Neuroendocrine system
Endocrine system releases hormones. Nervous system uses neurotransmitters
Endocrine glands
Release hormones directly into the blood
Hormones
After the activity of tissue that possess receptors to which the hormone can bind. Several classes based on chemical makeup. Amino acid derivatives. Peptides/protein. Steroids
Hormone
endocrine signal is released into the blood where it circulates to the tissue to have an effect
Neurotransmitter
use synaptic signals to relay messages. Relay messages from one nerve to the other, or from nerve to a tissue
Peptide
Amino acid chains. Insulin. Glucagon. Ghrelin. Leptin. Growth hormone. Thyroid stimulating hormone
Steroid
4 fused carbon rings. Estrogen. Testosterone. Progesterone. Cortisol
Factors influencing the effect of hormones have
The effect of a hormone on a tissue is determined by the plasma concentration. Determined by: Rate of secretion of hormone from endocrine gland. Magnitude of input. Rate of metabolism (inactivated) or excretion (removal) of hormone. At the receptor and by
Rate of secretion of the hormone from the endocrine gland
Influenced by the magnitude of stimulatory or inhibitory signals on the endocrine gland
Metabolism or excretion of hormones
Removal of hormones from the system. Kidney excretion. Liver metabolism
Plasma volume
By changing plasma volume (mostly water and dissolved proteins) that will alter hormone concentration without changing secretion or metabolism/excretion
How hormones work
Hormones only affect tissue with specific receptors. Receptors are not static fixtures." Magnitude of effect dependent on. Concentration of the hormone. Number of receptors on the cell. Affinity of the receptors for the hormone
Downregulation
A decrease in a cellular component. Decrease in receptor number in response to high concentration of hormone
Uppregulation
An increase in a cellular component. Increase in receptor number in response to low concentration of hormone
Cyclic AMP "second messenger" mechanism
Examples include: Breakdown of glycogen to glucose. Breakdown of triglycerides to FFA. This process is inactivated by phosphodiesterase. Phospholipase C second messenger mechanism
Gland specific hormones
Hypothalamus (Anterior & Posterior Pituitary Gland). Thyroid Gland. Parathyroid Gland. Adrenal Gland. Pancreas. Testes & Ovaries
Adrenocorticotropic hormone (ACTH)
Secretion of cortisol
Follicle-stimulating hormone (FSH)
Stimulate ovulation (women) or sperm production (men)
Luteinizing hormone (LH)
Stimulates production of testosterone and estrogen
Melanocyte-stimulating hormone (MSH)
Stimulates skin/hair growth as well appetite
Thyroid-Stimulating hormone (TSH)
Rate of thyroid hormone secretion
Growth hormone
stimulates IGFs (negative feedback loop)
Prolactin
stimulates the production of breast milk
Growth hormone and performance
GH increases protein synthesis in muscle and long bone growth. Use to treat childhood dwarfism. Also used by athletes and elderly. More adverse effects then benefits. No evidence that GH promotes strength gains. Minimal strength gains compared to resistan
Posterior pituitary gland
oxytocin and antidiuretic hormone
Oxytocin
Smooth muscle stimulator during birth. Milk release during breast feeding
Antidiuretic hormone
Reduces water loss from the body. Does exactly what the name implies. Favors the reabsorption of water from the kidneys tubules back into the capillaries to maintain body fluid
Thyroid Gland
T3 and T4 (iodine hormones) are released into circulation. Number refers to the atoms. Bound to plasma protiens for transportation. They need to separate from these proteins and become "free" to have an effect on tissue. Low T3= hypothyroid. Linked to wei
Parathyroid gland
Involved in plasma Ca++ regulation. Releases parathyroid hormone
Adrenal medulla
Catecholamine. Epinephrine. Norepinephrine. Blood pressure and substrate utilization
Adrenal cortex
Steroid hormones. Mineralocorticoids. Maintain sodium and potassium concentration. Glucocorticoids. Involved in plasma glucose regulation. Sex steroids
Mineralocorticoid (adrenal cortex)
Aldosterone. Control of Na+ reabsorption and K+ secretion. Na+/H2O balance. Regulation of blood volume and blood pressure (deliver oxygen). Part of renin angiotensin aldosterone system (released during exercise). All three hormones increase during exercis
Renin angiotensin aldosterone system
1. A decrease in plasma (water part) volume, a fall in BP at the kidney, or an increase in SNS activation to the kidney will stimulate the kidney to release Renin
Decrease in volume or sympathetic activation. 2. Renin enters the plasma and converts renin
Glucocorticoid
Maintain plasma glucose. Promote breakdown of tissue protein by inhibiting protein synthesis to form amino acids which are then used by the liver to form new glucose. Stimulate the mobilization of free fatty acids. Stimulate liver enzymes involved in the
Pancrease
insulin, glucagon, somatostatin
Insulin (?)
Stimulates glucose and amino acid uptake into cells. A lack of insulin causes an accumulation of glucose in the plasma and can lead to diabetes mellitus. Hyperglycemia (taking an insulin shot)
Glucagon (?)
Mobilize glucose from liver stores and fatty acids from adipose tissue. Use adenylate cyclase second messenger system. Exerts effects opposite if insulin
Somatostatin (?)
Controls the rate of entry of nutrient molecules into circulation in the GI tract
Insulin receptor
Glute 4 channels open. Once the insulin gets in it tells the glute 4 channels to open to increase glucose level
Testosterone
Released from testes promotes protein synthesis. Anabolic steroid. Androgenic.
Anabolic steroid
Promotes tissue (muscle) building. Performance enhancement
Androgenic steriod
Promotes masculine characteristics
Estrogen and progesterone
Released from ovaries. Establish and maintain reproductive function. Levels vary throughout the menstrual cycle
Follicular phase
When follicles in the ovary mature. Ends with ovulation
Luteal phase
After ovulation when the lining of the uterus thickens
How to use fuel
Largely dependent upon duration and intensity. Strenuous Exercise = CHO oxidation. Prolonged, Moderate Exercise = Fat oxidation, as CHO are depleted.
Muscle glycogen utilization
The heavier the exercise the faster glycogen breakdown occurs. This breakdown is initiated by second messengers, which activate protein kinases in the muscle cell. Plasma epinephrine is a powerful stimulator of glycogenolysis (breaking down glycogen into
Glycogen utilization
high intensity reduces glucagon quickly. Epi increase glycogen is increasing. When a drug blocks the ? receptors, glycogenolysis can still occur. Glycogen to glycolysis doesn't use ATP. Glucose to G6P, hexokinase (transferase)
Blood glucose homeostasis during exercise
Plasma glucose concentrations are maintained by 4 main processes. THE BODY WANTS TO SPARE BLOOD GLUCOSE...IT DOES NOT WANT TO USE. THIS FUEL SOURCE. Hormonal control of blood glucose acts in 2 ways (slow acting and fast acting)
mobilization glucose
from liver glycogen to maintain plasma glucose levels
mobilizing plasma FFa
from adipose tissue to spare plasma glucose
synthesizing new glucose
in the liver from amino acids, lactate, and glycerol
blocking glucose entry
into cells to force the substitution of FFA as fuel and thus spare glucose
Slow acting
Thyroid hormone. Cortisol . Growth hormone. Slow acting are slow because they need to penetrate the cell membrane and enter the nucleus of the cell
Fast acting
Epinephrine and norepinephrine. Insulin and glucagon. Fast acting only have to attach to the cell membrane to initiate their effect
Thyroid hormone
T3 & T4 are important for establishing the overall metabolic rate and allow other hormones to exert their full effect . They influence the # of receptors on the surface of a cell or the affinity of the receptor for the hormone (What is this called? Up reg
Cortisol "stress hormone
Released when there is low plasma [glucose]. Stimulates FFA mobilization from adipose tissue. Mobilizes tissue protein to yield amino acids for glucose synthesis in the liver. Decreases the rate of glucose utilization by cells. Light Ex = cortisol is remo
Growth hormone supports the action of cortisol
wants to preserve plasma glucose. Protein synthesis. Decreases glucose uptake by tissues. Increases FFA mobilization. Enhances gluconeogenesis in the liver
Norepinepherine
plasma levels are indicative of sympathetic nervous system activity
Epinephrine
primary catecholamine in mobilization of glucose from the liver, and FFA from adipose tissue
Epinephrine and norepinephrine
1. Mobilization of glucose from the liver
2. Mobilization of FFA from adipose tissue
3. Interference with the uptake of glucose by tissues
Insulin
Uptake and storage of glucose and FFA. Plasma concentration decreases during exercise. Decreased insulin response following training. secretion influenced by catecholamine
Glucagon
Mobilization of glucose and FFA fuels. Plasma concentration increases during exercise. Decreased response following training. secretion influenced by catecholamine