BSC1005 Unit I Movement and Physiology Physiology the science of bodily function Homeostasis is maintaining a constant internal environment with changes in activity example of internal changes increasing blood supply and oxygen to muscle during exercise maintains energy needed for muscle contraction example of external changes limit if not enough oxygen is supplied muscles produce lactic acid maintaining body temperature in cold environments mechanisms reduce heat loss by reducing blood flow to skin increase heat production by shivering muscle contractions Pathophysiology changes in physiology associated with diseases genetic mutations infections environmental factors etc learning about pathophysiology i e biomedical research leads to understanding disease mechanisms understanding our body s response to disease finding treatments and cures economically beneficial Blood connects tissues and cells in the body cells red blood cells white blood cells and platelets cell fragments plasma water electrolytes ions and small molecules includes gasses food molecules and metabolic wastes proteins chemical signals hormones hematocrit percent of blood volume by red blood cells determines oxygen carrying capacity of blood in normal individuals Red Blood Cells RBCs or Erythrocytes specialized to transport oxygen bi concave shape short diffusion distance for oxygen cytoskeleton protein spectrin maintains shape like the frame of a building oxygen transport in blood dissolves in plasma and cytoplasm of blood cells some most oxygen is bound to hemoglobin Hb RBCs are filled with lots of Hb myoglobin and hemoglobin are oxygen binding proteins in muscle and blood binding 1 oxygen myoglobin increases the binding of the next Hb binds 4 oxygen Sir A V Hill carbon dioxide transport in blood most CO2 is transported in blood converted to carbonic acid H2CO3 and bicarbonate HCO3 dissolved in plasma and cytoplasm of blood cells bound to Hb after ut has released oxygen converted to carbonic acid by an enzyme carbonic anhydrase in RBCs carbonic acid comes apart bicarbonate and hydrogen proton erythripoiesis new red blood cells come from red bone marrow 3 4 months new RBCs come from stem cells that divide replicate ad specialize differentiate into RBCs maturation takes about one weeks RBC loses nucleus during maturation to make more room for Hb RBC production is primarily controlled by a hormone erythropoietin EPO produced by kidneys molecular origin of sickle cell disease a single mutation in an Hb gene White Blood Cells WBCs or Leukocytes new white blood cells come from red bone marrow come from stem cells that divide replicate and specialize differentiate in WBCs WBCs in blood help immune system Platelets Thrombocytes cell fragments cell fragments produced by megakaryocytes involved in blood clotting new platelets come from red bone marrow Blood Plasma Composition most in plasma is water Major Proteins in Blood Plasma albumins globulins includes antibodies fibrinogen blood clotting with platelets lipoprotein assemblies also electrolytes ions small molecules O2 CO2 N2 and food molecules metabolic wastes proteins and chemicals signals hormones apolipoproteins and lipids including cholesterol high density lipoprotein HDL good cholesterol low density lipoprotein LDL bad cholesterol protein hormones Hb and carbonic anhydrase are within RBCs not plasma proteins Blood Clotting Antibodies coagulation involves both platelets and fibrinogen stops bleeding from damaged blood vessels blood proteins globulins that help protect against infections a protein component of the immune system WBCs vaccination primes the immune system to produce antibodies against new infections Blood Role in Body Temperature heat transport by blood throughout body cold days results in constriction vasoconstriction of blood vessels less blood flow meaning losing less heat hot days results in expansion and dilation of blood vessels increased heat loss Blood Cancers cancers and cardiovascular diseases are the top two killers and why people are hospitalized in the developed world cancer occurs when cells multiply at an abnormally high rate several types of cancer involve abnormal production of WBCs cancer cells do not function normally can also affect production of RBCs and platelets some treatments for cancers decrease WBC count cancer cells travel in the blood from a tumor to other parts of the body Metastasis Lymph not blood forms from fluid between cells interstitial fluid travels in vessels of the lymphatic system and eventually ends up mixing with the blood travels one way does not circulate like blood Cardiovascular Physiology the heart and vasculature circulatory system CV cardiovascular system blood heart vasculature blood vessels vascular system Human Heart pump of CV system 4 chambers 2 atria 2ventricles 4 valves cardiac muscle blood vessels that supply blood to the heart 2 between atria and ventricles 2 between ventricles and arteries left atrium and ventricle pump oxygenated blood to all parts of body except lungs more muscular Circulation of Blood right atrium and ventricle pump de oxygenated blood to the lungs blood is pumped through the body in a circuit one way route pulmonary circulation top right atrium and ventricle pump de oxygenated blood white to lungs O2 gained and CO2 released in lungs oxygenated blood gray returns to left atrium systemic circulation bottom parts of body except lungs left atrium more pressure and ventricle pump oxygenated blood gray to all tissues use O2 and produce CO2 de oxygenated blood white returns to right atrium icliker question when they work the valves in the heart ensure that blood moves only in one direction Cardiac Cycle Electrical contraction of heart must be highly coordinated to pump blood effectively SA node sinoatrial node pacemaker AD node introduces a delay coordinated spread of electrical signal across heart triggers contraction of atria first then ventricles Electrocardiogram ECG or EKG electrical activity of heart measured outside the body iclicker question the sinoatrial node SA in the right ventricle is also called the heart s pacemaker Cardiac Cycle Mechanical Diastole heart is relaxed atria and ventricles fill with blood valves open between atria and ventricles valves closed between ventricles and arteries Cardiac Cycle Mechanical Systole heart contracts atria pump blood into ventricles valves open between atria and ventricles ventricles eject blood into arteries valves closed
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