Circulatory Systems Internal transport

Blood Connective Tissue…2 parts 1) Matrix = plasma 2) Cells: red , white, platelets Spongy bone tissue w/ red marrow stem cells Blood cells

Plasma 50-60 % volume Mostly water Transport medium for 1) blood cells 2) blood proteins, hormones 3) nutrients & oxygen 4) waste & CO2 5) thermal energy 6) ions (regulate pH)

Blood Cells 1) Erythrocytes (RBC) 2) Leukocytes (WBC) 3) Megakaryoctyes (break into fragments called platelets)….role in clotting

Leukocyte Roles Phagocytosis/inflammation: basophils & neutrophils Phagocytosis/immune response: Macrophages & dendritic cells Kill abnormal body cells: natural killer cells

Erythrocytes No nucleus – only live 120 days Require iron Transport O2 via hemoglobin Transports CO2 via hemoglobin Carry ABO blood typing markers Lack of RBC = anemia

Agglutination Antibodies (immune proteins) bind foreign cells into clumps that attract phagocytes Clumps may clog vessels A & B markers are attacked by antibodies present in all individuals lacking A or B Rh marker only attacked the second time an Rh- person is exposed ….the body needs time to make anitbodies against Rh markers

Erythroblastosis fetalis Rh – mom 1st child is Rh+ so mom develops antibodies against Rh 2nd child is Rh+ Problem = child may receive some of mom’s antibodies from placenta. Antibodies cause Agglutination in fetus

Heart Structures Pericardium = connecitve tissue sac 2 layers w/ fluid between inner layer fused to wall of heart Myocardium = layer of cardiac muscle elastin & collagen fibers reinforce Endothelium – epithelial lining of chambers

Myocardium 1) striated muscle (sarcomeres) 2) single branching cells 3) strong adhering junctions 4) many gap junctions 5) many mitochondria 6) can store small amts glycogen

Valves Atrioventricular valve Semilunar valve

Heart Heart’s Left side = pumps to body more muscular blood enters from pulmonary veins blood leaves through aorta

Heart’s Right Sinoatrial node pacemaker pumps to lungs less muscular blood enters from vena cavas blood leaves through pulmonary arteries

Cardiac Cycle: cycle of expansion and contraction Diastole (expansion) Systole (contraction) 1) atria relax & fill with blood 2) fluid pressure opens AV valves 3) blood flows to ventricles / atria contract 4) ventricles contract = highest pressure 5) ventricles relax as atria are already filling

Blood Pressure Highest in contracting ventricles Lowest in relaxed atria Measured in brachial artery Systolic = peak pressure as V contract Diastolic = lowest pressure as V relax 120/80 Systolic = start to hear sound Diastolic = sounds stop

Controlling Blood pressure Based on 1) total blood volume 2) cardiac output 3) arteriole resistance Regulated by baroreceptors in walls of arteries ex in carotids.

Cardiac Conduction System 1) Sinoatrial node = clump of cells in rt atrium. Send action potentials. Atria contract 2) junctional fibers = bundles of long thin cells send AP to Atrioventricular node as atria are contracting 3)Atrioventricular node is bridge btwn Atria and ventricles.

4) once AP enters ventricles junction fibers spread AP to both ventricles so both contract at same time Action Potentials pass Directly from one cell to The next through gap junctions

Arteries = away Large diameter = low resistance Bands of elastic tissue Elastic walls bulge & recoil (equalize pressure) Artierioles regulate flow vasodilate & vasoconstrict

Veins = back to heart Large = low resistance Smooth muscle contracts to prevent bulging Contracting skeletal muscles push against veins Too much bulge= varicose veins Backflow valves

Capillaries RBC fit single file Wall of cap = 1 cell layer thick Gaps between cap cells let small mol & WBC slip out into interstitial fluid Other things exit by diffusion across cell membrane of cap cells or by exocytosis Blood-brain barrier is the exception….no leaking there!

Bulk Flow Movement of water & solutes by pressure Ultrafiltration – pressure pusses plasma out of cap at start of cap bed Capillary reabsorption – interstitial fluid moves into cap near end of bed Normal = slight outward flow into tissues

Lymphatic System A) Lymph vascular system – 1) vessels collect excess interstital fluid 2) collected fluid called lymph 3) transports lymph to veins in lower neck B) Lymphoid organs, tissues 1) nodes: lymphocytes filter lymph 2) spleen: filters out old RBC & pathogens 3) Thymus: T lymphocyte differentiation