Essential Knowledge: - PowerPoint Presentation

Essential Knowledge: 2.A.3 Organisms must exchange matter with the environment to grow, reproduce, and maintain organization 2.D.2 Homeostatic mechanisms reflect both common ancestry and divergence due to adaptation in different environments. 4.A.4 Organisms exhibit complex Properties due to interactions between constituent parts 4.B.2 Cooperative interactions within organisms promote efficiency in the use of energy and matter

How do simple organisms like jelly fish and flat worms exchange reactants and products of cellular respiration? Simple animals have a body wall that is only two cells thick and that encloses a gastrovascular cavityThis cavity functions in both digestion and distribution of substances throughout the bodyMaterials can diffuse in or out of the gastrovascular cavity as needed. Circulation of Glucose, Oxygen, and Carbon Dioxide

Fig. 42-2 Circular canal Radial canal Mouth (a) The moon jelly Aurelia , a cnidarian The planarian Dugesia , a flatworm (b) Mouth Pharynx 2 mm 5 cm

How do more complex organisms exchanges the reactants and products of cellular respiration? They have either an open or closed circulatory system.How does an open circulatory system work?In insects, other arthropods, and most molluscs, blood bathes the organs directly in an open circulatory systemIn an open circulatory system, there is no distinction between blood and interstitial fluid, and this general body fluid is more correctly called hemolymph Circulation of Glucose, Oxygen, and Carbon Dioxide

How does a closed circulatory system work? In a closed circulatory system, blood is confined to vessels and is distinct from the interstitial fluidClosed systems are more efficient at transporting circulatory fluids to tissues and cellsWhat do we call our circulatory system?Humans and other vertebrates have a closed circulatory system, often called the cardiovascular system The three main types of blood vessels are arteries, veins, and capillaries Circulation of Glucose, Oxygen, and Carbon Dioxide

Fig. 42-3 Heart Hemolymph in sinuses surrounding organs Heart Interstitial fluid Small branch vessels In each organ Blood Dorsal vessel (main heart) Auxiliary hearts Ventral vessels (b) A closed circulatory system (a) An open circulatory system Tubular heart Pores

What are the major components of the vertebrate circulatory system? Arteries branch into arterioles and carry blood to capillaries Networks of capillaries called capillary beds are the sites of chemical exchange between the blood and interstitial fluid Venules converge into veins and return blood from capillaries to the heartVertebrate hearts contain two or more chambersBlood enters through an atrium and is pumped out through a ventricleCirculation of Glucose, Oxygen, and Carbon Dioxide

Fig. 42-4 Artery Ventricle Atrium Heart Vein Systemic capillaries Systemic circulation Gill circulation Gill capillaries Single circulatory loop with a 2 chambered heart

Fig. 42-5 Amphibians Lung and skin capillaries Pulmocutaneous circuit Atrium (A) Ventricle (V) Atrium (A) Systemic circuit Right Left Systemic capillaries Reptiles (Except Birds) Lung capillaries Pulmonary circuit Right systemic aorta Right Left Left systemic aorta Systemic capillaries A A V V Systemic capillaries Pulmonary circuit Systemic circuit Right Left A A V V Lung capillaries Mammals and Birds Double heart circulation w/ 3 chambered Double circulation with a 3 chambered heart – ventricle partially divided Double circulation with a 4 chambered heart

How does blood flow in a mammal? Blood begins its flow with the right ventricle pumping blood to the lungsIn the lungs, the blood loads O2 and unloads CO2Oxygen-rich blood from the lungs enters the heart at the left atrium and is pumped through the aorta to the body tissues by the left ventricle The aorta provides blood to the heart through the coronary arteries Blood returns to the heart through the superior vena cava (blood from head, neck, and forelimbs) and inferior vena cava (blood from trunk and hind limbs) The superior vena cava and inferior vena cava flow into the right atrium Circulation of Glucose, Oxygen, and Carbon Dioxide

Fig. 42-6 Superior vena cava Pulmonary artery Capillaries of right lung 3 7 3 8 9 2 4 11 5 1 10 Aorta Pulmonary vein Right atrium Right ventricle Inferior vena cava Capillaries of abdominal organs and hind limbs Pulmonary vein Left atrium Left ventricle Aorta Capillaries of left lung Pulmonary artery Capillaries of head and forelimbs

Fig. 42-7 Pulmonary artery Right atrium Semilunar valve Atrioventricular valve Right ventricle Left ventricle Atrioventricular valve Left atrium Semilunar valve Pulmonary artery Aorta

How does the heart contract? What are the two phases of the cardiac cycle? The contraction, or pumping, phase is called systoleThe relaxation, or filling, phase is called diastoleWhat is another name for the heart rate?The heart rate, also called the pulse, is the number of beats per minute Circulation of Glucose, Oxygen, and Carbon Dioxide

Fig. 42-8 Semilunar valves closed 0.4 sec AV valves open Atrial and ventricular diastole 1 2 0.1 sec Atrial systole; ventricular diastole 3 0.3 sec Semilunar valves open AV valves closed Ventricular systole; atrial diastole

What are the four valves in the heart called? And what is their purpose? Four valves prevent backflow of blood in the heartThe atrioventricular (AV) valves separate each atrium and ventricleThe semilunar valves control blood flow to the aorta and the pulmonary artery The “ lub -dup” sound of a heart beat is caused by the recoil of blood against the AV valves ( lub) then against the semilunar (dup) valves Circulation of Glucose, Oxygen, and Carbon Dioxide

How does the heart maintain its rhythmic beat? The sinoatrial (SA) node, or pacemaker, sets the rate and timing at which cardiac muscle cells contractImpulses from the SA node travel to the atrioventricular (AV) node At the AV node, the impulses are delayed and then travel to the Purkinje fibers that make the ventricles contract The pacemaker (SA node) is influenced by nerves, hormones, body temperature, and exercise Circulation of Glucose, Oxygen, and Carbon Dioxide

Fig. 42-9-5 Signals spread throughout ventricles. 4 Purkinje fibers Pacemaker generates wave of signals to contract. 1 SA node (pacemaker) ECG Signals are delayed at AV node. 2 AV node Signals pass to heart apex. 3 Bundle branches Heart apex

How is the structure of blood vessels adapted to transport material throughout the body? Capillaries have thin walls, the endothelium plus its basement membrane, to facilitate the exchange of materialsArteries and veins have an endothelium, smooth muscle, and connective tissueArteries have thicker walls than veins to accommodate the high pressure of blood pumped from the heartIn the thinner-walled veins, blood flows back to the heart mainly as a result of muscle action, valves prevent back flow Circulation of Glucose, Oxygen, and Carbon Dioxide

Fig. 42-10 Artery Vein SEM 100 µm Endothelium Artery Smooth muscle Connective tissue Capillary Basal lamina Endothelium Smooth muscle Connective tissue Valve Vein Arteriole Venule Red blood cell Capillary 15 µm LM

How does blood flow change as it moves from arteries to capillaries to veins? Blood flow is fast in arteries due to pumping of the heartBlood flow slows in capillaries as the volume from one artery spreads to feed an entire capillary bed – this is good it slows things down and allows for exchange of materialsBlood flow increases slightly in veins due to decreased surface areaCirculation of Glucose, Oxygen, and Carbon Dioxide

Fig. 42-11 5,000 4,000 3,000 2,000 1,000 0 0 50 40 30 20 10 120 80 100 60 40 20 0 Area (cm 2 ) Velocity (cm/sec) Pressure (mm Hg) Aorta Arteries Arterioles Capillaries Venules Veins Venae cavae Diastolic pressure Systolic pressure

How can blood flow through capillaries be controlled? Two mechanisms regulate distribution of blood in capillary beds:Contraction of the smooth muscle layer in the wall of an arteriole constricts the vesselPrecapillary sphincters control flow of blood between arterioles and venules Circulation of Glucose, Oxygen, and Carbon Dioxide

Fig. 42-15 Precapillary sphincters Thoroughfare channel Arteriole Capillaries Venule (a) Sphincters relaxed (b) Sphincters contracted Arteriole Venule

Where does the critical exchange of nutrients and gasses takes place in the circulatory system? The critical exchange of substances between the blood and interstitial fluid takes place across the thin endothelial walls of the capillariesThe difference between blood pressure and osmotic pressure drives fluids out of capillaries at the arteriole end and into capillaries at the venule end Circulation of Glucose, Oxygen, and Carbon Dioxide

Fig. 42-16 Body tissue Capillary INTERSTITIAL FLUID Net fluid movement out Direction of blood flow Net fluid movement in Blood pressure Inward flow Outward flow Osmotic pressure Arterial end of capillary Venous end Pressure