BIOL 320 1 st Edition Lecture 4 Outline of Last Lecture I Adrenal Glands A Adrenal Corticosteroids B Homeostatic Imbalances C Stress Response D Disorders II Pancreas A Cell Types i Target ii Effects B Diabetes Mellitus Outline of Current Lecture III Female Gonads IV Male Gonads V Pineal Gland VI Thymus VII Other Hormone Producing Structures VIII Developmental Considerations IX Aging Effects I Blood II Composition of Blood III Erythrocytes A Production B Life Cycle C Disorders Current Lecture Female Gonads Ovaries o Produce estrogen and progesterone Male Gonads Testes o Produce testosterone Pineal Gland Pinealocytes o Produce melatonin important for sleep Suprachiasmatic Nucleus of the Hypothalamus o Biological clock important for circadian rhythms Light signal detected by photoreceptors in retina of eye and send info to suprachiasmatic nucleus of the hypothalamus which sends info to the pineal gland The pineal gland then secretes melatonin back to the suprachiasmatic nucleus Melatonin o Kids have higher levels of melatonin since they need more sleep for growth o Use plays a big role in shift work shift from night activity to day activity and vice versa Seasonal Affective Disorder SAD o Not enough light o Cause results from overproduction of melatonin o Treatment full spectrum phototherapy Thymus Produces thymosin important for white blood cells especially T cells of immune system and thymopoietin maturation of T cells Governs production of white blood cells WBC Most active in childhood Atrophies with age Immune response declines with age Other Hormone Producing Structures Adipose cells o Leptin released when satiated o Resistin antagonizes insulin promotes glucose in blood Skin o Cholecalciferol converted to calcitriol uptake of calcium active form of vitamin D GI Tract o Enteroendocrine cells release several peptide hormones that help regulate a variety of digestive functions also have paracrine type functions Kidney o Erythropoietin EPO maturation of RBC Heart o Atrial Natriuretic Peptide ANP reverse of ADH promotes urination Placenta o Human chorionic gonadotropin o Human placental lactogen o Human chorionic somatomammotropin Developmental Consideration Endocrine cells come from all three germ layers Germ layers o Endoderm endocrine glands derived form this layer produce amine peptides or protein hormones o Mesoderm endocrine glands derived form this layer produce steroid hormones o Ectoderm endocrine glands derived form this layer produce amine peptides or protein hormones Growth Hormone o Ethical issues with trying to give or use this but also for safety of individual Substances that disrupt endocrine function o Pesticides o Industrial chemicals o Arsenic o Dioxin o Pollutants tree frogs are the canary of results these have on development Aging Effects Structural changes do occur over time General endocrine functions decline with age Ovaries function but then decline with age Testosterone gradually declines with age Growth Hormone decline more abruptly with age Thyroid Hormone declines with age Parathyroid Hormone does NOT decline with age increases blood calcium levels leading to osteoporosis Adrenals o Medulla epinephrine and norepinephrine are not affected with age o Cortex cortisol and aldosterone decline with age Insulin release declines with age and receptor sensitivity declines with age Blood Connective tissue Non living Characteristics o Tissue type connective o Taste metallic salty o Color scarlet red depending on the presence of oxygen o pH 7 35 7 45 o Temperature slightly warmer than body temperature o Functions Protection route that defensive cells travel against infection and blood loss Regulatory body temperature pH water fluid balance Transport gases enzymes hormones waste nutrients moved around Composition of Blood Plasma 55 of whole blood o 90 water o 10 solutes Formed Elements 45 of whole blood o Buffy Coat 1 of whole blood Leukocytes and platelets clotting factors o Erythrocytes 45 of whole blood Erythrocytes Characteristics o Anucleate do not have a nucleus o Biconcave increases surface area to carry multiple units of hemoglobin for oxygen gas exchange o Essentially no organelles o Normal values Males tend to have higher count higher muscle mass than females o Hemoglobin pigment that plays a role in gas exchange 2 alpha chains each with a heme group 2 beta chains each with a heme group Binds four molecules of oxygen 33 mass of RBC Will aslo bind to carbon monoxide stronger affinity and carbon dioxide 20 of waste gass for cycling process Oxygen loading in the lungs Produces oxyhemoglobin ruby red Oxygen unloading in the tissues Produces deoxyhemoglobin or reduced hemoglobin dark red Carbon dioxide loading in the tissues Produces carbaminohemoglobin carries 20 of carbon dioxide in the blood o Primary function gas transport o Spectrin flexible protein in walls of RBCs allows it to bend twist torque in changing diameter shape for travel through blood vessels o RBCs perfectly suited for job gas transport because Large surface area High hemoglobin content Anaerobic don t steal from oxygen cargo Production o All three types of blood cells start from same hematopoietic stem cells o Erythropoiesis production of RBC Made in bone marrow of flat bones and irregular bones in adults almost all bones in children Hormonal Control of Erythropoiesis EPO stimulates blood production o Effects of EPO More rapid maturation of committed bone marrow cells Increased circulating reticulocyte count in 1 2 days Testosterone also enhances EPO production resulting in higher RBC counts in males Dietary requirements Fat Protein and Carbohydrates for structural proteins Iron needed for hemoglobin structure lost regularly in fecal material Vitamin B12 and Folic Acid needed for normal DNA synthesis Formation of RBCs Hemocytoblast o Stem cell going to be some type of blood cell Proerythroblast o Committed cell know what type of blood cell definitely will become a RBC Developmental Pathway o Phase 1 ribosome synthesis Early erythroblast o Phase 2 hemoglobin accumulation Late erythroblast Normoblast with nucleus o Phase 3 ejection of nucleus Normoblast without nucleus Reticulocyte should not be in circulation if it is then good indication of severe anemia o Erythrocyte o Leucopoiesis production of WBC o Thrombopoiesis platelet genesis Life Cycle o Life Span 3 4 months must be carefully recycled since iron is dangerous floating around freely in blood o Aging Plasma membrane becomes fragile