Endocrine-Lecture.pdf

1 Endocrine System Joseph Peter V. Arguillas, MD © 2019 McGraw-Hill Education  2...

1 Endocrine System Joseph Peter V. Arguillas, MD © 2019 McGraw-Hill Education  2 Endocrine System Glands Figure 10.1 © 2019 McGraw-Hill Education  3 Chemical Messengers Are hormones that allows the cells to communicate with each other to regulate body activities. Four classes: Autocrine, Paracrine, Neurotransmitter, and Endocrine Endocrine chemical messengers are called HORMONES © 2019 McGraw-Hill Education  4 Cell Secretion Types 1 Autocrine Secreted by cells in local effect area and influences the activity of the same cell. Example - eicosanoids Paracrine Produced by a wide variety of tissues and secreted in ECF Example – somatostatin, histamine © 2019 McGraw-Hill Education  5 Cell Secretion Types Neurotransmitter produced by neuron, secreted in the synaptic cleft that activate adjacent cell Example – Acetylcholine, Epinephrine Endocrine secreted into blood and bind to receptor sites Example - epinephrine and insulin, estrogen, GH, testosterone, and estrogen © 2019 McGraw-Hill Education  6 Endocrine System Functions 1 Metabolism Control of food intake and digestion Tissue development Ion regulation Water balance © 2019 McGraw-Hill Education  7 Endocrine System Functions 2 Heart rate and blood pressure regulation Control of blood glucose and other nutrients Control of Reproductive functions Uterine contraction and milk release Immune System regulation © 2019 McGraw-Hill Education  8 Endocrine System composed of endocrine glands and specialized endocrine cells located throughout the body. Endocrine glands and cells secretes chemical messengers called hormones into the bloodstream or blood circulation to target tissues or effectors. © 2019 McGraw-Hill Education  9 Types of Hormones Water-soluble hormones: includes proteins, peptides, amino acids most common, can dissolve in blood Examples - growth hormone, antidiuretic, prolactin Lipid-soluble hormones: includes steroids and eicosanoids Examples - LH, FSH, androgens © 2019 McGraw-Hill Education  10 Regulation of Hormone Levels Negative Feedback mechanism the hormone’s secretion is inhibited by the hormone itself once blood levels have reached a certain point. Positive Feedback mechanism hormones are regulated as exemplified by tropic hormone action. The response to the stimulus does not stop or reverse the stimulus, but instead keeps the sequence of event going. © 2019 McGraw-Hill Education  11 Negative and Positive Feedback Figure 10.5 © 2019 McGraw-Hill Education  12 Classification of HORMONES 1. AMINES Structural variations of the amino acids tyrosine, thyroxine and epinephrine norepinephrine. 2. PROTEINS Are chains of amino acids Insulin, growth hormones, and calcitonin. © 2019 McGraw-Hill Education  13 STEROIDS Includes cortisol, and aldosterone, estrogen and progesterone, and testosterone. © 2019 McGraw-Hill Education  14 HYPOTHALAMUS superior to the pituitary gland and inferior to the thalamus regulates the secretions of hormones of the pituitary gland © 2019 McGraw-Hill Education  15 Pituitary Gland Small gland in brain Controlled by hypothalamus Divided into 2 regions: Anterior and Posterior Secretes at least 8 hormones © 2019 McGraw-Hill Education  16 Pituitary Gland 2 Figure 10.12 © 2019 McGraw-Hill Education  17 Anterior Pituitary Hormones 1 Growth Hormone Target tissues: most stimulates growth of bones, muscles, and organs Stimulate cells to produce insulin like growth factors Increase the rate of CHON synthesis increases the use of fats as energy metabolism. © 2019 McGraw-Hill Education  18 Growth Hormone It increases blood glucose levels by reducing glucose utilization (insulin antagonist) Abnormalities Too much GH causes gigantism Too little GH causes pituitary dwarfism © 2019 McGraw-Hill Education  19 Anterior Pituitary Hormones 5 Prolactin AKA mammotropic hormone, lactotropic hormone Target tissues: mammary glands and ovaries Functions: milk production It is necessary for breast development and lactation © 2019 McGraw-Hill Education  20 Prolactin Releasing Hormone (PRH) stimulate the secretion from the hypothalamus. Prolactin Inhibiting Hormone inhibits the secretion from the hypothalamus © 2019 McGraw-Hill Education  21 Anterior Pituitary Hormones Thyroid-Stimulating Hormone (TSH) AKA thyrotropin Target tissues: thyroid gland Functions: regulates thyroid gland secretions Thyroxine (T4) and thriodothyronine T3 by the TG Thyrotropin releasing hormone - triggers the pituitary gland to release TSH. © 2019 McGraw-Hill Education  22 Abnormalities: Too much TSH, thyroid gland enlarges Too little TSH, thyroid gland shrinks © 2019 McGraw-Hill Education  23 Regulation of Thyroid Hormone Secretion Figure 10.16 © 2019 McGraw-Hill Education  24 Gonadotrophin Hormone LH (Luteinizing) for females Target tissue: ovaries Function: promotes ovulation and progesterone production LH for males Target tissue: testes Function: sperm production and testosterone © 2019 McGraw-Hill Education  25 Anterior Pituitary Hormones 4 Gonadotrophin Hormone Follicle-Stimulating for females Target tissue: follicles in ovaries Function: follicle maturation and estrogen secretion FSH for males Target tissue: seminiferous tubules (testes) Function: sperm production © 2019 McGraw-Hill Education  26 Anterior Pituitary Hormones 6 Melanocyte Stimulating Hormone (MSH) Target tissues: melanocytes in the skin Functions: stimulate melanin production in melanocytes to make skin darker Adrenocorticotrophic Hormone (ACTH): Target tissues: cells of adrenal cortex Functions: stimulate production of certain corticosteroids © 2019 McGraw-Hill Education  27 ANTERIOR PITUITARY GLAND 1. Growth Hormone 2. Thyroid-Stimulating Hormone (TSH) 3. Gonadotropin Hormone LH FSH 4. Prolactin 5. Melanocyte Stimulating Hormone 6. Adrenocorticotrophic Hormone (ACTH) © 2019 McGraw-Hill Education  28 Posterior Pituitary synthesizes and releases hormones produced by neuroendocrine cells in the hypothalamus. Antidiuretic hormone (ADH) and Oxytocin. © 2019 McGraw-Hill Education  29 PPG Hormones 1. Antidiuretic Hormone (ADH) AKA VASOPRESSIN Target tissues: KIDNEYS Functions: conserve water, decreases sweating, urinary output is decrease VASOCONSTRICTION in arterioles to raise or maintain BP © 2019 McGraw-Hill Education  30 Abnormalities: Diabetes Insipidus Low ADH production kidneys produce large amounts of dilute (watery) urine can lead to dehydration and thirst © 2019 McGraw-Hill Education  31 Posterior Gland Hormones 2 Oxytocin Target tissues: Uterus Cause contraction of myometrium of the uterus during labor has begun. Stimulus: nerve impulses from the hypothalamus as cervix is stretched and as infants suck the nipple © 2019 McGraw-Hill Education  32 Hypothalamus and Posterior Pituitary Figure 10.14 © 2019 McGraw-Hill Education  33 Thyroid Gland One of largest glands located in front and on the side of the trachea just below the larynx. Requires iodine to function Secretes Thyroid hormone and Calcitonin © 2019 McGraw-Hill Education  34 Thyroid hormones secreted by follicular cells produces T3 and T4 Target tissues: most regulates metabolic rates and is needed for growth Regulate CHON, CHO and fat metabolism Necessary for normal physical, mental and sexual development. Act as insulin antagonist © 2019 McGraw-Hill Education  35 Calcitonin secreted or produced by parafollicular cells Target tissues: bone and some other tissues reduces blood calcium level when high It inhibits osteoclastic activity It lowers phosphate levels It helps maintain stable and strong bones matrix. High Calcitonin- Low Calcium Low Calcitonin- High Calcium © 2019 McGraw-Hill Education  36 Thyroid Hormone Disorders Hypothyroidism: Hyperthyroidism: Decreased metabolism Increased metabolism Weight gain, reduced Weight loss, increased appetite, fatigue appetite, nervousness Low temp. and pulse Higher temp. and pulse Dry, cold skin Warm, flushed skin Myxedema in adults Graves’ disease (leads to goiter) Cretinism in infants © 2019 McGraw-Hill Education  37 Parathyroid Gland Parathyroid hormone (PTH) Target tissues: bones and kidneys Functions: regulates blood Ca2+ levels (more than calcitonin) If Ca 2+ is low then osteoclasts break down bone matrix and less Ca 2+ is lost in urine. If Ca 2+ is high then osteoclasts don’t break down bone matrix and more Ca 2+ is lost in urine. © 2019 McGraw-Hill Education  38 Regulation of Blood Calcium Levels Figure 10.17 © 2019 McGraw-Hill Education  39 Thyroid Gland and Parathyroid Glands Figure 10.15 © 2019 McGraw-Hill Education (d) ©Victor Eroschenko  40 Adrenal Glands two small glands located superior to each kidney Each adrenal gland has an inner part, called the adrenal medulla, and an outer part, called the adrenal cortex. The adrenal medulla and the adrenal cortex function as separate endocrine glands. © 2019 McGraw-Hill Education  41 Adrenal Glands Figure 10.18 © 2019 McGraw-Hill Education (c) ©Victor Eroschenko  42 Adrenal Gland Hormones 1 Adrenal medulla hormones: Epinephrine/Norepinephrine: Target tissues: heart, blood vessels, liver, fat cells Functions: released as part of fight or flight response © 2019 McGraw-Hill Education  43 Regulation of Adrenal Medullary Secretions Figure 10.19 © 2019 McGraw-Hill Education  44 Adrenal Gland Hormones 2 Adrenal cortex hormone Aldosterone Type of mineralocorticoids Target tissues: kidneys Causes Na+ and H2O to be retained and K+ to be secreted, indirectly involved with blood pressure and blood volume © 2019 McGraw-Hill Education  45 Regulation of Aldosterone Secretion Figure 10.20 © 2019 McGraw-Hill Education  46 Adrenal Gland Hormones 3 Cortisol: Type of glucocorticoids Target tissues: most Functions: increases breakdown of fat and protein for energy uses reduces inflammatory and immune responses © 2019 McGraw-Hill Education  47 © 2019 McGraw-Hill Education  48 © 2019 McGraw-Hill Education  49 Regulation of Cortisol Secretion Figure 10.21 © 2019 McGraw-Hill Education  50 Adrenal Gland Hormones 4 Androgens: Target tissues: most Functions: Males: secondary sexual characteristics Females: sex drive © 2019 McGraw-Hill Education  51 Pancreas is a mixed gland, with an exocrine portion and an endocrine portion. The exocrine portion of the pancreas secretes digestive enzymes. The endocrine part of the pancreas consists of pancreatic islets (islets of Langerhans), which are dispersed throughout the exocrine portion of the pancreas. © 2019 McGraw-Hill Education  52 Pancreas The islets consist of three cell types, each of which secretes a separate hormone. Alpha cells secrete glucagon Beta cells secrete insulin Delta cells secrete somatostatin. These three hormones regulate the blood levels of nutrients, especially glucose © 2019 McGraw-Hill Education  53 Pancreas Structure Figure 10.22 © 2019 McGraw-Hill Education ©Biophoto Associates/Science Source  54 Pancreas Hormones 1 Insulin Target tissues: liver, skeletal muscle, adipose tissue Functions regulates blood glucose levels after a meal glucose levels are high and insulin is secreted extra glucose is stored in form of glycogen © 2019 McGraw-Hill Education  55 Insulin Abnormalities Diabetes mellitus: Causes: too little insulin or faulty insulin receptors Symptoms: exaggerated appetite, excess urine, dehydration, thirst, fatigue Type I: insulin dependent (daily injections required) Type II: insulin independent, often found in obese people, can be treated with diet but can turn into type I © 2019 McGraw-Hill Education  56 Pancreas Hormones 2 Glucagon Target tissues: liver Function: regulates blood glucose levels between meals glucose levels drop and glucagon is secreted glucagon allows glycogen to be broken down into glucose © 2019 McGraw-Hill Education  57 Regulation of Blood Glucose Levels Figure 10.23 © 2019 McGraw-Hill Education  58 Testes Hormone Testosterone Target tissues: most Functions: Produced by interstitial cells Promotes maturation of sperm Stimulates the development of secondary sex characteristics Promotes the closure of epiphysis of long bones © 2019 McGraw-Hill Education  59 Ovarian Hormones Estrogen/Progesterone: Target tissues: most Functions: involved in uterine and mammary gland development and menstrual cycle © 2019 McGraw-Hill Education  60 Thymus Gland Hormone Thymosin: Target tissues: immune system tissues Functions: promotes immune system development and function © 2019 McGraw-Hill Education  61 Pineal Gland Hormone Melatonin: Target tissues: hypothalamus Functions: plays a role in onset of puberty controls circadian rhythms. Light affects its function. © 2019 McGraw-Hill Education  62 © 2019 McGraw-Hill Education