Chapter 14 Cardiovascular System

erythrocytes

red blood cells are the planes, trains, and cars that move oxygen and other substances from place to place.

leukocytes

white blood cells are the military vehicles ready for battle at a moments notice.

thrombocytes

the platelets or EMTs the first responders to the scene of a vessel wall injury

cardiovascular system

aka circulatory system, it is responsible for the movement of blood and everything it carries through the body. It is made up of the heart, blood vessels, and blood.

arteries

carry blood away from the heart

veins

carry blood to the heart

capillaries

form the transition between arteries and veins

pulmonary and systemic circulation

two parts that blood cycles through a figure 8 configuration

pulmonary circulation

right side of the heart controls this circulation. It receives deoxygenated blood from the body and pumps it into the lungs where it becomes oxgenated.

Systemic circulation

left side of the heart controls this circulation, oxygenated blood from the lungs and pumps it into the body

mediastinum

the heart is located here between the lungs and it is bound cranially by the thoracic inlet, caudally by the diaphragm, ventrally by the sternum, and dorsally by the spinal column.

mediastinum contents

contains blood vessels, thoracic portion of the trachea, the esophagus, thymus (young animals), lymph nodes, and nerves.

base of the heart

rounded cranial end that is shifted to the right and faces dorsally

apex of the heart

more pointed caudal end that is shifted to the left and sits more ventrally

pericardium

divided into two parts: pericardial sac and serous pericardium, it is the sac that contains the heart.

pericardial sac

the fibrous sac that is loose so the heart can beat but is not elastic

serous pericardium

2 membranes parietal and visceral later

parietal layer

lines the pericardial sac

visceral layer

membrane that lies directly on the heart

pericardial space

area between the two serous membranes

pericardial fluid

fluid that lubricates the two membranes

myocardium

middle and thickest layer made up of cardiac muscle (held together by intercalated disks) in sheets that wrap around the chambers of the heart

autorhythmic

doesnt fatigue and beats continually

epicardium

the outermost layer that lies on the outside of the myocardium aka the visceral layer.

endocardium

membrane that lies on the internal surface of the of the myocardium (thin, flat, squamous cells) forms the lining of the heart.

myocardium characteristics

not smooth, form ridges and nipple like projections called papillary muscles

atria

receive blood into the heart, for m the base of the heart

ventricles

pump blood out of the heart, form the apex of the heart

interatrial septum

separates the left and right atrium

auricles

blind pouches that come off the main part of the atria and look like ear flaps (term cannot be used interchangeably)

myocardium of the atrium

not very thick because it only has to contract enough force to move blood into a ventricle

interventricular septum

separates the left and right ventricles

atrioventricular septum

formed by interatrial and interventricular septums

interventricular groove

an area of the interventricular septum which is visible on the outside of the heart and contains coronary blood vessels that is filled with fat.

pulmonary artery

right ventricle pumps blood to pulmonary circulation through a one way valve called

Aorta

left ventricle pumps blood to systemic circulation through a one-way valve called

right ventricle wall

wall that doesn‘t have to go as far so it is thinner

left ventricle wall

wall that has to do the most work by pumping blood to the rest of the animal, walls are thicker

atrioventricular valve (AV valves)

valve located between atria and ventricles

Right AV Valves

consists of three cusps of endothelium aka tricuspid, it opens when pressure from the right atrium allows blood to flow into the right ventricle

tricuspid shuts

blood pressure from the right ventricle exceeds the pressure of blood in the right atrium and causes what valve to shut

Chordae tendon

collagen fiber chords that prevent the tricuspid valve from opening backea

Left AV valve

consists of 2 cusps aka bicuspid aka mitral valve

Semilunar valves

2 valves that control the blood flow out of the ventricle into the artieries

Right semilunar valve

aka pulmonary valve bc blood from right ventricle flows through pulmonary circulation

Left semilunar valve

aortic valve bc blood from the left ventricle flows through it into the aorta (systemic circulation)

skeleton of the heart

located btwn the atria and ventricles made of 4 fibrous connective tissues rings

functions of the heart skeleton

seperates atria

defilbrillation

process that has to do with the electrical conduction of the heart

ectopic

means out of place

ectopic pacemaker

outside of the hearts normal pacemaker which is in the sinoatrial node (SA node) in the right atrium

ventricular fibrillation

a condition that will develop in which the heart muscle cells in different areas contract independently from one another, the pumping activity is lost in the ventricle.

cardiac cycle

one cycle of atrial and ventricle contraction and relaxation, produces a heartbeat

heartbeat travels

impulse is generated by SA node and travels from the base of the heart to the apex and back to the base

Sinoatrial node (SA node)

the pacemaker of the heart located on the wall of the right atrium

Sodium and calcium ions

located on the outer membrane of the cardiac cell

Potassium

located on the inside of the cardiac cell

cardiac conduction system

SA node, atrioventricular node (AV), bundle of his fiber, Purkinje fibers

SA node does

initiates the right atrium and spreads waves across both atria, causing them to contract and send blood through the AV valves

Systole

is the myocardium contracting causing a chamber to empty itself of blood, depolarization

Diastole

is the myocardium relaxing and repolarizing after contracting allowing the blood to fill the chambers again, the resting phase

lub

The first heart sound produced when the tricuspid and mitral valve snap shut after the atrial systole

dub

2nd heart sound produced after the ventricular systole when pulmonary and aortic or semilunar valve shut

valvular insufficiency

a heart condition where one or more of the cardiac valves doesn’t close all the way aka murmur

murmur

caused by blood backflowing abnormally into the chamber

valvular stenosis

is a heart condition where any one or more of the cardiac valves don’t open all the way , the murmur is caused by blood flowing through a partially open valve and producing the same whooshing sound

cardiac output (CO)

the volume of blood that is ejected out to the left ventricle over a unit of time usually one minute, 2 factors determine the CO stroke volume and heartrate

Congestive heart failure

occurs when the pumping ability of the heart decreases usually due to the disease of the heart muscle or a valve malfunction

ascites

fluid in the abdomen

edema

fluid in the tissues

pulmonary edema

due to the left side of the heart failing and venous return from the lungs decrease causing respiratory issues

glycosides

medication used to treat CHF it increases the strength of the cardiac contraction

diuretics

medication to help treat CHF used to promote elimination of extra fluid to relieve edema

Vasodilators

medication to treat CHF used to enhance blood flow to organs and decrease vascular resistance

stroke volume

the volume of blood ejected from the left ventricle during one contraction or systole aka systolic discharge

heart rate

the number of times the ventricle contracts or beat in one minute

2 facts that determine stroke volume

preload and afterload

preload

the volume of blood the ventricle receives from the atrium

afterload

the physical resistance presented by the artery the ventricle is ejecting blood into

endothelium

inner layer that lines the lumen of the vessel, composed of thin simple squamous epithelium

middle layer of blood vessels

made of smooth muscle, elastic fiber, or both pertaining to the blood vessel walls

outer layer of blood vessel

composed of the fibrous connective tissue and collagen fiber, it is string and flexible and prevents walls from tearing

2 types of arteries

elastic and muscular

elastic arteries

arteries that have the best ability to stretch when blood passes through

what is the largest elastic artery

aortic

muscular arteries

arteries that have more smooth muscle fibers than elastic fiber muscles

arterioles

the smallest branches of the arterial tree

capillaries

arterioles branch into many microscopic blood vessels, they do not occur singly but in groups

venules

capillaries join together to form these

veins

venules join together to form these, the largest is the vena cava

umbilical vein

fetus receives oxygen through the placenta from the materal circulation through this vein

foramen ovale

first bypass btwn the right and left atria in the fetus

ductus arterious

blood form the pulmonary artery may flow into the lungs through this other bypass (fetus)

umbilical arteries

deoxygenated blood is sent back to the placenta for oxygenation through this artery (fetus)

ductus arteriousus

shortcut opening btwn pulmonary artery and aorta, closes soon after birth

patent ductus arteriosus

opening fails to close in the newborn causing inadequate oxygen for their blood and or death

pulse

the rate of alternating stretching and recoiling of the elastic fibers in an artery as blood passes through with each heartbeat

pulse wave

every time the left ventricle contracts it ejects bolus of blood into aorta. when left ventricle relaxes blood flows into the aorta stop

femoral artery

cat, dog, sheep, goat, and piglet pulse point

coccygeal and facial artery

cow pulse point