Chapter 8 Flashcards

1
Q

Cardiac muscle cells are responsible for

A

the force of contraction in the ventricles and atria

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2
Q

All muscles cells have the ability to

A

Propagate an action potential across their surface.

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3
Q

Functional Syncytium

A

a tissue in which the cytoplasm of different cells can communicate via gap junctions found in intercalated disks

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4
Q

There are no chemical synapses in what kind of cell

A

cardiac muscle cells

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5
Q

Cardiac conduction system

A

System which transmits the action potential in the heart from the arterial syncytium to the ventricles

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6
Q

Membrane depolarization lasts longer in

A

cardiac muscle cells than in neurons, calcium channels stay open longer than the fast sodium channels

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7
Q

Neuronal or hormonal influences

A

can change the rate and strength of contraction|Do not stimulate the heart to contract

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8
Q

Initiation of each action potential that starts each cardiac cycle occurs in

A

region of the right atrium called the sinoatrial (SA) node|Under normal circumstance the SA node acts as a pace maker

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9
Q

SA node action potential phases

A

Phase : (automatic slow depolarization) sodium leak channels start the rhythmic, automatic excitation. Inward flux of sodium = cell potential thresh|Phase O: Voltage gated sodium channels open and cause the upstroke of the pacemaker potential. Ca+ causes depolarization in the SA node.|Phase : Repolarization. Ca+ channels close and K+ channels open, leading to an outward flow of K+ from the cell.

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10
Q

SA cannot spontaneously depolarize because

A

it has the most Na+ leak channels of all the conduction system. It reaches threshold before any other region of the heart and sets rate of contraction

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11
Q

What happens if the SA node cells are damaged or depolarization pathways are blocked

A

The AV node (purknjie fibers) will take over as the new pacemaker at a slower rate

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12
Q

Cardiac muscle cell action potential phases

A

Phase : (depolarization) threshold is reached and Na channels open with sodium rushing into the cell.|Phase : (initial repolarization) Na+ channels inactivate and K+ channels open. Phase : (plateau phase) influx of Ca+ ions balance the K+ efflux|Phase : (repolirization) Ca+ channels close and the K+ channels open, K+ leaves the cell again. Phase : (resting membrane potential) inward=outward

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13
Q

How are the SA and AV nodes connected

A

AP started by the heart beat in the SA node also spreads down a special conduction pathway that transmits action potentials rapidly w/o contraction|Its called the internodal tract

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14
Q

Why does the impulse travel to the AV node almost instantly but spreads through the atria more slowly?

A

contracting heat muscle cells pass the impulse more slowly than specialized conduction fibers

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15
Q

Av bundle (bundle of His)

A

divides into the right and left bundle branches and then into the Purkinje fibers, which allows the impulse to spread rapidly evenly over both ventricles

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16
Q

what role does the autonomic nervous system play with the heart

A

It regulates the rate of contraction. The intrinsic firing rate of the SA node is bpm reduced to- by the parasympathetic nervous system

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17
Q

The para sympathetic nervous system inhibits depolarization of the SA node using

A

the vagus nerve, which causes the release of ACh. This constant inhibition is known as the Vargas tone and it reduces the intrinsic firing rate

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18
Q

The parasympathetic system and the vagus are mostly in charge of the heart at rest. When is the sympathetic system used?

A

during fight or flight responses. The sympathetic postganglionic neurons directly innervate the heart, releasing norepinephrine.|Epinephrine is then secreted by the adrenal medulla and binds to receptors on cardiac muscle cells. The heart rate and force of contraction increases

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19
Q

Systemic arterial pressure

A

force per unit area exerted by blood upon the walls of arteries

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20
Q

Systolic pressure

A

the highest pressure that ever occurs in the circulatory system of this paticular person|this is obtained when ventricles contact

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21
Q

Diastolic pressure

A

as low as the pressure gets between heartbeats

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22
Q

Blood pressure indicates

A

arterial pressure

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23
Q

In what areas of the heart are the highest pressure in the circulatory system achieved

A

left ventricle, aorta and other large arteries

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24
Q

Why does diastolic pressure remain so high?

A

During diastole the arteries exert pressure on the blood and maintains diastolic pressure, providing a driving force for blood

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25
Q

Components of blood

A

Plasma (%)- liquid portion of the blood. Contains electrolytes, buffers, sugars, blood proteins, lipoproteins, CO, O and metabolic waste products|Formed elements- cellular portion of the blood

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26
Q

Principal sugar of blood

A

Glucose. Constant concentration is needed to ensure all cells receive proper nutrition.

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27
Q

Blood proteins

A

Albumin, immunoglobulins (antibodies), fibrinogen and lipoproteins

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28
Q

Albumin

A

essential for maintain effective of oncotic pressure (osmotic pressure in the caps due only to plasma proteins)

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29
Q

Immunoglobulins

A

key part of the immune system

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30
Q

Fibrinogen & lipoproteins

A

essential for blood clotting (hemostasis)|large particles consisting of fats, cholesterol and carrier proteins. Transport lipids in the bloodstream

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31
Q

CO2 & O2

A

involved in respiration.CO2 is also important in buffering blood

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32
Q

Main waste product

A

Urea, a break down of amino acids. Bilirubin, a breakdown product of heme.

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33
Q

Hematocrit

A

Volume occupied by the red blood cells (erythrocytes). Males -%, Females -%|White blood cells (leukocyte) and platelets a count for about %|All the formed elements of the blood develop from special cells in the bone marrow –> bone marrow stem cells

34
Q

Serum

A

similar to plasma except it lacks all the proteins involved in clotting

35
Q

Erythrocytes (RBC)

A

cell that has no nucleus or other organelles. Uses ATP for ion pumping and cell maintenance. Relies on glycolysis for ATP synthesis.|Purpose is to transport O to the tissues from the lungs and CO from the tissues to the lungs. RBC’s require a large surface area for gas exchange.

36
Q

universal recipients

A

Type AB+ and O- individuals do not make antibodies of any of the blood group antigens. Their blood cells posses all three of the antigens.

37
Q

Leukocytes

A

The white blood cell’s role is to fight infection and dispose of debris.|White blood cells are large complex cells with all normal eukaryotic cell structures (nucleus, mitochondria, etc.) WBC’s also respond to chemotaxis|Some WBC’s (macrophages & neutrophils) - amoeboid motility. Able to squeeze out of capillary intercellular junctions, roam free & look for pathogens.

38
Q

Monocytes

A

monocytes- phagocytosis debris and micro organisms; amoeboid motility; chemotaxis

39
Q

Lymphoytes

A

B cell- mature into plasma cell and produce antibodies|T cell- kill virus-infected cells, tumor cells and reject tissue grafts; also control immune responses

40
Q

Granulocytes

A

Neutrophil- phagocytose bacteria resulting in pus; amoeboid motility; chemotaxis|Esinophil- destroy parasites; allergic reactions|Basophil- store and release histamine; allergic reactions

41
Q

What is the function of playlets?

A

contain no nuclei and a limited lifespan. Aggregate at the site of damage to a blood vessel wall forming a platelet plug.

42
Q

Fibrin

A

another component of the hemostatic response. Fibrin is a threadlike protein that forms a mesh which holds the platelet plug together.|Dries and becomes a scab

43
Q

Thrombin

A

Converts fibrinogen into fibrin.|A blood clot of thrombus is a scab circulating the blood stream

44
Q

Several proteins depend on vitamin K for their function. Defects with these proteins cause?

A

Hemophilia- loving to bleed an X-linked recessive group of diseases involving excessive bleeding

45
Q

Role of heme (multi ring structure that has a single iron atom bound at its center)

A

bind O, each hemoglobin has subunits. Heme will bind more oxygen in an area w high oxygen concentration more than in a low concentration area. A lot of oxygen is picked up by the RBC’s in the lungs, and most of it is released as they pass through active tire uses that need oxygen.

46
Q

Bohr Effect (reduces oxygen affinity)

A

Decreased pH, increased pCO (level of CO in the blood and increased temperature. This means hemoglobin is ready to release its load of oxygen in region of the body where oxygen is most needed

47
Q

Carbon dioxide is transported in the blood in ways

A

Converting it into carbonic acid which is catalyze by the RBC enzyme called carbonic anhydrase. Hitching a ride w hemoglobin. Dissolves into the blood and is carried from the tissues to the lungs

48
Q

What is the site of exchange between blood and tissues?

A

Capillaries, they have walls of only a single layer of flattened endothelial cells and spaces (intercellular clefts) which allow substances to pass main types of nutrients|Amino acids and glucose are absorbed from the digestive tract & carried by the hepatic portal vein to the liver -> holds & releases them as needed.|Lipids (fats)- absorbed from the intestine & packaged into chylomicrons,|they enter a tiny lymphatic vessels in the intestinal wall and empty into larger lymphatics which eventually empty into a large vein near the neck.

49
Q

How does the liver manage waste

A

it removes waste and converts them into forms which can be excreted in the form of feces, these compounds pass through the gut (bile)|Other wastes are excreted directly by the kidneys

50
Q

Why does water have a big tendency to flow out of capillaries through the clefts?

A

() hydrostatic pressure (fluid pressure) created by the heart tends to squeeze water our of the capillaries|() High osmolarity of the tissues tends to draw water out of the blood stream

51
Q

Effects of plasmas high osmolarity

A

relative concentration of plasma proteins increases which causes water to flow back into the tissues

52
Q

Edema

A

water in tissues, or swelling. Small amounts of albumin in alcoholics cause water to be lost to the tissues.

53
Q

The lymphatic system

A

one-way flow system which starts with tiny lymphatic capillaries in all the tissues of the body –>larger lymphatic vessels –> lymphatic ducts|Acts like a suction pump to retrieve water, proteins, and WBC’s from the tissues

54
Q

Lymphatic nodes

A

contain many white blood cells that can initiate an immune response

55
Q

Large lymphatic ducts merge to form

A

the thoracic duct, located in the chest. It emptiness into a large vein near the neck.

56
Q

Lymphatic vessels from the intestines are in charge of

A

dumping dietary fats in the form of chylomicrons into the thoracic duct types of immunity. Innate, humoral and cell-mediated

57
Q

Innate immunity

A

general nonspecific protection the body provides against various invaders (skin, tears, saliva, macrophages and neutrophils, complement system)

58
Q

Complement system

A

group of about blood proteins that can no specifically bind to the surface of foreign cells, leading to their destruction

59
Q

Hummoral Immunity

A

specific protection by proteins in the plasma called antibodies (Ab) or immunoglobulins (Ig)|Antibodies- specifically recognize and bind to microorganism leading to their destruction and removal from the body|Immunoglobins- IgG, IgA, IgM, IgD and IgE.

60
Q

Antibody molecules are composes of two copies of two different polypeptides

A

Light chains and heavy chains joined by disulfide bonds.

61
Q

Antibody molecules also contain two different regions

A

Variable region- responsible for specificity of antibodies in recognizing foreign particles|Constant region- same for all antibodies in a given class. ( most are in the IgG)

62
Q

Epitope

A

Small site that an antibody recognizes within a larger molecule

63
Q

Hapten

A

when a small molecule does not elicit the production of antibodies on their own so they will bind to a protein and become the antigenic

64
Q

Removal of the antigen from the body can occur by

A

binding of an antibody may directly inactivate the antigen|Binding of an antibody can induce phagocytosis of a particle by macrophages and neutrophils|Presence of antibodies on the surface of a cell can activate the complement system to form holes in the cell membrane and lyse the ceLil

65
Q

B cells are responsible for producing

A

Antibodies. Antibodies procured by an individual B cell can recognize only one specific antigen.

66
Q

Plasma and Memory cells roles in antibody production

A

Plasma cells actively produce and secrete antibody protein into the plasma.|Memory cells are produced from the same cline and have the same variable regions, but do not secret antibodies. They are pre-activated, dormant B cell

67
Q

Colonal selection

A

method of selecting B cells with specific antigen binding

68
Q

Primary immune response

A

the st time an antigen is encountered during an infection it takes a week or more for B cells to proliferate and secrete significant levels of Ab

69
Q

Secondary immune response

A

swifter and stronger. Symptoms never develop.

70
Q

Cell

A

mediated immunity: types of T cells - T helper cells (CD cells) and T killers (CD cells)

71
Q

T helper

A

activate B cells, T killer cells and other cells of the immune system.|Central controller of the immune response|releases special hormones (lymphokines & interleuukins) to communicate with other cells

72
Q

Role of the T killer cells

A

destroy abnormal host cells (virus infected host cells, cancer cells, foreign cells such as the cells from a skin graft from an incompatible donor)

73
Q

In what gland is the T cell developed during childhood?

A

the thymus; the thymus destroys all self-specific T cells in order to avoid an autoimmune response

74
Q

Major histocompatibility complex (MHC) I

A

proteins are found on the surface of every uncleared cell in the body.|Their role is to randomly pick up peptides from inside cells and display them on the surface

75
Q

MHC II

A

antigen-presenting cells (APC’s). Role is to phagocytize particles or cells, chip them up and display fragments using the MCH II display system

76
Q

Bone marrow

A

site of synthesis of all cells of the blood from a common progenitor

77
Q

Bone marrow stem cell

A

cells that gives rise to all the various blood cells

78
Q

Spleen

A

filters blood and is the site of immune cell interactions|destroys aged RBC’s

79
Q

Tonsils

A

masses of lymphatic tissue in the back of the throat that help catch pathogens that enter the body through respiration or ingestion

80
Q

Appendix

A

similar to tonsils, both in structure and function and is found near the beginning of the large intestines