Anatomy & Physiology Exam 2 Quizlet Quiz

• Blood maintains homeostasis by transporting gases, nutrients, and waste, transporting processed molecules and regulatory molecules, regulating pH and osmosis, maintaining body temperature, protecting against foreign substances, and clot formation.

Blood Plasma

• Blood plasma consists of 90% water, proteins (albumin, globulins, and fibrinogen), and electrolytes.

Formed Elements

• The three formed elements in blood are erythrocytes (RBCs), leukocytes (WBCs), and platelets.

Hemoglobin Structure

• Hemoglobin's structure includes four globin molecules (two alpha and two beta) and four heme groups, each containing iron.

Hemoglobin Function

• Globin transports carbon dioxide and nitric oxide and heme transports oxygen.

RBC Life History

• Red blood cells develop from stem cells to proerythroblasts, then erythroblasts, and finally reticulocytes.

Types of WBCs

• The five types of white blood cells are neutrophils, eosinophils, basophils, lymphocytes, and monocytes.

Neutrophils

• Neutrophils are the most abundant WBCs, function as phagocytes, and serve as the first line of defense.

Eosinophils

• Eosinophils attack worms and parasites, are overactive in asthma, and break down histamines.

Basophils

• Basophils are involved in inflammation, release histamine, and are the least populous WBCs.

Monocytes

• Monocytes are larger than neutrophils, can move out of the blood, and become macrophages.

Platelet Formation

• Platelets are formed from the fragmentation of megakaryocytes in the red bone marrow.

Platelet Structure

• Platelets are small fragments of cells without a nucleus, possessing surface receptors to bind to molecules like collagen.

Platelet Function

• Platelets prevent blood loss by promoting the formation and contraction of clots and forming platelet plugs.

ABO Blood Groups

• ABO blood groups are genetically determined classes of human blood based on the presence or absence of carbohydrates A and B on the surface of red blood cells. The phenotypes are A, B, AB, and O.

ABO Blood Incompatibilities

• Type A blood has anti-B antibodies, type AB has neither antibody, and type O blood has both anti-A and anti-B antibodies; type O is a universal donor, and type AB is a universal acceptor.

Rh Factor

• The Rh factor is a blood antigen, named after the Rhesus monkey, where it was first identified; Rh-positive blood has the Rh antigen on the surface of RBCs, while Rh-negative blood does not.

Hemolytic Disease of the Newborn

• This disease occurs in a fetus who is Rh-positive while the mother is Rh-negative, especially in subsequent pregnancies if the mother has developed antibodies to Rh factors.

Additional Definitions

• Plasma is the fluid portion of blood.
• Erythropoiesis is the production of red blood cells.
• A megakaryoblast is the precursor to a megakaryocyte, which becomes platelets.
• Bilirubin is a byproduct of hemoglobin breakdown.
• Chemotaxis is cell movement in response to a chemical stimulus.
• Diapedesis is the passage of white blood cells through intact vessel walls into tissue.
• A thrombus is a blood clot attached to the interior wall of an artery or vein.
• An embolus is a mobile blood clot.
• Agglutination is the clumping of red blood cells.
• An antigen is a substance that triggers an immune response.
• An antibody is a protein that acts against a specific antigen.
• Reticulocytes are immature red blood cells.

Heart Functions

• The heart functions to maintain blood pressure, route blood, ensure one-way flow, and regulate blood supply.

Heart Layers

• The layers of the heart are the pericardium, myocardium, and endocardium.

Pericardium

• The pericardium consists of a fibrous outer layer as an anchor and a serous layer with parietal and visceral components that form a cavity with pericardial fluid.

Heart Wall Layers

• The layers of the heart wall are the epicardium, myocardium, and endocardium

Epicardium

• The epicardium is a serous membrane forming a smooth outer surface of the heart.

Myocardium

• The myocardium is the middle layer, composed of cardiac muscle cells, responsible for heart contraction.

Endocardium

• The endocardium is the smooth inner surface of the heart chambers.

Veins Entering Right Atrium

• The inferior and superior vena cava and the coronary sinus empty into the right atrium.

Veins and Arteries

• The right atrium receives blood from the body via the superior vena cava, inferior vena cava, and coronary sinus. The left atrium receives blood from the pulmonary veins. The right ventricle pumps blood into the pulmonary trunk.

Heart Valves

• Aortic semilunar valve: Located between the left ventricle and the aorta.
• Bicuspid valve: Located between the left atrium and the left ventricle.
• Tricuspid valve: Located between the right atrium and the right ventricle.
• Pulmonary semilunar valve: Located between the right ventricle and the pulmonary trunk.

Blood Flow Through The Heart

• Blood flows from the superior and inferior vena cava to the right atrium, through the tricuspid valve to the right ventricle, through the pulmonary semilunar valve to the pulmonary trunk, to the lungs, through the pulmonary veins to the left atrium, through the bicuspid valve to the left ventricle, through the aortic semilunar valve to the aorta, and then to the body.

Cardiac Muscle Cells

• Cardiac muscle cells are branched and connected by intercalated discs.

Cardiac Cell Structure and Function

• Cardiac cells behave as a single unit, with gap junctions allowing action potentials to move from cell to cell.

Heart's Conduction System

• The heart's conduction system consists of the SA node, AV node, AV bundle, right and left bundle branches, and Purkinje fibers.

SA Node

• It is the heart's pacemaker, generating about 60 beats per minute; it passes conduction to the AV node.

AV Node

• It slows down action potentials to ensure the ventricles receive the signal to contract after the atria have contracted; it then passes the signal to the AV bundle.

AV Bundle

• It passes through a hole in the cardiac skeleton to reach the interventricular septum.

Bundle Branches

• They extend beneath the endocardium to the apices of the right and left ventricles.

Purkinje Fibers

• These are large-diameter cardiac muscle cells with few myofibrils and many gap junctions; they conduct action potentials to ventricular muscle cells.

Long Refractory Period

• A long refractory period in the heart prevents cramping.

EKG Elements

• The elements of an EKG are the P wave, QRS complex, and T wave.

EKG - P Wave

• The P wave represents atrial depolarization (contraction).

EKG - QRS Complex

• The QRS complex represents ventricular depolarization and atrial repolarization.

EKG - T Wave

• The T wave represents ventricular repolarization.

Heart Sounds

• Heart sounds are caused by the closing of the heart valves.

First Heart Sound

• The first heart sound, "lubb," is caused by the closing of the AV valves.

Second Heart Sound

• The second heart sound, "dubb," is caused by the closing of the aortic and pulmonary semilunar valves.

Mean Arterial Pressure

• Mean arterial pressure equals cardiac output (stroke volume multiplied by heart rate) multiplied by peripheral resistance.

Dicrotic Notch

• The dicrotic notch occurs when the aortic semilunar valve closes, causing a slight increase in pressure within the aorta.

Extrinsic Regulation of the Heart

• The three forms of extrinsic regulation of the heart are parasympathetic, sympathetic, and hormonal.

Parasympathetic Stimulation

• The vagus nerve decreases heart rate via acetylcholine secretion, which hyperpolarizes the heart.

Sympathetic Stimulation

• Cardiac nerves in the SA node, AV node, and coronary vessels increase heart rate and force of contraction by releasing epinephrine and norepinephrine.

Hormonal Control

• Epinephrine and norepinephrine from the adrenal medulla are released in response to stress/activity.

Temperature

• Heart rate increases when body temperature increases.

Pulmonary Circuit

• The pulmonary circuit carries blood to the lungs for gas exchange and returns it to the heart.

Systemic Circuit

• The systemic circuit carries blood between the heart and the rest of the body.

Pectinate Muscle

• Pectinate muscles are prominent ridges lining the surface of the atria.

Papillary Muscle

• These small bunches of cardiac muscle are responsible for pulling the atrioventricular valves (tricuspid and mitral) closed via the chordae tendineae.

Chordae Tendineae

• These fibers are attached to the tricuspid valve and pull it closed when papillary muscles contract, preventing backflow of blood.

Coronary Sinus

• The coronary sinus is an enlarged vessel on the posterior aspect of the heart that empties blood into the right atrium.

Angioplasty

• Angioplasty Is the surgical repair of a vessel

Baroreceptors

• They monitor blood pressure in the walls of the internal carotids and aorta.

Circulatory System Order

• The order is elastic arteries, muscular arteries, arterioles, metarterioles, capillaries, venules, small veins, medium/large veins, and the heart.

Capillary Structure

• Capillaries consist of endothelial cells, one cell thick; materials cross through diffusion or fenestrae (if water-soluble or larger). Precapillary sphincters regulate blood flow.

Arteries

• Arteries carry blood away from the heart, have thick muscular walls, a small internal diameter (lumen), carry blood under high pressure, and typically carry oxygenated blood (except for the pulmonary artery); the tunica media and intima have elasticity for vasoconstriction and vasodilation, and the tunica externa is connective tissue.

Elastic Arteries

• They have the largest diameter and are more elastic than muscular arteries, with a thick tunica intima and a thin tunica media.

Muscular Arteries

• They are most smaller, unnamed arteries, with 25-40 layers of smooth muscle that regulate blood supply through constriction or dilation.

Veins

• A unique feature of veins are valves.

Medium and Large Veins

• They possess all three tunics, a thin tunica media, but can regulate vessel diameter as BP in the venous system is low. Thickest layer is the tunica adventitia, with walls thinner than those of arteries.

Innervation of Blood Vessels

• Unmyelinated sympathetic nerve fibers form plexi in the tunica adventitia for vasoconstriction (small arteries and arterioles have the most innervation); myelinated nerves are present for baroreceptors.

Arteriosclerosis

• It is general aging of arteries with a thick tunica intima and a less elastic tunica media.

Atherosclerosis

• Atherosclerosis is the hardening and narrowing of arteries due to the buildup of cholesterol plaques.

Major Arteries: Head and Upper Extremities

• Aorta exits the left ventricle and divides into three segments: the ascending aorta, the aortic arch (giving rise to the brachiocephalic artery, left common carotid, and subclavian artery), and the descending aorta (thoracic and abdominal aorta). The blood supply to the upper limbs is via the subclavian, axillary, and brachial arteries.

Superior Vena Cava

• Drains blood from Head, neck, thorax & Upper limbs

Blood Pressure

• Blood pressure is the force of blood against arterial walls.

Blood Pressure Measurement

• Measured by listening for Korotkoff sounds produced by turbulent flow in arteries as pressure is released from a cuff.

Viscosity and Blood Flow

• As viscosity increases, the pressure required for flow increases, influenced largely by hematocrit (altered by dehydration or uncontrolled RBC production).

Laplace's Law

• Critical closing pressure is the pressure at which a blood vessel collapses and blood flow stops. Laplace's Law states that the force acting on blood vessel walls is proportional to the vessel's diameter times blood pressure; as diameter increases, force on the wall increases, and a weakened vessel wall may bulge out, forming an aneurysm.

Pulse Pressure

• Pulse pressure is the difference between systolic and diastolic pressure.

Pulse Sites

• Pulse can be felt in superficial arteries that lie over a firm surface, such as the radial artery, common carotid artery, brachial artery, femoral artery, etc.

Additional Definitions

• Angiotensin II increases blood pressure by stimulating kidneys to reabsorb more water and releasing aldosterone.
• Vasopressin (antidiuretic hormone) is released by the posterior pituitary, raising blood pressure and enabling kidneys to conserve water.
• Aldosterone is a "salt-retaining hormone" that promotes sodium retention, which promotes water retention and higher blood volume and pressure.