Chapter 9 - The Cardiovascular System Flashcards

Question

Compare the size of the right heart and left heart

Answer 1

Because the right heart pumps blood only to the lungs, which are nearby and whose vasculature offers lower resistance, it can operate at lower pressures. Consequently the walls of the right heart are not as thick as those of the left. In the left heart, which is responsible for systemic circulation, the walls are thicker and more muscular because they must generate stronger contractions to maintain higher pressures to move blood over a longer distance and against higher resistance.

Answer 2

The stage of the heart cycle in which the heart muscle contracts and pumps blood. During this stage the ventricles contract and the atrioventricular valves close; blood is pumped out of the heart.

Answer 3

The stage of the heart cycle in which the heart muscle relaxes and collects blood into its four chambers. The semilunar valves close to prevent backflow of blood from the pulmonary arteries and aorta into the heart.

Answer 4

Contraction of the ventricular muscles generates the higher pressures of systole, while their relaxation during diastole cases the pressure to decrease.

Answer 5

The total volume of blood the left ventricle pumps into circulation per minute. The cardiac output can be increased by increasing either the heart rate or the stroke volume. Cardiac output is the product of heart rate and stroke volume: (Cardiac output) = (heart rate) x (stroke volume) (volume/minute) = (beats/minute) x (blood volume/beat)

Answer 6

Autonomic nervous system

Answer 7

Cardiac muscle cells located in sinoatrial node (SA node), in right atrium

Answer 8

Group of special cardiac cells located in the right atrium. Causes atria to contract.

Answer 9

Located in the wall of muscle between the atria. Causes ventricles to contract (after atria have finished pumping contents into ventricles).

Answer 10

Conductive fibers in heart. Located in wall separating ventricles. Action potential spreads here after AV node.

Answer 11

Conductive fibers in heart. Located in ventricular walls. Allow for more unified, stronger contraction of the heart.

Answer 12

SA node ⇒ (atrial contraction) → AV node ⇒ (signal delay, ventricles fill) → bundle of His → Purkinje fibers ⇒ (ventricular contraction, systole)

Answer 13

SA node is autorhythmic (contracts by itself at regular intervals). Impulse initiation begins at the SA node. Depolarization spreads from SA node causing both atria to contract simultaneously and blood is pumped into ventricles. Action potential spreads to atrioventricular node (AV node) and signal is delayed until ventricles are filled. From AV node, potential moves down bundle of HIS (conductive fibers) and splits in two (left and right). The signal subsequently branches out through Purkinje fibers to the ventricular walls. Depolarization at the neuromuscular junction causes the ventricles to contract, and blood is forced out of the heart.

Answer 14

The autonomic division, which consists of the parasympathetic ("rest and digest") and sympathetic ("fight or flight") branches, controls the heart. **Parasympathetic** - slows heart rate via the vagus nerve (utilyzes vagusstoff). **Sympathetic** - utilyzes neurotransmitters (norepinephrin) to speed up heart rate

Answer 15

The parasympathetic **vagus** nerve innervates the SA node. Slows heart contractions and increases digestive activity.

Answer 16

While neural signals from the autonomic nervous system can modulate the rate at which the heart beats, since cardiac muscle demonstrates myogenic activity, the heart will continue to function even without input from the nervous system.

Answer 17

Elastic; stretch as they fill with blood. Wrapped in smooth muscle (innervated by sympathetic nervous system). Larger arteries have less smooth muscle than medium ones, so are less affected by innervation. Medium arteries can constrict with sympathetic stimulation to reroute blood.

Answer 18

Smaller than arteries. Also wrapped by smooth muscle (innervated by sympathetic nervous system). Constriction/dilation can regulate blood pressure AND reroute blood.

Answer 19

Blood vessels with a single endothelial cell layer; nutrient/gas exchange (except vascular tissue) takes place only across capillary walls. Capillaries are usually so small that blood cells must traverse them single-file.

Answer 20

Thin-walled and inelastic; capacitive and stretch out easily as they fill with blood, but do not recoil. Wrapped in smooth muscle, but with a thinner (or absent) layer compared to arteries. Larger vains have one-way valves to prevent backflow. Most large veins are surrounded by skeletal muscle, which squeezes the vains as muscles contract, forcing the blood forward.

Answer 21

1. Pinocytosis (endocytosis of small molecules) 2. Diffusion/transport through capillary cell membrane 3. Movement through pores (fenestrations) 4. Movement through space between cells

Answer 22

Arteriole end: hydrostatic pressure greater than osmotic pressure, so net flow is OUT of the capillary Venule end: Hydrostatic pressure drops, osmotic pressure (which is pretty constant) overcomes hydrostatic pressure and net flow is INTO capillary. Net result: 10% loss of fluid to interstitium.

Answer 23

Veins (venules, etc.); they act as a blood reservoir.

Answer 24

Capillaries (blood flow inverseley proportional to cross-sectional area).

Answer 25

A measure of the force per unit area that is exerted on the wall of blood vessels. Measured by a sphygmomanometer as the gauge pressure (that above atmospheric pressure, 760 mmHg). Expressed as a ratio of systolic (ventricular contraction) to diastolic (ventricular relaxation) pressures.

Answer 26

1. **Hydrostatic pressure **- force per unit area that the blood exerts against the vessel walls. Hydrostatic pressure forces fluid (and nutrients) out of the bloodstream and into the tissues. 2. **Oncotic (osmotic) pressure **- the osmotic pressure generated by the concentration of particles (mostly proteins) in the plasma compartment. Unlike hydrostatic pressure, oncotic/osmotic pressure exerts an inward force and draws fluid, nutrients, and wastes out of the tissue.

Answer 27

Blood pressure is highest in the arteries and lowest in the veins. Although osmotic pressure is constant, hydrostatic pressure drops significantly as blood moves through the capillaries.

Answer 28

A valve system in the veins prevents backflow of blood, and skeletal muscle contraction (from general movement) squeezes blood forward into the heart.

Answer 29

The circulation of blood in the blood vessels of the heart muscle (myocardium).

Answer 30

Blood vessels that supply heart muscle (myocardium) with oxygenated blood. Originate from the aorta. Blockage of the coronary arteries can lead to a heart attack.

Answer 31

Blood vessels that transport deoxygenated blood from the heart muscles (myocardium). It delivers deoxygenated blood to the right atrium, as do the superior and inferior vena cava.

Answer 32

Increasing cncentration of H⁺ and CO₂ reduces hemoglobin's affinity for oxygen, allowing for the transfer of oxygen to cells that require it most.

Answer 33

Several conditions produce a rightward shift, meaning that for a given partial pressure of O₂, less O₂ will be bound to Hb due to decreased affinity. These conditions include an increase in the partial pressure of CO₂, a decrease in pH, and an increase in temperature. These conditions often correspond to periods of increased metabolic rate (lactic acid buildup, increased CO₂ generation, increased temperature) and signal a need for more oxygen.

Answer 34

Enzyme that catalyzes the conversion of carbonic acid to carbon dioxide and water, as well as the formation of carbonic acid from carbon dioxide and water. The reaction proceeds according to the following equation: H₂CO₃ ⇔ H₂O + CO₂

Answer 35

Transports nutrients, waste products, hormones, heat. Protects from injury and invasion. Contains matrix and cells (is connective tissue).

Answer 36

**Plasma** - 55% of blood volume, liquid portion of blood that is an aquous mixture of nutrients, salts, respiratory gases, hormones, and blood proteins (albumin, apolipoproteins, antibodies, etc.). **Cells** - 45% of blood volume, consists primarily of erythrocytes, leukocytes, and platelets. All blood cells originate from hematopoetic stem cells in the (red) bone marrow.

Answer 37

Transport fatty acids and steroids; regulate blood osmotic pressure.

Answer 38

Lymph tissue

Answer 39

The oxygen carrying component of blood (red blood cells). These anaerobic cells, which lack organelles, are packed with hemoglobin and have a characteristic biconcave, disclike shape that facilitates gas exchange and mobility within blood vessels.

Answer 40

A protein found in erythrocytes made up of four polypeptide chains, each containing a heme group. Hemoglobin is responsible for transporting oxygen from the alveoli to the cells. Hemoglobin exhibits cooperativity: one O₂ binds (or releases), others do so more easily. This results in an S-shaped binding curve and is an allosteric effect.

Answer 41

White blood cells; the component of blood involved in cell defense and immunity. Comprise both the active and innate immune systems. Basophils, neutrophils, and eosinophils are granular leukocytes; monocytes, megakaryocytes, and lymphocytes are agranular leukocytes.

Answer 42

A system of vessels and lymph nodes that collect interstitial fluids and return them to the circulatory system, thereby maintaining a plasma protein and fluid balance. The lymphatic system is also involved in lipid absorption and lymphocyte maturation.

Answer 43

Swellings along the lymph vesses where lymph is filtered by leukocytes to remove antigens.

Answer 44

Named because cytoplasmic granules that are visible by light microscopy, these consist of neutrophils, eosinophils, basophils. Granular leukocytes mount nonspecific, innate immune responses such as inflammatory reactions, allergies, pus formation, and destruction of bacteria and parasites.

Answer 45

Named because they do not contain cytoplasmic granules, these consist of monocytes and lymphocytes. * **Monocytes** mature into macrophages, which phagocytose foreign matter such as bacteria. * **Lymphocytes** are important in specific immune responses against viruses and bacteria. Lymphocytes mature into B- and T-cells.

Answer 46

Lymphocytes that mature in the spleen or lymph nodes. B-cells are responsible for antibody generation.

Answer 47

Lymphocytes that mature in the thymus, T-cells kill infected cells and activate others. There are four types of T-cell: helper, memory, suppressor, and killer T cells.

Answer 48

Immunity resulting from the production of antibodies during a previous infection or a vaccination.

Answer 49

The initial response to a specific antigen. During primary response, T and B lymphocytes are activated adn specific antibodies and memory cells to the antigen are produced.

Answer 50

Subsequent infections by antigens trigger more immediate response by the memory cells produced during primary response

Answer 51

A short-lived immunity resulting from the transfer of antibodies into an individual who does not produce those antibodies

Answer 52

The synthesis of specific antibodies by activated B-cells in response to an antigen. These antibodies bind to the antigen and either clump together to become insoluble or attract other cells that engulf them.

Answer 53

First reaction to tissue injury / infection. Blood vessel dilation, capillary permeability, swelling, migration of granulocytes and macrophages. Purpose: sequester affected tissue and keep infection from spreading.

Answer 54

A protein antibody produced in response to a specific foreign substance that recognizes and binds to that specific antigen and triggers an immune response.

Answer 55

Proteins found on the erythrocyte cell surface. Three antigens are used to differentiate blood: A, B, and Rh. If a host organism is transfused with erythrocytes containing antigens that the host does not have, an immune response will be triggered, such as in the case of erythroblastosis fetalis.

Answer 56

1. ABO group - based on the existence of three alleles for a cell surface protein that defines blood type. A and B alleles are codominant. O is recessive and does not code for a recognized antigen. Universal blood donor is Type O, while universal blood acceptor is Type AB. 2. Rh factor - one predominant variant whose presence or absence defines blood type and is indicated by a superscript on the ABO blood type (e.g. O⁺, AB^-). The presence of the Rh factor is a dominant condition.

Answer 57

Pieces of membrane-bound cytoplasm from megakaryocytes. Like tiny cells w/o nucleus. Make prostaaglandins, some enzymes. Membrane d/n adhere to healthy endothelium, but DOES adhere to injured endothelium. Coagulation of injured tissue involves platelets, and many other factors including prothrombin and fibrin (plasma proteins).

Answer 58

Enzyme released by platelets in response to exposed collagen. Thromboplastin converts prothrombin into thrombin. Its cofactors are calcium and vitamin K.

Answer 59

Protein responsible for blood clotting. Fibrin is the processed, active form of the inactive zymogen fibrinogen. Fibrinogen is converted to fibrin by thrombin.