Showing posts from August, 2010

The Digestive System, gastrointestinal system - GIT

Biomolecules are organic molecules that are associated with living organisms. Four groups Carbohydrates Monosaccharides Fructose, Glucose, Galactose Disaccharides Sucrose (table sugar) Fructose + Glucose Maltose Glucose + Glucose Lactose Glucose + Galactose Polysaccarides Polymers of Disaccharides Glycogen  Lipids - lipid related molecules Phospholipids 3 carbon glycerol plus long fatty acids. Phosphate group (-H2PO4) saturated fatty acids - no double bonds -palmitic acid monounsaturated - one double bond - oleic acid, or Olive oil is healthy polyunsaturated - two or more double bonds - associated with atherosclerosis Trans fats - are as likely to cause atherosclerosis - OH bonds in margarines that make it solid at room temp - So it does not matter if trans fatty acid free margarine - they "all the same" Triglicerides - 90% of all fats in the body Steroids Cholesterol is the source Important component of cell membranes Eicosano

Acid Base Disturbances

Respiratory Acidosis alveolar hypoventilation results in carbon dioxide retention and elevated PCO2. Respiratory depression due to alcohol or drugs Increased airway resistance due to asthma impaired gas exchange due to pulmonary fibrosis or severe pneumonia Loss of alveolar surface area in COPD emphysema  Muscle weakness of muscular dystrophy and other muscle diseases Increase plasma CO2 Decrease HCO3 and an increase in pH  Because the problem is respiratory you dont expect respiratory compensation.  we dont have buffers as they are used up - hence your abnormal blood test So we only left with renal compensation  Excrete H+ and reabsorb HCO3, increasing pH,  COPD patients have chronic compensation Metabolic Acidosis:  Increased H+ but Decreased HCO3 - Normal alveolar exchange therefore normal PCO2 Dietary and Metabolic H+ in is greater than H+ excretion -  Metabolic causes of acidosis anaerobic metabolism causes lactic acidosis excessive breakdown of fat and protein

The Cardiovascular System, Blood

PLASMA AND THE CELLULAR ELEMENTS OF BLOOD Plasma is Extracellular Martix Plasma Plasma Proteins. Albumin.  Plasma is identical to the interstitial fluid except for the presence of Plasma Proteins. Albumin makes up 60% of plasma proteins. Albumin, with globulins , and clotting protein fibrinogen , and the iron transporting protein transferrin  make up more than 90% of all plasma proteins. Liver makes most proteins Immunoglobulins are not made in the liver Protein makes the osmotic pressure in the blood higher than the interstitial fluid Functions: Albumin - osmotic pressure of plasma, carrier protein. Globulins - Clotting factors, enzymes, antibodies, carrier protein Fibrinogen - Fibrin threads essential for clotting Transferrin - Iron transport Cellular Elements Including RBCs, WBCs, and Platelets BLOOD CELL PRODUCTION All blood descend from a pluripotent hematopoietic stem cell. This cell is found primarily in the  bone merrow .  Become uncommitted stem cells

The Cardiovascular System, Blood flow and the Control of Blood Pressure

Pressure produced by the LV is stored by the elastic walls of the arteries and slowly released through elastic recoil. Arteries are the Pressure Reservoir of the circulatory system Arterioles - give downstream variable resistance -  Arteriole diameter is controlled by: Local factors: [Oxygen] Hormones Autonomic nervous system  Veins are the Volume Reservoir BLOOD VESSELS endothelium - has  paracrine function   regulates BP, blood vessel growth, and absorption of material Blood vessels contain Vascular Smooth Muscle arranged in circular or spiral layers Muscle tone Calcium Channels Arteries and Arterioles Carry Blood Away from the Heart  Some arterioles branch into METARTERIOLES - the walls of which are only partly surrounded by smooth muscle - unlike arterioles PRECAPILLARY SPHINCTERS direct blood from the metarterioles, if Dilated directs blood to the capillaries Constricted directs blood to the venous system Metarterioles allow WBC to migrate directly

The Cardiovascular system, Heart Muscle, The Heart as a pump

The Cardiovascular System is a  closed system , with a  one way circuit. efficiency Transports Materials throughout the body: Exogenous Endogenous Waste and heat elimination Brain is Oxygen dependent Cannot meed oxygen needs by using the anaerobic pathway 2 ATP + 1 NADH Must use the aerobic pathway - Glycolysis, Citric Acid cycle + Electron Transport System 6H2O+ 30 ATP + 6CO2 Nutrient, Hormone, Immunity transport CO2 and metabolic waste and heat removal How Blood flows: Down a pressure Gradient (dP) from high pressure to a low pressure Pressure, Volume, Flow and Resistance Pressure of a fluid in motion decreases over distance Hydrostatic Pressure: = may also be referred to as the hydraulic pressure - as fluid is in motion In a system that flows, pressure falls over distance as energy is lost to resistance / friction Pressure in Liquid changes without changes in Volume Driving pressure - the pressure of the ventricles on the systemic circulation -   dis