Blood and Cardiovascular System: Anatomy & Physiology Study Notes

Study Guide - Smart Notes

Tailored notes based on your materials, expanded with key definitions, examples, and context.

Blood: Structure and Function

Components of Blood

Blood is a specialized connective tissue composed of plasma and formed elements. It plays a vital role in transport, regulation, and protection within the body.

Plasma: The liquid matrix, making up about 55% of blood volume.
Formed Elements: Includes erythrocytes (red blood cells), leukocytes (white blood cells), and platelets.

Type of Tissue

Blood is classified as a connective tissue due to its origin from mesenchyme and its function in connecting body systems.

Cell Types

Erythrocytes (RBCs): Transport oxygen and carbon dioxide.
Leukocytes (WBCs): Defend against pathogens.
Platelets: Involved in blood clotting.

Definition of Hematocrit

Hematocrit is the percentage of blood volume occupied by red blood cells. It is a key indicator of oxygen-carrying capacity.

pH and Approximate Volume in Humans

pH: Blood is slightly alkaline, with a normal pH range of 7.35–7.45.
Volume: Average adult blood volume is 4–6 liters.

Plasma

Plasma is the straw-colored, liquid portion of blood that serves as a transport medium for nutrients, hormones, and waste products.

Major Components: Water (90%), plasma proteins (albumin, globulins, fibrinogen), electrolytes, nutrients, gases, and waste products.
Significance of Plasma Proteins & Albumin: Albumin maintains osmotic pressure and transports substances; globulins are involved in immunity; fibrinogen is essential for clotting.

Origin of White Blood Cells (WBCs)

WBCs originate from hematopoietic stem cells in the bone marrow.

Red Blood Cells (RBCs): Shape & Size

Shape: Biconcave discs, increasing surface area for gas exchange.
Size: Approximately 7–8 μm in diameter.
Other Characteristics: Lack nuclei and mitochondria; filled with hemoglobin.

Blood Viscosity

RBCs are the major contributors to blood viscosity, affecting flow and pressure.

Function of Erythrocytes

Transport oxygen from lungs to tissues via hemoglobin.
Carry carbon dioxide from tissues to lungs.

Hemoglobin

Hemoglobin is a protein in RBCs that binds oxygen and carbon dioxide.

Each hemoglobin molecule can carry four oxygen molecules.
Gives blood its red color.

Hematopoiesis

Hematopoiesis is the process of blood cell formation, occurring primarily in the red bone marrow.

Location: Red bone marrow of flat bones (e.g., sternum, pelvis).

Stem Cells

Hematopoietic stem cells are multipotent cells that give rise to all blood cell types.

Erythropoiesis

Erythropoiesis is the production of RBCs, regulated by erythropoietin (EPO).

Balance: Maintains equilibrium between RBC production and destruction.

Erythropoietin (EPO)

Location: Produced mainly by the kidneys.
When Released: In response to hypoxia (low oxygen levels).

Red Blood Cell Disorders

Too Few or Too Many RBCs

Too Few: Leads to anemia, reduced oxygen delivery.
Too Many: Causes polycythemia, increased viscosity.

Anemia

Anemia is a condition characterized by a deficiency of RBCs or hemoglobin, resulting in reduced oxygen transport.

Signs: Fatigue, pallor, shortness of breath.
Symptoms: Weakness, dizziness.
Causes: Blood loss, decreased production, increased destruction.

Types of Anemia

Hemorrhagic Anemia: Caused by blood loss.
Iron Deficiency Anemia: Due to insufficient iron; diagnosed by blood smear.
Pernicious Anemia: Caused by vitamin B12 deficiency; blood smear shows large, immature RBCs.
Renal Anemia: Resulting from kidney disease and decreased EPO production.
Aplastic Anemia: Failure of bone marrow to produce blood cells.
Hemolytic Anemia: Increased RBC destruction.

White Blood Cells (Leukocytes)

Leukocyte Overview

Leukocytes: Defend against infection and disease.
% of Blood Volume: Less than 1%.

Types of Leukocytes

Neutrophils: Increase in bacterial infections.
Eosinophils: Increase in parasitic infections.
Basophils: Increase in allergic reactions.
Lymphocytes: Involved in immune responses.
Monocytes: Become macrophages in tissues.

Leukopoiesis

Leukopoiesis is the formation of WBCs in bone marrow.

Leukopenia and Leukemia

Leukopenia: Abnormally low WBC count.
Leukemia: Cancer of WBCs, leading to uncontrolled proliferation.

Platelets and Hemostasis

Platelets

Platelets are cell fragments essential for blood clotting.

Hemostasis

Hemostasis is the process of stopping bleeding, involving vascular spasm, platelet plug formation, and coagulation.

Blood Groups

Blood groups are classified based on the presence of antigens on RBC membranes (e.g., ABO and Rh systems).

Heart Anatomy and Physiology

Structure of the Heart

The heart is a muscular organ with four chambers: two atria and two ventricles.

Chambers

Atria: Receive blood returning to the heart.
Ventricles: Pump blood out of the heart.

Vessels

Arteries: Carry blood away from the heart.
Veins: Carry blood toward the heart.

Pericardium

Fibrous Pericardium: Outer protective layer.
Parietal Pericardium: Lines the fibrous pericardium.
Visceral Pericardium (Epicardium): Covers the heart surface.

Heart Wall Layers

Epicardium: Outer layer.
Myocardium: Muscular middle layer responsible for contraction.
Endocardium: Inner lining.

Internal Structures

Interatrial Septum: Separates the atria.
Interventricular Septum: Separates the ventricles.
Fossa Ovalis: Remnant of fetal circulation.
Papillary Muscles: Anchor chordae tendineae.
Chordae Tendineae: Prevent valve prolapse.

Heart Valves

Atrioventricular (AV) Valves: Separate atria from ventricles.
- Names: Tricuspid (right), Mitral/Bicuspid (left).
- Location: Between atria and ventricles.
- Purpose: Prevent backflow during ventricular contraction.
- Homeostatic Imbalances: Valve stenosis or regurgitation.
Semilunar Valves: Separate ventricles from major arteries.
- Names: Pulmonary (right), Aortic (left).
- Location: At exits of ventricles.
- Purpose: Prevent backflow into ventricles.
- Homeostatic Imbalances: Valve insufficiency or stenosis.

Cardiovascular Physiology

Circulation Pathways

Systemic Circulation: Delivers oxygenated blood to tissues.
Pulmonary Circulation: Exchanges gases in the lungs.

Cardiac Muscle

Automaticity: Ability to generate impulses without neural input.
Similarities/Differences with Skeletal Muscle: Both are striated; cardiac muscle has intercalated discs and is involuntary.
Anaerobic/Aerobic Respiration: Cardiac muscle relies primarily on aerobic metabolism.

Intrinsic Conduction Pathway

Locations: SA node, AV node, bundle of His, bundle branches, Purkinje fibers.
Features: Coordinates heartbeats.

Arrhythmias

Tachycardia: Abnormally fast heart rate.
Bradycardia: Abnormally slow heart rate.

Extrinsic Innervation

Autonomic Nervous System (ANS): Regulates heart rate and force.

Cardiac Cycle

Systole: Contraction phase.
Diastole: Relaxation phase.
S1 & S2: Heart sounds due to valve closure.

Venous Return & Contractile Force

Venous return affects stroke volume and cardiac output.
Excessive stretch can lead to decreased contractility.

Cardiac Output

Cardiac output is the volume of blood pumped by the heart per minute.

Congestive Heart Failure (CHF)

Definition: Inability of the heart to pump sufficient blood.
Contributing Factors: Hypertension, coronary artery disease, valve disorders.

Right vs. Left Heart Failure

Right Heart Failure: Causes peripheral edema.
Left Heart Failure: Causes pulmonary congestion.

Type of Leukocyte	Function	Increases in
Neutrophil	Phagocytosis of bacteria	Bacterial infections
Eosinophil	Combat parasites	Parasitic infections
Basophil	Release histamine	Allergic reactions
Lymphocyte	Immune response	Viral infections
Monocyte	Phagocytosis, become macrophages	Chronic infections

Additional info: Some explanations and definitions have been expanded for clarity and completeness, based on standard Anatomy & Physiology curriculum.