Cardiovascular System

Blood

Heart

Blood Vessels

Pericardial Membranes

Layers of Heart Wall

Microscopic Anatomy - Myocardium

Heart Valves

Conduction System

Artery Types

Capillary Types

Vein Types

Plasma

Blood Cells

Blood is a connective tissue; it has spaced cells & extracellular matrix called plasma

Extracellular matrix. Is 90% liquid and > 100 different molecules (ions, minerals, hormones, sugars, etc.)

Created in red bone marrow

Erythrocytes lose some organelles and nucleus before release into bloodstream

Erythrocytes are biconcave for increased surface area

Erythrocytes have hemoglobin to bind to oxygen for transport and diffusion

Leukocytes

Play a role in immunity

There are neutrophils, basophils, eosinophils, lymphocytes, and monocytes.

Thrombocytes or platelets

Pieces of large megakaryocyte cytoplasm

Aid blood clotting with help of fibrinogen

Proteins

Albumin

(Immuno)globulins

A.K.A antibodies, some transport hydrophobic substances

Helps keep water in capillaries

Fibrinogen

Involved in blood clotting (with thrombocytes)

Elastic/Conducting Arteries

Most proximal to heart and largest

Have much stretch/recoil to propel blood forward

Muscular/Distributing Arteries

Have more muscle relative to size

Takes blood to organs and parts of organs

Examples include hepatic and renal arteries

Example would be aorta

Arteriole

Smallest artery. 1-2 layers of smooth muscle in tunica media which constrict/dilate

Continuous Capillaries

Most common

In CNS, lungs, skin, smooth and skeletal muscle

Have intercellular clefts to be somewhat leaky

Fenestrated capillaries

Have 'windows" or pores allowing for increased exchange.

In small intestine, kidneys, choroid plexus, endocrine glands

Sinusoid capillaries

Broken capillaries with large clefts and noncontinuous basement membrane

Allow for proteins and cells to pass

In the red bone marrow

Capillaries are not in epithelium, cartilage, and the cornea and lens of the eye

Network of veins is an anastomosis (sometimes with arteries)

Venules

Smallest veins (some exchange)

1-2 layers of smooth muscle and all 3 tunics

Medium vein

Have valves to prevent backflow in parts of body, especially the (lower) extremities

Large veins

They are large veins. Have less elastic than arteries

Blood Vessel Transition

Elastic artery to distributing artery to arteriole to capillary (bed) to venule to medium vein to large vein

Fibrous Pericardium

Dense irregular connective tissue covers heart from the diaphragm to roots of large blood vessels

Keeps heart in place and prevents overfilling

Pericardial cavity

Contains serous fluid to reduce friction between heart and rest of body/mediastinum

Tricuspid/right atrioventricular vlave

Bicuspid/left atrioventricular/mitral valve

Pulmonary semilunar valve

Aortic semilunar valve

Between the right atrium and the right ventricle

Between the left atrium and the left ventricle

Between the left ventricle and the aorta

Between the right ventricle and the pulmonary artery

Myocardium/Heart muscle

Made of cardiac muscle

Endocardium

Deep to the epicardium and superficial to the endocardium

Epicardium or the visceral pericardium

Simple squamous epithelium and some areolar connective tissue

Epicardium

Parietal pericardium

Pericardium lines the heart's cavity (mediastinum)

Simple squamous epithelium (little areolar connective tissue)

Same as visceral pericardium

Lines the heart and covers valves

Simple squamous epithelium and some areolar connective tissue

Composed of cardiac muscle

Has intercalated discs, striations, myofibrils

Intercalated discs have fascia adherens (like desmosomes)

The gap junctions as well between the fibers allows for ions/electrical impulses to travel

Sinoatrial node

The "pacemaker" sets intrinsic rhythm/heart rate

Generates electrical signals that go through the myocardium of atria; then, atria contract

Sends electrical signals to the AV node

AV node

Has a short delay to allow ventricles to fill

Right and left bundle branches

Next parts of conduction system that extend in the interventricular septum and on each side of each ventricle

Purkinje Fibers

Extend off branches into the papillary muscles of the myocardium of the ventricles

Apex squeezes 1st to push blood forcefully upward and to rest of body