Cardiovascular System Part 2

What is the function of the cardiovascular system?

• Heart and blood vessels transporting blood

Where is the heart located? What is the base and apex?

• Heart; located behind sternum

  • Base: superior, containing major BV

  • Apex: inferior, intercostal space

What is the mediastinum?

• Space in thorax between pleural cavities (lungs)

  • pericardial cavity + major BV

What is pericardium? What are its structures?

• Sac like structure wrapped around heart

  1. Fibrous pericardium

  2. Serous pericardium (2 layers)

  3. Pericardial cavity

What is the fibrous pericardium made up of? What does mesothelium produce?

• Outermost layer

• Made up of; areolar tissue and mesothelium

  • Mesothelium: secretes pericardial/serous fluid

What is the serous pericardium? What are the 2 layers?

• Contains serous/pericardial fluid

  1. Parietal (outer layer)

  2. Visceral (inner layer)

What is the pericardial cavity?

• Space filled with serous fluid around heart

What is the difference between the pericardium and pericardial cavity?

• Pericardium; all the structures attached to the heart

• Pericardial cavity; fluid filled space only

What are the three layers of the arteries and veins?

1. Tunica intima; innermost

2. Tunica media; middle

3. Turnica externa

What does the turnica intima contian?

• Endothelial cells; simple squamous tissue for diffusion

What structure does the turnica intima of arteries contain?

• Internal elastic membrane; expand and recoil

  • veins lack elastic fibers

What is the tunica media made up of? What does this do?

• Smooth muscle; constricts/dilates

  • Vasoconstriction: decreases vessel diameter

  • Vasodilation: increases vessel diameter

What structure does the tunica media of the arteries have?

• External elastic membrane; separates from tunia externa

  • veins lack elastic fibers

What is unique about the arteries tunica media?

• Arteries; larger tunica media

What is the tunica externa? Its function?

• Tunica externa (outermost layer): anchors vessels to surrounding tissues

  • same in veins and arteries

What are the five general blood vessel classes?

Order of Formation

1. Arteries

2. Arterioles; small arteries

3. Capillaries

4. Venules; small veins

5. Veins; large and med.

What are the two types of arteries?

• Elastic arteries; large

• Muscular arteries; med. sized

What are elastic arteries? Example?

• Large vessels directly attach to heart; stretch and recoil

  • pulmonary trunk, aorta, branches

What are muscular arteries?

• Med.; distribute blood to skeletal muscles and organs (to body)

What are arterioles? What about their tunica externa?

• Small arteries moving into/serving as beginning to capillaries

  • thin turnica externa

What are capillaries? What are the types?

• Vessels allow exchange between blood and interstitial fluid

  1. Continuous capillary

  2. Fenestrated capillary

  3. Sinusoidal capillary

What are venules?

• Small veins that collect blood from capillaries

What are the two sizes of veins?

• Medium sized veins

• Large veins

Where are large veins found? Examples?

• Near heart

  • superior and inferior vena cava

What is the general function of capillaries?

• Drop off site; for what’s needed

• Pick up site; for wastes

What is the function of a continuous capillary? What about its endothelium?

• Permits diffusion of water, small solutes (ions)

  • endothelium complete lining; NO pores

What is the function of fenestrated capillaries? What about is epithelium?

• Permits rapid exchange of water and larger solutes (urea)

  • contains pores in endothelial lining

Where are fenestrated capillaries found?

• Found; absorptive areas of intestinal tract and kidney

What is the function of sinusoidal capillaries? What about its endothelium?

• Permits more waste, large molecules/ solutes (plasma proteins)

  • gaps in endothelial lining

Where are sinusoidal capillaries found?

• Found; in liver

  • liver produces plasma proteins (albumins, globulin, fibrinogens)

What is a capillary bed?

• Contains connections between arterioles and venules

  • exchange site

What are collaterals?

• Collaterals; multiple arteries

What happens to the arteries of the capillary bed?

• Arteries/branches fuse to give rise to arterioles

What is the fusion of arteries an example of?

• Arterial anastomosis

  • anastomosis: joining of blood vessels

What color is pulmonary trunk (artery) and the pulmonary veins?

• Pulmonary trunk; blue bc carrying deoxygenated blood to lungs

• Pulmonary vein; red bc carrying oxygenated blood to heart

What are the three layers of the pericardium?

1. Fibrous pericardium

2. Serous pericardium

   • Visceral layer

   • Parietal layer

What are the three layers of the heart? From most superficial to deepest?

1. Epicardium; is the visceral layer

2. Myocardium

3. Endocardium

What is the epicardium made up of? What is it a part of?

Outermost

• Made up of mesothelium and areolar CT

  • is the visceral layer of pericardium, does NOT include parietal

What is the myocardium made up of?

Middle

• Layers of cardiac muscle containing intercalating discs

What is the endocardium made up of?

Innermost

• Made up of endothelium (squamous epithelium) and areolar CT

What are the intercalated discs of cardiac muscle?

• Gap junctions between cardiac muscle cells

  • pathway for chemical communication

• Involuntary

What are the main structures of the heart?

• Right and Left Atrium

• Right and Left ventricle

• Superior/inferior vena cava; on right side

What are the structures on the anterior surface of the heart?

1. Auricle

2. Coronary sulcus

3. Anterior interventricular sulcus

4. Ligamentum Arteriosum

What is an auricle?

• Expandable pouch in each atrium

What is the coronary sulcus? What does it contain?

• Groove separating atria and ventricles

  • fat and BV

What is the anterior interventricular sulcus? What does it contain?

• Groove separating right from left ventricle

  • fat and BV

What is the ligamentum arteriosum?

• Remnant of fetal connection between aorta and pulmonary trunk

What is the function of pulmonary veins?

Red

• Dumps oxygenated blood into left atrium

What is the function of the superior and inferior vena cava?

Blue

• Dumps deoxygenated blood into right atrium

What is the function of the coronary sinus?

Posterior Heart

• Returns blood from myocardium to right atrium

  • posterior vein between left ventricle and atrium

What is the posterior interventricular sulcus?

Posterior heart

• Groove between two ventricles

What structures branch from the right coronary artery (must be able to label)?

1. Right coronary artery

2. Marginal arteries

3. Posterior interventricular artery; between 2 ventricles

What structures branch from the left coronary artery (must be able to label)?

1. Left coronary artery

2. Circumflex artery; wraps around pulmonary trunk

3. Anterior interventricular artery

What are the coronary circulation veins? What do they all dump into?

1. Great cardiac vein

2. Middle cardiac vein

3. Small cardiac vein

ALL dump into coronary sinus

Where is the great cardiac vein located?

• Below circumflex artery and right coronary artery

Where is the middle cardiac vein located?

• Next to posterior interventricular artery

Where is the small cardiac vein located?

• Above right coronary artery between right atrium and right ventricle

Where is the coronary sinus found? What does it dump into?

• Posterior between right and left ventricle

• Dumps into right atrium

How does the right atrium recieve blood?

• Receives deoxygenated blood from superior/inferior vena cava

How does the left atrium receive blood?

• Receives oxygenated blood from pulmonary veins

What are the pectinate muscles?

• Muscular ridges around atria

Where does the superior vena cava dump the deoxygenated blood?

• Dumps deoxygenated blood into right atrium

What happens when the right atrium contracts?

• Opens tricuspid valve dumping deoxygenated blood into right ventricle

What happens when the right ventricle contracts?

• Opens pulmonary semilunar valve pushing deoxygenated blood to pulmonary trunk (to lungs)

  • semilunar valve closes to prevent backflow

Where do the pulmonary veins dump the oxygenated blood?

• Dump oxygenated blood in left atrium

What happens when the left atrium contracts?

• Opens mitral/bicuspid valve, dumping blood into left ventricle

What happens when the left ventricle contracts?

• Opens aortic valve pushing blood to aorta (rest of body)

  • aortic valve closes to prevent backflow

Why is the left ventricle much thicker than the right?

• Needs enough pressure to pump blood to the aorta and rest of body

What is trabeculae carnae?

• Muscular ridges in both ventricles

How many cusps does the tricuspid and mitral valve have?

• Tricuspid; 3 cusps

• Mitral/Bicuspid; 2 cusps

What is chordae tendineae? What is it anchored by?

• CT bands attached to cusps

  • anchored by papillary muscles

What is the cardiac conducting system?

• Electrical conduction; action potential pathway

What is the sinoatrial node? Its function?

• Sinoatrial node; pacemaker

  • generates AP for heartbeat

  • impulse is intiated

What is the order of the cardiac conducting system?

1. Sinoatrial (SA) node

2. Internodal pathways

3. Atrioventricular (AV) node

4. AV bundle; bundle branches

5. Purkinje fibers

What is the difference between mesothelium and endothelium?

Both simple squamous cells

• Mesothelium; lines body cavities

• Endothelium; lines BV and heart