ______
hemoglobin
The more excess blood glucose, the more/less hemoglobin will be saturated
more
For a hemoglobin A1c test, anything above ___% is considered diabetic
6.5
Which type of diabetes can be improved with exercise?
Type II
Results of exercise in those with Type II Diabetes
Improved glucose tolerance
Increased insulin sensitivity
Decreased HgbA1c
The risk of ______ does exist in individuals taking insulin or some oral medications when exercising
hypoglycemia (please check your BG levels before and after you exercise)
The Metabolic Syndrome
Cluster of risk factors that correlate increase risk for coronary artery disease, stroke, and diabetes
5 symptoms of The Metabolic Syndrome
Elevated blood glucose
Overweight with a large waist girth
High triacyglycerols
Low levels of HDLs
Hypertension
Can all the factors of The Metabolic Syndrome be controlled by exercise?
Yeah…exercise seems to be the answer to everything, hehe…
In general, the magnitude of hormonal secretion to an absolute exercise load will increase/decrease with chronic endurance training
decrease
Response of GH to chronic aerobic training
No effect on resting values
Less dramatic rise during exercise
Response of ACTH to chronic aerobic training
Increase release during exercise
Increase fat catabolism and spares glycogen to enhance prolonged exercise performance
Response of PRL to chronic aerobic training
Resting levels reduced with repeated, high intensity training
Response of ADH to chronic aerobic training
Slightly reduced levels at a given absolute workload between trained and untrained
No change when intensity is relative to fitness level
Response of PTH to chronic aerobic training
Endurance training enhances exercise-related increases in PTH
Potentially related to preservation of bone mass with weight-bearing exercise in the elderly
Response of the thyroid hormones to chronic aerobic training
Increased turnover of T3 and T4 during exercise
What is turnover?
How quickly a hormone can bind to a receptor, be released, and then bind again
Response of aldosterone to chronic aerobic training
N/A
Response of cortisol to chronic aerobic training
Plasma levels increase less in trained individuals at the same absolute intensity
Repeated bouts of intense training actually leads to enlargement of the adrenal gland
Response of the catecholamines to chronic aerobic training
Decreased secretion at rest and with training at the same absolute intensity as untrained
Increased release post-training at relative intensities
Why is there an increased release of the catecholamines post-training?
Greater need for substrate use, increased cardiac output, larger muscle mass activation
Response of insulin to chronic aerobic training
Increased cell sensitivity to insulin
Normal decrease in insulin with acute exercise is reduced with training
Type II Diabetics show an increase in _____ sensitivity in response to chronic aerobic exercise
insulin
Response of gonadal hormones to chronic aerobic training
Reduction in reproductive hormones in women and men
True or false: Men may have an increase in testosterone with long-term strength training
True
Early-phase adaptations to resistance training reflect a hormonal response that mediates _______ ____ adaptations to improve strength
neuromuscular system
______ and ___ are two hormones that affect resistance training adaptations
Testosterone; GH
Testosterone augments __ release and interacts with the _______ system to increase strength
GH; nervous
Why do men achieve hypertrophy more often than women?
Resistance training in men displays an increase in frequency and amplitude of testosterone and GH secretion not seen in females
Most effective methods to increase testosterone release through resistance training methods such as…
Intense activation of large-muscle groups with dead-lifts, power cleans, etc.
High-volume training with multiple sets
Long-term resistance training in men increases resting _____ levels
testosterone
Prolonged exhaustive/moderate physical activity boosts natural immune function and host defenses for up to several hours
moderate
Prolonged exhaustive/moderate exercise severely depresses the body’s first line of defense against infection
Prolonged exhaustive
True or false: Upper respiratory tract infections are common after intense training
True
Chronic aerobic exercise training positively affects ______ ______ function
natural immune
True or false: strength training significantly improves long-term immune system function
False. It doesn’t do ANYTHING.
What are four ways to improve immunity?
Well-balanced diet
Reducing stress
Adequate sleep
Regular physical activity and exercise
How does exercise reduce risk of cancer?
Increased capacity of cells that inhibit cancer cell growth
improved antioxidant function
altered endocrine function
body composition changes
improved intestinal transit time (take that, colon cancer!)
