TJ Medical Society 2008
A Presentation brought to you by:
Alison Jarmas, Jerry Liu, Nikhil Prakash, Jimmy Wu, Judy Zeng, and the Officer Corps.
Blood Circulation and AtriaBlood Circulation and Atria
Blood enters heart through veins: Superior vena cava and Inferior vena cava.
Heart muscles in atria contract- push blood into ventricles
Ventricles force blood through the arteries.
Blood, oxygenated by lungs, flows into left chambers of the heart
Aorta pushes blood from heart to the body
Blood FlowBlood Flow Deoxygenated Blood Deoxygenated Blood
Oxygenated Blood Oxygenated Blood
Blood from tissues throughout body Blood from tissues throughout body Superior and Inferior vena cava Superior and Inferior vena cava
Right Atrium Right Atrium Tricuspid Valve Tricuspid Valve Right Ventricle Right Ventricle
Pulmonary Semilunar Valve Pulmonary Semilunar Valve Pulmonary Artery Pulmonary Artery
LungsLungs
Blood FlowBlood Flow Deoxygenated Blood Deoxygenated Blood
Oxygenated Blood Oxygenated Blood
Pulmonary Veins Left Atrium
Bicuspid (Mitral) Valve Left Ventricle
Aortic Semilunar Valve Aorta
Body Tissue
Hearts have right and left atria
Atria relax to fill with blood
Atria contract to release blood to body
Chambers of heart with thin walls
Diastole and SystoleDiastole and Systole
Consists of cyclic periods of high or low blood pressure, measured in mmHg
Systole – all four heart chambers simultaneously contract to propel blood through the cardiovascular system; causes increased pressure on arterial walls
Diastole – the period of relaxation during which blood flows back into the atria and ventricles; causes decreased pressure on arterial walls
Represented as systole/diastole (ie. 120/80)
RED – aortic pressureBLUE – left ventricular pressureYELLOW – left atrial pressure
Ventricles and the Ventricles and the “Cardiums”“Cardiums”
Ventricles Myocardium –
muscle tissue Endocardium –
tissue that lines the interior of heart
Pericardium – sac that contains heart and roots of great blood vessels
Valves, Muscles, TendinaeValves, Muscles, Tendinae
http://www.mitroflow.com/immagini/bassa/0_2005127191719-patients_chambers.jpg
Allows blood to enter ventricles Prevents backflow into atriums Connected to papillary muscles by
chordae tendinae Tricuspid (right AV)
◦ 3 membrane flaps between right atrium and ventricle
Bicuspid (mitral or left AV)◦ 2 membrane flaps between left atrium and
ventricle
Prevents backflow from arteries to ventricles
3 small membranous pockets; crescent-shaped flaps of endocardium
Pulmonary (right)◦ Connects pulmonary trunk to right ventricle
Aortic (left)◦ Connects aorta to left ventricle
Flaps of muscles connected to various valves on one end by chordae tendinae and to ventricular walls on the other
Stabilize valves
“heartstrings” Connective tissues connecting valves to
papillary muscles Prevent valves from being turned inside out
www.byedr.com/medicine/1781-medicine-5.html
AortaAorta
The largest artery in the body: stems from LV and brings oxygenated blood to all parts of
body in systemic circulation.
Diagram of Aorta in SHEEP
Pulmonary CirculationPulmonary Circulation
Serves to oxygenate the depleted blood Circuit led in to by the pulmonary trunk
(artery) Systemic circulation vena cava right
atrium right ventricle pulmonary artery (right and left) lungs (capillary beds) pulmonary veins (right and left) left atrium left ventricle aorta systemic circulation
Arterioles intertwined with tubular bronchioles bring deoxygenated blood away from the heart
Capillary beds in the saclike alveoli have increased surface area for gas exchange by diffusion (facilitated by a partial pressure gradient)
Venules carry newlyoxygenated bloodback to the heart
A blood vessel that ALWAYS carries blood toward the heart
Generally contains deoxygenated blood, except for the pulmonary and umbilical veins
Path: Right Atrium Right Ventricle Pulmonary Arteries Lungs Becomes oxygenated
Very low blood pressure- rely on skeletal-muscle pump
Smallest veins are the venules
Three Layers◦ Tunica Adventitia: Outer
covering of vessel; composed of connective tissue, collagen, and elastic fiber
◦ Tunica Media: Middle layer; composed of smooth muscle and elastic fiber
◦ Tunica Intima: Inner layer; composed of an elastic membrane lining and smooth endothelium
Types: Portal and
Nonportal Superficial and
Deep Pulmonary and
Systemic
Major Ones: Great Saphenous
vein (GSV) – located in lower limbs
Pulmonary veins: carry oxygenated air to the lungs
Jugular Vein Inferior and
Superior Vena Cava
Cranial/Caudal Vena CavaCranial/Caudal Vena Cava
Cranial/Caudal Vena Cava
ArteriesArteries
Arteries are a type of blood vessel in the circulatory system. They generally carry blood away from the heart to the rest of the body.
The further away from the heart, the smaller the arteries get until they become arterioles
Arteries are tough on the outside, muscular in the middle to help force blood throughout, and smooth on the inside.
Generally arteries are thicker than veins because they need to withstand greater pressure
Aorta Common carotids Common iliacs Pulmonary trunk
Arterioles, Venules, Arterioles, Venules, CapillariesCapillaries
http://www.deconstructdesign.com/st_projects/mm_mania_2003/the_heart/functions.htm
Capillaries are the connectors between arterioles and venules. ◦ Smallest blood vessels that are involved in
regulation of osmotic pressure (internal body heat)◦ Capillary wall consists of only the endothelium.
Venules are small blood vessels that allow deoxygenated blood to flow from capillary beds to veins. ◦ Has endothelial membrane, muscle/elastic tissue,
and fibrous connective tissue.
Arterioles are the blood vessels from the arteries to the capillaries.
Blood pressure in arteries = result o work needed to pump cardiac output through the vascular resistance.
© TJHSST Medical Society 2007-2008