2. NEUROENDOCRINOLOGY
ā¢ The two major homeostatic systems involved in the control
and regulation of various functions are the nervous and
endocrine system
ā¢ These two systems often work together to maintain
homeostasis this is called neuroendocrine response
ā¢ Endocrine glands release hormones directly into the blood
ā¢ Hormones alter the activity of tissues that possess receptors
to which the hormone can bind
ā¢ The plasma hormone concentration determines the magnitude
of the effect at the tissue level
3. BLOOD HORMONE
CONCENTRATION
Determined by:
ā¢ Rate of secretion of hormone from endocrine
gland
ā¢ Rate of metabolism or excretion of hormone
ā¢ Quantity of transport protein
ā¢ Changes in plasma volume
4. CONTROL OF HORMONE
SECRETION
ā¢ Rate at which a hormone is secreted from and
endocrine gland is dependent on
ļ§ Magnitude of input
ļ§ Stimulatory vs. inhibitory
ļ e.g., Rate of insulin secretion from the pancreas
5. HORMONE-RECEPTOR
INTERACTIONS
ā¢ Trigger events at the cell
ā¢ Magnitude of effect dependent on:
ā¢ Concentration of the hormone
ā¢ Number of receptors on the cell
ā¢ Affinity of the receptor for the hormone
6. HORMONE-RECEPTOR
INTERACTIONS
ā¢ Hormones bring about effects by:
ā¢ Altering membrane transport
ā¢ Stimulating DNA to increase protein synthesis
ā¢ Activating second messengers
ā¢ Cyclic AMP
ā¢ Ca++
ā¢ Inositol triphosphate
ā¢ Diacylglycerol
9. HORMONES:
REGULATION AND ACTION
ā¢ Hormones which are secreted from endocrine glands
ā¢ Hypothalamus and pituitary glands
ā¢ Thyroid and parathyroid glands
ā¢ Adrenal glands
ā¢ Pancreas
ā¢ Testes and ovaries
11. GROWTH HORMONE
ā¢ Secreted from the anterior pituitary gland
ā¢ Essential for normal growth
ā¢ Stimulates protein synthesis and long
bone growth
ā¢ Increases during exercise
ā¢ Mobilizes fatty acids from adipose tissue
ā¢ Aids in the maintenance of blood glucose
12. POSTERIOR PITUITARY GLAND
ā¢ Secretes oxytocin and antidiuretic hormone (ADH) or vasopressin
ā¢ Reduces water loss from the body to maintain plasma volume
ā¢ Stimulated by:
ā¢ High plasma osmolality and low plasma volume due to
sweating
ā¢ Exercise
13. CHANGE IN THE PLASMAADH
CONCENTRATION DURING EXERCISE
14. THYROID GLAND
ā¢ Triiodothyronine (T3) and thyroxin (T4)
ā¢ Important in maintaining metabolic rate and allowing
full effect of other hormones
ā¢ Calcitonin
ā¢ Regulation of plasma Ca++
ā¢ Parathyroid Hormone
ā¢ Also involved in plasma Ca++
regulation
15. PARATHYROID GLAND
ā¢ Parathyroid gland releases parathyroid hormone in response to low
plasma Ca++ concentration
ā¢ Hormone stimulates bone to release calcium into plasma
ā¢ It also increases the renal absorption of Ca++
ā¢ It stimulates the kidney to convert a form of vitamin D ( D3) into a
hormone that increases absorption of Ca++ from GIT tract
19. ADRENAL CORTEX
ā¢ Sex steroids ( androgens and estrogens)
ļ§ Supports prepubescent growth
ļ§ Androgens being associated with post
pubescent sex drive in women
20. PANCREAS
ā¢ Secretes digestive enzymes and bicarbonate into small intestine
ā¢ Releases
ā¢ Insulin - Promotes the storage of glucose, amino acids, and
fats
ā¢ Glucagon - Promotes the mobilization of fatty acids and
glucose
ā¢ Somatostatin - Controls rate of entry of nutrients into the
circulation
23. ESTROGEN
ā¢ Group of hormones it includes estradiol,
estrone and estriol
ā¢ Establish and maintain reproductive function
ā¢ Levels vary throughout the menstrual cycle
25. MUSCLE GLYCOGEN
UTILIZATION
ā¢ Breakdown of muscle glycogen is under dual control
ā¢ Epinephrine-cyclic AMP
ā¢ Ca2+-calmodulin
ā¢ Delivery of glucose parallels activation of
muscle contraction
ā¢ Glycogenolysis ā breakdown of glycogen
26. MUSCLE GLYCOGEN
UTILIZATION
ā¢ Glycogenolysis is related to exercise intensity
ā¢ High-intensity of exercise results in greater and
more rapid glycogen depletion
ā¢ Plasma epinephrine is a powerful simulator of
glycogenolysis
ā¢ High-intensity of exercise results in greater
increases in plasma epinephrine
27. MAINTENANCE OF PLASMA
GLUCOSE DURING EXERCISE
ā¢ Mobilization of glucose from liver glycogen
stores
ā¢ Mobilization of FFA from adipose tissue
ā¢ Spares blood glucose
ā¢ Gluconeogenesis from amino acids, lactic acid,
and glycerol
ā¢ Blocking the entry of glucose into cells
ā¢ Forces use of FFA as a fuel
28. BLOOD GLUCOSE HOMEOSTASIS
DURING EXERCISE
ā¢ Permissive and slow-acting hormones
ā¢ Thyroxin
ā¢ Cortisol
ā¢ Growth hormone
ā¢ Act in a permissive manner to support
actions of other hormones
29. CORTISOL
ā¢ Stimulates FFA mobilization from adipose
tissue
ā¢ Mobilizes amino acids for gluconeogenesis
ā¢ Blocks entry of glucose into cells
30. PLASMA CORTISOL DURING EXERCISE
ā¢ At low intensity
ā¢ plasma cortisol decreases
ā¢ At high intensity
ā¢ plasma cortisol increases
31. GROWTH HORMONE
ā¢ Important in the maintenance of plasma
glucose
ā¢ Decreases glucose uptake
ā¢ Increases FFA mobilization
ā¢ Enhances gluconeogenesis
32. BLOOD GLUCOSE HOMEOSTASIS
DURING EXERCISE
ā¢ Fast-acting hormones
ā¢ Norepinephrine and epinephrine
ā¢ Insulin and glucagon
ā¢ Maintain plasma glucose
ā¢ Increasing liver glucose mobilization
ā¢ Increased levels of plasma FFA
ā¢ Decreasing glucose uptake
ā¢ Increasing gluconeogenesis
33. EPINEPHRINE & NOREPINEPHRINE
DURING EXERCISE
ā¢Increase linearly during exercise
ā¢Favor the mobilization of FFA and
maintenance of plasma glucose
35. EPINEPHRINE & NOREPINEPHRINE
FOLLOWING TRAINING
ā¢ Decreased plasma levels in response to
exercise bout
ā¢ Parallels reduction in glucose mobilization
36. INSULIN DURING EXERCISE
ā¢ Plasma insulin decreases during exercise
ā¢ Prevents rapid uptake of plasma glucose
ā¢ Favors mobilization of liver glucose and lipid FFA
ā¢ Trained subjects during exercise
ā¢ More rapid decrease in plasma insulin
ā¢ Increase in plasma glucagon
37. FREE FATTY ACID MOBILIZATION
DURING HEAVY EXERCISE
ā¢ FFA mobilization decreases during heavy exercise
ā¢ This occurs in spite of persisting hormonal
stimulation for FFA mobilization
ā¢ May be due to high levels of lactic acid
ā¢ Promotes resynthesis of triglycerides
ā¢ Inadequate blood flow to adipose tissue
ā¢ Insufficient transporter for FFA in plasma
