Circulatory System

Protection

• limits spread of infection

• destruction of microorganisms and cancer cells

• neutralization of toxins and pathogens

• clotting to minimize blood loss

Heart Pumping

• the heart creates enough pressure to overcome resistance in the arteries (left ventricle contracts and pressure increases or blood is forced into the aortic arch and pressure increases)

Heart Wall

• consists of three layers

• epicardium

• myocardium

• endocardium

Epicardium

• outermost layer of the heart wall

• visceral layer of the pericardium

• sometimes overlying a layer of adipose tissue

• largest branches of coronary blood vessels found here

• mainly consists of simple squamous epithelium

Myocardium

• thickest muscle tissue of heart

• middle layer of the heart wall

• main cardiac muscle

• thickness is proportional to the workload of each individual chambers

Endocardium

• lines the interior of the heart chambers (inner layer of the heart wall)

• simple squamous epithelium

• no adipose tissue

• thickness varies inversely with the thickness of the myocardium

Right Atrium

• receives blood from the superior vena cava, inferior vena cava and coronary sinus

• covered externally by the right auricle

Right Venticle

• blood from right atrium passes through the tricuspid valve and enters the right ventricle

• covers most of the anterior portion of the heart

• blood is pumped into pulmonary circulation through the pulmonary trunk

Left Atrium

• makes up most of the posterior surface of the heart

• receives oxygen-rich blood from the lungs through the two right and two left pulmonary veins

Left Ventricle

• blood enters from the left atrium through the mitral (bicuspid or mitral valve)

• pumps blood into the systemic circuit through the aortic arch

First Step in Blood Movement through the Heart

• deoxygenated blood from the body into the right atrium

Second Step in Blood Movement through the Heart

• enters the right ventricle through the tricuspid valve

Third Step in Blood Movement through the Heart

• blood gas exchange occurs in the pulmonary trunk

Fourth Step in Blood Movement through the Heart

• oxygenated blood enters the left atrium

Fifth Step in Blood Movement through the Heart

• blood enters the left ventricle through the mitral/bicuspid valve

Last Step in Blood Movement through the Heart

• blood is moved into the aorta to be distributed around the body

Lub Sound

• atrioventricular valve closes

• ventricular pressure is greater than the atrial pressure

Dub Sound

• semilunar (aortic and pulmonary) valves close

• ventricular relaxation begins

Arteries

• carry oxygenated blood away from the heart

• red blood vessels

• have a thick tunica media to provide strength to offset the pressure from heart contraction

• the larger the artery, the more elastic fibers contained in middle layer

Veins

• carry deoxygenated blood to the heart

• blue blood vessels

• tunica media consists of small bundles of smooth muscle cells, reticular fibers, and some elastic fibers

• large veins (close to heart) have thin tunica media and very thick tunica external

• tunica externa is well-developed

• drainage system of the

Capillaries

• gas and nutrient exchange between blood and tissues

• Penetrate tissue to allow for material exchange

• Are the switch between veins and arteries

• Allow for diffusion across their membranes

Elastic Arteries

• very thick walls located near the heart

• makes up the aorta and its major branches

• about 40 layers (laminae) in newborns, 70 in adults

• important in stabilizing blood flow and acts as a pressure reservoir

Differences Between Veins and Arteries

• arteries are always deeps

• veins are deep and superficial

• names of superficial veins are unique (basilic vein)

What vessel is used in diagnostics?

arteries

Vein System for the Brain

Dural Venous Sinuses

Vein System for the Digestive System

Hepatic Portal System

Naming Arteries and Veins

• location

• organ served

• bone followed

What three major veins enter the heart?

• superior vena cava

• inferior vena cava

• coronary sinus

Superior Vena Cava

• drains all body regions superior to the diaphragm

Inferior Vena Cava

• widest vessel in the body

• drains all body regions inferior to the diaphragm

• runs along the side of the abdominal aorta

Movement of Blood in Arteries and Capillaries

• contraction of left ventricle supplies pressure

Left Ventricle Contracting Affecting Large Arteries

• very high blood pressure to high blood pressure

• muscle and elastic expand or contract to maintain the blood pressure

What are the 5 primary functions of blood?

• transport

• Protection against infection

• Regulation on pH

• Maintain body temperature

• Clot formation

Pulmonary vs. Systemic circulation

Pulmonary

• carries deoxygenated blood from the heart to the lungs

• Blood drops of CO2 and picks up oxygen in the lungs

• Carries oxygenated blood from the lungs to the hearts

• Significantly shorter route

Systemic

• carries oxugenated blood from the hearts throughout the body

• Carries deoxygenated blood from the body to the heart

• Significantly longer route

Name the 3 layers of the wall of the heart

• epicardium

• Myocardium

• Endocardium

What are the 4 chambers of the heart

• right atrium

• Left atrium

• Right ventricle

• Left ventricle

What is interventricular septum

The muscular wall that separates the heart into right halves

Name the 4 heart valves

• tricuspid valve

• Bicuspid (mitral) valve

• Pulmonary valve

• Aortic valve

What is the purpose of the chordate tendineae?

To prevent the artioventricular valves from being pushed into the atria during ventricular systole.

Systole

The heart is contracting and blood is pumped out to the entire body.

What produces the S1 sound?

The tricuspid and bicuspid valves closing at the start of systole

What produces the S2 sound

The semi lunar valves closing at the end of systole/ beginning of diastole

What triggers the heart to beat?

The sa node (aka pacemaker)

What is a heart attack

The death of cardiac muscle due to lack of blood or O2

Diffrences between arteries and veins

Arteries

• much thicker walls

• Much more elastic, more rigid

• Carry oxygenataed blood

• The pressure is higher

• You can feel the pulse

• Come from the left ventricles

Veins

• thinner muscle walls

• Elastic

• Carry deoxygenated blood

• Much lower pressure

• 1 way valves

• Blood id going to the right artia ( mostly)

what are the function of the heart valves, tricupid, bicuspid, aortic, pulmonary

• The tricuspid valve prevents backflow from the right ventricle to the right atrium.

• The bicuspid (mitral) valve prevents backflow from the left ventricle to the left atrium.

• The aortic valve prevents backflow from the aorta to the left ventricle.

• The pulmonary valve prevents backflow from the pulmonary artery to the right ventricle.

diastole

The heart is relaxed and blood is refilling