Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Anatomy and Physiology Heart, Lungs, Pancreas, Liver, Kidneys and Skin B. Paul White, MD HOD ID#: 2078 HODS - November 2006 1 HODS - November 2006 2 HEART HODS - November 2006 3 HEART • • • • • Hollow, muscular organ 300 grams (size of a fist) 4 chambers found in chest between lungs surrounded by membrane called Pericardium • Pericardial space is fluid-filled to nourish and protect the heart. HODS - November 2006 4 HEART ANATOMY • The heart is a complex muscular pump that maintains blood pressure and flow through the lungs and the rest of the body. • The heart pumps about 100,000 times and moves 7200 liters (1900 gallons) of blood every day. HODS - November 2006 5 HEART ANATOMY The heart has four chambers. Two atria act as collecting reservoirs. Two ventricles act as pumps. The heart has four valves for: Pumping action of the heart. Maintaining unidirectional blood flow. HODS - November 2006 6 Functions of the Heart • Generates blood pressure • Routes blood – Heart separates pulmonary and systemic circulation • Ensures one-way blood flow – Heart valves ensure one-way flow HODS - November 2006 7 Functions of the Heart • Regulates blood supply – Changes in contraction rate and force match blood delivery to changing metabolic needs – Most healthy people can increase cardiac output by 300–500% • Heart failure is the inability of the heart to provide enough blood flow to maintain normal metabolism HODS - November 2006 8 Cardiac Cycle • The heart is two pumps that work together, right (pulmonary) and left (systemic) half • Repetitive, sequential contraction (systole) and relaxation (diastole) of heart chambers • Blood moves through circulatory system from areas of higher to lower pressure. – Contraction of heart produces the pressure HODS - November 2006 9 Cardiac Cycle HODS - November 2006 10 HEART Deoxygenated blood returns to the heart via the superior and inferior vena cava, enters the right atrium, passes into the right ventricle, and from here it is ejected to the pulmonary artery. Oxygenated blood returning from the lungs enters the left atrium via the pulmonary veins, passes into the left ventricle, and is then ejected to the aorta. HODS - November 2006 11 Blood Vessels • Blood vessels are divided into a pulmonary circuit and systemic circuit. • Artery - vessel that carries blood away from the heart. Usually oxygenated • Vein - vessel that carries blood towards the heart. Usually deoxygenated. • Capillary - a small blood vessel that allow diffusion of gases, nutrients and wastes between plasma and interstitial fluid. HODS - November 2006 12 Blood Vessels • Systemic vessels – Transport blood through the body part from left ventricle and back to right atrium • Pulmonary vessels – Transport blood from right ventricle through lungs and back to left atrium • Blood vessels and heart are regulated to ensure blood pressure is high enough for blood flow to meet metabolic needs of tissues HODS - November 2006 13 Blood Flow HODS - November 2006 14 LUNGS • Lungs comprised of – Airways – Alveoli http://www.aduk.org.uk/gfx/lungs.jpg HODS - November 2006 15 What do the lungs do? • Primary function is gas exchange • Let oxygen move in • Let carbon dioxide move out HODS - November 2006 16 How do the lungs do this? • First, air has to move to the region where gas exchange occurs. • For this, you need a normal ribcage and respiratory muscles that work properly (among other things). HODS - November 2006 17 Conducting Airways • Air travels via laminar flow through the conducting airways comprised of the following: trachea, lobar bronchi, segmental bronchi, subsegmental bronchi, small bronchi, bronchioles, and terminal bronchioles. HODS - November 2006 18 How do the lungs do this? • The airways then branch further to become transitional/respiratory bronchioles. • The transitional/respiratory zones are made up of respiratory bronchioles, alveolar ducts, and alveoli. HODS - November 2006 19 The Airways Weibel ER: Morphometry of the Human Lung. Berlin and New York: SpringerVerlag, 1963 HODS - November 2006 • Conducting zone: no gas exchange occurs – Anatomic dead space • Transitional zone: alveoli appear, but are not great in number • Respiratory zone: contain the alveolar sacs • Over 8 million branches 20 How does gas exchange occur? • Numerous capillaries are wrapped around alveoli. • Gas diffuses across this alveolarcapillary barrier. • This barrier is as thin as 0.3 μm in some places and has a surface area of 50100 square meters! HODS - November 2006 21 Gas Exchange • Diffusion Barrier crossed by O2 moving from air to blood and CO2 from blood to air is made up of: • 1. an aqueous surface film • 2. epithelial cells of alveolus • 3. interstitial layer • 4. endothelial cells of capillaries • 5. blood plasma • 6. membrane of RBCs HODS - November 2006 22 Alveoli • Approximately 300 million alveoli • 1/3 mm diameter • Total surface area about 85 sq. meters (size of a tennis court) HODS - November 2006 23 Gas Exchange HODS - November 2006 From Netter Atlas of Human Anatomy, 1989 24 Control of Ventilation • Arterial PO2 – When PO2 is VERY low, ventilation increases • Arterial PCO2 – The most important regulator of ventilation, small increases in PCO2, greatly increases ventilation • Arterial pH – As hydrogen ions increase, alveolar ventilation increases, but hydrogen ions cannot diffuse into CSF as well as CO2 HODS - November 2006 25 PANCREAS Anatomy of the Pancreas • 5" long by 1" thick • Head close to curve in Cshaped duodenum • Main duct joins common bile duct from liver • Sphincter of Oddi on major duodenal papilla • Opens 4" below pyloric sphincter HODS - November 2006 27 Anatomy of the Pancreas Gray’s Anatomy of the Human Body HODS - November 2006 28 Anatomy of the Pancreas Exocrine glands have ducts that carry their secretions to specific locations. Gray’s Anatomy of the Human Body Robbins Basic Pathology http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/default.htm HODS - November 2006 Digestive gland that secretes digestive enzymes into the duodenum through the pancreatic duct. 29 Histology of the Pancreas Histology of the Pancreas • Acini- dark clusters – 99% of gland – produce pancreatic juice • Islets of Langerhans – 1% of gland – pale staining cells – produce hormones HODS - November 2006 31 Bicarbonate Ion Production Functions of the Pancreas • Anatomy – Endocrine • Pancreatic islets produce insulin and glucagon – Exocrine • Acini produce digestive enzymes – Regions: Head, body, tail • Secretions – Pancreatic juice (exocrine) • • • • • • Trypsin Chymotrypsin Carboxypeptidase Pancreatic amylase Pancreatic lipases Enzymes that reduce DNA and ribonucleic acid Bicarbonate Ion Production LIVER LIVER • Largest gland in the body (1.4 kg – 3 lbs.) • Produces bile – Stored in GB – Emulsifies fats • • • • • Involved in metabolism Diaphramatic and visceral surface Right and left lobes Porta hepatis = major vessels and nerves Right and left hepatic ducts, common bile, common HODS - November 2006 36 Histology of the Liver HODS - November 2006 • Hepatocytes arranged in lobules • Sinusoids in between hepatocytes are blood-filled spaces • Kupffer cells phagocytize microbes & foreign matter 37 Histology of the Liver HODS - November 2006 38 Histology of the Liver HODS - November 2006 39 Functions of the Liver • Bile production – Salts emulsify fats, contain pigments as bilirubin • Storage – Glycogen, fat, vitamins, copper and iron • Nutrient interconversion • Detoxification – Hepatocytes remove ammonia and convert to urea • Phagocytosis – Kupffer cells phagocytize worn-out and dying red and white blood cells, some bacteria • Synthesis – Albumins, fibrinogen, globulins, heparin, clotting factors HODS - November 2006 40 Bile • About 600 ml of bile is produced daily – Bile acid – Phospholipids – Cholesterol – Bilirubin – Waste products – Electrolytes – Mucin HODS - November 2006 41 KIDNEYS HODS - November 2006 42 KIDNEYS • Play a major role in maintaining homeostasis • Maintain water balance • Regulate the quantity and concentration of ECF ions • Regulate the plasma volume • Regulate pH by controlling elimination of acid and base in urine • Maintain osmolarity • Regulate the concentration of plasma constituents (e.g. electrolytes and water) HODS - November 2006 43 KIDNEYS • Kidneys have excellent blood supply: 0.5% total body weight but ~20% of Cardiac Output. • Kidneys process plasma portion of blood by removing substances from it, and in a few cases, by adding substances to it. • Works with cardiovascular system (and others!) in integrated manner HODS - November 2006 44 Functions of the kidneys • Regulation of H2O and inorganic ion balance – most important function! • Removal of metabolic waste products from blood and excretion in urine. • Removal of foreign chemicals in the blood (e.g. drugs) and excretion in urine. • Gluconeogenesis • Endocrine functions (e.g. renin, erythropoetin, 1,25dihydroxyvitamin D) • In kidney disease, build-up of waste serious, but not a bad as ECF volume and composition disturbances. HODS - November 2006 45 Functions of the kidneys • • • • • • • Water balance Electrolyte balance Plasma volume Acid-base balance Osmolarity balance Excretion Hormone secretion HODS - November 2006 46 Acid-Base Balance • Kidneys VERY important for acid-base balance, along with respiratory system. • Important because all biochemical processes must occur within an optimal pH window. • Prevent ACIDOSIS or ALKALOSIS. • Although the lungs excrete a large amount of CO2, a potential acid formed by metabolism, the kidneys are crucial for excreting non-volatile acids. • To maintain acid-base balance, kidney must not only reabsorb virtually all filtered HCO3-, but must also secrete into the urine the daily production of non-volatile acids. HODS - November 2006 47 KIDNEY HODS - November 2006 48 Internal Anatomy of Kidneys • Cortex: Outer area – Renal columns • Medulla: Inner area – Renal pyramids • Calyces – Major: Converge to form pelvis – Minor: Papillae extend • Nephron: Functional unit of kidney – Juxtamedullary – Cortical HODS - November 2006 49 Kidney Failure • at age 49 years, the expected duration of life of a patient with end-stage renal disease on hemodialysis is 7 additional years compared with approximately 30 additional years for a person of the same age from the general population. HODS - November 2006 50 Dialysis and Transplant Hemodialysis Peritoneal dialysis HODS - November 2006 51 SKIN HODS - November 2006 52 SKIN • • • • Largest organ of the body. Surface area 1.5 - 2 m2. Average adult weight 9 kg. Functions - protection, defence, sensation, thermoregulation, vit D synthesis, excretion, storage. HODS - November 2006 53 SKIN 2 Principal portions • Epidermis - epithelium • Dermis – areolar & dense irregular connective tissue • Hypodermis – “beneath the dermis” – the subcutaneous layer next to: • • • adipose layer or muscle or bone HODS - November 2006 54 Functions of the Skin • Protection – • Prevents invasion of environmental toxins and microorganisms Immunologic – • Sebum has antibacterial properties which helps shed topical bacteria Thermoregulation – Insulates from heat loss and controls loss of heat through evaporation HODS - November 2006 55 Functions of the Skin • Fluid and Electrolyte Balance – Controls sodium excretion – Sebum retards fluid loss from skin • Metabolism – Produces Vitamin D – Prevents excessive fluid loss • Neurosensory – Nerve endings and receptors process environmental stimuli for pain, touch, heat and cold • Social and Interactive – Provides body image and personal identity HODS - November 2006 56 Epidermis • Provides barrier function. • Multilayered structure, continually regenerating. • Thickness dependent on exposure to friction. • Stratified squamous epithelium, organised in five layers. – Stratum basale; Stratum spinosum, Stratum granulosum, Stratum lucidum, Stratum corneum. HODS - November 2006 57 Epidermis • First layer of defense • Composed of dead, keratinized cells and surrounded by a lipid monolayer • There are no blood vessels. It is fed by capillaries in the dermis. • If the epidermis is destroyed but the appendages of the dermis remain, a new epidermis is formed when the epithelial grow out of the hair follicles. HODS - November 2006 58 • EPIDERMIS • 4 cell types – Keratinocytes - 90% • filled with keratin (protein) • waterproof barrier – Melanocytes - 8% • produce melanin (pigment) • pass melanin to keratinocytes – Langerhans cells • phagocytes (from immune system) • easily damaged by UV light – Merkel cells • in deepest layer of hairless skin • sensory transduction touch HODS - November 2006 59 Epidermis SC SG SS B HODS - November 2006 60 Dermis • Varies in thickness across body. • 1 mm on face , 4 mm on back. • Responsible for most major functions of the skin. • Two distinct layers: Papillary dermis, Reticular dermis. HODS - November 2006 61 Dermis • Few cells present - fibroblasts, macrophages, adipocytes • Intracellular matrix thick with many protein fibers: collagen, elastin, reticular • The location for blood vessels, nerves and sensory receptors, glands, hair follicles HODS - November 2006 62 Dermis • Collagen and fibrous connective tissue • Contains capillaries and arterioles • Has special sensory nerve fibers and lymph system – Meissner Corpuscle: light touch, just beneath epidermis – Vater Pacini Corpuscles: pressure sensors, deep in subq – Ruffini Corpuscles: heat sensors, deep in subq tissue – Krause Corpuscles: cold sensors, deep in subcutaneous tissue HODS - November 2006 63 • Papillary region outer layer - 20% Dermis – areolar connective tissue, elastic fibers – dermal papillae – mound-like projections to increase the surface area for nutrition from capillaries – some papillae contain Meissner's corpuscles (for light touch) HODS - November 2006 64 • Reticular region80% Dermis – dense, irregular connective tissue – collagen, elastic fibers in a network surrounding the various cells – fibers give strength, elasticity, extensibility – tears in reticular region - "stretch marks“ - long straight red or white streaks HODS - November 2006 65 Layers of the Dermis. HODS - November 2006 66 Subcutaneous Tissue • • • • • • Connective tissue Fat cells in most areas Blood vessels Nerves Base of hair follicles Function: • Insulation • Storage of nutrients HODS - November 2006 67 Skin Blood Vessels Superficial dermal plexus. Cutaneous plexus Subcutaneous plexus. HODS - November 2006 68 Types of Burns • • • • Superficial Superficial partial thickness Deep partial thickness Full thickness HODS - November 2006 69 Partial Thickness Burn • • • • • • Can be superficial or deep Involves epidermis and dermis Has blister formation Moist appearance Tactile and pain sensors intact Will usually heal on own but will scar HODS - November 2006 70 Full Thickness Burn • • • • • Involves all layer of skin Has waxy and dry appearance Elasticity destroyed Painless Does not heal without intervention – Autologous skin graft or banked skin HODS - November 2006 71