Mihee Yeom - Oil on Canvas
The Endocrine System
This system is comprised of hormones (chemicals) that are secreted and then circulated by the blood into the body. All organs of the endocrine system are ductless glands, unlike exocrine glands, like sweat and saliva glands, that have ducts. Hormones are the main regulators of metabolism, growth and development, reproduction, and play important roles in homeostasis, balancing fluid and electrolytes for example. Endocrine glands secrete hormones that bind to a target organ cell that has specific receptors for that hormone. The two major classes of hormones, protein hormones and steroid hormones, differ in the mechanisms by which they influence target organ cells. Protein hormones serve as first messengers, providing communication between endocrine glands and target organs. Steroid hormones, like estrogen, pass directly through the cell membrane of the target organ and through a complex process, form a new protein that produces specific effects in the target cell.
Prostaglandins or tissue hormones, are found in a wide variety of body tissue, and influence many body functions, including respiration, blood pressure, gastrointestinal secretions, and reproduction.
The pituitary gland, although no larger than a pea, is a very important structure of the endocrine system. It’s actually two glands, the anterior pituitary gland and the posterior pituitary gland. This gland lies deep within the skull. The anterior pituitary gland is also called the master gland because it exerts control over the structure and function of the thyroid gland, the adrenal cortex, the ovarian follicles, and the corpus luteum (a glandular structure transformed after ovulation). The posterior pituitary gland releases two hormones, one responsible for water reabsorption in the kidney back into the blood, the other a hormone secreted by a woman before and after she has a child. Actual production of these two hormones occurs in the hypothalamus, which plays an important role in the regulation of many body functions, including regulation of body temperature, appetite, and thirst.
The thyroid gland secretes two thyroid hormones whose primary role is to stimulate cellular metabolism. The parathyroid gland regulates the concentration of calcium in the blood.
The adrenal glands have many important functions, including the secretion of sex hormones, and the maintenance of normal blood glucose concentrations and blood pressure.
The thymus gland plays an important role in the development and function of the body’s immune system.
A woman’s two ovaries are her female sex glands which include the ovarian follicles and the corpus luteum. Ovarian follicles secrete estrogen; the corpus lutem secretes mostly progesterone.
The cells in the testes, or testicles, secrete the male sex hormone testorsterone.
The pineal gland, located in the brain, produces a number of hormones in very small quantities, with melatonin being the most significant. Melatonin is believed to be involved in regulating the onset of puberty and the menstrual cycle in women. The pineal gland also uses information regarding changing light levels to adjust its output of melatonin
More...
|
The Skeletal System The Muscular System The Nervous System The Digestive System The Respiratory System |
The Endocrine System The Lymphatic System The Urinary System The Reproductive System |
Back to the Body Art Project
