Comprehensive Human Anatomy and Physiology: Blood, Heart, Respiratory, Reproductive, Digestive Systems

What is the primary component of blood?

connective tissue

What is the origin of blood?

mesenchyme

What color does oxygenated blood appear?

appears lighter

What color does deoxygenated blood appear?

appears darker

What are the main functions of blood?

Distribution, regulation, and protection.

How does blood help in distribution?

It moves gases, hormones, and regulates temperature.

What is the role of blood in regulation?

regulates body temperature, fluid amount, and pH.

How does blood protect the body?

It stops blood loss through clotting and supports the immune system.

What is plasma?

non-living fluid matrix of blood, making up 55% of total volume.

What is the main component of plasma?

90% water

What is the function of albumin in plasma?

maintains osmotic balance and buffers pH.

What is the role of globulins in blood?

involved in immune response and lipid transport.

What is the function of fibrinogen?

essential for blood clotting.

What are erythrocytes?

red blood cells that transport oxygen.

What is the lifespan of erythrocytes?

100-120 days.

What is hemoglobin's role in blood?

binds reversibly with oxygen for gas transport.

What is hematopoiesis?

formation of blood cells in red bone marrow.

What is the hematocrit equation?

Hematocrit = (Volume of RBC / Volume of total blood) x 100.

What does leukocytosis indicate?

indicates a WBC count greater than 11,000/μL, often due to infection.

What is the function of leukocytes?

defend against disease.

What are the two types of leukocytes?

Granulocytes and agranulocytes.

What are platelets?

cytoplasmic fragments involved in blood clotting.

What hormone regulates platelet formation?

Thrombopoietin.

What is erythropoiesis?

process of making red blood cells.

What triggers the release of erythropoietin (EPO)?

Low oxygen levels

What is anemia?

a condition where blood has an abnormally low oxygen-carrying capacity.

What is hemolytic anemia?

caused by the premature destruction of red blood cells.

What is sickle-cell anemia?

caused by a mutation in the hemoglobin beta chain, leading to crescent-shaped RBCs.

What is polycythemia vera?

a bone marrow cancer that results in excess red blood cells.

What is hemostasis?

A series of reactions for the stoppage of bleeding.

What are the three steps of hemostasis?

1. Vascular spasm, 2. Platelet plug formation, 3. Coagulation.

What occurs during vascular spasm?

A change in the muscle wall of blood vessels leading to vasoconstriction.

What is the role of activated platelets in hemostasis?

They form a temporary platelet plug by sticking to collagen fibers.

What is the von Willebrand factor?

A protein that helps platelets stick to the collagen in blood vessel walls.

What is coagulation?

The process of blood clotting that reinforces the platelet plug with fibrin.

What are the phases of coagulation?

1. Prothrombin activator formation, 2. Conversion of prothrombin to thrombin, 3. Thrombin catalyzes fibrinogen to fibrin.

What is the function of fibrin in blood clotting?

reinforce the platelet block and transform blood from liquid to gel.

What is thromboembolic condition?

A condition involving a thrombus (attached clot) or embolus (free-floating clot).

What is thrombocytopenia?

A deficiency of circulating platelets, diagnosed when platelet count is <50,000/μL.

What is hemophilia?

A hereditary condition characterized by factor deficiencies leading to bleeding disorders.

What is the Rh factor?

An antigen on red blood cells that determines if blood type is positive or negative.

What happens during an incompatible blood transfusion?

Donor's cells are attacked by recipient's plasma agglutinins, leading to agglutination and potential renal failure.

What is erythroblastosis fetalis?

A hemolytic disease of the newborn that occurs when an Rh- mother has an Rh+ fetus.

What is the primary role of antibodies in the immune system?

To bind to specific antigens, temporarily inactivating them and marking them for destruction.

What are the two types of humoral immunity?

1. Active (naturally or artificially acquired), 2. Passive (naturally or artificially acquired).

What is the difference between active and passive humoral immunity?

Active immunity involves the body producing antibodies, while passive immunity involves receiving antibodies from another source.

What triggers the inflammatory response?

Injured tissues, extreme heat, or infection, swelling

What is the role of macrophages in the immune system?

They are the chief phagocytic cells that engulf and digest pathogens.

What is the function of interferons?

They are antibacterial proteins that hinder the ability of microorganisms to reproduce.

What is the lymphatic system's main function?

To return leaked fluid from blood vessels back to the bloodstream and support immune function.

What are the main structures of the lymphatic system?

Spleen, thymus, tonsils, and lymph nodes.

What is the function of PDGF in vessel repair?

It promotes the division of smooth muscle cells and fibroblasts to rebuild blood vessel walls.

What is fibrinolysis?

The process that removes unneeded clots after healing, beginning within two days.

What is the role of plasmin in fibrinolysis?

It is a fibrin-digesting enzyme produced by activated plasminogen.

What is the difference between intrinsic and extrinsic coagulation pathways?

Intrinsic is triggered by negatively charged surfaces, while extrinsic is triggered by exposure to tissue factor (Factor III).

What is the significance of memory B cells?

They provide a faster immune response upon re-exposure to the same pathogen.

What is artificially acquired immunity?

Injection of exogenous antibodies, providing no long-term immunity.

What role do lymphocytes play in cellular immunity?

They act against target cells directly by destroying them or indirectly by enhancing the inflammatory response.

What are the five classes of immunoglobulins?

IgM, IgA, IgD, IgG, IgE.

What is the primary function of IgM?

It is the first class of antibodies to appear in plasma after an immune response and cannot cross the placenta.

Where is IgA primarily found?

In secretions such as tears, saliva, skin, and breast milk.

What is the function of IgD?

It acts as an antigen receptor on the surface of B cells.

What is the main function of IgG?

It is the most abundant antibody in plasma, crosses the placenta, and provides long-term immunity.

What is the role of IgE?

It is associated with allergic reactions and the release of histamine.

What is the humoral immune response?

It involves B cells that produce antibodies against antigens.

Where do B cells mature?

In the bone marrow.

Where do T cells mature?

In the thymus.

What is the function of helper T cells?

They activate B and T cells and induce proliferation, helping to increase white blood cells.

What do cytotoxic T cells do?

They attack and kill infected cells by searching for foreign antigens.

What is the role of regulatory T cells?

They suppress the immune response after it has been activated to return to normal.

What are antigen-presenting cells (APCs)?

Cells that engulf antigens and present fragments to T cells for recognition.

What are the major types of APCs?

Dendritic cells, macrophages, and B cells.

What is the primary line of defense in the innate immune system?

Physical, chemical, and biological barriers such as skin and mucous membranes.

What is the second line of defense in the innate immune system?

Includes antimicrobial proteins, natural killer cells, fever, phagocytes, and inflammation.

What is immunological memory?

The ability of the immune system to respond faster and more effectively upon re-exposure to the same antigen.

What happens during the primary immune response?

There is a lag period of 3-6 days before peak antibody levels are reached.

What characterizes the secondary immune response?

It is faster, more prolonged, and more effective due to sensitized memory cells.

What is the mediastinum?

The area superior to the diaphragm and medial to the left and right lungs.

What is the function of arteries?

They carry blood away from the heart.

What is the function of veins?

They carry blood towards the heart.

What is the myocardium?

The thick cardiac muscle layer of the heart that provides the force to pump blood.

What are the layers of the heart wall?

Epicardium (outermost), myocardium, and endocardium (innermost).

What are the two types of atrioventricular (AV) valves?

Tricuspid valve (right) and mitral/bicuspid valve (left).

What causes the 'lub-dup' sounds of the heartbeat?

The closing of the heart valves: 'lub' from AV valves and 'dup' from semilunar valves.

What is a heart murmur?

An abnormal heart sound usually indicating incompetent or stenotic valves.

What are intercalated discs?

Structures in cardiac muscle that contain desmosomes and gap junctions, allowing the heart to function as a syncytium.

What is the primary function of cardiomyocytes?

99% are contractile and 1% are autorhythmic, allowing coordinated contraction.

What initiates the electrical signal for heart contraction?

The sinoatrial (SA) node sends out an electrical change.

What is the role of the atrioventricular (AV) node?

It slows the electrical signal to allow the atria to fully contract and empty blood into the ventricles.

What is the pathway of electrical conduction in the heart?

SA node -> AV node -> AV Bundle (Bundle of His) -> Right and left bundle branches -> Subendocardial conducting network (Purkinje fibers).

What is pacemaker potential?

A slow depolarization due to Na+ channels opening and K+ channels closing, leading to a net increase of positive ions.

What happens during depolarization in cardiac action potentials?

There is an influx of Na+ through fast voltage-gated Na+ channels.

What maintains the plateau phase in cardiac action potentials?

Calcium influx through slow calcium channels while some K+ channels remain open.

What occurs during repolarization of cardiac action potentials?

Calcium channels inactivate, K+ channels open, allowing K+ to leave and restoring resting membrane potential (RMP).

What does an electrocardiogram (ECG/EKG) represent?

The electrical activity of the heart, showing all action potentials at a given time.

What does the P wave in an ECG indicate?

Atrial depolarization initiated by the SA node.

What does the QRS complex in an ECG represent?

Ventricular depolarization and atrial repolarization.

What does the T wave in an ECG indicate?

Ventricular repolarization.

What is systole?

The phase of contraction in the cardiac cycle.

What is diastole?

The phase of relaxation in the cardiac cycle.