Endocrine system Chapter 13

Objectives: Describe the vital function of the endocrine system State the description and primary functions of the organs and structures of the endocrine system Identify some of the hormones produced Identify medical words Introduce and review Root words, prefixes and suffixes in the endocrine system

Contd: Endocrinology is the study of the endocrine system Endocrinologist is a physician who specializes in the medical practice of endocrinology

Anatomy and Physiology: the endocrine system influences almost every cell, organ, and function of our bodies. It is instrumental in regulating mood, growth and development, tissue function, metabolism, and sexual function and reproductive processes.

Contd: The vital function of the endocrine system involves the production and regulation of chemical substances called Hormones The word hormone is derived from the Greek language Means to excite or urge on

Contd: The foundations of the endocrine system are the hormones and glands. hormones transfer information and instructions from one set of cells to another. Each type of hormone is designed to affect only certain cells.

Contd: Hyposecretion or hypersecretion of specific hormones can cause or be associated with many pathological conditions. Too much or too little of any hormones can be harmful to the body Controlling the production of or replacing specific hormones can treat many hormonal conditions

Parts of the Endocrine System: The major glands that make up the human endocrine system are: the hypothalamus, pituitary, thyroid, parathyroid's, adrenals, pineal body, and the reproductive glands, which include the ovaries and testes.

Glands: The Hypothalamus a collection of specialized cells that is located in the lower central part of the brain is the primary link between the endocrine and nervous systems. The hypothalamus controls the pituitary gland by producing chemicals that either stimulate or suppress hormone secretions from the pituitary.

The Pituitary Gland: it is no bigger than a pea located at the base of the brain just beneath the hypothalamus is considered the most important part of the endocrine system It's often called the "master gland" because it makes hormones that control several other endocrine glands.

Contd: The tiny pituitary gland is divided into two parts: the anterior lobe and the posterior lobe. The anterior lobe regulates the activity of the thyroid, adrenals, and reproductive glands. also secretes endorphins, chemicals that act on the nervous system to reduce sensitivity to pain.

Contd: The anterior lobe also secretes hormones that signal the ovaries and testes to make sex hormones. also controls ovulation and the menstrual cycle in women.

Contd: The posterior lobe of the pituitary releases antidiuretic hormone, which helps control body water balance through its effect on the kidneys and urine output; Also releases oxytocin, which triggers the contractions of the uterus that occur during labor.

The Pineal Gland: is located in the middle of the brain. It secretes melatonin, a hormone that may help regulate the wake-sleep cycle. Cone shaped structure attached by a stalk to the posterior wall of the cerebrum

The Thyroid: located in the front part of the lower neck is shaped like a bow tie or butterfly produces thyroid hormones These hormones (thyroxine and triiodothyronine) control the rate at which cells burn fuels from food to produce energy.

Contd: Thyroid hormones also play a key role in bone growth and the development of the brain and nervous system in children. The production and release of thyroid hormones is controlled by thyrotropin, which is secreted by the pituitary gland.

Parathyroid: Are four tiny glands attached to the thyroid that function together They release parathyroid hormone, which regulates the level of calcium in the blood with the help of calcitonin, which is produced in the thyroid.

Pancreas: The pancreas produces (in addition to others) two important hormones, insulin and glucagon. They work together to maintain a steady level of glucose, or sugar, in the blood to help maintain and store energy Composed of three major types of cells: alpha, beta and delta See page 447 of your text for each function

The Adrenal Glands: The body has two triangular adrenal glands, one on top of each kidney. The adrenal glands have two parts, each of which produces a set of hormones and has a different function.

Contd: The outer part, the adrenal cortex, produces hormones called corticosteroids that influence or regulate salt and water balance in the body Also influences the body's response to stress, metabolism, the immune system, and sexual development and function.

Contd: The inner part, the adrenal medulla, produces catecholamines, such as epinephrine. Also called adrenaline, epinephrine It increases blood pressure and heart rate when the body experiences stress.

Gonads: The gonads are the main source of sex hormones. In males, they are located in the scrotum. Male gonads, or testes, secrete hormones called androgens, the most important of which is testosterone. These hormones regulate body changes associated with sexual development. Working with hormones from the pituitary gland, testosterone also supports the production of sperm by the testes.

Contd: The female gonads, the ovaries, are located in the pelvis. They produce eggs and secrete the female hormones estrogen and progesterone. Estrogen is involved in the development of female sexual features. Both estrogen and progesterone are also involved in pregnancy and the regulation of the menstrual cycle.

Thymus: is an organ located in the upper anterior portion of the chest cavity just behind the sternum. The main function of the thymus is to provide an area for T cell maturation, and is vital in protecting against autoimmunity.

Abbreviations: ADA American diabetes Association BMR Basal metabolic rate DI Diabetes insipidus DM Diabetes mellitus FBS Fasting blood sugar GTT Glucose tolerance test

Contd: IDDM Insulin-dependant diabetes mellitus (Type I) NIDDM Non –insulin dependent diabetes mellitus (Type 2) PRL Prolactin

Adenectomy Aden gland -ectomy surgical excision Surgical excision of a gland