Blood, Heart, and Blood Vessels: ANP Study Guide (Chapters 17-19)

Blood

Formed Elements of Blood

The formed elements are the cellular components of blood, each with distinct functions and characteristics.

• Erythrocytes (Red Blood Cells): Transport oxygen; lose their nucleus during maturation, so mature RBCs lack nuclei and cannot undergo mitosis.

• Leukocytes (White Blood Cells): Defend against infection; possess nuclei.

• Platelets (Thrombocytes): Cell fragments involved in clotting; lack nuclei.

Lifespan of Erythrocytes: Approximately 120 days due to absence of nuclei and inability to repair or divide.

Thrombocytopenia: Condition characterized by a decreased number of platelets.

Plasma Components

Plasma is the liquid portion of blood, containing water, proteins, nutrients, hormones, and waste products.

• Albumin: Maintains osmotic pressure.

• Globulins: Include antibodies for immune defense.

• Fibrinogen: Precursor to fibrin, essential for blood clotting.

Erythropoiesis and Regulation

Erythropoiesis is the process of RBC formation, triggered by low oxygen levels.

• Stimulus: Hypoxia (lack of oxygen).

• Source of Erythropoietin: Kidney.

• Site of RBC Production: Red bone marrow.

Blood Clotting Disorders

• Hemophilia: X-linked disorder, more common in males, impairs clotting.

Anemia Types

Anemia is a reduction in RBCs or hemoglobin, leading to decreased oxygen delivery.

• Iron-deficiency anemia: Caused by insufficient iron.

• Pernicious anemia: Due to vitamin B12 deficiency.

• Renal anemia: Caused by insufficient erythropoietin from kidneys.

• Aplastic anemia: Failure of bone marrow to produce RBCs.

• Sickle-cell anemia: Genetic disorder causing abnormal hemoglobin.

White Blood Cell Classification

• Granulocytes: Neutrophils (multi-lobed nuclei), basophils, eosinophils.

• Agranulocytes: Lymphocytes, monocytes.

Differential WBC Count: Elevated eosinophils may indicate allergy or parasitic infection.

Blood as Connective Tissue

Blood is a liquid connective tissue; solid fibers appear only during clotting.

Coagulation and Hemostasis

• Coagulation: Prothrombin is converted to thrombin; fibrinogen is converted to fibrin.

• Three Steps of Hemostasis:

  1. Vascular spasm: Vessel constricts to reduce blood loss.

  2. Platelet plug formation: Platelets adhere to damaged area.

  3. Coagulation: Fibrin reinforces the plug.

Blood Types and Transfusion

• Antigens: Located on RBC membranes.

• Antibodies: Found in plasma.

• Universal Recipient: AB+ (no antibodies in plasma).

• Universal Donor: O- (no antigens on RBCs).

Erythroblastosis Fetalis

Occurs when an Rh- mother has an Rh+ baby; maternal antibodies attack fetal RBCs during subsequent pregnancies.

Heart

Anatomical Landmarks

• Mediastinum: Central thoracic cavity location.

• Diaphragm: Heart sits atop.

• Apex: Formed by left ventricle, points leftward.

Gross Anatomy

• Coronary sulcus: Separates atria from ventricles.

• Chambers: Right/left atria (receive blood), right/left ventricles (discharge blood).

• Valves: AV valves (tricuspid, bicuspid/mitral), SL valves (aortic, pulmonary).

Coronary Circulation

• Left coronary artery: Anterior interventricular, circumflex branches.

• Right coronary artery: Posterior interventricular, marginal branches.

• Blockage: Causes ischemia in affected cardiac muscle.

Cardiac Cycle

• Atrial contraction: Ventricular filling.

• Ventricular contraction: Blood ejected into aorta/pulmonary trunk.

• Isovolumetric contraction/relaxation: All valves closed; volume unchanged, pressure changes.

• Valves closed at ventricular systole: AV valves.

• Valves closed at ventricular diastole: SL valves.

Intrinsic Conduction System

• SA node: Pacemaker.

• AV node, bundle of His, bundle branches, Purkinje fibers: Conduct impulses.

Electrocardiogram (ECG)

• P wave: Atrial depolarization.

• QRS complex: Ventricular depolarization.

• T wave: Ventricular repolarization.

Openings and Valves

• Right atrium: Tricuspid opening, coronary sinus, superior/inferior vena cava.

• Left atrium: Bicuspid opening, pulmonary veins.

• AV valves: Between atria and ventricles.

• SL valves: Between ventricles and great vessels.

Muscular Structures

• Papillary muscles: In ventricles, control AV valves via chordae tendineae.

• Pectinate muscles: Rough part of atria.

• Trabeculae carneae: Rough part of ventricles.

• Moderator band: Right ventricle.

Fetal Adaptations

• Foramen ovale: Bypass between atria; closes at birth to become fossa ovalis.

• Ductus arteriosus: Bypass between aorta and pulmonary trunk; closes at birth to become ligamentum arteriosum.

Blood Vessels

Types and Examples

• Elastic (conducting) arteries: Aorta.

• Muscular (distributing) arteries: Brachial artery.

• Arterioles (resistance vessels): Small arteries.

• Capillaries (exchange vessels): Site of nutrient/gas exchange.

• Venules: Small veins.

• Veins: Vena cava.

Blood Vessel Structure

• Tunica intima: Inner layer.

• Tunica media: Middle, muscular layer.

• Tunica adventitia: Outer layer.

• Capillaries: Only have tunica intima.

Major Blood Vessels and Circulations

• Internal carotid artery: Supplies brain, part of Circle of Willis.

• Anastomosis: Vessel connection; e.g., Circle of Willis.

• Aortic arch branches: Right brachiocephalic, left common carotid, left subclavian.

• Ascending aorta branches: Right and left coronary arteries.

• Inferior vena cava formation: Right and left common iliac veins.

• Hepatic portal circulation: Portal vein (splenic + superior mesenteric veins) carries nutrient-rich blood to liver.

• Abdominal aorta branches: Celiac trunk, renal, superior/inferior mesenteric arteries.

• Popliteal artery: Leads to anterior/posterior tibial arteries.

• Internal iliac artery: Supplies uterus.

• Veins draining into inferior vena cava: Renal, hepatic, common iliac veins.

Cardiac Output and Blood Pressure

• Cardiac Output (CO): Amount of blood ejected per minute.

• Formula:

$CO = SV \times HR$

• Stroke Volume (SV): Amount of blood ejected per beat.

• Heart Rate (HR): Beats per minute.

• Athletes: Maintain normal CO with low HR due to high SV.

EDV and ESV

• EDV (End Diastolic Volume): Blood in ventricles after relaxation.

• ESV (End Systolic Volume): Blood remaining after contraction.

• High HR: Decreases EDV due to shorter relaxation time.

Blood Pressure and Regulation

• Essential hypertension: BP > 130/90 mmHg; cause unknown.

• Tachycardia: Increased HR.

• Bradycardia: Decreased HR.

• Sympathetic nervous system: Increases HR and contractility.

• Parasympathetic nervous system: Decreases HR via vagus nerve.

• Factors affecting BP: Peripheral resistance, cardiac output.

• Blood doping: Increases peripheral resistance due to higher viscosity.

• Hemorrhage/shock: Body constricts vessels to raise BP.

• Chemicals increasing BP: ADH, epinephrine, angiotensin.

• Chemicals decreasing BP: Atrial natriuretic peptide (ANP).

Summary Table: Blood Vessel Types and Functions

Type	Example	Function
Elastic artery	Aorta	Conducts blood from heart
Muscular artery	Brachial artery	Distributes blood to organs
Arteriole	Small arteries	Regulates blood flow to capillaries
Capillary	Capillary beds	Exchange of gases/nutrients
Venule	Small veins	Collects blood from capillaries
Vein	Vena cava	Returns blood to heart

Summary Table: Plasma Proteins and Functions

Protein	Function
Albumin	Maintains osmotic pressure
Globulins	Immune defense (antibodies)
Fibrinogen	Clot formation

Summary Table: Blood Types and Transfusion Compatibility

Blood Type	Can Receive From	Can Donate To
AB+	All types	AB+
O-	O-	All types

Example: A patient with elevated eosinophils may be experiencing an allergic reaction or a parasitic infection.

Example: If the pulmonary valve is stenotic, blood flow from the right ventricle to the pulmonary trunk is impaired.

Example: Blood doping increases peripheral resistance, making it harder for the heart to pump blood.

Additional info: Academic context was added to clarify the functions of blood vessel types, plasma proteins, and the physiological effects of nervous system regulation on the heart.