Chapter 4 shit Flashcards
What is the endocrine system?
-a complex signaling system in the human body that affects changes and supports exercise demands and recovery
-The endocrine system uses chemical messengers known as hormones to signal responses from tissues in the body
What is an Anabolic hormone response?
This is a tissue building response
What is a Catabolic hormone response?
This is a tissue breakdown response
What is a permissive hormone response?
It allows processes to occur
What is General adaptation syndrome?
-Adrenal response to stimulus/stressor
-Begins with the alarm reaction in the body
-When stress is due to training the body adapts and increases its resistance to stressors
Where are hormones synthesized, stored, and released?
Endocrine glands which are specialized structures dedicated to this function
What happens to hormones once they are released by their endocrine gland?
They are released into the blood and are delivered to specific receptors on the surface or in the cytosol of the target tissue cells
Where are the receptors for peptide hormones?
The receptors are located on the cell surface
Where are the receptors for steroid and thyroid hormones?
The receptors are located in the cytosol of the cell
What are binding proteins?
-any protein that acts as an agent to bind two or more molecules together.
-prevent hormone degradation during transit and may also play a hormonal role in of themselves
What are the 12 endocrine glands?
-Anterior pituitary gland
-Posterior pituitary gland
-Thyroid gland
-Parathyroid glands
-Pancreas
-Adrenal cortex
-Liver
-Adrenal medulla
-Ovaries
-Testes
-Heart
-Kidney
What is muscle remodeling?
-process that occurs from training muscles
-Disruption and damage of muscle fibers
-Inflammatory response
involves immune cells such at T and B cells, influenced by endocrine system
-Degradation of damaged proteins
-Hormonal, growth factor, and cytokine interactions
-Synthesis of new proteins and incorporation into existing or new sarcomeres
-Contractile proteins - actin, myosin
-Structural proteins - titin, desmin
What are the physiological roles of anabolic hormones?
-Promote tissue building
-Insulin, insulin-like growth factors (IGFs), testosterone, and growth hormone
-Block negative effect of catabolic hormones that degrade cell proteins
What are the physiological roles of thyroid hormones?
Permissive hormones that allow other hormone actions to occur
What are the physiological roles of Catabolic hormones?
-Degrade cell proteins
-Cortisol, progesterone
-Cortisol can deactivate immune cells and block other signaling pathways
What provides the basis for hormones influencing hypertrophy?
Hormones, muscle fibers, and changes in muscle fiber capabilities provides the basis for the influence of hormones in hypertrophy
Describe lock and key theory?
-States that specific hormones react with specific receptors
-Actual hormone reactions are more complex
-Hormones can partially bind with other receptors but can fully bind with their own specific receptor
What is Cross-reactivity?
-Some hormones partially interact with other receptors
-Ex. allosteric binding where non-binding hormones can block a receptor’s primary binding site
What is allosteric binding?
-Non-hormone substances enhance or reduce response to primary hormone
-Some hormones may need to link together to produce optimal signals through the receptor like GH
How does downregulation occur and what is it?
-downregulation is when a hormone receptor will become less responsive or even non-responsive to the relevant hormone
-Occurs when adaptation is no longer possible (i.e. max protein has been added to muscle fiber)
-Occurs from overstimulation - i.e. insulin resistance
-Binding sensitivity can be increased or decreased and the number of receptors can also be altered - results in dramatic adaptations comparable to increased hormone release
What are steroid hormones?
-Hormones from adrenal cortex and gonads - cortisol, testosterone, estradiol
-Fat-soluble
-Passively diffuse across the cell membrane
-Bind with the receptor in the cell to form a hormone-receptor complex (H-RC)
-H-RC binds with other H-RCs and opens up nucleus to expose DNA
-Transcribes DNA that releases mRNA into sarcoplasm
-mRNA begins the process of producing the protein promoted by the steroid
What are polypeptide hormones?
-Composed of amino acid chains
-Examples - growth hormone, insulin
-Cannot cross cell membrane - rely on secondary messengers inside the cell
-Signaling cascade from secondary messenger affects metabolic processes, DNA transcription, and mRNA translation initiation in the ribosome
-Regulated via negative feedback
What are amine hormones?
-Synthesized from amino acids tyrosine or tryptophan
-Tyrosine - epinephrine, norepinephrine, dopamine
-Tryptophan - serotonin
-Bind to membrane receptors on cell surface
-Act through secondary messengers within cells
How does heavy resistance training influence hormones?
-Long-term resistance training results in significant adaptive responses
-Increased anabolic hormone concentration
-Increased receptors
-Caused in part by increased recruitment of large motor units that stimulates
-Caused in part by increased recruitment of large motor units that stimulates receptors and sensitivity to anabolic factors
-Leads to muscle growth and strength gains
What are the Mechanisms of Hormonal interactions?
-Increased hormone blood concentration
-Increases probability of interaction with receptors
increased/decreased receptor affinity to hormones
-Genetic predisposition determines the ultimate limit in muscle size growth
-Recovery mechanisms needed for anabolic processes to occur
-Exercise prescriptions will also determine the degree of catabolic effect or lack of anabolic effect
-Combination of mechanisms results in exercise-induced hypertrophy
What are hormonal changes in peripheral blood?
-Increased hormone concentration in blood increases probably of receptor interaction
-Decreased hormone blood concentration may indicate increased hormone uptake by receptors
-Interpretation of hormone blood concentration very tricky
-Increased hormone concentration not a prerequisite for muscle growth
-Indicates increased activation of endocrine gland
What are the ways that an endocrine system adapts?
-Changes in synthesis and storage of hormones
-Changes in the transport of hormones via binding proteins
-Change in the time needed for hormone clearance in liver and tissues
-Variation in the rate of hormone degradation
-Blood-to-tissue fluid shift with exercise stress
-Receptor affinity for hormone (uncommon training response)
-Number of receptors in tissue
-Change in content and size of secretory cells in gland
-Change in the magnitude of the signal sent to nucleus via the H-RC
-Change in the degree of interaction with the cell nucleus
What is testosterone?
-Primary androgen that interacts with skeletal muscle tissue
-Produced in testes (male)
-Testosterone binding to receptor key to stimulating anabolic function
-Increase in testosterone alone not an absolute marker for anabolic function
-Resistance exercise may increase the number of receptors
-Promotes growth hormone release
-GH has synergistic effect with testosterone
-Interacts with neuron receptors, increasing the amount of neurotransmitter released and influencing structural protein changes
-Transported via binding protein in blood
-Binds to receptors inside cell and on cell surface
How does intense aerobic exercise affect testosterone?
-Increases in free testosterone seen in men following intense aerobic endurance exercise and resistance training
-Aerobic exercise does not increase hypertrophy
-Testosterone may be released to avoid excessive muscle tissue breakdown
How does resistance training influence testosterone?
It increases serum testosterone
What is a protocol for increasing testosterone in men?
-Train large muscle groups - i.e. squat bench, dl, power cleans
-Use heavy resistance - at or above 85%
-Use moderate to high volume of exercise via multiple sets or exercises
-Shorter rest intervals - 30 seconds to 1 minute
-2 years or more of resistance training
How does testosterone levels in women change after resistance training?
-Testosterone levels in women not as elevated, if at all, following resistance training
-Increase in testosterone sensitivity of the androgen receptors in muscle occur in women following resistance training
-Despite little change in testosterone concentration in blood, increased sensitivity to testosterone in women may drive adaptations in resistance training
What is Growth Hormone?
-Important for both child development and adaptations to resistance training
-Produced in anterior pituitary gland
-Multiple variants of growth hormone exist
-Relationship unclear between different forms
-Full effects of GH not fully understood
-GH refers to superfamily of different molecular forms of growth hormone
-Many different target tissues including bone, immune cells, skeletal muscle, fat cells, and liver tissue
What is the GH family responsible for?
-Decreased glucose utilization
-Decreased glycogen synthesis
-Increased amino acid transport across cell membrane
-Increased protein synthesis
-Increased utilization of fatty acids
-Increased lipolysis
-Increased availability of glucose and amino acids
-Increased collagen synthesis
-Stimulates cartilage growth
-Increase retention of nitrogen, sodium, potassium, and phosphorus
-Increased renal plasma flow and renal hypertrophy
-Enhances immune cell function
What affects GH release?
-Age, sex, sleep, nutrition, alcohol, and exercise
-Resistance training protocol - shorter rest periods associated with higher serum GH
-Not clear how various forms of GH are individually affected by rest period
How does GH in women differ from GH in men?
-Women have higher 22kDa GH than men
-Hormone concentrations vary throughout the menstrual cycle
-When workouts were compared, GH response between men and women were similar
What are insulin-like growth factors?
-Polypeptide amino acid chains
-Produced in liver
Superfamily with multiple variations with different numbers of amino acids
-IGF 1 - 70 aminos
-IGF 2 - 67 aminos
-Regulated by GH, testosterone, thyroid hormone, and others
-Bind with binding proteins in blood
-At least 6 different binding proteins regulate availability of IGF-1
Mechanisms of IGF influenced by strength training factors
-Exercise stress
-Acute hormonal responses
-Need for bone, muscle, and nerve tissue remodeling at the cellular level
Crucial component of protein anabolism
What strength training factors influence IGF?
-Exercise stress
-Acute hormonal responses
-Need for bone, muscle, and nerve tissue remodeling at the cellular level
-Crucial component of protein anabolism
What is the IGF response to training?
-Acute increases of IGF after training depend on resting IGF levels
-Low levels pre-training are elevated post training
-Normal/High levels pre training are unchanged by training
-Increased total IGF-1 and reduced IGF binding protein 1 seen in women post-exercise
-Full implications not fully understood
What hormone stimulates the adrenal gland to release hormones?
Adrenocorticotropic hormone
What are the 2 most important adrenal hormones related to s + c?
Cortisol and catecholamines
What is Cortisol?
-Exerts catabolic effects by stimulating conversion of amino acids to carbohydrates
-Increases level of proteolytic enzymes - the enzymes that break down proteins
-Inhibits protein synthesis
-Suppresses glucose-dependent processes
-Produced in the adrenal cortex when stimulated by adrenocorticotropic hormone
-Anabolic effects of testosterone counter the catabolic effects of cortisol
-Relative binding of each hormone determines anabolic vs catabolic state
-Cortisol increases with resistance exercise
-Effect most dramatic when rest periods are short and work volume is high
-Cortisol’s catabolic effect in men may be reduced by adaptations during training
-Cortisol levels rise acutely from the same stimulus that increases GH
-Acute elevated cortisol levels may be part of remodeling process and are associated with high volume, large muscle groups, short rest period resistance training
-Chronic elevated cortisol levels have negative effect on tissue growth and are associated with overtraining
-Cortisol’s role in suppressing immune cells has direct effect on remodeling of muscle tissue and may be associated with immunosuppression following intense exercise
What are Catecholamines?
-Primarily epinephrine but also include norepinephrine and dopamine
-Secreted by adrenal medulla and act as powerful central motor stimulators and peripheral vascular dilators
-Enhance enzyme systems and calcium release in muscle
What are the role of Catecholamines?
-Increased force production via central mechanisms and metabolic enzyme activity
-Increased muscle contraction rate
-Increased blood pressure
-Increased energy availability
-Increased blood flow to muscles via vasodilation
-Augment secretion rates of testosterone and other hormones
What are the training adaptations of Catecholamines?
-Heavy resistance training increases the ability to secrete epinephrine during maximal exercise
-Stimulation of catecholamines likely one of the first endocrine responses to resistance exercise
What is a general principal for muscle remodeling?
More muscle fibers being recruited = greater potential remodeling.
Only the fibers being activated will be subject to adaptation
How should you structure training to increase serum testosterone?
-Focus on large muscle groups
I.e. deadlift, squat, power clean
-Use heavy resistance
85%+ 1rm
-Use a moderate to high volume of exercises with multiple sets and exercises
How should you structure training to increase GH?
-Use workouts with higher lactate concentrations
-High intensity
-High total work
-Short rest periods
-Supplement with carbs pre and post workout
How should you structure training to optimize adrenal response?
-High volume, large muscle groups, short rest periods
-Vary training protocols and variables over time
-Provide days of complete rest
-Cycle in low-volume workouts to allow adrenal glands to recover and prevent chronic cortisol secretion
