Cardiovascular System and Blood Vessels

Anatomy of the Heart

Great vessels

Valves

Muscles of the heart

Four Chambers

Right Ventricle

Left Atrium

Right Atrium

Left ventricle

Valves have muscles attached

Valves do not have muscles attached

Bicuspid valve

Tricuspid valve

Also known as the Right Atrioventricular valve

Also known as mitral valve or Left atrioventricular valve

Pulmonary semilunar valve

Aortic semilunar valve

Arteries transport blood away from the heart

Veins transport blood towards the heart

Pulmonary trunk transports from the right side

Vena cavae (superior and inferior) drain into the right side

Aorta transports from the left side

Pulmonary veins drain into left side

Myocardium

Endocardium

Epicardium

outermost heart layer

middle layer of the heart

internal surface of the heart and the external surfaces of the heart valves

simple squamous epithelium and areolar connective tissue and adipose connective tissue

cardiac muscle

simple squamous epithelium and areolar connective tissue

Septum

Interatrial

Interventricular

Right and left atrial chambers are separated by a thin wall

Right and left ventricles are separated by a thick wall

Papillary muscles

Pectinate muscles

Found in the right and left atrium

Found in the right and left ventricles

Right ventricle extending from the internal wall are typically 3 cone-shaped, muscular projections

Muscular ridges found on the anterior wall and within the auricle

The number of papillary muscles can range from 2-9

Left ventricle extending from the internal wall are 2 cone-shaped, muscular projections

Papillary muscles anchor thin strands of collagen fibers called chordae tendineae

Electrical conduction

Atrioventricular bundle (AV) also called the bundle of His, extends from the AV node into and through the inter ventricular septum. It divides into left and right bundles.

Purkinje fibers extend from the left and right bundles from the apex of the heart and then continue through the walls of the ventricles.

Atrioventricular node (AV) is located in the floor of the right atrium between the right AV valve and the opening for the coronary sinus.

Heart rate is initiated by the SA node, both heart rate and the strength of the contraction are regulated by the autonomic nervous system.

Sinoatrial node (SA) is located in the posterior wall of the atrium, adjacent to the entrance of the superior vena cava.

Cardiac muscle contraction

Blood vessels

Capillaries

Veins

Arterioles

Venules

Arteries

Terms related to heart function

End diastolic volume

End systolic volume

Heart rate

Venous return

Stroke volume

Preload

Cardiac output

Afterload

Frank-Starling Law

Cardiac muscle tissue is made up of relatively short, branched cells that usually house one or two central nuclei

These muscle cells are supported by areolar connective tissue, called endomysium, that surrounds the cells.

The cells here initiate the heartbeat and are commonly referred to as the pacemaker of the heart.

Sympathetic innervation

Parasympathetic innervation

Cardioacceleratory center sends nerve signals along sympathetic nerves, which results in an increase in both heart rate and force of contraction.

Cardioinhibitory center sends nerves signals along vagus nerves (CN X), which results in a decrease in heart rate and contraction.

Cardiac cycle

  1. Ventricular ejection
  1. Isovolumetric relaxation
  1. Atrial relaxation and ventricular filling
  1. Isovolumetric contraction
  1. Atrial contraction and ventricular filling

Ventricles are filled and hold their maximum blood volume approximately 130 mL of blood

Amount of blood pumped out during ventricular systole approximately 70 mL of blood

Not all blood in either ventricle is ejected, the blood remaining in a ventricle after systole; ESV is found by subtracting SV from EDV

the amount of blood that is pumped by a single ventricle in 1 minute; HR x SV=CO

number of beats per minute

stretch of the heart wall due to "the load to which cardiac muscle is subjected before shortening

the volume of blood entering the heart increases, there is a greater stretch of the heart wall. This results in a greater overlap of the thick and thin filaments in the sarcomeres of the cardiac muscle cells composing the myocardium.

volume of blood returned to the heart via the great veins and is directly related to stroke volume

resistance in arteries to the ejection of blood by the ventricles and it represents the pressure that must be exceeded before blood is ejected from the chamber

blood away from the heart

thicker

exchange of substances between blood and tissues

bring blood towards the heart

thinner lined walls

have valves

smallest arteries, with diameters ranging from 0.3 mm to 10 micrometers

smallest veins, measuring from 8 to 100 micrometers in diameter