Endocrine System G10 PDF

Endocrine 03 System  Glands - A gland is an organ whose cells secrete materials to be brought to the different regions of the body via tube- like structures called ducts. - DUCTS: a bodily tube or vessel especially when carrying the secretion of a gland...

Endocrine 03 System  Glands - A gland is an organ whose cells secrete materials to be brought to the different regions of the body via tube- like structures called ducts. - DUCTS: a bodily tube or vessel especially when carrying the secretion of a gland.  Endocrine Glands - Endo means “within”, krinein means “separate” such as to secrete. - These are ductless glands that secrete hormones directly into either bloodstream or the fluid around the cells. - Organs like brain, stomach, small intestine, kidney, liver, and heart also secrete hormones.  Hormones - Hormones are chemical messengers, carrying instructions to cells to change their activities. - The effect of hormone can last for hours, days, weeks or even years - Hormones are produced by the glands of the endocrine system.  Hormones - Each hormone that a particular endocrine gland produces or secretes is very specific to a cell type that receives its instructions. - After a hormone is released from the cell in which it is made, it binds and acts only on a specific cell called target cells. - Each hormone acts like a key that opens a lock; it will act only on cells with the right “lock”, which is a receptor on the surface if the target cell or inside it. Hormones - Involved in coordinating the activities that the endocrine system carry out to keep the body functioning properly.  Hormones IMPORTANT CONCEPTS TO REMEMBER: 1. Some glands do not function until the organism reaches a certain age. 2. There is a difference between short-term and long-term hormones. 3. The production of each hormone must be the correct amount. 4. Hormones work only on their target cells or organs. 5. Hormones are destroyed in the liver after they have performed their function. Endocrine System - Coordinates all of the body’s sources of hormones. Pancreas - Both Endocrine and Exocrine glands  Major Endocrine Glands in the Body The Hypothalamus - Found at the base of the brain. - Produces hormones that help turn other endocrine glands in your body on and off. - The link between nervous system and endocrine system. - Secretes hormones that stimulate or suppress the release of the hormones in the pituitary gland.  Major Endocrine Glands in the Body The Pituitary Gland or hypophysis - A pea-sized gland found in the center of the skull, right behind the bridge of the nose and below the hypothalamus of the brain. - The hypothalamus is responsible for triggering the production of hormones by the pituitary gland. - For many years, pituitary was referred to as the “master gland” because the hormones it produces control many activities of the other endocrine glands. - Divided into ANTERIOR pituitary and POSTERIOR pituitary glands that secretes different hormones. Posterior and Anterior Pituitary Gland  Pituitary Gland PITUITARY HORMONES ACTION Anterior Pituitary Adrenocorticotropic hormone (ACTH) Stimulates the adrenal glands to produce related steroid hormones Growth hormone (GH) Stimulates the growth of bones and tissues Melanocyte Stimulating hormone (MSH) Regulates melanin production Thyroid Stimulating hormone (TSH) Stimulates the thyroid gland to produce thyroid hormone Follicle Stimulating hormone (FSH) and Controls sexual function and Luteinizing hormone (LH) production of sex hormones: estrogen and progesterone in females, or testosterone in males Prolactin Stimulates milk production in women  Pituitary Gland PITUITARY HORMONES ACTION Posterior Antidiuretic hormone (Vasopressin) Controls water loss in the kidneys Pituitary Oxytocin Stimulates milk production and contraction of the uterus during childbirth  Major Endocrine Glands in the Body The Thyroid Gland - Located just under the larynx or voice box. - Secretes three hormones: T3 (triiodothyronine), T4 (thyroxine), and calcitonin. - Thyroid hormones help in maintaining heart rate, blood pressure, muscle tone, and reproductive functions. - T3 and T4 contain the element iodine that regulates metabolism, development, and maturation.  The Thyroid Gland Hyperthyroidism - Excess amount of T3 (triiodothyronine), T4 (thyroxine) - Can develop high blood pressure, feel irritable, sweat profusely and lose weight.  The Thyroid Gland Hypothyroidism - Insufficient amount of T3 (triiodothyronine), T4 (thyroxine) in the body - Can cause weight gain, lethargy, and intolerance to cold. - Severe iodine deficiency in the diet can cause goiter in adults.  The Thyroid Gland Calcitonin - Lowers the blood calcium level in the body  Major Endocrine Glands in the Body The Parathyroid Gland - Are four tiny glands embedded in the surface of the thyroid. - These glands release the parathyroid hormone which, together with calcitonin regulates blood calcium levels in the body.  Major Endocrine Glands in the Body Thymus - Responsible for the development of the defense system of our body against disease-causing organisms. - Found just behind the breastbone. - At young age, thymus is very large, producing WBC that protect body tissues by triggering an immune response against infectious agents. - But gradually decreases in size as one gets older, it shrunk to about the size of the thumb.  Major Endocrine Glands in the Body Adrenals - Adrenals means “above kidney”. Each adrenal is located atop each of our kidneys. - Two parts: OUTER ADRENAL CORTEX AND INNER ADRENAL MEDULLA. - OUTER ADRENAL CORTEX: secretes corticosteroids which regulate the body’s metabolism, electrolyte balance, immune system, and long-term stress response. - INNER ADRENAL MEDULLA: produces ADRENALINE that plays a role in the body’s coping mechanism against short-term physical and emotional stress. Part of the body’s emergency action team.  Major Endocrine Glands in the Body The Pancreas - Produces two type of hormones: INSULIN and Glucagon.  Major Endocrine Glands in the Body The Pancreas (INSULIN) - produced by a small group of cells called islets of Langerhans. - Keeps the level of sugar in the bloodstream under control. - Help cells absorb sugar and turn into energy. - Help change excess sugar into glycogen to be stored in the liver. - Prevents level of sugar from rising too high. - Without enough insulin, a person can develop diabetes mellitus.  Major Endocrine Glands in the Body The Pancreas (GLUCAGON) - Increases the level of sugar in the body by speeding up the conversion of glycogen to sugar in the liver.  Major Endocrine Glands in the Body Gonads - Collective term of human reproductive organs. - Both testes and ovaries produce sex hormones responsible for the secondary sexual characteristics that develop at the start of our teenage years.  Major Endocrine Glands in the Body Gonads (Testes) - Produce androgen - Anterior Pituitary gland secretes Luteinizing Hormone (LH) to stimulate sex hormone testosterone and Follicle-stimulating Hormone (FSH), along with testosterone, stimulates sperm production in the seminiferous tubules. - Testosterone is produced by the cells located between the seminiferous tubules. - Testosterone is responsible for the development of characteristics during puberty such as deepening of the voice, growth of facial hair, broadening of the shoulders, and development of muscles.  Major Endocrine Glands in the Body Gonads (Ovaries) - Produce estrogen and progesterone - Estrogen and Progesterone control the development of breasts, menstruation, and fertility. - Female reproductive structures, such as the placenta and uterus, release other hormones during pregnancy and childbirth.  Major Endocrine Glands in the Body The Pineal Gland - Located near the thalamus of the brain, where the two halves of the brain join. - It produces melatonin, which regulates body rhythm and sleep patterns. - It synchronizes daily rhythms, times body systems, and help us adapt to seasonal change.