The Endocrine System
A system of glands that secrete hormones into the blood stream to regulate a variety of bodily function
-Control of mood, growth and development, tissue function, metabolism
Endocrine System Dynamics
Consists of host organs (glands), chemical messengers (hormones), and target (receptor) cells
Hormone Secreted from Gland
Travels through the bloodstream to target cells designed to receive its message
Endocrine Glands
-Hypothalamus, pituitary, thyroid, and adrenal glands
Pituitary Gland
Master Gland because it controls the functions of all other endocrine glands
3 Sections of Pituitary Gland
Anterior, intermediate, posterior lobes
-Each lobe secretes specific types of hormones
Anterior Lobe Hormones (6)
- Growth Hormone
- Prolactin
- Adrenocorticotropic Hormone (ACTH)
- Thyroid-Stimulating Hormone (TSH)
- Follicle-Stimulating Hormone (FSH)
- Luteinizing Hormone (LH)
Intermediate Lobe Hormone
Melanocyte-Stimulating Hormone
Posterior Lobe Hormones (2)
- Antidiuretic Hormone (ADH)
- Oxytocin
Prolactin Function
Stimulate milk production after giving birth
ACTH Function
Stimulates the adrenal glads
TSH Function
Stimulates the thyroid gland
FSH Function
Stimulates testes and ovaries
LH Function
Stimulates ovaries or testes
Melanocyte-Stimulating Hormone Function
Control skin pigmentation
ADH Function
Increase absorption of water into the blood by the kidneys
Oxytocin Function
Contracts the uterus during childbirth and stimulate milk production
Thyroid Gland Function
Produces hormones that regulate metabolism and affect the growth and rate of function of many other systems in the body
Adrenal Glands Function
Secrete hormones such as corticosteroids and catecholamines, including cortisol and adrenaline in response to stress
Hypothalamus and Pituitary Gland
Represent an important link between the nervous and endocrine systems
Blood Glucose
Carbs, specifically glucose, is the primary energy source during vigorous exercise and principal fuel for the brain
Control of Blood Glucose
Regulated by pancreas, which produces two specific hormones: Insulin and Glucagon
Insulin Trigger of Release
Released by elevated levels of glucose in the blood (eating a meal)
Circulating Insulin in Blood
Binds with receptors of its target cells making cell more permeable to glucose
-Glucose then diffuses out of blood and into cell leading to a drop of blood glucose levels
Insulin Result
Causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle
Glucagon Effects
Opposite to that of insulin, as it functions to raise blood glucose levels by triggering the release of glycogen stores from the liver back into glucose
Glucagon Trigger of Release
Drop in circulating blood glucose levels (Hours after a meal or physical activity)
Exercise and Control of Blood Glucose
As activity levels increase, glucose uptake by the body’s cell also increase due to an increased sensitivity of the cells to insulin, thus leading to a drop of insulin levels during physical activity
Catecholamines
Epinephrine (adrenaline) and norepinephrine are produced by the adrenal glands atop the kidneys
Catecholamines Function
Prepare the body for activity (fight or flight response)
Testosterone Production
Produced in the testes of males and in small amount in the ovaries and adrenal glands of females
Testosterone Functions
The development of male secondary sexual characteristics such as facial and body hair and greater muscle mass
-Large role in growth and repair of tissues
Estrogen Production
In the ovaries of females and small amounts in the adrenal glands of males
Estrogen Function
- Give rise of female secondary sexual characteristics such as breast development and regulation of menstrual cycle
- Large influence on fat deposition around hips, buttocks, and thighs
Cortisol
Associated with tissue breakdown, referred to as a catabolic hormone
Cortisol Secretion
Secreted by adrenal glands under times of stress
Cortisol Function
Serves to maintain energy supply through the breakdown of carbs, fats, and proteins
High Levels of Cortisol
Brought about through overtraining, excessive stress, poor sleep, and inadequate nutrition can lead to significant breakdown of muscle tissue and other potentially harmful side effects
Growth Hormone Location of Release
Released from pituitary gland in brain and is regulated by hypothalamus
Growth Hormone Stimulus of Release
Estrogen, Testosterone, deep sleep, and vigorous exercise
GH Functions
Anabolic hormone responsible for most growth and development during childhood
-Also increases development of bone, muscle tissue, protein synthesis, fat burning, and strengthens immune system
Thyroid Hormones Area of Release
Released from thyroid gland regulated by the pituitary gland
Thyroid Hormones Function
Carb, protein, and fat metabolism, basal metabolic rate, protein synthesis, sensitivity to epinephrine, heart rate, breathing rate, and body temperature.
Hormones and Effects of Exercise
- Testosterone and GH levels increase after traingin
- Cortisol is indicative of overtraining