Cardiovascular System

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Cardiovascular System
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I. Anatomy of the Heart
A. Coverings
1. Pericardium

• fibrous pericardium

• parietal pericardium

• visceral pericardium

B. Heart wall layers

1. Epicardium (visceral
pericardium)

• protects heart

2. Myocardium cardiac muscle
3. Endocardium epithelial/
connective/ fibers
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C. Chambers, Vessels, and Valves
1. Four chambers

• upper chambers rt and left atria

Collects blood

• lower chambers rt and left ventricle

pumps blood from heart
2. Arteries

• carry blood away from heart

3. Veins

• blood toward heart

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4. Valves

• AV valves

Tricuspid rt atrium
Bicuspid or mitral - lt atrium

• Semilunar valves

Pulmonary semilunar (pulmonary trunk)
Aortic semilunar (aortic arch)
II. Pulmonary and Systemic Circulation
A. Pulmonary pathway
oxygenated blood rt ventricle from
rt atrium
myocardium (rt ventricle) contracts
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low oxygen blood through pulmonary
semilunar
pulmonary trunk -gt arteries -gt lungs
oxygenated blood -gt rt lt pulmonary
veins -gt
left atrium
B. Systemic pathway
Oxygenated blood -gt lt atrium to lt
ventricle
Left ventricle contracts -gtaortic
semilunar
Aortic arch -gt arteries to tissues
oxygen depleted blood from tissues -gt
veins to heart -gt rt atrium (vena cava)
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III. Cardiac cycle and heart sounds
1. Diastole - relax

• atrial diastole atria fill valves closed

• ventricular diastole ventricles fill

2. Systole - contraction

• atrial systole contracts blood to ventricles

• ventricular systole closes AV valves/open
  semilunar

3. Sounds
Lubb - dubb
Lubb AV close dubb semilunar
close
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IV. Cardiac Conduction
A. Cardiac muscle

• sarcomeres

• contraction similar to skeletal

• intercalated disks

B. Signal conduction

• specialized cardiac cells

Undergo AP spontaneously
Sinoatrial (SA node) pacemaker
Atrioventricular node (AV)
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Signal pathway

• SA action potentials -gt contraction in atrium

• AV action potentials (slower) -gt bundle of HIS-gt

through septum -gt Purkinje
fibers -gt contraction
C. Electrocardiography

• electrical events corresponding to mechanical

• P wave atrial fibers depolarize

• QRS complex ventricles depolarize

• T wave ventricles repolarize

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D. Regulation

• ANS Sympathetic Parasympathetic

Sympathetic Norepinephrine
increase (Na)
Parasympathetic Acetylcholine
decrease (K)

• Hormones

Epinephrine/Norepinephrine/T3,T4

• Ions K/Ca2

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V. Physiology of Circulation
A. Pulse

• ejection of blood from lft ventricle (wave)

• pressure through arteries heart beat/min

B. Blood Pressure

• pressure blood exerts on walls of arteries

• measurements systolic pressure

peak of ventricular
contraction
diastolic pressure ventricles
relaxed 120/70
C. Factors affecting pressure

• Neuronal in CO2,O2,pH

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increase in CO2 / decrease pH
-gt Sympathetic norepinephrine -gt
vasoconstriction

• Chemicals Histamine (immune response)

-gt vasodilation

• Temperature cold exposure -gt vasoconstriction