Endocrine System - Thyroid PDF

Endocrine system Presented by: Dr. Yasmine Gamal Sabry Lecturer in the physiology department, faculty of medicine, Ain Shams university 1  Thyroid Gland The thyroid gland secretes thyroid...

Endocrine system Presented by: Dr. Yasmine Gamal Sabry Lecturer in the physiology department, faculty of medicine, Ain Shams university 1  Thyroid Gland The thyroid gland secretes thyroid hormones. a- Thyroxin T4 By Follicular cells b- Triiodothyronine T3 c-Thyrocalcitonin (Ca lowering hormone) (by Parafollicular cells). 2  Thyroid hormones The two thyroid hormones (T3 & T4) contain Iodine T4 and T3 have a very similar structure as each is made up of two tyrosine amino acids linked together and either 4 or 3 atoms of iodine, respectively. 3 Transport and Regulation of Release  Functions of the Thyroid hormones: 1-Metabolic 3- Effect on body 2- Growth functions systems Physical A- Calorigenic B- Metabolic action processes Mental Sexual 6  1-Metabolic functions A- Calorigenic action Increase the size and number of mitochondria within the cells which leads to an increase in the rate of ATP formation. Increase Basal metabolic rate and energy consumption. 7  1-Metabolic functions B- Metabolic processes Carbohydrate Lipids Protein Increase Glucose level & Has a powerful At a normal level utilization in blood by lipolytic action on fat stimulate protein increasing glycolysis, stores, causing synthesis (Anabolic). glycogenolysis, and depletion of fat stores But high levels of thyroid gluconeogenesis and decrease in hormones causes protein weight. catabolism 8  3- Effect on body systems - Cardiovascular system: Increase in heart rate, and strength of contractility. Increased systolic blood pressure. - Respiratory system: Increase rate and depth of respiration - Gastrointestinal tract: Increase appetite, Increased food intake, Increased secretion and motility. - Bone marrow: Increase red blood cells synthesis. 11 Control of Thyroid Gland Function Negative feedback mechanisms Control the thyroid hormonal secretion 13 Control of Thyroid Gland Function Control of Thyroid Gland Function  Abnormalities of Thyroid H. secretion Hyperfunction Hypofunction Hyperthyroidism Before puberty After puberty (Grave’s disease) (Cretinism) (Myxedema) 16 Clinical Features Clinical Features Clinical Features Clinical Features  Anemia Treatment