Anatomy and Physiology Cardiovascular System

Heart Cone shaped Muscular Large arteries and veins continuous at base Surrounded by pericardium

Myocardium Muscular part of heart Forms walls for the chambers When muscle fibers contract, blood is ejected from the chambers

Heart Valves Located between the atria and ventricles are called atrioventricular (A-V) valves Valve on right = tricuspid valve (3 cusps) Valve on left = bicuspid valves (2 cusps) Prevent expulsion of ventricular blood into atria when ventricles contract

Blood Flow Through the Heart Blood from the body flows to the superior and inferior vena cava –then to the right atrium –through the tricuspid valve –to the right ventricle –through the pulmonic valve –to the pulmonary artery –to the lungs Why does blood need to go to the lungs before it goes to the rest of the body?

Blood Flow Through the Heart The blood picks up oxygen in the lungs, and then flows from the lungs –to the pulmonary veins –to the left atrium –through the mitral valve –to the left ventricle –through the aortic valve –to the aorta –to the body

Resting Heart Rates a Speciesbpm (range) Cat120–140 Chick350–450 Chicken (adult)250–300 Dairy cow48–84 Dog70–120 Elephant25–35 Goat70–80 Guinea Pig200–300 Hamster300–600 Horse28–40 Mouse450–750 Ox36–60 Pig70–120 Rabbit180–350 Rat250–400 Rhesus monkey (anesthetized)160–330 Sheep70–80 a Adapted from Detweiler D.K. and Erickson H.H., Regulation of the Heart, in Dukes' Physiology of Domestic Animals, 12th ed., Reece W.O., Ed. Copyright 2004 by Cornell University

Blood Pressure (measured in millimeters of mercury) Systolic BP –top number –measures the pressure in the arteries when the heart beats (when the heart muscle contracts) Diastolic BP –bottom number –measures the pressure in the arteries between heartbeats (when the heart muscle is resting between beats and refilling with blood)

SpeciesSystolic/diastolic (mm Hg) Mean (mm Hg) Giraffe260/ Horse130/95115 Cow140/95120 Swine140/80110 Sheep140/90114 Human120/70100 Dog120/70100 Cat140/90110 Rabbit120/80100 Guinea pig100/6080 Rat110/7090 Mouse111/80100 Turkey250/ Chicken175/ Canary220/ Characteristic Blood Pressures in Adult, Resting Animals Species Detweiler D.K. and Erickson H.H., Regulation of the Heart, in Dukes' Physiology of Domestic Animals, 12th ed., Reece W.O., Ed. Copyright 2004 by Cornell University Determines average rate at which blood flows through the vessels