Cardiovascular System Lecture Notes

Review Questions for Quiz

• What is the most common white blood cell?

• What type of cells do all the formed elements of blood come from?

• Which of the following is not a disorder of erythrocytes?

Announcements

• Consider withdrawing from the class with a W grade if averaging below 70%.

• Last day to withdraw with a W: June 12.

• Exam 2 and Practical 2: June 16.

Agenda: To finish discussing blood and introduce the heart

• Finish going over white blood cells.

• Platelets.

• Disorders related to the blood.

• Hematopoiesis (how blood cells are produced).

Granulocytes: Neutrophils, Eosinophils, Basophils

• Have granules in their cytoplasm and lobed nuclei.

Neutrophils

• Have two types of granules: one takes up acidic dye, the other takes up basic dye.

• Result: Lilac color of the cytoplasm.

• Main purpose: Kill bacteria.

• Most plentiful white blood cell.

• Contain peroxidases, hydrolytic enzymes, and defensins (antibiotic-like proteins).

Eosinophils

• Low contribution to white blood cell count (1-4%).

• Acid-loving (acidophilic): reddish-orange-pink color.

• Focus on parasitic worms.

• Lessen severity of allergies by phagocytizing immune complexes.

• Lysosome-like granules: lysosomes are membrane-bound cell organelles containing digestive enzymes.

Basophils

• Lowest number contributing to white blood cell count.

• Basic-loving (basophilic): blue-purple color granules.

• Functionality similar to mast cells: found in loose areolar connective tissue throughout the body and play an important role in the inflammatory cascade.

• Histamine: involves inflammatory responses (vasodilator, attracts white blood cells); antihistamines counteract the effect.

• Treating symptoms versus the cause: inflammation means there's a problem and the body is trying to deal with it and heal. It may be better to address the cause rather than just managing symptoms.

Agranulocytes: Lymphocytes and Monocytes

• Lack granules.

• Nuclei tend to be kidney-shaped or rounded.

Monocytes

• 2-8% of leukocytes.

• Largest white blood cells.

• Pale blue cytoplasm.

• Kidney-shaped or folded nucleus.

• After a few days, they leave blood vessels and turn into macrophages, which move in an amoeboid way and engulf things.

• Associated with lymphocytes, activating them to deal with the immune response.

Lymphocytes

• The most common white blood cell after neutrophils, accounting for 20-40% of them.

• Dark purple, round-shaped nucleus.

• Two types: T cells (involved with the immune response) and B cells (give rise to plasma cells, which produce antibodies).

Platelets (Thrombocytes)

• Fragments of cells from megakaryocytes (giant cells in bone marrow).

• Important in the blood clotting process.

• Come together and stick to tears in blood vessel walls, adhering to exposed collagen.

• Release substances to bring more platelets to the area, initiating the inflammatory response.

• Clump together to restrict blood flow out of the vessel, helping to repair the tear.

• Thrombin acts as an enzyme, cutting amino acid side chains from fibrinogen to form fibrin threads.

• Fibrin threads wind around platelets to form the clot; red blood cells can get trapped in the clot.

Summary Table

• Reference it but if it goes into more detail than what we've covered do not worry.

Hematopoiesis

• Process by which blood cells are formed in red marrow.

• Begins in early embryonic stages and continues throughout life.

• After birth, blood cells originate in bone marrow at a rate of approximately 100,000,000,000 new cells per day.

• Various types of blood cells differentiate from a single cell type, hemocytoblasts (blood stem cells).

• Hemocytoblasts are pluripotent hematopoietic stem cells that divide continuously to renew themselves and produce progenitor cells.

• Two types of progenitor cells: lymphoid (lymphocytes) and myeloid (most other blood cells).

• Erythropoiesis: red blood cell production.

• Thrombopoiesis: platelet production.

• Leukopoiesis: white blood cell production.

Blood Disorders (Erythrocytes)

• Polycythemia: Abnormal excess of erythrocytes.

• Anemia: Erythrocyte levels or hemoglobin concentrations are low.

  • Sickle cell disease: Erythrocytes are a different shape (sickle-like) due to a defective hemoglobin molecule; it is inherited.

• Leukemia: Excessive white blood cell formation; a form of cancer (lymphoblastic or myeloblastic; acute or chronic).

• Thrombocytopenia: Low number of platelets (thrombocytes), leading to diminished clot formation and internal bleeding from small vessels.

The Heart

• Center of the cardiovascular system.

• Adult average: 75 beats per minute, 5. 35 liters pumped per ventricle per minute at rest (can increase 5-6 times when active).

• Connects to blood vessels (arteries and veins).

• Arteries: Carry blood away from the heart (usually oxygen-rich, but not always).

• Veins: Carry blood back to the heart (usually oxygen-poor, but not always).

Pulmonary Veins vs Pulmonary Arteries

• Pulmonary veins carry oxygen-rich blood to the heart from the lungs.

• Pulmonary arteries carry oxygen-poor blood from the heart to the lungs.

• Oxygen-rich vs. oxygen-poor (preferred terms): There is oxygen in the blood in both cases, just a higher concentration in the arterial system.

• Great vessels: Largest diameter veins and arteries closest to the heart.

• A muscular double pump.

Circuits

• Pulmonary: The right side of the heart pumps oxygen-poor blood to the lungs, where it becomes oxygen-rich and returns to the heart.

• Systemic: The left side of the heart receives oxygen-rich blood from the lungs and pumps it throughout the body, then returns oxygen-poor blood to the right side of the heart.

• Four chambers: Two atria (receive blood) and two ventricles (pump blood).

• Blood pressure: The force of blood pushing against the inside walls of vessels.

  • Important for getting blood to the tips of the toes and back, but too much pressure can stress blood vessels and organs.

• Size: About the size of your fist, weighs about 300 grams.

• Location: Thorax.

Heart Anatomy

• Apex: More anterior and inferior.

• Base: More superior and posterior.

• Enlarged or displaced heart can indicate heart disease.

• Four normal landmarks for heart: superior right, inferior right, superior left, and inferior left corners.

Layers

• Pericardium.

• Myocardium.

• Chambers.

• Valves.

Pericardium

• Triple-layered sac.

• Fibrous: Outer layer, strong, adheres to the diaphragm and great vessels, holds the heart in place, and prevents overfilling.

• Serous: Deep to the fibrous pericardium.

  • Parietal and visceral layers, with serous fluid in between to reduce friction when the heart beats.

Pericardial Cavity

• Space between the parietal and visceral layers of the serous pericardium, containing serous fluid to reduce friction.

The Heart Wall

• Epicardium (same as visceral layer of the serous pericardium):

  • Outer layer of the heart wall and inner layer of the pericardium; tends to get fatty with age.

• Myocardium:

  • The main, thickest part of the heart wall; contracts to pump blood.

• Endocardium:

  • Deep to the myocardium, the innermost layer of the heart wall; looks like saran wrap.

Muscular Bundles

• Spiral bundles: When they contract, they shorten the heart and push blood in a specific direction.

• Circular bundles: When they contract, they decrease the diameter of the heart, helping to force blood out.

Chambers

• Atria (superior).

• Ventricles (inferior).

• Interventricular septum.

• Interatrial septa.

Sulci

• Coronary sulcus: Between atria and ventricles, contains blood vessels.

• Interventricular sulcus: Separation between ventricles, contains blood vessels.

Right Atrium

• Receives oxygen-poor blood from the systemic circuit via three vessels:

  • Coronary sinus (blood from the heart tissues).

  • Inferior vena cava (blood from the lower body).

  • Superior vena cava (blood from the upper body).

• Auricles: Ear-like extensions of the atria.

• Crista terminalis: C-shaped structure that helps locate where veins enter the right atrium.

Inside of the Atrium

• Pectinate muscles (anterior part).

• Crista terminalis: Located where superior vena cava enters (top of the C).

• Inferior vena cava (bottom of the C).

• Coronary sinus: More anterior to the inferior part, at the terminus of the C.

• Fossa ovalis: An oval-shaped depression that used to be an opening (foramen ovale) between the atria in the fetus.

Right Ventricle

• Forms the anterior surface of the heart.

• Pumps oxygen-poor blood through the pulmonary trunk into the pulmonary arteries.

• Trabeculae carneae: Ridges on the inner surface.

• Papillary muscles: Connect to chordae tendineae.

• Chordae tendineae (heartstrings): Attach to the cusps of the tricuspid valve to prevent them from flapping back into the atrium during ventricular contraction.

Pulmonary Semilunar Valve

• Located where the right ventricle leads to the pulmonary trunk; blood must pass through here to go to the lungs.

Left Atrium

• Receives oxygen-rich blood from the lungs via the pulmonary veins.

• Bicuspid Mitral valve:

  • Synonyms: Bicuspid valve and left atrioventricular valve.

Left Ventricle

• Myocardium is approximately three times thicker than is the right ventricle.

• Needs to pump blood all the way from the top of the head to the tips of the fingers to the tips of the toes and get back to the heart, so it pumps harder and has stronger myocardium.

Aortic Semilunar Valve

• Between the left ventricle and the aorta.

Valves

• Atrioventricular valves.
  * Right (tricuspid).
  * Left (bicuspid/mitral).

• Basic composition: Endocardium outer layer and connective tissue core.

• Semilunar valves (pulmonary and aortic).

• Pulmonary semilunar valve: Between the right ventricle and the pulmonary trunk.

• Aortic semilunar valve: Between the left ventricle and the aorta.
  *Note: AV/atrioventricular is used for reference only, always write atrioventricular and never AV.

• Cut of a heart: you can see all four valves.

Fibrous Skeleton

• Dense regular connective tissue between the atria and the ventricles.

• Functions:

  • Structural support boundaries.

  • Supportive fibrous rings that anchor the heart valves.

  • Rigid framework for attachment of cardiac muscle tissue.

  • Electrical insulator (does not conduct action potentials), preventing ventricular contraction at the same time as atrial contraction.

Blood Flow

• Blood is flowing into the atrio-ventricular valves.

• AV valves: the ventricles will fill and the atrioventricular flaps are hanging limply into the ventricles.

• Atria: It will contract with more blood to go down.

• You have the ventricles contracting, if the blood shot back up into the atria (What if it did not pump the pulmonary semilunar out (aorta)!

• Chordae tendineae- attaching up to the cusps, is preventing the cusps from flapping back and blood entering the AV vales back up.

• AV: So when ventricles' contract, the pressure is going to force up and close up the valves/blood cannot flow backward.

• Lack of that pressure by the contraction, you have gravity and the blood by gravity ends up closing it up.

• Then prevent blood coming back into the opposite direction of what you want.

• Recap blood flow through the heart.

• You should be able to do like back of your head, back of your hand of how blood travels through the heart.

Right Side

• Superior/inferior vena cava.

• Right Atrium -> (cross the Tricuspid valve) -> Right Ventricle -> (forced through Pulmonary Semilunar Valve) ->Pulmonary Trunk -> pulmonary arteries

Left Side

• Pulmonary veins (coming back from the lungs, with oxygenated blood).

• Left Atrium (cross the Mitral Valve) -> Left Ventricle -> (through the Aortic stem lunar valve) -> Aorta -> throughout the body

Blood supply

• Coronary arteries -arise from the aorta

• Right versus Left, in the coronary sulcus

• Oxygen poor blood carried by cardiac veins. You have coronary sinus- blood going from the veins into the sinus and out.
  Great cardiac vein, small cardiac vein, Middle cardiac vein.
  *Sinus and sulcus are two different things. Sinus is where blood is flowing, sulcus is what causes a groove to go through.

Heart Sounds

• The four corners of the heart- can hear the heart sounds best through those.

• Mitral valve at the bottom left, tricuspid at the bottom right, aortic is at the top right, you hear it over on the left side. Pulmonary is at the left superior, one of the sounds on the right
  Heart sounds are lubdub, the lub is the AV valve closing, the dupp- the fat sound. Is the Semilunar valve shutting. The atria and ventricles contracting at the same time.

Systole

• Contraction of a heart chamber

Diastole

• Relaxation of a heart chamber

*That is why blood pressure is represented by two numbers. For example- 120 over 80, systole is usually the smaller number, at 80/120.
*Ventricles- are the main walls that have the pumping effects throughout them. The aorta, left ventricle is much
*Thicker and then the pulmonate circuit so the left is more to go to long so more resistance, than the right! Systemic Circuit, is there to do things, to take the oxygen take that take that oxygen to that system.