Human Anatomy Cardiovascular system

EXAM 5

What are the main functions of blood?

• Transport: gases (O₂/CO₂), nutrients, wastes, hormones.

• Regulation: pH, osmosis, body temperature.

• Protection: immune defense and clot formation.

What are the two major components of blood, and what percentage does each make up?

• Plasma (55%) — mostly water, proteins, ions, hormones, and waste.

• Formed elements (45%) — red blood cells (RBCs), white blood cells (WBCs), and platelets.

What are the three main plasma proteins and their functions?

• Albumin: most abundant; maintains osmotic pressure and transports fatty acids & hormones.

• Globulins: act as antibodies and transport lipids/hormones.

• Fibrinogen: converted to fibrin during clot formation.

Where does hematopoiesis occur, and how does it differ in children vs. adults?

• Occurs in red bone marrow.

• In children: primarily red marrow throughout bones.

• In adults: most red marrow converts to yellow marrow (fatty tissue).

• Stem cells differentiate into RBCs, WBCs, and platelets.

About how many hemoglobin molecules are found in each RBC, and what element binds O₂?

• Each RBC has about 280 million hemoglobin molecules.

• Iron (Fe) in the heme group binds oxygen.

• RBCs lack nuclei and mitochondria to maximize space for hemoglobin and oxygen transport.

Name and describe four RBC-related disorders

• Carbon Monoxide Poisoning: CO binds iron in hemoglobin, blocking O₂ transport.

• Iron Deficiency Anemia: not enough iron → less hemoglobin → reduced O₂-carrying capacity.

• Hemorrhagic Anemia: blood loss → fewer RBCs.

• Erythrocytosis: overproduction of RBCs → sluggish flow, risk of capillary blockage.

What are the two categories of WBCs, and which cells belong to each?

• Granulocytes: have cytoplasmic granules.

  • Basophils

  • Eosinophils

  • Neutrophils

• Agranulocytes: lack visible granules.

  • Lymphocytes

  • Monocytes

What is the main role of basophils, eosinophils, and neutrophils?

• Basophils: release histamine (inflammation) & heparin (anticoagulant).

• Eosinophils: reduce inflammation; attack parasites (worms).

• Neutrophils: most abundant; phagocytize bacteria and debris.

What do lymphocytes and monocytes do?

• Lymphocytes: produce antibodies, regulate immune response, reject grafts, fight infections.

• Monocytes: become macrophages once they leave the blood; phagocytize bacteria and dead tissue.

What are platelets, and what is their function?

• Cell fragments derived from megakaryocytes in bone marrow.

• Form platelet plugs during blood clotting.

• Diameter ≈ 2–4 μm (smallest formed element).

Explain how antigens and antibodies determine blood type in the ABO system.

• Antigens (on RBCs) determine blood type.

• Antibodies (in plasma) target foreign antigens → cause agglutination (clumping).

Which blood type is the universal donor and which is the universal recipient?

• O-negative (O–): universal donor — no antigens on RBCs.

• AB-positive (AB+): universal recipient — no antibodies in plasma.

What is the Rh factor, and why can it cause problems in pregnancy?

• Rh+ = presence of antigen D; Rh– = absence.

• Problem: Rh– mother with Rh+ fetus → mother makes antibodies that attack fetal RBCs (hemolytic disease of the newborn).

What are the major steps of blood coagulation (clotting)?

• Formation of Thromboplastin (extrinsic) or Factor XII activation (intrinsic).

• Prothrombin → Thrombin.

• Fibrinogen → Fibrin, which forms the clot.

What’s the difference between thrombosis, embolus, and hemophilia?

• Thrombosis: stationary (attached) clot.

• Embolus: clot that breaks free and travels.

• Hemophilia: inherited disorder causing defective or absent clotting.

Four main functions of the heart:

• Generate blood pressure to move blood.

• Route blood through pulmonary & systemic circuits.

• Ensure one-way flow (valves).

• Regulate blood supply according to tissue needs.

What is the pericardium and its function?

• Thick double-layered sac around the heart.

  • Fibrous pericardium: tough outer layer.

  • Serous pericardium: inner layer (parietal + visceral).

• Pericardial fluid reduces friction.

• Pericarditis = inflammation of serous pericardium.

Layers of the heart wall (outer → inner):

• Epicardium (visceral pericardium): protective outer surface.

• Myocardium: cardiac muscle, contraction.

• Endocardium: smooth lining for blood flow inside chambers.

Name the four chambers and what divides them:

• Atria (2): upper chambers → receive blood.

• Ventricles (2): lower chambers → pump blood out.

• Interatrial septum and interventricular septum separate right/left sides.

What is the foramen ovale?

• Opening between right & left atria in the fetus, bypasses pulmonary circulation.

• Normally closes after birth.

What enters each atrium?

• Right atrium:

  • Superior vena cava (from upper body)

  • Inferior vena cava (from lower body)

  • Coronary sinus (from heart wall)

• Left atrium:

  • 4 pulmonary veins (from lungs)

What exits each ventricle?

• Right ventricle → pulmonary trunk → lungs

• Left ventricle → aorta → body

What are the four major valves and their roles?

• Tricuspid valve: right atrioventricular (3 cusps).

• Bicuspid/Mitral valve: left atrioventricular (2 cusps).

• Pulmonary semilunar valve: between RV & pulmonary trunk.

• Aortic semilunar valve: between LV & aorta.

• Valves ensure unidirectional blood flow.

What is the function of the cardiac conducting system?

It initiates and transmits action potentials through the heart to coordinate contraction.

List the five parts of the conduction pathway in order:

• Sinoatrial (SA) node — “pacemaker,” starts the impulse (right atrium).

• Atrioventricular (AV) node — delays impulse, allows ventricles to fill.

• AV bundle (Bundle of His) — transmits impulse down septum.

• Right & left bundle branches — carry impulse through septum.

• Purkinje fibers — stimulate ventricular contraction.

What are normal and abnormal heart rates called?

• Sinus tachycardia: >100 bpm (fast).

• Sinus bradycardia: <60 bpm (slow, normal in athletes).

Components of the ECG (electrocardiogram):

• P wave: atrial depolarization → atrial contraction.

• QRS complex: ventricular depolarization → ventricular contraction.

• T wave: ventricular repolarization → relaxation.

What do Atrial Fibrillation and Ventricular Fibrillation show on an ECG?

• Atrial Fibrillation (A-Fib): no P wave; quivering atria, less efficient pumping.

• Ventricular Fibrillation (V-Fib): no QRS complex; heart can’t pump — life-threatening.

How does the nervous system control heart rate?

• Parasympathetic (Vagus Nerve):

  • Releases acetylcholine, hyperpolarizes SA node → slows HR.

• Sympathetic Nerves:

  • Release epinephrine & norepinephrine, depolarize SA node → increase HR and contractility.

• Exercise, stress, or excitement increase sympathetic stimulation.

Cardiac Output formula and meaning:

• CO = HR × SV (heart rate × stroke volume)

• Example:

  • Rest: 72 bpm × 70 mL = 5 L/min

  • Exercise: 190 bpm × 115 mL = 22 L/min

• Cardiac reserve = difference between rest and max output (greater in athletes).

Blood Pressure definitions:

• Systolic: pressure during contraction.

• Diastolic: pressure during relaxation.

• Normal: <120/80 mmHg.

• Prehypertension: 120–139 / 80–89.

• Stage 1: 140–159 / 90–99.

• Stage 2: >160 / >100.

What are the main functions of the peripheral circulation?

• Carry blood

• Exchange gases, nutrients, and waste

• Transport hormones

• Regulate blood pressure

• Direct blood flow to active tissues

Trace the general blood flow path starting from the heart:

Heart → Aorta → Large arteries → Medium/small arteries → Arterioles → Capillaries → Venules → Veins → Vena cava → Heart

Compare arteries, capillaries, and veins:

Type	Function	Blood Direction	Features
Arteries	Carry oxygenated blood (except pulmonary arteries)	Away from heart	Thick, elastic walls
Capillaries	Gas/nutrient exchange	Connect arterioles to venules	1 cell thick; form networks
Veins	Carry deoxygenated blood (except pulmonary veins)	Toward heart	Thinner walls, valves prevent backflow

What are vasoconstriction and vasodilation?

• Vasoconstriction: vessel narrows → ↓ blood flow.

• Vasodilation: vessel widens → ↑ blood flow.

Define arteriosclerosis and atherosclerosis:

• Arteriosclerosis: general hardening/loss of elasticity of arteries.

• Atherosclerosis: buildup of fatty plaques inside arterial walls (specific type of arteriosclerosis).

What are the three types of circulation?

• Pulmonary circulation: heart → lungs → heart (gas exchange).

• Systemic circulation: heart → body → heart.

• Portal circulation: blood flows through two capillary beds before returning to the heart (e.g., hepatic portal system).

Name the three main parts of the aorta:

• Ascending aorta — gives off coronary arteries.

• Aortic arch — gives off brachiocephalic, left common carotid, left subclavian.

• Descending aorta — splits into thoracic and abdominal portions.

What are the first three branches off the aortic arch and what do they supply?

1. Brachiocephalic artery (right side only) → right common carotid & right subclavian.

2. Left common carotid → head & neck.

3. Left subclavian → left upper limb.

Key arteries to know:

• Common carotid → Internal & External carotid arteries (head/face).

• Subclavian → Axillary → Brachial → Radial/Ulnar (arm).

• External iliac → Femoral → Popliteal → Tibial → Dorsalis pedis (leg).

Key veins to know:

• Head/neck: Internal & external jugular → subclavian → brachiocephalic → superior vena cava.

• Upper limb: Cephalic, basilic, brachial → axillary → subclavian.

• Lower limb: Great saphenous (superficial, used in bypass) & small saphenous → femoral → external iliac.

• Thorax: Azygos (right), hemiazygos (left) → superior vena cava.

• Abdomen: Common iliac → inferior vena cava.