350 likes | 570 Views
Outline. Endocrine Glands Pheromones Steroid Hormones Peptide Hormones Hypothalamus and Pituitary Gland Other Endocrine Glands and Hormones Thyroid Parathyroid Adrenal Pancreas Gonads. The Human Endocrine System. Chemical Signals. Pheromones
E N D
Outline • Endocrine Glands • Pheromones • Steroid Hormones • Peptide Hormones • Hypothalamus and Pituitary Gland • Other Endocrine Glands and Hormones • Thyroid • Parathyroid • Adrenal • Pancreas • Gonads
Chemical Signals • Pheromones • Chemical signals that work at a distance between individuals • A woman’s axillary extract can alter another woman’s menstrual cycle • Hormones • Chemical signals that work • At a distance between organs, or • Locally between adjacent cells
Action of Hormones • Hormones • Chemical signals produced by one cell that regulate the metabolism of other cells • Steroid Hormones • Can cross cell membranes • Peptide Hormones • Most bind to receptor in plasma membrane • First Messenger • Causes internal release of cAMP • Second Messenger
Human Endocrine System • Endocrine glands • Ductless glands that secrete hormones directly into the bloodstream • Most endocrine hormones are peptides • Only gonads and adrenal cortex produce steroid hormones • Effects of hormones are moderated in two ways • Negative feedback opposes release • Antagonistic hormones oppose each other’s actions
Hypothalamus and Pituitary Gland • Hypothalamus regulates internal environment • Acts through autonomic system • Also controls glandular secretions of pituitary gland • Posterior Pituitary • Antidiuretic Hormone (ADH) • Controlled by negative feedback • Oxytocin • Controlled by positive feedback • Anterior Pituitary • Hypothalamus controls by producing • Hypothalamic-releasing hormones, and • Hypothalamic-inhibiting hormones
Anterior Pituitary Hormones • Anterior pituitary hormones that affect other glands: • Thyroid-Stimulating Hormone (TSH) • Adrenocorticotropic Hormone (ACTH) • Gonadotropic Hormones • Anterior pituitary hormones that do NOT affect other glands • Prolactin (PRL) • Melanocyte-Stimulating Hormone (MSH) • Growth Hormone (GH)
Thyroid Glands • Composed of large number of follicles filled with • Triiodothyronine (T3), and • Thyroxine (T4) • Thyroid hormones increase metabolic rate • Thyroid-induced abnormalities • Simple goiter - Poor hormone production • Cretinism - Poor thyroid development • Myxedema - Hypothyroidism • Exophthalmic goiter - Hyperthyroidism
Calcitonin • Regulates blood calcium level (in part) • Secreted by thyroid gland when blood calcium level rises • Brings about deposit of calcium in the bones • Low calcium level in blood stimulates the release of parathyroid hormone (PTH) • Parathyroid hormone causes • Phosphate level in blood to decrease, and • Calcium level in blood to increase • Insufficient production of parathyroid hormone leads to tetany
Adrenal Glands • Paired – One sits atop each kidney (ad-renal) • Each consists of outer cortex and inner medulla • Inner portion, the adrenal medulla • Produces • Epinephrine, and • Norepinephrine • Short-term response to stress (fight or flight) • Outer portion, adrenal cortex • Produces • Mineralocorticoids, and • Glucocorticoids • Long-term response to stress
Glucocorticoids • Cortisol • Raises blood glucose level • Promotes breakdown of muscle proteins to amino acids • Promotes metabolism of fatty acids • Counteracts inflammatory response
Mineralocorticoids • Aldosterone • Promotes two renal functions: • Absorption of sodium, and • Excretion of potassium • Renin-angiotensin-aldosterone system • Raises blood pressure • Angiotensin II constricts arterioles • Aldosterone causes kidneys to reabsorb sodium (causing water retention) • Atrial natriuretic hormone (ANH) is antagonistic to aldosterone
Pancreas • Made up up exocrine and endocrine tissue • Endocrine Portion of the Pancreas: • Consists of pancreatic islets • Produce and secrete • Insulin • Secreted during high blood glucose level • Stimulates uptake of glucose by cells • Glucagon • Secreted during low blood glucose level • Stimulates liver to break down glycogen • Exocrine Portion of the Pancreas: • Secretes enzymes and buffers into intestine
Other Endocrine Glands • Gonads • Testes • Produce testosterone • Secondary sex characteristics • Ovaries • Produce estrogen and progesterone • Reproduction • Secondary sex characteristics
Other Endocrine Glands • Pineal Gland • Produces melatonin • Involved in Circadian rhythms • Thymus Gland • Secrete thymosins • Aid in differentiation of lymphocytes • Prostaglandins • Produced within cells • Not distributed in blood
Review • Endocrine Glands • Pheromones • Steroid Hormones • Peptide Hormones • Hypothalamus and Pituitary Gland • Other Endocrine Glands and Hormones • Thyroid • Parathyroid • Adrenal • Pancreas • Gonads