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

Species bpm (range)

Cat 120–140

Chick 350–450

Chicken (adult) 250–300

Dairy cow 48–84

Dog 70–120

Elephant 25–35

Goat 70–80

Guinea Pig 200–300

Hamster 300–600

Horse 28–40

Mouse 450–750

Ox 36–60

Pig 70–120

Rabbit 180–350

Rat 250–400

Rhesus monkey (anesthetized) 160–330

Sheep 70–80

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)

Species Systolic/diastolic(mm Hg)

Mean(mm Hg)

Giraffe 260/160 219

Horse 130/95 115

Cow 140/95 120

Swine 140/80 110

Sheep 140/90 114

Human 120/70 100

Dog 120/70 100

Cat 140/90 110

Rabbit 120/80 100

Guinea pig

100/60 80

Rat 110/70 90

Mouse 111/80 100

Turkey 250/170 190

Chicken 175/145 160

Canary 220/150 185

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