Cardiovascular & Hematology/Lymphatic Study Guide Flashcards
1
Q
Describe lymphatic circulation and the filtration role of lymph nodes.
A
- Lymphatic circulation:
- Lymph only carries fluid away from tissues.
- Lymph capillaries drain into larger lymph vessels.
- Upper right quadrant drains into right lymphatic duct; rest into thoracic duct, then into left subclavian vein.
- Lymph enters lymph nodes through afferent lymph vessels, leaves lymph nodes through efferent lymph vessels toward the bloodstream.
- Filtration role:
- Filters and destroys pathogens and other foreign substances in blood.
- Filtering out and destroying pathogens; may appear swollen and painful during infections.
- Lymph nodes may either filter out cancer or spread to other body sites
2
Q
What is hematopoiesis?
A
The formation of blood cells, originates in stem cells in red bone marrow.
3
Q
What are all the blood types, who can receive blood, who is a universal donor and who is a universal recipient.
A
- Human blood falls into one of four inherited (genetic) groups (blood types):
- A, B, AB, and O
- Rh factors are inherited antigens.
- The Rh system is named after the rhesus monkey used in early experiments.
- The most commonly found Rh factor and the one most likely to cause a transfusion reaction is abbreviated D (Duffy).
- Blood is tested for the presence of D antigen.
- If the blood contains D factor, the person is said to be Rh-positive ( Rh or D ); if this factor is absent, the person is Rh-negative ( Rh− ).
- Blood group AB is known as the universal recipient because people of this group may receive red blood cells from donors of any ABO group in an extreme emergency.
- Blood group O is known as the universal donor because these red blood cells may be given to people of any ABO group in an extreme emergency.
4
Q
What is vitamin promotes blood clotting?
A
Vitamin K
5
Q
What are the functions of red blood cells?
A
-
Red blood cells: (erythro=red, cyte=cell)
- Most numerous in body, made in bone marrow, very fragile, last about 120 days
- Erythropoiesis begins in kidney cells with secretion of erythropoietin which stimulates bone marrow to produce RBCs, about 120 to 180 million RBCs produced every minute.
- Macrophages in the liver and spleen ingest old, used RBCs and salvage iron, which is transported to bone marrow to make new RBCs.
- Each BC contains more than 250 million molecules of the compound hemoglobin. (Hgb or Hb)
- As RBCs move through capillaries, oxygen transfer occurs.
- Pulse oximetry indirectly measures arterial oxygen content.
- Specific blood tests: RBC count, hematocrit, hemoglobin, glycosylated Hgb (HA1C, A1C)
- Functions:
- Transports oxygen.
- Produces and releases ATP.
- Releases substances which assist in dilation of blood vessels.
- Stores iron in the body.
- Participates in the immune response and acid-base balance.
- Influences specific gravity of blood.
- Functions:
6
Q
Describe the three major layers of the heart wall and how they relate to the pericardium; identify the three layers of arteries and veins.
A
- The heart wall has three layers:
- Endocardium
- The endocardium (inner heart) is a membrane lining the heart’s interior wall. It is made up of endothelial tissue, small blood vessels, and some smooth muscles.
- Myocardium
- Thick, strong muscles make up the myocardium ( myo = muscle), the middle and thickest layer. Cardiac muscle (Chapter 18) is a unique type of involuntary muscle with lightly striated cells, found only in the heart.
- Epicardium
- The epicardium ( epi = upon) is the thin, outer layer of the cardiac wall (also called the visceral layer of the serous pericardium). It is composed of squamous epithelial cells over connective tissue.
- The epicardium portion of the heart wall, which also makes up the pericardium’s visceral layer, adheres to the heart’s surface.
- (A space between the visceral and parietal layers is the pericardial space or cavity.
- It houses a small amount of serous fluid, pericardial fluid , which acts as a lubricant and reduces friction between the layers as the heart contracts and relaxes.)
- The parietal layer:
- is the inner serous pericardium .
- The outermost layer:
- is the fibrous pericardium (composed of dense fibrous connective tissue).
- This tissue protects and anchors the heart in the mediastinum and prevents overfilling.
The layers within arteries and veins are as follows:
- Tunica adventitia , the outermost layer, is composed of connective tissues and nerve cells, as well as nutrient capillaries in larger vessels. This layer protects the outside of the vessel.
- Tunica media , the middle layer, contains the thickest elastic fibers, as well as connective tissue composed of polysaccharides. This layer is covered by a thick elastic band (the external elastic lamina ) and smooth muscle fibers, which control vessel’s caliber (size).
- Tunica intima , the innermost layer, is the thinnest, a single layer of simple squamous endothelium (Fig. 15-10), held together by an intercellular matrix. This layer is surrounded by connective tissue interlaced with elastic bands ( internal elastic lamina)
7
Q
Which path does blood travel in the body?
A
In approximately 1 minute, a drop of blood travels through the right side of the heart, the lungs, the left side of the heart, and the systemic circulation, completing its circuit by returning to the right side of the heart.
8
Q
Describe the path of an electrical impulse through the heart’s conduction system; describe the purpose of this electrical activity.
A
SA (sinoatrial) node (pacemaker) →
AV (atrioventricular) node →
Bundle of His (AV bundle) →
Right and left bundle branches →
Purkinje fibers to muscles of ventricles
The electrical activity of the heart must occur before mechanical, pumping, activity of the heart can respond with a heartbeat.
9
Q
What makes the implantation of an electronic pacemaker necessary?
A
- Special bundles of unique tissue in the heart transmit and coordinate electrical impulses to stimulate the heart to beat.
- The first of these bundles is embedded in the wall of the right atrium at the junction of the superior vena cava.
- It is called the sinoatrial node (SA node or sinus node) and is considered the heart’s “pacemaker.”
- A person with a poorly functioning SA node usually requires the implantation of an electronic pacemaker.
10
Q
Know your valves of your heart
A
Chambers The interior of the heart is divided into four chambers. (Right/Left Atrium, Right/Left Ventricle).
- Atria
- The two upper chambers are the right and left atria (singular: atrium).
- These thin-walled, low-pressure chambers are receiving centers for blood.
- Ventricles
- The two lower chambers are right and left ventricles .
- Ventricles are high-pressure chambers; they pump blood out of the heart.
- The left ventricle must contract with sufficient force to send blood to the entire body; therefore, its muscle walls are thickest and its internal pressures the highest.
- The right ventricle needs only to pump blood into the low-pressure lungs; therefore, it is a thinner walled chamber.
- The left ventricle contains the heart’s thickest muscles and must pump strongly enough to send blood out to the entire body.
- The right ventricle also has thick muscles; the muscles in the atria are thinner than those of either ventricle.
- Atrioventricular Valves
- The atrioventricular ( AV ) valves lie between the atria and ventricles.
- The valve between the right atrium and right ventricle, the tricuspid valve , is formed of three flaps (cusps) of tissue.
- The valve between the left atrium and left ventricle, the mitral or bicuspid valve , has only two flaps of tissue.
- The tissue flaps of these valves attach to tendon-like strands, the chordae tendineae (tendinous cords), which are anchored to papillary muscles located on the inner surface of the ventricles.
- Blood flows from the atria to the ventricles through open AV valves when ventricular pressure is lower than atrial pressure.
- During this time, the papillary muscles and chordae tendineae relax.
- As the ventricles contract, increased pressure causes the AV valves to close.
- The papillary muscles also contract at this time, tightening the chordae tendineae, to prevent the valve cusps from everting (turning inside out).
- If the AV valves, chordae tendineae, or papillary muscles become damaged, backflow of blood ( regurgitation ) into the atria can occur with ventricular contraction.
- Overflow valves
- Each ventricle empties through a valve with three crescent-shaped (half-moon) cusps, the semilunar valves.
- The pulmonary semilunar valve ( pulmonic valve ) separates the right ventricle from the pulmonary artery.
- The aortic (semilunar) valve separates the left ventricle from the aorta, the body’s largest artery.
- Increased ventricular pressure, as when the ventricles contract, opens the semilunar valves.
- As the ventricles relax, blood begins to flow backward toward the ventricles.
- Blood fills the semilunar cusps and causes the valves to close.
- Therefore, semilunar valves prevent backflow from their respective arteries into their ventricles.
11
Q
Describe cardiac output, including factors involved in its regulation.
A
- Cardiac output ( CO )
- The amount of blood pumped by the ventricles in 1 minute, is normally from 4 to 6 L in the resting adult.
- Stroke volume ( SV )
- The volume of blood ejected by the left ventricle with each heartbeat, is only about two-thirds of the blood contained in the left ventricle.
- CO is related to SV and beats per minute (heart rate—HR) Factors called preload and afterload can affect SV.
- Preload
- is the amount of pressure or “stretching force” against the ventricular wall at end diastole (maximum relaxation of the heart).
- When more blood volume is returned to the ventricles, the muscle fibers in the ventricles stretch to accommodate the excess.
- Starling law
- States that the greater the stretch, the greater the following force of contraction ( contractility ).
- The greater the contraction, the more volume ejected, resulting in increased SV.
- Afterload
- The amount of pressure or resistance the ventricles must overcome to empty their contents, must be powerful enough to overcome resistance in the aorta and other arteries.
12
Q
Know the primary functions of lymphatic system, hematologic system.
A
- The hematologic system consists of the components of the blood (i.e., plasma and formed elements) and the bone marrow, the primary organ that manufactures blood cells.
- The function of the hematologic system involves the removal of hematologic waste products, the delivery of nutrients and oxygen to cells, blood volume regulation, blood cell and antibody production, and blood coagulation.
- The lymphatic system consists of the lymphatic vessels and tissues.
- The lymphatic system transports dietary fats to the blood, drains interstitial fluid, helps protect the body from infection, and provides immunity.
- It also returns any excess proteins that may escape from the blood vessels to the systemic circulation
13
Q
What is a cardiac cycle?
A
In less than 1 second, both atria contract as both ventricles relax. Immediately, both ventricles contract as both atria relax. This process is considered one cardiac cycle or one heartbeat.
14
Q
How do you prevent cardiovascular disease?
A
The nurse should include the following instructions in the client teaching plan for the prevention of cardiovascular disorders:
- Stop smoking and avoid smoking’s harmful effects.
- Reduce sodium (salt) intake.
- Maintain weight within standard guidelines.
- Avoid foods high in animal fats and cholesterol.
- Avoid foods that contain caffeine:
- Coffee
- Cola drinks
- Tea
- Chocolat.
- Exercise regularly and moderately.
• Avoid crossing the legs at the knees when sitting.
• Have both feet comfortably touch the floor when sitting.
• For a few minutes in the morning and evening, elevate the feet.
• Avoid constrictive garments, especially around the legs, arms, and waist.
• Wear properly fitted shoes.
• Avoid and minimize environmental stress - Anxiety-producing factors.
- Learn ways to handle stress effectively.
• Follow medication regimens for prescribed medications.
• Get plenty of rest and relaxation. - Learn relaxation techniques if necessary.
15
Q
What is the function of hemoglobin?
A
- Hemoglobin is composed of the iron-containing pigment heme and a protein, globin . (Iron is the pigment that makes RBCs appear red.)
- As blood circulates through the lungs, the iron in hemoglobin attracts and binds to oxygen in a loose combination.
- (Hemoglobin allows blood to carry 60 times more oxygen than would plasma.)
- Hemoglobin saturated with oxygen, oxyhemoglobin , causes blood to appear bright red.
- As blood circulates through the capillaries, hemoglobin gives its oxygen to the body cells.
