BIO 446L 1st Edition Lecture 20 Outline of Last Lecture I. Endocrine System Contda. Pancreasb. Thyroid glandc. Parathyroid glandOutline of Current Lecture I. Endocrine System continueda. Adrenal medullab. Pancreasi. Alpha, beta, delta, and peptide cellsii. Diabetesc. Thyroid glandd. Parathyroid glandII. Circulatory System 1—The hearta. Heart gross anatomyi. Atria and ventriclesii. Position and vesselsiii. Valvesb. Blood flowc. Conducting systemd. Innervation and blood supplye. Microscopic anatomyi. Heart wall layers and membranesCurrent LectureEndocrine System contd- Adrenal medullao Secretes epinephrine and norepinephrine Primarily secretes epinephrine (only place where it is secreted) Secretes NE from here and also sympathetic post ganglionic nerve terminalso Stimulus for secretion is sympathetic nervous system Sympathetic pre-ganglionic neuronThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Plump, secretory cellso Derived from neurocrest and migrates to center of adrenal glando Big sinusoid (blood vessel) that pick up epi and NEo Pheochromocytoma= over secretion- Pancreaso Secretes hormone into blood stream and secretes enzymes into ducts and into the small intestineo Darker stain—enzyme secretiono Lighter stain—eyelet cells Secrete hormones, surround capillarieso Beta cells= secrete insulin, decrease blood glucose levelso Alpha cells= secrete glucagon, increase blood glucose levelso Delta cells= secrete somatostatin (GH) and inhibits alpha and betao Peptide cells= stimulates functiono Stimuli= eating, sympathetic, parasympathetico Diabetes mellitus—increased glucose levles Type I= beta cells are non functioning, no insulin secretion, insulin dependent Type II= receptors are non-functioning  Symptoms- Polyuria= frequent urinationo Sugar in urine/fluid in kidney causes osmolarity gradient that causes lots of water to be secreted- Glycosuria= sugar in the urine- Polydipsia= decreased fluid due to frequent urination, so causes thirst- Polyphagia= hungry due to low energy/glucose levels Difference between type I and II- II has higher insulin levels due to increased blood glucose levels EXTRA CREDIT ON TEST= come with 2 additional symptoms of diabetes- Thyroid glando Highly vascularo Thyroidglobulin protein secretes thyroid hormones, T3 and T4 T3 and T4 control metabolic rateso Interior is organized into follicles = where TH is made and storedo C cells secrete calcitonin—decrease blood calcium levels, inhibits breakdown of bone matrixo Cilia to increase surface areao T3 and T4 are synthesized by transporting iodide into follicular cell and thyroidglobulin is made by rough ER and incorporated with 3-4 molecules of iodide Then transported and stored until needed TSH= stimuli from anterior pituitary- Binds to thyroidglobulin and disassembles it to release T3 and T4 Amino acid derivatives but not water soluble so needs to be attached to thyroid binding globulin to be transportedo Grave’s= excesso Hashimoto= low hormone levelso In both, there’s a hyperstimulation of thyroid gland- Parathyroid glando Target is in boneo Binding sites Osteoblasts to inhibit them and cause secretion of osteoclast stimulator Kidney to increase calcium reabsorption Digestive tract to increase absorption of calcium from dieto Blood calcium levels and muscle function Decreased calcium causes increased muscle contraction and vice versa due to effect on sodium channelsCirculatory System 1- The heart- Gross anatomyo Wall of left ventricle is thicker than right Left side is a high pressure system and right is a low pressure systemo valves AV valves connect atrium to ventricle Semilunar valves- Aortic semilunar connects left ventricle to aorta- Pulmonary semilunar connects right ventricle to pulmonary arteryo Diastole—relaxation of ventricles AV valve is closed initially as atrium fills with blood AV valve opens for ventricle filling and right and left atria contract o Systole—contraction of ventricles Ventricles contract, AV valve closes, semilunar open Ejection of blood from aorta and pulmonary arteryo Mediastinum= cavity of the body where heart is locatedo Blood enters superior and inferior vena cava vessels into atriao Orientation of heart “top” of heart is flat= base “bottom” of heart is pointed and angled= apexo Coronary sinus—blood collected from coronary vein into sinus Supplies right atriumo Valve structure and function Right AV= tricuspid (three cusps) Left AV= bicuspid, AKA mitral (two cusps) Papillary muscles= muscular anchors Tendonous cords= support leaflets of valves Diastole: AV opens, blood flows through Systole: pressure build up in muscular wall causes backflow of blood into valve leaflets and valves close to prevent further backflow- Blood flowo Blood flows because there’s a pressure gradiento Superior vena cava, inferior vena cava and aortic sinusright atrium tricuspid AV right ventricle pulmonary SL pulmonary trunk pulmonary arteries lungs pulmonary veins left atrium bicuspid (mitral) AV left ventricle aortic SL aorta body- Structure—fibrous skeletono Cardiac muscle attaches to fibrous skeleton because no boneso Forms walls between atria and ventricleso Tunnel for AV bundle—conducting pathway for atria to ventricles- Conducting systemo Autorhythmic—non contractile, specialized, pacemaker cells Set rhythm via wave of depolarizationo Pacemaker cells include SA node, AV node and bundles, Purkinje fiberso Starts with SA node Initiator because depolarizes the fastesto Depolarization spreads through gap junctionso SA node atria muscle cells depolarize AV node through AV bundle tunnel AV bundle branches (left and right) apex of ventricular septum Purkinje fibers depolarization of ventricular muscles- Innervation and blood supplyo Autonomic nervous system—sympathetic and parasympathetic Parasympathetic: dorsal motor nucleus of vagus vagus nerve SA node and AV node Sympathetic: ventral root sympathetic ganglion SA node, AV node, and cardiac muscle- Increase heart rate and contractility, which increase blood flow- Heart wall layerso Endocardium—innermost, contact with blood, epithelial cells on layer of loose connective tissueo