Cardiovascular system

Blood and Lymph

fluid of the system that needs to get around the body

Heart

acts as a pump, generating pressure to move around blood and lymph

Vessels

the tunnels in which the fluid travels through the body

Lymphatics

a drainage system of the fluid

Hematolymphoid complex

55% plasma, 45% red blood cells

Erythrocytes

red blood cells that carry oxygen

Platelet

thrombocytes that form clots

Leukoctyes

white blood cells that act as body defense

Lymph

mostly water, white blood cells, and lymphocytes

Where is Epicardium found?

outermost layer of the heart

Serosa of Epicardium

mesothelium (simple squamous) that reduces friction

Subserosa of Epicardium

endothelium (simple squamous) made of adipose/ loose connective tissue

Where is the myocardium of the heart?

the middle layer (thickest)

Cardiac Muscle cells of myocardium

striated cardiac myocytes

Connective tissue of Myocardium

Connective tissue to supply nutrients to heart

Where is the endocardium found?

innermost layer of the heart

Endocardial endothelium

simple squamous epithelium

Subendothelial layer of endocardium

loose connective tissue

Atrial chambers

receiving chambers

Right atrium associated veins

1. superior vena cava

2. inferior vena cava

3. coronary sinus

Left atrium associated veins

left and right pulmonary veins

auricles of atrial chambers

expand to hold more blood volume

Pectinate muscles of auricles

cardiac muscle with even distribution everywhere

Sinuatrial node

initiates electrical activity of heart (pacemaker)

interatrial band and internodal fibers

sends signals to atria and different nodes, activating the myocytes in that area

Atrioventricular node

slows/ delays electrical signal

why is it important for the atrioventricular node to slow the electrical singal?

so that the chambers of the heart pump at different times, keeping the rhythm and pressure consistent

Ventricular chambers

pumping chambers

Right ventricle associated artery

pulmonary trunk

Left Ventricle associated artery

aorta

Muscle structure of ventricles

1. trabeculae carnae

2. papillary muscle

Trabeculae carnae

little beams of muscle that help the ventricle to contract

papillary muscle

little muscles that help the chordae tendineae move

Atrioventricular bundle

expanding between ventricles, sends signals to cause contraction of ventricles

Conduction system trace

1. sinuatrial node generates signal

2. moves through atrial bundles

3. atria contract

4. atrioventricular node delays signal

5. signal moves through atrioventricular bundle

6. ventricles contract

Arterial Outlet valves

the pulmonary valve and aortic valve prevent backflow

Structure of pulmonary and aortic valves

Three juxtaposed semilunar cusps

Endocardiac epithelium of pulmonary and aortic valves

outside layer

Subendothelial connective tissue of pulmonary and aortic valves

inside layer made of dense irregular tissue to add strength

function of arterial outlet valves

semilunar valves attached to ventricles where blood flows out towards the body (no muscular involvement)

Atrioventricular valves

1. right atrioventricular valve (tricuspid valve)

2. left atrioventricular valve (bicuspid valve)\

connects atria and ventricles

Structure of atrioventricular valves

1. cusps (endocardiac epithelium and subendothelial connective tissue)

2. Chordae tendineae

3. Papillary muscle

Function of atrioventricular valves

ventricle wall squeezes blood out, the pulling of chordae tendineae prevent backflow when the walls move closer to the valves

Tunica Intima of vessel

1. vascular endothelium (simple squamous)

2. internal elastic membrane (elastic connective tissue)

Tunica media of vessel

1. smooth muscle cells

2. elastic lamellae

3. external elastic membrane

Tunica externa of vessel

dense irregular connective tissue to reinforce vessel wall, introduce blood supply, vasa vasorum

Elastic artery

aorta and its main branches, these are the principle conducting vessels

muscular artery

medium to small arteries, main distributing arteries

arterioles

smallest vessels, these are resistance vessels, regulating blood flow

capillaries

sites of molecular exchange (simple squamous epithelium)

Venule

allow fluid exchange and leukocyte migration

vein

thinner walls, capacitance vessels (holds 65% ish amount of blood in body)

What are the differences between veins and arteries?

1. veins have thinner walls

2. veins have wider diameters

3. veins return to the heart, arteries move towards the body

4. veins hold most of the blood in our body

Lymphatic capillaries

larger than blood capillaries, these are dead end tubes that allows interstitial fluid to move in, becoming lymph

Right lymphatic duct field of drainage

right upper limb, right thorax, right head and neck

right lymphatic duct junction with venous system

right brachiocephalic vein, right internal jugular vein

Thoracic lymphatic duct field of drainage

left head and neck, left upper limb, left thorax, pelvis, lower limb

Thoracic lymphatic duct junction with venous system

left brachiocephalic vein

Role of Lymph in body defense

pathogens pass through gaps of simple squamous epithelium and go into lymph capillaries