Unit 1 Biology Review Physiology is the science of biological function Function is closely related to structure To study physiology look at the atoms ions cells tissues organs organ systems which all make up an organism Maintaining homeostasis which is a constant internal environment despite external changes A common example is maintaining body temperature despite the climate Pathophysiology changes in physiology associated with disease genetic mutation infections environmental factors Learning about pathophysiology allows us to Understand disease mechanisms Understand body s response to disease Find treatment cures More understanding sympathy towards people Biomedical research helps us understand normal and Blood part of circulatory system and cardiovascular pathophysiology Blood is A connective tissue A complex fluid Composition cell component RBC WBC platelets Plasma Hematocrit volume of blood occupied by RBC RBC s are specialized to transport oxygen Most O2 in the blood is bound to hemoglobin Hb protein in RBC dissolved in plasma and cytoplasm of blood cells RBC s also participate in CO2 transport Most CO2 is transported in blood form of carbonic acid and bicarbonate which is dissolved in blood plasma and cytoplasm of blood cells CO2 converted to H2CO3 by a protein enzyme in RBC carbonic anhydrase Sickle cell disease genetically inherited disease where the RBC s become crescent shape Types of WBC lymphocytes neutrophils eosinophhils basophils monocytes all part of the immune system which protects against infection New blood cells are made in the red bone marrow RBC s come from stem cells stems cells only specialize when they go through differentiation new RBC s formed through erythropoiesis Blood plasma made up of Water Electrolytes ions small molecules includes gases O2 CO2 food molecules metabolic wastes Proteins Chemical signals hormones some are proteins and some are bound to proteins Blood has a role in many physiological processes Transport molecules O2 CO2 blood cells Protection against infection immune system Repair clotting coagulation Temperature regulation heat transport Cardiovascular System Circulates throughout the body Structure of human heart Pump of cardiovascular system Left the more dominant side Right side which pumps deoxygenated blood to the lungs Atria ventricles blood enters atria first then ventricle Valves sinoatrial SA node pacemaker and atrioventricular AV node Cardiac and electrical cycle electrical signals spread through the body by 2 main pathways travel either by gap junctions or along conduction pathways ECG or EKG reflects electrical activity of cardiac cycle Cardiac mechanical cycle systole and diastole Systole versus Diastole Systole contractile phase of the cardiac cycle Diastole non contractile phase of the cardiac cycle when the cardiac muscle is relaxed Blood pressure in ventricles and major arteries aorta major Heart sounds lub dupp is from the changes in blood motion as the valves close open Relationship between parts of cardiac cycle Cardiac output CO definition control Types of structure function of blood vessels vasculature Arteries capillaries veins Smooth muscle connective tissue and endothelium Common cardiovascular diseases Atherosclerosis Heart attack stroke Heart failure Circulatory system relation between cardiovascular system lymphatic system Respiratory System Major structures airway and lungs Protective role mucus Alveoli are functional units of the lungs Gas O2 CO2 exchange between air and blood occurs by diffusion across alveoli Breathing Inhalation active because major respiratory muscles diaphragm rib muscles contract Exhalation passive because major respiratory muscles relax Lung volumes and ventilation Exchange of air within lungs Only part of air within lungs exchanged with each breath Air within alveoli in lungs has less O2 more CO2 than air in atmosphere Pulmonary circulation of blood Deoxygenated blood is pumped to lungs by the right side of the heart Oxygenated blood returns from lungs to left side Pulmonary system circulatory system Blood carrying O2 CO2 is pumped through the entire circulatory system by the heart active contraction of cardiac muscle Diffusion Gas O2 CO2 exchange between air in alveoli and blood capillaries occurs by diffusion Gas O2 CO2 exchange between blood in capillaries and cells in tissues occurs by diffusion Carbonic acid H2CO3 bicarbonate HCO3 transported in the blood converted back to CO2 in the lungs by carbonic anhydrase in RBC s Control of breathing rate and volume roles of CO2 carbonic acid H2CO3 bicarbonate HCO3 also O2 levels in blood Respiratory diseases Asthma Cystic fibrosis Lung cancer Muscle 3 major muscle types classified by their function location in body subcellular structure Skeletal muscle striations voluntary located on one or both ends attached to skeleton via tendon Responsible for body movements posture Skeletal muscle cells typically long are referred to as fibers because their structure size several fibers are organized into bundles surrounded by connective tissue Within each muscle fiber are myofibrils which are made up of sarcomeres Skeletal Muscle cell fiber myofibril sarcomere Skeletal muscle fibers have more than one nucleus makes them unique skeletal muscles are formed by myoblasts fusing together to form large fibers Cardiac Muscle striations involuntary located in heart wall Make up muscular walls of heart s atria ventricles Responsible for systolic contraction of the heart that pumps blood throughout all tissues of body individual cardiac cell cardiac myocyte which are smaller than most skeletal muscles with elongated irregular shapes have striations unlike skeletal muscle cells they do not have multiple nuclei just 1 Smooth Muscle no striations involuntary major componene tof tissues organs and organ systems located in blood vessels lymphatic vessels trachea digestive system excretory system excretory system reproductive system skin individual smooth muscle cells very small have no striations because they do not have organized arrays of contractile protein filaments as found in the skeletal cardiac muscle cells have a single nuclei Common features of all 3 types of muscle Myosin actin proteins both break down ATP Molecular basis of contraction is actin myosin cross bridge cycling which uses ATP as a source of energy Contraction is activated by a temporary increase in calcium ion Ca2 called Ca2 transient A motor unit consists of one or more neuron all
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