Anatomy and Physiology Exam: Cardiovascular/ Immune / Lymphatic

Pericardium

doubled-walled sac that surrounds the heart; has two layers

Parietal layer

lines the internal surface of the fibrous pericardium

Visceral layer (epicardium)

The external surface of the heart

Myocardium

circular or spiral bundles of cardiac contractile muscles

Endocardium

innermost layer; is continuous with endothelial lining of blood vessels; lines the heart chambers and covers cardiac skeleton of valves

Atria

the receiving chambers; small, thin-walled chambers that contribute little to the propulsion of blood

Right atrium

receives deoxygenated blood from the body

What three veins empty into the right atrium

Superior vena cava, inferior vena cava, and coronary sinus

Superior vena cava

returns blood from body regions above the diaphragm 

Inferior vena cava

returns blood from body regions below the diaphragm

Coronary Sinus

return blood from coronary veins

Left Atrium

receives oxygenated blood from the lungs

Ventricles

the discharging chambers

right ventricle

most of the anterior surface; pumps from body regions below the diaphragm

Left ventricle

posteroinferior surface; pumps blood into the aorta

Trabeculae carneae

Irregular ridges of muscle on ventricular walls

papillary muscles

project into the ventricular cavity

Atrioventricular valves

Located between the atria and the ventricles; they prevent backflow into the atria when the ventricles contract

Tricuspid valve (right AV valve)

made up of three cusps and lies between the right atria and ventricle

Mitral valve (left AV valve)

made up of two cusps and lies between the left atria and ventricle

Chordae tendieae

Anchor cusps of AV valves to papillary muscles that function to: hold valve flaps in the closed position, and prevent flaps from everting back into atria

Semilunar valves

Located between the ventricles and major arteries; prevent backflow from major arteries back into the ventricles; each valve consists of three cusps that roughly resemble a half moon

Pulmonary semilunar valve

located between the right ventricle and pulmonary trunk

Aortic semilunar valve

Located between the left ventricle and aorta

pathway of blood through the right side of the heart

Superior vena cava (SVS), inferior vena cava (IV), and coronary sinus -> right atrium -> tricuspid -> right ventricle -> pulmonary semilunar valve -> pulmonary trunk -> pulmonary arteries ->  lungs \`

Pathway of blood though the left side of the heart

Four pulmonary veins -> left atrium -> mitral valve -> left ventricle -> aortic semilunar valve -> aorta-> systemic circulation 

Coronary circulation

functional blood supply to the heart muscle itself; shortest circulation and delivered when the heart is relaxed; both left and right coronary arteries arise form the base of the aorta and supply arterial blood to the heart

Left coronary artery

supplies the interventricular septum, anterior ventricular walls, left atrium, and posterior wall of the left ventricle; has two branches

the right coronary artery

Supplies the right atrium and most of the right ventricle; has two branches

what are the two branches of the left coronary artery

anterior interventricular artery

circumflex artery

what are the two branches of the right coronary artery

posterior interventricular artery

right marginal artery

Angina pectoris

thoracic pain is caused by a fleeting deficiency in blood delivery to the myocardium; cells are weakened

Myocardial infarction (heart attack)

prolonged coronary blockage; areas of cell death are repaired with non contractile scar tissue

Arrhythmias

irregular heart rhythms

Fibrillation

rapid, irregular contractions; the heart becomes useless for pumping blood, causing circulation to cease; may result in brain death

P wave

depolarization of SA node and atria

QRS complex

Ventricular depolarization and atrial repolarization

T wave

ventricular repolarization

P-R interval

beginning of the atrial excitation to beginning of the ventricular excitation

S-T segment

entire ventricular myocardium depolarized

Q-T interval:

the beginning of ventricular depolarization through ventricular repolarization

Systole

the period of heart contraction

Diastole

the period of heart relaxation

End Diastolic Volume (EDV)

volume of blood in each ventricle at the end of ventricular diastole

isovolumetric contraction

atria relax and ventricles begin to contract

End Systolic Volume (ESV)

the volume of blood remaining in each ventricle after systole

Lub-dub

two sounds; the first sound is the closing of the AV valves at the beginning of the ventricular systole; the second sound is the closing of SL valves at the beginning of the ventricular diastole

Heart Murmurs

abnormal sounds heard when the blood hits obstructions, usually indicating valve problems

Incompetent (or insufficient) valve

fails to close completely, allowing backflow of blood

Stenotic valve

fails to open completely, restricting blood flow through the valve

Cardiac output

the amount of blood pumped out by each ventricle in 1 minute

* CO = HR(heart rate) x SV(stroke volume) 

Preload

degree of stretch of heart muscle just before the contract

Frank-Starling Law of the heart

the relationship between the preload and SV

Afterload

back pressure exerted by arterial blood that the ventricles need to overcome to eject blood 

The sympathetic nervous system

can be activated by emotional or physical stressors; the pacemaker fires more rapidly, increasing HR, also increased contractility 

The parasympathetic nervous system

opposes sympathetic effects; it slows down HR

Blood vessels

a delivery system of dynamic structures that begins and ends at the heart; works with the lymphatic system to circulate fluids 

Arteries

carry blood away from the heart; oxygenated except for pulmonary circulation and umbilical vessels of the fetus

Capillaries

direct contact with tissue cells; directly serve cellular needs

Veins

carry blood towards the heart; deoxygenated except for pulmonary circulation and umbilical vessels of the fetus 

Tunica intima 

Innermost layer that is is “intimate” contact with blood 

Tunica media

The middle layers are composed mostly of smooth muscle and sheets of elastin; the bulkiest layer is responsible for maintaining blood flow and blood pressure 

vasoconstriction

decreased lumen diameter

Vasodilation

 increased lumen diameter

Tunica externa

The outermost layer of the wall; is composed mostly of loose collagen fibers that protect and reinforce the wall and anchor it to surrounding structures 

Vasa vasorum

a system of tiny blood vessels found in larger vessels 

Capillaries

endothelium with the sparse basal lamina 

Endothelium

simple squamous epithelium that lines the lumen of all vessels 

Elastic arteries

thick-walled with large, low-resistance lumen; they conduct blood from the heart to the medium vessels; act as pressure reservoirs 

Muscular arteries

distributes blood to the body's organs; have the thickest tunica media 

Arterioles

smallest of all arteries; control flow into the capillary beds via vasodilation and vasoconstriction of smooth muscle 

Veins

carry blood toward the heart; consists of endothelium and very porous

Venous valves

prevent backflow of blood; most abundant in veins of limbs

Venous sinuses

flattened veins with extremely thin walls; composed only of endothelium 

Blood flow

volume of blood flowing through a vessel, organ, or entire circulation in a given period 

Blood pressure

force per unit area exerted on the wall of blood vessels by blood 

Blood viscosity

the thickness or “stickiness” of blood due to formed elements and plasma proteins; increased viscosity equals increased resistance 

Total blood vessel length

the longer the vessel. The greater the resistance encountered 

Blood vessel diameter

has the greatest influence on resistance; frequent changes alter peripheral resistance 

Systolic pressure

pressure exerted in the aorta during ventricular contraction 

Diastolic pressure

lowest level of aortic pressure when the heart is at rest

Pulse pressure

the difference between systolic and diastolic pressure 

Pulse

throbbing of arteries due to the difference in pulse pressure, which can be felt under the skin 

Mean Arterial Pressure (MAP)

pressure that propels blood to tissues

Muscle pump

contraction of skeletal muscles “milk” blood back toward the heart; valves prevent backflow 

Respiratory pump

pressure changes during breathing moving blood toward the heart by squeezing abdominal veins as thoracic veins expand 

Sympathetic vasoconstriction

under sympathetic control, smooth muscles constrict, pushing blood back toward the heart 

Hypertension

 sustained elevated arterial pressure of 140/90 mm Hg or higher; causes heart failure, vascular disease, renal failure, and stroke

Primary hypertension

90% of hypertensive conditions, no underlying cause

Secondary hypertension

less common, due to identifiable disorders including obstructed renal arteries, kidney disease, and endocrine disorders such as hyperthyroidism and Cushing’s syndrome 

Hypotension

low blood pressure below 90/60 mm Hg 

Lymphoid organs and tissues

provide the structural basis of the immune system by housing phagocytic cells and lymphocytes 

Lymphatic vessels (lymphatics)

 an elaborate network of drainage vessels

T cells

manage immune response, and some also attack and destroy infected cells 

B cells

produce plasma cells, which secrete antibodies

Primary lymphoid organs

areas where T and B cells mature - red none marrow and thymus 

Secondary lymphoid organs

areas where mature lymphocytes first encounter their antigen and become activated

Innate (nonspecific) defense system

Constitutes first and second lines of defense 

* The first line of defense: external body membranes (skin and mucosae) 
* The second line of defense: antimicrobial proteins, phagocytes, and other cells 9inhibit spread of invaders; inflammation mot an important mechanism 

Adaptive (specific) defense system

The third line of defense attacks particular foreign substances (takes longer to react) 

Natural Killer (NK) Cells

Nonphagocytic, large granular lymphocytes that police blood and lymph; kill by inducing apoptosis in cancer cells and virus-infected cells