Cardiovascular System Chapter 17&18

Blood Connective tissue composed of fluid, cells, and fragments of cells 1.Plasma: fluid part of blood straw-colored 55% of blood volume

Blood 2. Red blood cells: (erythrocytes) round, disk-shaped cells carry oxygen to cells and carbon dioxide away attached to hemoglobin 44% of blood volume produced in red bone marrow of long bones lack a nucleus once enter blood stream only live about 120 days

Blood 3. White blood cells: (leukocytes) 1% of blood volume protect body from pathogens large and many different types contain a nucleus neutrophils lymphocytes eosinophils monocytes basophils

Blood 4. Platelets: cell fragments produced in bone marrow remain in blood for about 7 days clotting with fibrin (becomes scab)

Blood Types Types: Red blood cells: Plasma: –I A i or I A I A A: A antigen B antibodies –I B i or I B I B B: B antigen A antibodies –I A I B AB: A and B antigens NO antibodies –i i O: NO antigens A and B antibodies Universal donor: Type O-negative (no antigens) is compatible with all blood types because it has no antigens for other blood types to recognize with their antibodies Universal Recipient: Type AB-positive has no antibodies in its plasma so it can accept any type without destroying those foreign cells

Rh factor Rh factor is an additional antigen found on the red blood cells and it is a separate gene from the ABO gene. If a person has two (+) genes for Rh or one (+) and one (-) they will test (+). A person will be (-) ONLY if they have two (-) because Rh(+) is dominant. Positive means you have the Rh antigen, negative means you don’t. Other minor antigens include Kell, Lewis A, Lewis B, rho, P etc. and doctors also attempt to match as many of those minor antigens as possible when selecting blood for transfusions.

Exchange of materials Animal cells exchange material across their cell membrane –Diffusion –Osmosis –Passive Transport –Active Transport If you are a 1-cell organism that’s easy! If you are many-celled that’s harder

In circulation… What needs to be transported –Nutrients from digestive system –Gases O 2 & CO 2 from & to gas exchange systems: lungs, gills –Wastes waste products from cells –water, salts, nitrogenous wastes (urea) –Protective immune defenses –Antibodies and white blood cells blood clotting agents –Stimulants hormones

Closed circulatory system Taxonomy –Some Invertebrates earthworms, squid, octopuses –Vertebrates Structure –blood confined to vessels & separate from interstitial fluid 1 or more hearts large vessels to smaller vessels More effective at transporting fluids closed system = higher pressures

Vertebrate cardiovascular system Chambered heart –Atria = receive blood –Ventricles = pump blood out Blood vessels –Arteries = carry blood away from heart arterioles –Veins = return blood to heart venules –Capillaries = thin wall, exchange / diffusion capillary beds = networks of capillaries

Blood vessels Arteries arterioles Capillaries venules Veins artery arteriolesvenules veins

Arteries: Built for high pressure pump Thick wall provide strength for high pressure pumping of blood Connective tissue Smooth Muscle elastic recoil helps maintain blood pressure even when heart relaxes

Veins: Built for low pressure flow Veins –Thinner Connective tissue –Thinner Smooth Muscle blood travels back to heart at low velocity & pressure lower pressure –distant from heart –blood must flow by skeletal muscle contractions when we move »squeeze blood through veins –Contains valves in larger veins one-way valves allow blood to flow only toward heart Open valve Blood flows toward heart Closed valve

Capillaries: Built for exchange Small diameter –No connective tissue or smooth muscle lack 2 outer wall layers only endothelium –enhances exchange across capillary –This allows exchange between blood & cells

Controlling blood flow to tissues Blood flow in capillaries controlled by pre-capillary Spincters supply varies as blood is needed after a meal, blood supply to digestive tract increases during strenuous exercise, blood is diverted from digestive tract to skeletal muscles –capillaries in brain, heart, kidneys & liver usually filled to capacity sphincters opensphincters closed

Lymphatic system Parallel circulatory system –Part of Immune system defending against infection –collects interstitial fluid & returns to blood maintains volume & protein concentration of blood drains into circulatory system near junction of vena cava & right atrium

Lymph system Production & transport of WBCs Traps foreign invaders lymph node lymph vessels (intertwined amongst blood vessels)

Mammalian circulation What do blue vs. red areas represent? pulmonary systemic

Mammalian heart Coronary arteries to neck & head & arms

Coronary arteries bypass surgery

AV SL AV Heart valves 4 valves in the heart –flaps of connective tissue –prevent backflow AV valves –between atrium & ventricle –keeps blood from flowing back into atria when ventricles contract “lub” SL valves –between ventricle & arteries –prevent backflow from arteries into ventricles while they are relaxing “dub”

AV SL AV Lub-dub, lub-dub Heart sounds –closing of valves –“Lub” recoil of blood against closed AV valves –“Dub” recoil of blood against semilunar valves Heart murmur –defect in valves causes hissing sound when stream of blood squirts backward through valve

Cardiac cycle systolic ________ diastolic pump (peak pressure) _________________ fill (minimum pressure) 1 complete sequence of pumping –heart contracts & pumps –heart relaxes & chambers fill –contraction phase Systolic ventricles pumps blood out –relaxation phase Diastolic atria refill with blood 120 ____ 80