Blood & Cardiovascular Exam

• Blood transports oxygen, nutrients, and hormones to the body, and removes carbon dioxide.
• Blood regulates body temperature, pH balance, and fluid volume.
• Blood prevents blood loss and infections.

Blood Composition

• The two major components of whole blood are plasma and packed red blood cells.
• Blood is connective tissue with plasma as the matrix.
• Dissolved fibrous proteins in plasma become fibrin strands during clotting.
• Blood is a sticky, opaque fluid with a metallic taste, making up about 8% of body weight.
• Adult men have 5-6 L of blood, while adult women have 4-5 L.
• Whole blood consists of 55% plasma, less than 1% buffy coat, and 45% packed red blood cells.
• Buffy coat contains leukocytes (WBCs) and platelets for immunity and clotting.
• Hematocrit, or blood fraction, is the total volume of blood within a sample, approximately 47% in men and 42% in women.

Plasma Components

• Plasma contains water, electrolytes, proteins, and other substances like nutrients and gases.
• Water and electrolytes maintain osmotic pressure and pH balance.
• Plasma proteins include albumin, globulins, and fibrinogen.
• Albumin maintains osmotic pressure.
  • Globulins (alpha, beta, and gamma) transport proteins and contain antibodies.
• Fibrinogen forms fibrin for clotting. Serum is plasma without proteins.

Formed Elements

• Formed elements are cells and cell fragments suspended in plasma, including erythrocytes, leukocytes, and platelets.
• Erythrocytes lack nuclei and organelles, platelets are cell fragments, and leukocytes are complete cells.
• Most formed elements survive only a few days and are replaced by stem cells from red bone marrow.
• Erythrocytes' shape and small size increase their surface area for gas exchange.

Hemoglobin

• Hemoglobin consists of heme (red pigment w/ iron) bound to protein globin.
• Globin contains 4 polypeptide chains (2 alpha, 2 beta), enabling oxygen transport.

Erythrocyte Lifecycle

• Erythrocytes circulate for about 120 days.
• Erythropoiesis takes about 15 days.
• Stem cells in bone marrow become proerythroblasts, then basophilic erythroblasts where ribosomes are synthesized.
• Hemoglobin is synthesized and iron accumulates as the basophilic erythroblast develops into polychromatic then orthochromatic erythroblasts.
• The nucleus is ejected during the process forming a reticulocyte which matures into erythrocyte.
• Erythropoiesis, is controlled by hormones and requires amino acids, iron, and B12 vitamins.
• Damaged erythrocytes are sent to the spleen, where iron is recycled for new erythrocytes.
• Heme becomes bilirubin, which is sent to the liver, and carbon dioxide is exhaled.

Anemia

• Anemia is a compromised oxygen-carrying capacity.
• Hemorrhagic anemia is due to rapid blood loss.
• Iron deficiency anemia is the most common and caused by lack of iron.
• Pernicious anemia is an autoimmune disorder affecting older adults.
• Renal anemia is caused by lack of EPO due to kidney damage.
• Aplastic anemia is where the production of RBCs is stopped.
• Hemolytic anemia is excessive RBC destruction, potentially caused by genetic disorders such as Thalassemia.
• Thalassemia is a genetic disorder causing thin, delicate, hemoglobin deficient RBCs.
• Sickle cell anemia is a genetic disorder causing abnormal hemoglobin, resulting in sickle-shaped RBCs, leads to organ failure etc.

Polycythemia

• Polycythemia is an excess of erythrocytes increases blood volume.
• It increases risk clotting and stroke and can be treated with medication or phlebotomy.

Leukocytes Function

• Leukocytes counter infections and include bacterial, viral, parasitic, toxic, and tumor cells.
• Diapedesis is the action of the white blood cells slipping out of capillary blood vessels.
• Amoeboid motion assists movement to affected areas through tissue spaces.
• Positive chemotaxis pinpoints damage or infections for destruction.
• Neutrophils are most common and fight bacteria. Eosinophils kill parasitic worms, and basophils release histamine.
• Lymphocytes attack via direct cell or antibodies, and monocytes become macrophages.

Leukemia

• Leukemia is abnormal leukocyte overproduction, forming cancerous cells.
• These cells will attack the lymph nodes and travel through the blood stream.
• Leukopenia is a low white blood cell count.
• Mononucleosis is caused by epstein-barr virus, transmitted orally, causes fatigue, sore throat, enlarged nodes, spleen, and fever.

Platelets

• Platelets are cell fragments critical for blood clotting.
• They create a temporary plug when vessels are ruptured or damaged.
• Endothelial cells secrete platelets.

Hemostasis

• Hemostasis is the clotting process with three mechanisms: vascular spasm, platelet plug formation, and coagulation.

Vascular Spasm & Platelet Plug Formation

• Vascular spasm occurs when chemicals are released from damaged endothelial cells and platelets.
• Platelet plug formation involves proteins, ADP,serotonin, and thromboxane A2.
• ADP causes platelets to stick and release their contents.
• Serotonin and thromboxane A2 enhance vascular spasm and aggregation.
• A positive feedback cycle occurs with chemicals aggregating more platelets.

Coagulation

• Coagulation occurs in three phases.
• Prothrombin activator pathways: intrinsic (slower, stronger) and extrinsic (faster).
• Prothrombin becomes thrombin and then fibrinogen is catalyzed into fibrin.

Further Clotting Reactions

• Clot retraction occurs 30-60 minutes post-clotting via platelet action.
• Fibrinolysis removes unneeded clots with rapid coagulation and endothelial secretions.
• Thromboembolic disorders: thrombus (clot in vessel) and embolus (traveling thrombus).
• Bleeding disorders: thrombocytopenia (platelet deficiency), hemophilia (genetic clotting factor disorder), and liver disease.
• Disseminated Intravascular Coagulation (DIC) causes widespread clotting and bleeding.
• Compatibility is essential in blood transfusions to prevent clotting reactions.
• Reactions include fever, chills, low blood pressure, nausea, and kidney damage.
• ABO groups classify antigens on red blood cells.

Other Blood Group Determinations

• The Rh system uses the D antigen to determine positive or negative blood types.
• Agglutination is clumping due to antibodies binding to antigens.
  • Agglutinogens are surface antigens, and agglutinins are plasma antibodies.
• Blood typing mixes blood with anti-A, anti-B, and anti-D serums to observe agglutination.
• Blood testing is important for diagnosing health issues, infections, diabetes, heart disease, autoimmune disorders and allergies.

Cardiovascular System

Pulmonary and Systemic Circuits

• The right side of the heart pumps blood to the pulmonary circuit to pick up oxygen and dispose of carbon dioxide.
• The right atrium receives blood returning from the systemic circuit, and the right ventricle pumps blood into the pulmonary circuit.
• The left side receives oxygenated blood from the lungs and pumps it to the systemic circuit.
• The left atrium receives blood from the pulmonary circuit, and the left ventricle pumps blood into the systemic circuit.

Heart Location

• The heart is located obliquely within the mediastinum of the throax.
• It is mostly enclosed within this cavity and extends from the 2nd rib to the 5th intercostal space.

Heart Covering

• The heart is enclosed in a double-walled sac called the pericardium.
• The tough, dense connective tissue layer protects, anchors, and prevents overfilling.
• The serous pericardium is deep to this fibrous layer.

Serous Pericardium

• The serous pericardium is a thin, two-layered membrane forming a closed sac around the heart.
• Its parietal layer lines the fibrous pericardium.
  • It also provides lubrication and protection.
• The visceral layer (epicardium) adheres to the surface of the heart.
• The pericardial cavity between layers contains serous fluid for lubrication.

Heart Wall Structure & Function

• Epicardium is the outermost layer that are made up of connective and epithelial tissues. It provides a smooth lubricated surface.
• Myocardium is the middle, contractile layer composed of cardiac muscles and fibrous skeleton.
• Endocardium is the innermost layer that is composed of the smooth endothelium in the inner myocardial surface.

Heart Chambers

• The heart has four chambers: right atrium and ventricle, left atrium and ventricle.

Atria Anatomy

• Atria receive returning blood and have smooth walls.
• Pectinate muscles form ridges in the anterior walls of right atrium.
• Fossa ovalis is found only in the left atria, and only in the auricle.

Blood Vessels & Atria

• The right atrium gets blood through the superior and the inferior vena cava.
• The coronary sinus drains the blood from the myocardium.
• Four veins carry oxygenized blood into the left atria.

Ventricle Anatomy

• Ventricle walls are more massive.
• Trabeculae carneae and papillary muscles mark the internal walls.
• The right ventricle is the anterior surface and pumps blood into the pulmonary trunk.
• The left ventricle dominates the posteroinferior surface and pumps blood into the aorta.

Ventricle Size & Blood flow

• The right ventricle is thinner-walled to pump deoxygenated blood under less pressure into the lungs.
• The left ventricle pumps oxygenated blood to the rest of the body at a greater pressure making it thicker.

Atrioventricular Valves

• The AV valves are located at each atrial-ventricular junction to prevent backflow into the atria in contractions..
• The right AV valve is tricuspid valve with three flexible cusps. The left is only bicuspid.
• The cusps are attached to chordae tendineae that are made of white collagin fibers.
• When the heart is relaxed, the AV valve flaps hang limply into the ventricle chambers with blood flowing through.
• When the ventricles compress the blood, the intraventricular pressure rises forcing blood to close them.

Papillary Muscles

• These are tethers that anchors the flaps to the ventricle walls.
• They tense to prevent flaps blowing upward in contractions.

Semilunar Valves

• The pulmonary valve is located at the junction of the right ventricle and pulmonary trunk.
• The aortic valve is at the junction of the left ventricle and aorta.
• The valves have 3 pocket-like cups that open and close upon pressure differences, which then either flatten against arteries as blood rushes thru or are pushed closed.

Coronary Circulation

Function

• This circulation is the functional blood supply for the heart.
• The heart has its own system for nourishment, where despite being filled by blood it runs on its own vessels to nourish it.

Arteries

• The LCA runs towards the heart dividing into the anterior interventricular region as well as the circumflex region.
• RCA rises to the lateral sides and supplies blood to two more branches.
• The Posterior region serves both ventricles

Veins

• Cardiac veins collect the blood and merge into the coronary sinus.
• Great and small cardiac veins drain into it.
• Veins collect oxygen poor blood.

Cardiac Muscle Anatomy

Structure

• Muscle is defined by striations and sliding filament mechanism
• cells are branched and interconnected with only one or two nuclei. It is abundant in the mitochondria
• Intracellular includes connective-tissue filled matrix for the fibers and its skeleton
• intercalated disks connect the muscle end to end with desmosomes and gap junctions Myofilbrils are composed or sarcomeres , made with A and I bands

Function

• matrix helps the cardiac cells exert force
• desmosomes helps keep adjacent cells together in contraction
• gap junctions allow ions to pass from cell to cell, helping them behave as one unit.

Skeletal vs Cardiac Muscle

• Skeletal : Individual simulated
• Cardiac: Gap junction

Tetanic contractions

• Skeletal: possible short refractionary period
• Cardiac: not possible long duration

Aerobic

• Skeletal: can create ATP aerobically.
• Cardiac: relies on aerobic

Ca+ sources

• Skeletal: is released and contracted.
• Cardiac: comes from the SR and extracellular fluid/regeneration

Slow Ca2+ Channels - Function & Importance

• Specialized channels in plasma membrane of cardiac cells.
• Their opening is much slower, that they trigger the release of ions need for muscular contraction.
• Calcium ion prolongs in the depolarization phase.
• It is used in contractions and calcium release of continuous activities

Intrinsic Conduction Systen

• The system consists of non contractible cardiac cells used to initiate the wave.
• The Sino-atrial (SA) node is located in the right atria.
• The Atrioventricular (AV) node is located in the inferior portion.
• Runs along the septum, dividing at the apex.

Conduction System Function

• Specialized cells generate and transmit impulses to the cardiac cells, creating a coordinated functions.
• The SA node initiates by generating action potentials around 75 beats.
• AV nodes delay impulses so the atria will fully contract before the next beat (roughly 0.1 sec)
• Dysfunctions with the heart result in irregular ventricular constrictors, that may require a pace maker.
• The purkinje fibers will deliver the impulse to help ensure coordination.

Different Types of Arrhythmias

• Fibrillation: disorganized contractions
• Extrasystole: Hyperexcitable parts cause premature constrictions.
• Heart Block: damaged nodes or branches can lead to blocked impulses.

Extrinsic Innervation

• The autonomy of the heart is modified
• The autonomic nervous system modified through each beat.
• The nervous system increases more frequently and forcefully.
• Activation slows the heart.

Pacemaker Cells

• Pacemaker potential is unstable, depolarized and has less sodium.
• Repolarizes after peak opens and closes.

Action Potentials vs Muscle/Never

• pacemaker cells have an unstable resting potential.
• calcium vs sodium

Heart Rhythm

• Diastole: is a resting peroid
• Systole: is the contraction period

Vavlves

Atrial Systole

• pressure slightly goes up as atria contracts
• AV valves remain open
• no change with valves

Ejection

• pressure peaks high at the the ventricles
• SL valves remain open.
• volume decreases

Ventrilicular finshing

a. Atrial pressure rises.

Factors of blood and the heart

• definition and rate
• reserve to push out over and over/reserve.
• Factors help each other out

Stroke Volume Defition

Factors and regulation

• Volume is key factor to regulate contractions
• SV represents the difference between the end and diastolic cycle.
• pressure of blood in ventricles
• Three factor are preload, contractions, afterload

Preload

• The degree to which muscle cells are stretched right before they contract
• Frank Starling Law helps increase the rate of increasing blood as well

Afterload

• Must always always beat to protect blood.
• Afterload and hypertension =less pressure of ventrices as well.
• More blood remains Factors to decrease
• Cold reduces hr

heart rate

tacycardia

• more than 100 bpm 1 May result from elevated body temp, stress, certain drugs, or heart disease

bradycardia.

1.May results with low temp, activates PNS

Heart issues

a. Coronary problems = poor delivery of oxygen b. BP = constant high c. Heart Attacks d. D = unknown reasons