AP2 Exam 1

Semilunar Valves

(Aortic and Pulmonary Semilunar Valves) ejects blood into the aorta and pulmonary trunk when the volume pressure exceeds the pressure in the arteries. When the valves are relaxed blood starts to flow back to the heart, this closes the valves.

Atrioventricular Valves

(Tricuspid and Biscupid/Mitral Valves) prevent backflow into the atria when ventricles contract.

Functions of Plasma

- Carries nutrients including glucose which is the primary source of energy for cell metabolism. - Hormones are transported around the body in this attached to proteins named after it. - Contains inorganic ions which are important in regulating cell function and maintaining homeostasis. - Contains clotting agents and on exposure to air it will form a clot. Aids healing and stops bleeding. - Contains antibodies (gammaglobulins) to help resist/fight off infections.

Transportation Function of Blood

- O2 from the lungs to the cells - CO2 from the cells to lungs - Waste from cells to kidneys - Nutrients GI to cells

Last 3 phases of Coagulation

-1) A complex substance called prothrombin activator is formed. -2) Prothrombin activator converts a plasma protein called prothrombin into thrombin, an enzyme. -3)Thrombin catalyzes the joining of fibrinogen molecules present in plasma to a fibrin mesh, which traps blood cells and effectively seals the hole until the blood vessel can be permanently repaired.

List the influences of blood pressure

-1. How much the elastic arteries close to the heart can be stretched (their compliance or dispensability). -2. The volume of blood forced into them at any time.

Regulates pH Function of Blood

-Blood acts as a buffers to prevent changes in pH

Prevents Loss Function of Blood

-Blood clots

Hormone Movement Function of Blood

-From endocrine glands to cells

Defense Function of Blood

-White Blood Cells protect against disease - Blood proteins - antibodies

Temperature Function of Blood

-absorbs and distribute heat throughout the body and skin

Contrast the fetal heart from the adult heart.

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Basophil

0.05 - 1%, bilobed nucleus, purplish-black cytoplasmic granules, their release of histamine intensifies the inflammatory reactions.

Events of cardiac muscle cell contraction

1. Depolarization 2. Plateau Phase 3. Repolarization

Ventricular Filling

1st step of the cardiac cycle. AV valves are open, atrial depolarization, SL valves are closed, and ventricular volume increases.

Eosinophil

2-4%, bilobed nucleus, red cytoplasmic granules, weaker phagocytes when compared to neutrophils, they specialty is the elimination of parasites

Lymphocyte

25-45%, large spherical nucleus, they act directly against virus-infected cells and tumor cells, they also activate other immune response cells

Isovolumetric Systole

2nd step of the cardiac cycle. AV valve are closed, SL valves are closed, ventricular volume is constant, and ventricular pressure increases.

Monocyte

3-8%, kidney-shaped nucleus, they become large and powerful phagocytic macrophages. These cells are very important in starting an immune response.

Ventricular Ejection

3rd step of the cardiac cycle.AV valves are closed, SL valves are open, and ventricular volume decreases with pressure.

Isovolumetric Relaxation

4th step of the cardiac cycle.AV valves are closed, SL valves are closed, ventricular volume is constant, and ventricle is in diastole.

Neutrophil

50-70%, multilobed nucleus, twice as large as RBC, active in phagocytosis, they respond quickly to tissue desctruction by bacteria or fungus

Composition of Plasma

A straw-colored, sticky fluid. Although it is mostly water (about 90%), it contains over 100 different dissolved solutes, including nutrients, gases, hormones, wastes and products of cell activity, ions, and proteins.

Metarteriole

A vessel structurally intermediate between an arteriole and a capillary

Blood types have a classification which is based on two things.

ABO blood groups and Rh factor. Both factors combine to form the blood types as we know them today

Continuous Capillaries

Abundant in the skin and muscles, are most common. They are continuous in the sense that their endothelial cells provide an uninterrupted lining, adjacent cells being joined laterally by tight junctions.

Granulocyte

Are all roughly spherical in shape. They are larger and much shorter lived (in most cases) than erythrocytes. They characteristically have lobed nuclei (rounded nuclear masses connected by thinner strands of nuclear material). Functionally, all these types of cells are phagocytes to a greater or lesser degree.

Venous Valves

Are formed from folds of the tunica intima, and resemble the semilunar valves of the heart in both structure and function

Fenestrated Capillaries

Are similar to the continuous variety, except that some of the endothelial cells in these capallaries are riddled with oval pores. These oval pores are usually covered by a delicate membrane, or diaphragm (probably condensed basal lamina material), but even so, these capillaries are much more permeable to fluids and small solutes than continuous capillaries are.

Why is whole blood classified as a connective tissue?

Because it comes from mesenchyme. The collagen and elastic fibers typical of other connective tissues are absent from this, but dissolved fibrous proteins are still there.

Erythrocyte Production

Blood cell formation is referred to as hematopoiesis (hem ahto-poi-e sis), or hemopoiesis (hemo, hemato = blood; poiesis = to make). This process occurs in the red bone marrow. On average, the marrow turns out an ounce of new blood containing some 100 billion new cells each and every day. They arise from a hemocytoblast (stem cell) that's derived from mesenchyme. It begins when a hemocytoblast descendendant called a myeloid stem cell is transformed into a proerythroblast. After which the ribosome synthesize then the hemoglobins accumulate and then the nucleus is ejected. This process ic controlled hormonally and depends on adequate supply of iron, amino acids, and certain B vitamins. Such as vitamin B12, the intrinsic factor is needed for its absorption. Hemocytoblast-> Proerythroblast-> Early Erythoblast-> Late Erythroblast-> Normoblast-> Reticulocyte-> Erythrocyte

Explain the relationships between blood flow, blood pressure, and resistance.

Blood flow (F) is directly proportional to the difference in blood pressure (ΔP) between two points in the circulation, that is, the blood pressure, or hydrostatic pressure, gradient. Thus, when ΔP increases, blood flow speeds up, and when ΔP decreases, blood flow declines. Blood flow is inversely proportional to the peripheral resistance (R) in the systemic circulation; if R increases, blood flow decreases. These relationships are expressed by the formula F=∆P/R.

Elastic Arteries

Called conducting arteries, are thick-walled arteries near the heart—the aorta and its major branches. They help propel blood even when ventricles are relaxed. These arteries are the largest in diameter, ranging from 2.5 cm to 1 cm, and the most elastic. Large lumens make them low-resistance pathways that conduct blood from the heart to medium-sized arteries. They are relatively inactive in vasoconstriction, they can be visualized as simple elastic tubes. They're pressure reservoirs, expanding and recoiling as blood is ejected from the heart.

Serous Pericardium

Deep to the fibrous pericardium, a thin, slippery, two-layer serous membrane that forms a closed sac around the heart.

Describe the ABO blood groups

Depend on the presence or absence of two antigens; antigen A and antigen B. Which lies on the surface of the red blood cell (RBC). A person having an A antigen on his RBC cells will show a blood type of A. A person having a B antigen on his RBC cells will show a blood type of B. A person having both A & B antigens on his RBC cells will show a blood type of AB. A person having neither of those antigens will show a blood type of O.

Muscular Arteries

Distributing arteries, distally the elastic arteries give way to these arteries, which deliver blood to specific body organs. Their internal diameter ranges from that of a little finger (1 cm) to that of a pencil lead (about 0.3 mm). These arteries have the thickest tunica media of all vessels. Their tunica media contains relatively more smooth muscle and less elastic tissue than do elastic arteries active in vasoconstriction and less distensible.

Pericardium

Doubled-walled sac that encloses the heart.

Heart Valves

Ensure unidirectional blood flow through the heart.

Terminal Arteriole

Feeds the capillary bed

Venules

Formed when capillaries unite. The larger ones have one or two layers of smooth muscle cells (a scanty tunica media) and thin externa as well.

Capillaries

Have endothelial cells with spider-shaped pericytes scattered along the side. These microscopic blood vessels are the smallest. Their exceedingly thin walls consist of just a thin tunica intima. In some cases, one endothelial cell forms the entire circumference of the capillary wall. They exchange materials (gases, nutrients, hormones, and so on) between the blood and the interstitial fluid.

Explain the factors that influence blood pressure

If the amounts of blood entering and leaving the elastic arteries in a given period were equal, arterial pressure would be constant. Blood pressure rises and falls in a regular fashion in the elastic arteries near the heart.

Explain the basis of transfusion reactions

If you transfuse type B blood cells into a type A person then that persons immune system won't recognize the type B antigens as part of the body and will attack them just as it would invading bacteria. Transfusion reactions can range from the mild such as a fever too the more serious such as lung injury and acute hemolytic reaction where donor red cell are rapidly destroyed which is bad. (life threatening medical emergency bad).

Vascular Spasm

Immediate response to blood vessel injury; results in constriction. It's the first step of blood vessel repair, the damaged blood vessels respond to injury by constricting (vasoconstriction), triggers include direct injury to vascular smooth muscle, chemicals released by endothelial cells and platelets, and reflexes initiated by local pain receptors. The hormone serotonin is an example of this. It reduces blood loss for about 20 - 30 minutes.

Vasodilation

Increase in lumen diameter as the smooth muscle relaxes. Relaxation of the smooth muscles of the blood vessels, producing dilation.

Endocardium

Inside layer of the heart wall, sheet of endothelium, lines the heart chambers and covers the fibrous skeleton of the valves.

Thoroughfare Channel

Intermediate between a capillary and a venule.

Capillary Bed

Interwoven network formed by capillaries, where vessels are exchanged, and blood flows most slowly because their total cross-sectional area is the largest.

Erythrocyte Function

It transports respiratory gases (oxygen and carbon dioxide).

Describe the chemical makeup of hemoglobin.

It'a made up of the protein globin bound to the red heme pigment. Globin consists of four polypeptide chains—two alpha and two beta —each binding a ringlike heme group. Each heme group bears an atom of iron set like a jewel in its center . A hemoglobin molecule can transport four molecules of oxygen because each iron atom can combine reversibly with one molecule of oxygen. A single red blood cell contains about 250 million hemoglobin molecules, so each of these tiny cells can scoop up about 1 billion molecules of oxygen!

Physical Characteristics of Whole Blood

It's a sticky, opaque fluid with a characteristic metallic taste. Depending on the amount of oxygen it is carrying, the color of varies from scarlet (oxygen rich) to dark red (oxygen poor). It's more dense than water and about five times more viscous, largely because of its formed elements. It's slightly alkaline, with a pH between 7.35 and 7.45, and its temperature (38C or 100.4F) is always slightly higher than body temperature. It accounts for approximately 8% of body weight.

Composition of Whole Blood

It's the only fluid tissue in the body. The microscope reveals that it has both cellular and liquid components. It's a specialized type of connective tissue in which living _____ cells, called the formed elements, are suspended in a nonliving fluid matrix called plasma.

A brief description of the hemostasis process

It's the sequence of events that takes place to stop bleeding. 1. Vascular Spasm 2. Platelet Plug Formation 3. Coagulation

Agranulocyte

Lack visible cytoplasmic granules. Although they are similar structurally, they are functionally distinct and unrelated cell types. Their nuclei are typically spherical or kidney shaped. They attack bacteria, viruses and toxins.

Left Ventricle

Left inferior chamber of the heart that pumps oxygenated blood to the body

Left Atria

Left superior chamber of the heart that receives oxygenated blood from the lungs

Serous Pericardium's Parietal Layer

Lines the internal surface off the fibrous pericardium and attaches to the large arteries exiting the heart.

Myocardium

Middle layer of heart wall, composed mainly of cardiac muscle, the layer that pumps.

True Capillaries

Number 10 to 100 per capillary bed, depending on the organ or tissues served. They usually branch off the metarteriole.

Coagulation

Process in which blood is transformed from a liquid to a gel; blood clotting. The third step in blood vessel repair, blood clotting, reinforces the platelet plug with fibrin threads that act as a "molecular glue" for the aggregated platelets. This is a multistep process that leads to its critically important last three phases.

Erythrocyte Destruction

RBC become 'old' as they lose their flexibility and become increasingly rigid and fragile, their contained hemoglobin begins to degenerate. They have a life span of 100 to 120 days. Macrophages in spleen, liver, and red bone marrow phagocytize dying RBC.

Vasoconstriction

Reduction in lumen diameter as the smooth muscle contracts. Narrowing of blood vessels.

Right Ventricle

Right inferior chamber of the heart that pumps oxygen-poor blood to the lungs

Right Atria

Right superior chamber of the heart the receives oxygen-poor blood from the body

Erythrocyte Structure

Small cells, about 7.5 μm in diameter. Shaped like biconcave discs—flattened discs with depressed centers—they appear lighter in color at their thin centers than at their edges. Bound by a plasma membrane but lack a nucleus (are anucleate) and have essentially no organelles.

Factors preventing undesirable clotting

Smooth endothelium, antithrombic substances, & Vitamin E quinine (vit E + oxygen is a potent anticoagulant).

Pericytes

Smooth muscle-like cells that stabilize the capillary wall.

Fibrous Pericardium

Superficial part of pericardium, protects, anchors and prevents the heart from overfilling

Pathway of blood through the heart

Superior Vena Cava, Inferior Vena Cava, Coronary Sinus •Pulmonary circuit Right atrium-> tricuspid valve-> right ventricle-> pulmonary semilunar valve-> pulmonary trunk-> pulmonary arteries-> lungs-> pulmonary veins-> left atrium •Systemic circuit Left atrium-> bicuspid/mitral valve-> Left ventricle-> aortic semilunar valve-> aorta

Precapillary Sphincter

Surrounds the root of each true capillary at the metarteriole and acts as a valve to regulate blood flow into the capillary.

Factors limiting clot growth or formation

Swift removal of clotting factors, inhibition of activated clotting factors by antithrombin III, protein C and heparin.

Name the components of the conduction system of the heart, and trace the conduction pathway.

The conduction starts at the pacemaker region called the Sinoatrial Node (SA node) which is just under where the superior vena cava enters the right atrium. From here the conduction passes to the Atrioventricular Node (AV node) which is just to the right of the septum. From here the stimulation is passed through the Atrioventricular (AV) Bundle (Bundle of His) which carries the conduction to the septum where two Bundle Branches pick it up. These branches carry the conduction to the base of the septum where they separate into the Purkinje Fibres (Subendocardial Conducting Network). These fibers carry the conduction all around the heart.

Systole

The contraction of heart muscle.

Depolarization

The first event in cardiac muscle cell contraction. Caused by a Na+ influx through the fast voltage-gated Na+ Cannels. A positive feedback cycle rapidly opens many Na+ channels, revealing the membrane potential. Channel inactivation ends this phase.

Blood pressure (ΔP)

The force per unit area exerted on a vessel wall by the contained blood, is expressed in millimeters of mercury (mm Hg).

Tunica Intima

The innermost tunic, in intimate contact with the blood in the lumen. This tunic contains the endothelium, the simple squamous epithelium that lines the lumen of all vessels. The endothelium is continuous with the endocardial lining of the heart, and its flat cells fit closely together. In vessels larger than 1 mm in diameter, a subendothelial layer, consisting of a basement membrane and loose connective tissue, supports the endothelium. It forms a slick surface that minimizes friction as blood moves through the lumen.

Mitral/Bicuspid Valve

The left (AV) atrioventricular valve, has two flexible cusps (flaps of endocardium reinforced by connective tissue).

Tunica Media

The middle tunic, mostly circularly arranged smooth muscle cells and sheets of elastin, the bulkiest layer in arteries. Chief responsibility for maintaining blood pressure and continuous blood circulation. The activities of this tunica are critical in regulating circulatory dynamics because small changes in vessel diameter greatly influence blood flow and blood pressure.

Resistance

The opposition to flow and is a measure of the amount of friction blood encounters as it passes through the vessels

Tunica Externa

The outermost layer is composed largely of loosely woven collagen fibers that protect and reinforce the vessel, and anchor it to surrounding structures.

Leukocyte genesis (Leukopoiesis)

The production of white blood cells, is stimulated by chemical messengers. These messengers, which can act either as paracrines or hormones, & are glycoproteins that fall into two families of hematopoietic factors, interleukins and colony-stimulating factors, or CSFs. They are named for the leukocyte population they stimulate. Myeloid Stem cell: granulocytes and monocytes (agranulocyte). Lymphiod stem cell - Lymphocytes (agranulocyte).

Diastole

The relaxation of heart muscle.

Describe the Rh blood groups

The rhesus factor, which depends on a single antigen; antigen D, which also lies on the surface of the RBC. A person having a D antigen is called an Rh positive, e.g. A, B and D antigens' presence exhibit a blood type of AB+ (universal acceptor). A person without the D antigen is called an Rh negative, e.g. Neither A, nor B, nor D antigens' presence exhibit a blood type of O- (universal donor).

Tricuspid Valve

The right (AV) atrioventricular valve, has three flexible cusps (flaps of endocardium reinforced by connective tissue cores).

Plateau Phase

The second event in cardiac muscle cell contraction. It's due to a Ca2+ influx through flow of Ca2+ channels. This keeps cell depolarized because few K+ channels are open

Platelet Plug Formation

The second step of blood vessel repair, platelets play a key role in hemostasis by aggregating (sticking together), forming a plug that temporarily seals the break in the vessel wall. The platelets don't stick to endothelial cells or each other, instead they bind to collagen fibers that are exposed when damage is done to the vessel.

Arterioles

The smallest of the arteries. Larger ones have all three tunics, but their tunica media is chiefly smooth muscle with a few scattered elastic fibers. Smaller ones, which lead into the capillary beds, are little more than a single layer of smooth muscle cells spiraling around the endothelial lining

Postcapillary Venules

The smallest venules, consist entirely of endothelium around which pericytes congregate. They are extremely porous and fluid and white blood cells move easily from the bloodstream through their walls.

Repolarization

The third event in cardiac muscle cell contraction. This happens because Ca2+ channels are inactivating and K+ channels opening. This allows K+ influx, which brings the membrane potential back to its resting voltage.

Blood flow (F)

The volume of blood flowing through a vessel, an organ, or the entire circulation in a given period (ml/min).

Sinusoids Capillaries

They are highly modified, leaky capillaries found only in the liver, bone marrow, spleen, and adrenal medulla

Platelet Structure

They aren't cells in the strict sense. About one-fourth the diameter of a lymphocyte, they are cytoplasmic fragments of extraordinarily large cells (up to 60 μm in diameter) called megakaryocytes. They're anucleate.

Explain how veins differ from arteries.

They usually have three distinct tunics, but their walls are always thinner and their lumens larger than those of corresponding arteries. There is relatively little smooth muscle or elastin in the tunica media, which is poorly developed and tends to be thin even in the largest ones. The tunica externa is the heaviest wall layer. Consisting of thick longitudinal bundles of collagen fibers and elastic networks, it is often several times thicker than the tunica media. In the largest ones—the venae cavae, which return blood directly to the heart—longitudinal bands of smooth muscle make the tunica externa are even thicker. With their large lumens and thin walls, they can accommodate a fairly large blood volume.

Platelet Function

They're essential for the clotting process that occurs in plasma when blood vessels are ruptured or their lining is injured. By sticking to the damaged site, they form a temporary plug that helps seal the break.

Cardiac Cycle

This refers to all events associated with blood flow through the heart. It has four main steps & two different cycles; 1. Ventricular Filling, 2. Isovolumetric Systole, 3. Ventricular Ejection, 4. Isovolumetric Relaxation and the Systole and Diastole cycles.

Six Functions of Blood

Transportation, Defense, Temperature Regulation, Prevent Loss, Regulates pH, Hormone Movement

Aortic Semilunar Valve

Valve between the left ventricle and the aorta.

Pulmonary Semilunar Valve

Valve between the right ventricle and the pulmonary trunk.

Serous Pericardium's Visceral Layer (Epicardium)

Visceral layer of the Serous Pericardium that lines the external heart surface

Describe how blood pressure is regulated

•Central among the homeostatic mechanisms that regulate cardiovascular dynamics are those that maintain blood pressure (ΔP), principally cardiac output (CO), peripheral resistance (R), and blood volume. Cardiac output (blood flow of the entire circulation) and peripheral resistance relate to blood pressure. •F = ΔP/R or CO = ΔP/R or ΔP = CO X R •Blood pressure varies directly with CO and R. Additionally, blood pressure varies directly with blood volume because CO depends on blood volume (the heart can't pump out what doesn't enter its chambers). So in theory, a change (increase or decrease) in any of these variables would cause a corresponding change in blood pressure. However, what really happens in the body is that changes in one variable that threaten blood pressure homeostasis.