Mammalian Transport System Ch. 8 Part 1

Cardiovascular System Transport system of the body Carries nutrients (Glucose!) and oxygen TO the cells of the body Carries waste products and carbon dioxide (CO2) AWAY from the cells Transports chemical messages between cells (HORMONES) Fights Disease (White blood cells) Contains a variety of proteins

Members of the Cardiovascular System Heart (pump) Blood Vessels Arteries arterioles Veins venuoles Capillaries Blood Members of the Cardiovascular System

Closed, double circulation Closed= b/c blood travels inside vessels Double circulation Systematic circulation Vessels taking blood from left ventricle in heart to cells in tissue throughout the body and back to right atrium Pulmonary circulation Blood taken from right ventricle to lungs and back to left atrium

Click here to see it in action! The Heart Muscular (cardiac muscle) organ in chest 2 pumps (Right and left side) Work together to move blood all around your body Each side has a top (Atrium) and a bottom (ventricle) 4 chambers of heart Heart muscles contract push blood from the heart to the blood vessels

Overview of Heart (more next week) Right Atrium RA Right Ventricle RV Left Atrium LA Left Ventricle LV Aorta Superior/Inferior Vena Cava Pulmonary Artery PA Pulmonary Vein PV

Things to Know ATRIUM Blood is ALWAYS ENTERS atrium VENTRICALS Blood ALWAYS LEAVES the ventricles ARTERY ALWAYS carries blood AWAY from heart VEIN ALWAYS carries blood TOWARDS the heart

Anatomy of a Blood vessel Endothelium Squamous epithelium Single layer Smooth, no friction Rests on elastic fibers Tunica Media Middle layer THICKEST Contains: Smooth muscle Collagen Elastic fibers (tunica intima) Tunica Externa Outermost layer Elastic fibers

Blood Vessels Arteries Veins Capillaries Carry blood AWAY from heart Carry blood back TO the heart Capillaries Teeny, tiny blood vessels that connect to arteries and veins Nutrients and gas can pass through the capillaries from the blood to the cells that need them

Arteries Elasticity important Arteries close to heart Many elastic fibers in tunica media Arteries farthest from heart Less elastic fibers in tunica media More muscle fibers Highest pressure is in arteries Aorta (most pressure) Diameter= 2.5 cm Thickness of wall = 2 mm Arteries have mechanisms to alleviate drastic changes in pressure Ventricle contracts (HP in artery) Arteries widen a little @ HP Helps decrease pressure Ventricle relaxes (LP in artery) Arteries recoil (narrow) at LP Helps increase pressure slightly

Capillaries Tiny vessels Just enough space for Red blood cells to squeeze through Walls are one cell thick Endothelial cells Gaps in walls allow PLASMA to leak out into tissue spaces Function: deliver nutrients, hormones, and other body requirements to cells that make up tissues remove waste products from those cells Small size and thin walls minimize diffusion distance, enabling rapid exchange

Veins Carry low pressure blood back to the heart Walls do NOT need to be tough or elastic Lumen is larger than arteries, reduces friction that would slow down movement of blood Have SEMILUNAR VALVES One way valves that only allow blood into vein (not out) Moves due to contractions in skeletal muscle, pushes blood up against gravity

Pressure Highest pressure in vessels when blood is leaving the heart 120 mmHg or 16kPa 1 mmHg = 0.13 kPa Pressure changes in Circ. Sys. Arteries highest blood pressure Pressure oscillates with heart beat Stretching & recoiling of artery walls helps smooth oscillations so pressure becomes gradually steadier the further the blood moves along the arteries (pressure slowly decreases) Capillaries Total cross-sect. area greater than arteries that supply them Blood pressure is less inside capillaries Veins very low pressure Long way from pumping effect of heart