Skip to main content
Back

Endocrine and Cardiovascular System Study Guide

NotesPracticeVideo lessons

Study Guide - Smart Notes

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

Blood: Roles and Components

Functions of Blood

Blood is a vital fluid that performs multiple roles in the human body, including transportation, defense, and homeostasis.

  • Transportation: Delivers oxygen, nutrients, hormones, and removes metabolic wastes.

  • Defense: White blood cells (WBCs) and antibodies protect against toxins and pathogens.

  • Homeostasis: Regulates pH, ion composition, restricts fluid loss at injury sites, and stabilizes body temperature.

Major Components of Blood

Blood consists of plasma and formed elements.

  • Plasma: 90-92% water, 7% proteins (albumins, globulins, fibrinogen), 1% solutes (nutrients, hormones, electrolytes).

  • Formed Elements: Erythrocytes (RBCs), leukocytes (WBCs), thrombocytes (platelets).

Red Blood Cells (Erythrocytes)

RBCs are the most numerous formed element and are specialized for oxygen transport.

  • Contain hemoglobin, which binds oxygen.

  • Each RBC holds about 300 million hemoglobin molecules.

  • Hemoglobin types: oxyhemoglobin (with O2), deoxyhemoglobin (without O2), carbaminohemoglobin (with CO2).

White Blood Cells (Leukocytes)

Leukocytes are less numerous than RBCs and are key to immune defense.

  • Granular: Basophils, Eosinophils, Neutrophils.

  • Agranular: Monocytes, Lymphocytes.

  • Mnemonic: "Gran-dpa BEN" for granular types; "Never Let Monkeys Eat Bananas" for abundance order.

Platelets (Thrombocytes)

Platelets are cytoplasmic fragments involved in hemostasis and coagulation.

  • Derived from megakaryocytes.

  • Life span: 9–12 days.

Diagnostic Tests and Blood Pathologies

Common Blood Tests

  • Complete Blood Count (CBC): Measures WBC, RBC, and platelets.

  • Hemoglobin Concentration: Amount of hemoglobin in blood.

  • Hematocrit: Percentage of RBCs in total blood volume (W: 37-47%, M: 42-52%).

Blood Disorders

  • Anemia: Low hematocrit or hemoglobin; includes iron deficiency and sickle cell anemia.

  • Sickle Cell Anemia: Mutation in hemoglobin gene causes sickle-shaped RBCs.

Hemoglobin Structure and Function

Hemoglobin Components

Hemoglobin is a protein complex responsible for oxygen transport in blood.

  • Composed of four globin chains: alpha 1, alpha 2, beta 1, beta 2.

  • Each globin is bound to a heme group containing iron.

Example: The heme group binds oxygen via its iron ion, allowing hemoglobin to carry O2 throughout the body.

Structure of hemoglobin and heme group

Leukocyte Types and Disorders

Types of Leukocytes

  • Neutrophils, lymphocytes, monocytes, eosinophils, basophils.

  • Granular vs. agranular classification.

Leukocyte Disorders

  • Leukopenia: Low WBC count.

  • Leukocytosis: High WBC count.

  • Leukemia: Cancer affecting leukocytes (lymphocytic or myeloid).

  • Infectious Mononucleosis: Excessive atypical agranulocytes.

  • Septicemia: Blood infection.

  • Lymphoma: Cancer of lymphatic system.

Blood Typing and Compatibility

Blood Group Compatibility

Blood typing determines who can donate or receive blood based on antigens and antibodies.

  • Universal donor: O-

  • Universal recipient: AB+

  • Practice blood group compatibility for safe transfusions.

Blood Clotting Mechanisms

Clotting and Anticoagulants

  • Platelets and enzymes initiate clotting at injury sites.

  • Anticoagulants (e.g., protein C, antithrombin, heparin) prevent excessive coagulation.

The Heart: Structure and Function

Heart Chambers

The heart has four chambers, each with a specific role in blood circulation.

  • Right atrium: Receives blood from vena cava and coronary sinus.

  • Right ventricle: Pumps blood to pulmonary arteries.

  • Left atrium: Receives blood from pulmonary veins.

  • Left ventricle: Pumps blood to aorta.

Heart Valves

  • Tricuspid (right AV): Right atrium to right ventricle.

  • Mitral/Bicuspid (left AV): Left atrium to left ventricle.

  • Pulmonary semilunar: Right ventricle to pulmonary arteries.

  • Aortic semilunar: Left ventricle to aorta.

Myocardial Layers and Conduction System

  • Endocardium: Inner layer.

  • Myocardium: Muscular wall.

  • Epicardium: Outer layer.

  • Pericardial cavity: Contains fluid for heart movement.

  • Fibrous pericardium: Tough outer layer.

  • Intercalated discs: Connect cardiac muscle cells for synchronized contraction.

Cardiac Cycle

The cardiac cycle consists of systole (contraction) and diastole (relaxation).

  • Atrial systole: Atria contract, filling ventricles.

  • Ventricular systole: Ventricles contract, AV valves close, semilunar valves open.

  • Ventricular diastole: Ventricles relax, semilunar valves close, AV valves open.

Heart Sounds and EKG

Heart Sounds

  • S1 (lub): AV valves close.

  • S2 (dub): Semilunar valves close.

  • Murmurs: Turbulent blood flow, graded 1-6.

Electrocardiogram (EKG)

  • 3, 5, or 12 leads; 12-lead uses 10 electrodes.

  • P wave: Atrial depolarization.

  • QRS complex: Ventricular depolarization.

  • T wave: Atrial repolarization.

  • Intervals (P-R, QT, ST) indicate heart health.

Cardiac Pathologies

Common Conditions

  • Angina pectoris: Chest pain.

  • Myocardial infarction: Heart attack.

  • Ischemia: Reduced blood supply.

  • Hypoxia: Low oxygen.

  • Aneurysm: Arterial bulge.

  • Atherosclerosis: Plaque buildup.

  • Cardiac shock: Pump failure.

  • Cardiac tamponade: Fluid compresses heart.

  • Endocarditis: Inflammation of inner heart lining.

  • Pericarditis: Inflammation of pericardium.

  • Sepsis/Septicemia: Infection and widespread blood infection.

Blood Pressure and Heart Rate

Factors Affecting Blood Pressure

  • Blood volume, cardiac output, peripheral resistance, compliance.

  • Hypervolemia: Excess fluid volume.

  • Baroreceptors: Stretch receptors regulating BP.

Heart Rate Conditions

  • Bradycardia: HR < 60 BPM.

  • Tachycardia: HR > 100 BPM.

  • Normal adult HR: 60-100 BPM; BP: 120/80 mmHg.

Endocrine System Overview

Endocrine vs. Exocrine Glands

  • Endocrine: Secrete hormones into bloodstream.

  • Exocrine: Secrete substances directly to target tissue.

Major Endocrine Glands

  • Pituitary: Master gland; controls other glands.

  • Thyroid: Regulates metabolism.

  • Parathyroid: Regulates calcium.

  • Adrenal: Medulla (epinephrine), cortex (steroids).

  • Pancreas: Both endocrine (insulin, glucagon) and exocrine.

  • Testes/Ovaries: Sex hormones.

  • Pineal: Melatonin, circadian rhythm.

Hematopoiesis

Blood Cell Formation

  • Occurs in red bone marrow.

  • Erythropoiesis: RBC production; stimulated by hypoxia.

  • Leukopoiesis: WBC production; initiated by cytokines.

  • Thrombopoiesis: Platelet production; initiated by injury.

Platelet Disorders

Common Platelet Disorders

  • Hemophilia: Missing clotting factor.

  • Thrombus: Clot in unbroken vessel.

  • Embolus: Floating clot.

  • Thrombocytopenia: Low platelets.

  • Impaired liver function: Vitamin K deficiency.

  • DIC: Widespread clotting, uncontrolled bleeding.

Cardiac Muscle and Conduction

Structure of Cardiac Muscle

  • Uni-nucleate, striated, metabolically active.

  • Intercalated discs: Gap junctions for synchronized contraction.

Conduction System

  • SA node: Pacemaker.

  • AV node: Delivers stimulus to Bundle of His.

  • Bundle branches: Left and right, extend to apex.

  • Purkinje fibers: Trigger ventricular contraction.

Cardiac Output

  • CO = HR × SV

  • Factors: HR (hormones, fitness, age), SV (heart size, contractility, preload, afterload).

Equation:

Additional info: Congenital heart defects and EKG abnormalities (A Fib, V Fib) should be reviewed in textbook for further detail.

Pearson Logo

Study Prep