cardiovascular system ati teas 7

wall of the heart is composed of 3 layers

epicardium, myocardium, endocardium

outer layer of heart

epicardium, which protects the heart and secretes lubricating serous fluid

myocardium

muscular, middle layer of the heart

endocardium

innermost layer, lines chambers and valves

the heart is a ________ chambered organ

four

superior, "receiving" chambers

atria

receives blood from the vena cava

right atrium

receives blood from pulmonary veins

left atrium

muscular, "discharging" chambers

ventricles

pumps blood into the pulmonary trunk

right ventricle

pumps blood into the aorta

left ventricle

tricuspid valve

prevents back flow of blood into the right atrium when the ventricle contracts

pulmonary semilunar valve

prevents the return of blood into the right ventricle

bicuspid/mitral valve

Prevents blood from flowing back into the left atrium when the ventricle contracts

the thin inner lining of blood vessels

endothelium

blood vessels

carry blood throughout the body

arteries (rich)

oxygenated blood away from heart

veins (poor)

deoxygenated blood back to heart

septum

The wall separating the left and right sides of the heart

capillaries

connect arteries and veins

blood

carries oxygen and nutrients to cells and carbon dioxide and waste way cells

Two Cycles of contractions

systole and diastole

systole

"lub" contraction of the heart

diastole

"dub" relaxation of the heart

deoxygenated blood

veins -> right atrium -> right ventricle -> lungs

oxygenated blood

lungs -> left atrium -> left ventricle -> aorta -> body

systemic circuit

carries blood from the muscular left ventricle of the heart to the aorta

pulmonary circuit

carries blood from the heart to the lungs and back to the heart

electrical conduction system

SA node, AV node, Bundle of His, Purkinje fibers

p wave

represents depolarization of the atria

QRS interval

represents depolarization of the ventricle

P wave of ECG

corresponds to the wave of depolarization that spreads from the sinoatrial node to the atria, representing the activation of the atria.

q wave

- negative wave on ECG

- normal duration is small but actual value will depend on which lead is used to measure the wave in ECG

- often less than 0.03

- enlarged suggests abnormal conduction in the ventricles or a myocardial infarction

r wave

positive wave on an ECG

s wave

negative wave that follows the R wave in the QRS complex

t wave

-positive wave that represents ventricular repolarization

-abnormal t waves may indicate heart disease or electrolyte imbalances

u wave

represents the final repolarization of the ventricles

PR interval

0.12-0.20 seconds

QRS complex

indicates ventricular depolarization

0.06 to 0.1 seconds

ST segment

ventricle is completely depolarized

QT interval

represents the entire action potential

-lasts 0.2 to 0.4 seconds

cardiac arrhythmias

abnormal heart beats

bradyarrhythmia

pulse rates that are abnormally slow

complete AV block

may be congenital or a response to surgical trauma

Sinus Bradycardia

may be caused by autonomic nervous system or a response to hypotension and decrease oxygenation

Junctional (Nodal) Rhythm

often occur in post surgical patients when the absence of the P wave is noted but heart rate and output usually remain stable.

tachyarrhythmia

pulse rates that are abnormally fast

Sinus Tachycardia

often caused by fever or infection

Superaventricular Tachycardia

200 BPM-300BPM

may have sudden onset and result in congestive heart failure

Conduction irregularities

irregular pulses that often occur post-operatively and are usually not significant

premature contractions

May arise from the atria or ventricles

Walls of blood vessels have 3 layers

tunica intima (innermost), tunica media (middle) , tunica externa (outermost)

elastic arteries

-includes aorta and major branches

-tunica media has more elastin than other vessels

-largest vessels in the arterial system

function of elastic arteries

stretch when blood is forced out of the heart, and recoil under low pressure

muscular arteries

-includes arteries that branch off the elastic arteries

-tunica media has a higher proportion of smooth muscle cells, and fewer elastic fibers as compared to elastic arteries

function of muscular arteries

regulate blood flow by vasoconstriction/vasodilation

arterioles

tiny vessels that lead to the capillary beds

-tunica media is thin but composed of almost entirely smooth muscle cells

function of arterioles

primary vessels involved in vasoconstriction/vasodilation, control blood flow to capillaries

venules

tiny vessels that exist the capillary beds

-thin, porous walls; few muscle cells and elastic fibers

function of venules

empty blood into larger veins

veins

thin tunica media and tunica intima, wide lumen, valves prevent backflow of blood

function of veins

carry blood back to the heart

turbulence

unsteady, swirling flow of blood that can occur during periods of high velocity

laminar flow

steady, streamlined flow of blood that occurs throughout most of the circulatory system

intercellular clefts

a channel between two cells through which molecules may travel and gap junctions and tight junctions may be present.

capillaries with a nonporous continuous endothelium are called

continuous capillaries

fenestrated capillaries

have pores that increase their permeability and are found in the kidneys and small intestine

sinusoidal capillaries

discontinuous endothelium that permits the passage of large particles and even blood cells

peripheral resistance

resistance of the vessels to the flow of blood as a result of friction.

blood is a mixture of

plasma, chemicals, and blood cells

plasma is a solution of

water, plasma proteins, carbohydrates, amino acids, lipids, vitamins, salts, gases, hormones, and waste products

about 92% of plasma is

water

most of the cells in blood are

red blood cells

percentage of red blood cells by volume is called

hematocrit

platelets

• are cell fragments that allow blood to clot

Erthropoiesis

occurs in red bone marrow

Erthyropoietin

Kidney hormone that promotes red blood cell formation

myeloid stem cells

give rise to all other blood cells

erthyroblasts

immature RBCs, divide many times, filling up with newly synthesized hemoglobin

reticulocytes

immature red blood cells, in the bone marrow

lymphocytes

are a special type of white blood cell that play an important role in the immune system. B cells and T cells are the two types of lymphocytes

monocyte

white blood cell characterized by a well defined nucleus. produced in bone marrow

granulocyte

a type of white blood cell that contains granules of chemicals that are used to fight threats, such as pathogens

individuals with blood type A have

A antigens

individuals with blood type B

have B antigens

individuals with blood type AB

have A and B antigens

individuals with blood type O have

neither A nor B antigens

individuals with blood type A produce

anti-B antibodies

individuals with blood type B produce

anti-A antibodies

individuals with blood type AB

produce no antibodies

those with type O blood produce

anti A and anti B antibodies

hemoglobin

Oxygen carrying pigment in red blood cells

protoporphyrin

heme group consists of a single iron atom surrounded by a complex organic ring called

The oxygenated form of hemoglobin is called

oxyhemoglobin

carbaminohemoglobin

CO2 combined with hemoglobin

function 1 of cardiovascular system

delivers oxygen and nutrients to the cells of the body and removes carbon dioxide and waste

function 2 of cardiovascular system

maintains body's blood pressure

function 3 of cardiovascular system

regulates body temperature

function 4 of cardiovascular system

maintaining body's pH

functions 5-8 of cardiovascular system

-transporting hormones

-fighting infections

-aiding in digestion

-assisting in repair of damaged tissues