Gen Bio Circulatory Systems

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Circulatory Systems (Chapter 29)

1. Explain how the efficiency of animal circulatory systems has been improved by the evolution of internal body cavities, open circulatory systems, closed circulatory systems, respiratory pigments, atria and ventricles (29.3)

internal body cavities
* Sluggage seepage moves around body cavity like a whirlpool in insects (No veins) - open * Earthworms developed some veins and 5 hearts in their body cavity (some veins) * Mammals (Humans) have arteries and veins that go to every cell in their whole body - closed

open circulatory systems
* Dorsal heart pumps hemolymph into body cavity * Blood bathes the body tissue directly

closed circulatory systems
* Veins and capillaries bring nutrients, hormones, oxygen and rid CO2 at every cell in the body * Blood pressure due to hearts pumping to small veins makes closed circulatory systems more efficient

respiratory pigments
* Iron-rich protein called Hemoglobin inside red blood cells * Carries up to 4 oxygen molecules
* Also transports CO2

Atria and ventricles
* FISH had 1 of each but it had very low blood pressure. Okay for fish with no lungs (gills do work of 2nd heart) * FROGS 1 ventricle pumps to lungs and body 2 atriums – 1 from body, 1 from lungs, more efficient but moist body surface does gas exchange * HUMANS 2 atriums and 2 ventricles because lungs have no help from any form of external respiratory system * Atrium maximizes how full the ventricles are * Separate ventricles provided better pressure and efficiency to the lungs and body

2. Given a diagram of the human heart, label its structures (including chambers, valves and major blood vessels) and trace the flow of blood through the heart (29.4 A,B) * Deoxygenated blood enters the right side of the heart via the VENA CAVA * The vena cava funnels blood in to the RIGHT ATRIUM * The sinoatrial (SA NODE) pulsates, contracting cardiac muscle of the right atrium (both) * Blood goes down an ATRIOVENTRICULAR VALVE and fills up the RIGHT VENTRICLE * The atrioventricular (AV NODE) sends impulse via BUNDLE OF HIS, right ventricle contracts (both) * Blood goes through PULMONARY ARTERY to the LUNGS to rid CO2 and gain O2 * Freshly oxygenated blood goes through PULMONARY VEIN back to the LEFT ATRIUM * Again, the sinoatrial (SA NODE) pulsates, contracting cardiac muscle of the left atrium (both) * Blood goes down an ATRIOVENTRICULAR VALVE and fills up the LEFT VENTRICLE * The atrioventricular (AV NODE) sends impulse via BUNDLE OF HIS, left ventricle contracts (both) * Blood goes through the AORTA and pumps throughout the body

*FYI – blood branches off he aorta in to the coronary artery to provide blood to the heart muscle

3. Explain how the pumping efficiency of the vertebrate heart has been improved by the evolution of: atria, the AV node, the SA node, the bundle of His, the separation of right and left ventricles, atrioventricular valves and semilunar valves (29.4 B,C). Atria

* Tops off the amount of blood in the ventricles
* Maximizes efficiency by maximizing the amount of blood that is distributed with each pump AV node
* Electrical impulse Makes sure that the atriums contract at a consistent pace, filling the ventricles via AV valves. Pacemaker of the heart. SA node
* Electrical impulse makes sure that the ventricles don’t contract until they are total full bundle of His
* Nervous tissue...
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