Exam 2 Study Guide BIOL 277

Chapter 18: Cardiovascular System: Blood

Overview of Cardiovascular System Components

• Heart: Pumps blood throughout the body.

• Arteries: Transport blood away from the heart.

• Veins: Transport blood towards the heart.

• Capillaries: Sites of gas and nutrient exchange.

Composition of Blood

• Formed Elements:

  • Erythrocytes: Carry oxygen and carbon dioxide.

  • Leukocytes: Protect the body from pathogens.

  • Platelets: Involved in blood clotting.

• Plasma: Fluid portion containing plasma proteins and dissolved solutes.

Functions of Blood

• Transport:

  • Gases (O2, CO2), hormones, nutrients, and waste products.

• Regulation:

  • Body Temperature: Absorbs heat from cells.

  • pH Levels: Buffers balance acids and bases.

  • Fluid Balance: Maintains osmotic pressure for fluid exchange.

• Protection:

  • Functions of leukocytes and clotting factors to prevent excessive blood loss.

Characteristics of Blood

• Color: Dependent on oxygenation; bright red for high O2, dark red for low O2.

• Volume: Approximately 5L in adults; varies with size.

• Viscosity: Thicker than water; increases with higher erythrocyte count.

• Temperature: Blood temperature is about 1°C higher than body temperature.

• pH: Ranges from 7.35 to 7.45.

Components of Blood

• Whole Blood: Combination of formed elements and plasma.

  • Plasma: Pale yellow fluid; contains proteins and solutes.

  • Buffy Coat: Contains leukocytes and platelets; about 1% of blood volume.

  • Erythrocytes: Bottom layer, about 42% of volume (hematocrit).

Hematocrit Levels by Age and Gender

• Young Child: 30-40%

• Older Child: 35-40%

• Adult Female: 38-46%

• Adult Male: 42-56%

Chapter 19: Formation and Function of Blood Components

Plasma Components

• Plasma: Higher protein concentration, exerts osmotic pressure to maintain blood volume and pressure.

• Plasma Proteins:

  • Albumins: Most abundant; transport hormones, ions, and lipids.

  • Globulins: Transport lipids, hormones; includes antibodies.

  • Fibrinogen: Involved in clot formation, converted to fibrin.

  • Regulatory Proteins: Hormones and enzymes.

Hematopoiesis

• Production of Formed Elements: Occurs in the red bone marrow.

• Stem Cells:

  • Hemocytoblasts: Produce myeloid and lymphoid lines.

  • Colony Stimulating Factors (CSFs) stimulate hematopoiesis.

Erythropoiesis (Erythrocyte Formation)

• EPO (Erythropoietin): Stimulates erythrocyte production, primarily from kidneys in response to low O2.

• Process: Myeloid stem cells to proerythroblast, then to erythroblast, producing hemoglobin and maturing into reticulocytes, followed by erythrocytes.

Leukopoiesis (Leukocyte Formation)

• Myeloid Stem Cell Line: Produces granulocytes and monocytes; influenced by CSFs.

• Lymphoid Stem Cell Line: Produces lymphocytes; involved in adaptive immunity.

Thrombopoiesis (Platelet Formation)

• Myeloid Stem Cell: Produces megakaryoblasts, leading to megakaryocytes, which fragment to release platelets.

Erythrocyte Structure and Function

• Flexible and Small: Allows passage through capillaries in single file (rouleau).

• Hemoglobin Structure: Composed of globin and heme groups; transports O2 and CO2.

Regulation of Erythrocyte Production by EPO

• Mechanism: Detected by chemoreceptors, kidneys release EPO; stimulates erythrocyte production in red bone marrow.

Recycling and Elimination of Erythrocytes

• Lifespan: Average of 120 days; phagocytized in the liver and spleen.

• Hemoglobin Breakdown:

  • Globin to amino acids; iron stored in ferritin and hemosiderin; heme converted to bilirubin and excreted.

Chapter 20: Blood Vessels and Circulation

Types of Blood Vessels

• Arteries: Carry blood away from the heart.

• Capillaries: Site of exchange.

• Veins: Carry blood towards the heart.

Structure of Blood Vessels

• Three Layers:

  • Tunica Intima: Endothelium; smooth surface for blood flow.

  • Tunica Media: Smooth muscle; regulates vessel diameter (vasoconstriction/vasodilation).

  • Tunica Externa: Connective tissue; anchors vessels.

Artery Types

• Elastic Arteries: Largest; contain more elastic fibers (e.g., aorta).

• Muscular Arteries: Deliver blood to specific organs; thicker media.

• Arterioles: Smaller arteries; regulate blood flow to capillary beds.

Vein Structure

• Veins: Larger lumen and thinner walls; contain valves to prevent backflow.

Capillary Structure

• Capillaries: Only tunica intima; facilitate rapid exchange of substances.

Capillary Types

• Continuous Capillaries: Tight junctions for small solute transfer.

• Fenestrated Capillaries: Allow larger solute transfer.

• Sinusoidal Capillaries: Larger gaps for cells and proteins.

Blood Pressure Regulations

• Systolic/Diastolic Pressure: Pressure during contraction/relaxation of ventricles.

• Pulse Pressure: Difference between systolic and diastolic pressures.

• Mean Arterial Pressure (MAP): Diastolic pressure + 1/3 pulse pressure.

Chapter 21: Lymphatic System

Overview of the Lymphatic System

• Function: Returns excess interstitial fluid to circulation; supports immune function.

Lymph Composition

• Composed of water, dissolved solutes, proteins, and potentially pathogens.

Lymphatic Capillaries and Vessels

• Capillaries: Permeable to interstitial fluid; formed by overlapping endothelial cells.

• Vessels: Resemble veins; contain valves.

Lymphatic Trunks and Ducts

• Right Lymphatic Duct: Drains right side of the head, neck, and upper limb.

• Thoracic Duct: Main duct; drains from left side, abdomen, and lower limbs.

Lymphoid Organs

• Primary Lymphoid Structures: Sites of lymphocyte formation (e.g., red bone marrow and thymus).

• Secondary Lymphoid Structures: Sites for immune responses (e.g., lymph nodes, spleen).

Lymph Node Structure

• Components: Capsule, cortex, and medulla where lymph is filtered.

The Spleen

• Function: Filters blood, removing old red blood cells and pathogens.

Tonsils and MALT

• Tonsils: Protect against ingested and inhaled pathogens.

• MALT: Located throughout the mucosal surfaces; involved in immune defense.