Comprehensive Study Notes on Blood, Heart, and Vascular System

Flashcards covering key anatomy and physiology concepts from Chapters 14 (Blood), 15 (Heart), and 16 (Vascular System).

How many of each blood cell type does human red bone marrow produce on a daily basis?

Red bone marrow produces 400 billion platelets, 200 billion RBCs, and 20 billion WBCs every day.

What is the average lifespan of a red blood cell, and which organ removes old RBCs from circulation?

Red blood cells survive for about 120 days, and old RBCs are removed from circulation by the spleen.

What three main layers are formed when a blood sample is centrifuged in a test tube?

Plasma forms the top layer, a thin buffy coat containing WBCs and platelets forms the middle layer, and formed elements (RBCs) settle at the bottom.

Why are mature red blood cells incapable of cellular replication?

RBCs lose their nucleus and organelles during formation, leaving them unable to replicate.

Which hormone is secreted by the kidneys when blood oxygen levels drop?

Erythropoietin (EPO).

What are immature red blood cells called before they develop into fully mature erythrocytes?

Reticulocytes.

What are the breakdown products of hemoglobin when old red blood cells are destroyed by macrophages?

Hemoglobin breaks down into globin and heme; globin is converted into amino acids, while heme breaks down into iron and bilirubin.

What are the five specific types of leukocytes, divided into granulocytes and agranulocytes?

Granulocytes include neutrophils, eosinophils, and basophils. Agranulocytes include lymphocytes and monocytes.

From what precursor cell type are platelets (thrombocytes) derived?

Megakaryocytes.

What is the initial step in the process of hemostasis following a blood vessel injury?

Vascular spasm.

What structural component exposed by vessel injury causes platelets to adhere and form a platelet plug?

Collagen fibers.

Which factor is formed at the end of both the extrinsic and intrinsic clotting pathways?

Factor X.

What sequence of reactions occurs during the common pathway of blood clot formation?

Prothrombin activator converts prothrombin into thrombin, which then converts soluble fibrinogen into an insoluble web of fibrin.

How does intravenous heparin act to prevent blood clotting?

It acts as a fast-acting anticoagulant from basophils and mast cells that blocks the conversion of prothrombin to thrombin and thrombin to fibrin.

What antigens and plasma antibodies are present in Type A blood?

Type A blood contains A antigens on the RBC surface and anti-B antibodies in the plasma.

What occurs if a person with Type A blood receives a transfusion of Type B blood?

Anti-B antibodies in the recipient's blood attack the donor's Type B RBCs, causing them to clump together (agglutinate).

What causes erythroblastosis fetalis in an Rh-negative mother during a second pregnancy?

Anti-Rh antibodies produced by the Rh-negative mother after mixing with Rh-positive fetal blood during the first delivery cross the placenta and attack the Rh-positive RBCs of the subsequent fetus.

Where is the apex of the heart located relative to the rib cage?

In the fifth intercostal space at the left midclavicular line.

What are the structural layers that make up the pericardium?

The outer fibrous pericardium and the inner serous pericardium, which consists of a parietal layer, visceral layer (epicardium), and the pericardial cavity in between.

What are the three layers of the heart wall listed from inside to outside?

Endocardium, myocardium, and epicardium.

What structures connect the cusps of the AV valves to the papillary muscles inside the ventricles?

Chordae tendineae.

Which valve regulates blood flow between the left atrium and left ventricle?

The mitral valve (or bicuspid valve).

Which heart valve prevents backflow of blood from the pulmonary trunk into the right ventricle?

The pulmonary valve.

Where are the four primary heart sound auscultation sites located on the chest wall?

1) Aortic area: second intercostal space at right sternal border; 2) Pulmonic area: second intercostal space at left sternal border; 3) Tricuspid area: fourth or fifth intercostal space at left sternal border; 4) Mitral area: fifth intercostal space at left midclavicular line.

Where do the right and left coronary arteries originate to supply oxygenated blood to the myocardium?

Directly from the base of the aorta.

What vascular structure receives deoxygenated blood from the coronary veins and empties into the right atrium?

The coronary sinus.

Which structure serves as the primary pacemaker of the cardiac conduction system?

The sinoatrial (SA) node.

What is the complete pathway of an electrical impulse through the cardiac conduction system?

SA node $\rightarrow$ AV node -> AV bundle (Bundle of His) $\rightarrow$ Right and left bundle branches $\rightarrow$ Purkinje fibers.

What key physiological events occur during Phase 3 (Isovolumetric contraction) of the cardiac cycle?

Ventricles begin to contract with semilunar valves still closed, pressure increases rapidly, the R wave appears on the ECG, and the first heart sound (S1) is heard.

What electrical activity in the heart is represented by the P wave on an ECG?

Atrial depolarization.

What electrical event in the cardiac cycle corresponds to the QRS complex on an electrocardiogram?

Ventricular depolarization.

What is the mathematical equation for calculating Cardiac Output?

$$\text{Cardiac Output} = \text{Heart Rate} \times \text{Stroke Volume}$$

How does the acceleratory center in the medulla increase heart rate and myocardial contractility?

It sends impulses via the sympathetic nervous system through cardiac nerves that secrete norepinephrine to the SA node, AV node, and myocardium.

Through which nerve and neurotransmitter does the inhibitory center slow the heart rate?

Signals are sent via the vagus nerve, which secretes acetylcholine to the SA and AV nodes.

How is preload defined in cardiac physiology?

Preload is the amount of tension or stretch in the ventricular myocardium at the end of diastole just before it contracts.

What clinical signs and symptoms result from left ventricular heart failure?

Shortness of breath, pulmonary edema, and coughing, caused by blood backing up into the pulmonary circulation.

What clinical manifestations are characteristic of right ventricular heart failure?

Generalized swelling, enlarged liver and spleen, fluid pooling in the abdomen, and jugular vein distention, caused by blood backing up into systemic circulation.

What are the three major types of blood vessels and their primary roles?

Arteries carry blood away from the heart, veins return blood to the heart, and capillaries connect arterioles to venules and serve as exchange vessels.

What are the three structural layers that form the wall of a typical blood vessel?

Tunica intima (innermost), tunica media (middle), and tunica externa (outermost).

What are the three functional categories of arteries?

Conducting arteries (largest, elastic), distributing arteries (muscular, leading to specific organs), and arterioles (smallest, resistance vessels).

Why are veins referred to as capacitance vessels?

Because they have thin, highly stretchable walls and a great capacity to store blood volume.

What structures regulate blood flow into true capillaries from an arteriole?

Precapillary sphincters.

How does filtration drive fluid movement at the arterial end of a capillary?

Capillary blood pressure ($30 philosophy / mmHg$) exceeds tissue fluid pressure ($2 philosophy / mmHg$), forcing plasma and dissolved nutrients out through the capillary wall.

What mechanism causes reabsorption of fluid and metabolic waste at the venous end of a capillary?

Colloid osmotic pressure, generated by plasma proteins like albumin, draws fluid and wastes back into the capillary.

What arterial network at the base of the brain provides collateral circulation to safeguard cerebral blood supply?

The Circle of Willis.

What defines a portal circulation system, such as the hepatic portal system?

A circulatory pathway in which blood flows through two consecutive capillary networks before returning to the heart.

How do vasoconstriction and vasodilation affect blood pressure and blood flow?

Vasoconstriction increases pressure and decreases flow. Vasodilation decreases pressure and increases flow.

Where in the systemic vascular system is blood flow velocity highest, and where is it lowest?

Blood flow velocity is fastest in the aorta and slows to its lowest rate in the capillaries.

How does atherosclerosis contribute to hypertension?

Fatty atheroma buildup narrows the vessel lumen, and the loss of arterial elasticity prevents expansion during systole, raising peripheral resistance and blood pressure.

Which vasoactive substances are secreted by endothelial cells to regulate local blood vessel diameter?

Nitric oxide (causes vasodilation) and endothelins (cause vasoconstriction).

Which hormone promotes a reduction in blood pressure, counteracting hormones like aldosterone and ADH?

Atrial natriuretic peptide (ANP).

What two bodily pump mechanisms assist in returning venous blood from the lower limbs to the heart?

The skeletal muscle pump and the respiratory pump.

Plasma

The clear, light-yellow liquid extracellular matrix of blood that constitutes approximately $55\%$ of total blood volume.

Buffy Coat

The thin middle layer of centrifuged blood composed of white blood cells (leukocytes) and platelets (thrombocytes).

Erythrocytes

Biconcave red blood cells lacking a nucleus that transport oxygen ($O<em>2$) to tissues and carbon dioxide ($CO</em>2$) to lungs, with a lifespan of roughly $120\,\text{days}$.

Hemoglobin

An iron-containing protein made of four globin chains, each bound to a heme group capable of binding an oxygen molecule ($O_2$).

Hemostasis

The process of stopping bleeding through three sequential steps: vascular spasm, platelet plug formation, and coagulation (blood clotting).

Sinoatrial (SA) Node

The primary pacemaker of the heart, located in the upper wall of the right atrium, which spontaneously initiates electrical impulses.

Cardiac Output (CO)

The volume of blood ejected by each ventricle per minute, calculated as heart rate multiplied by stroke volume ($\text{CO} = \text{HR} \times \text{SV}$).

Capacitance Vessels

Veins, so named because their ability to stretch gives them a high capacity for storing blood.

Precapillary Sphincters

Smooth muscle rings at the entrance of capillary networks that open during exercise to perfuse tissue beds and constrict during rest.

Colloid Osmotic Pressure

An inward pressure exerted by non-diffusible plasma proteins (primarily albumin) that draws tissue fluid and metabolic waste back into venous capillaries.

Atherosclerosis

A condition in which fatty plaque buildup inside arterial walls narrows vessel lumens and reduces elasticity, leading to increased vascular resistance and high blood pressure.

Hepatic Portal System

A specialized circulatory route in which blood flows through two capillary networks in series (digestive system capillaries, then hepatic sinusoids) before returning to the heart.