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76 Cards in this Set

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What is the primary purpose of capillaries in the circulatory system?


How many veins bring blood back to the left atrium?

Four Pulmonary Veins.

Why is it important that the systemic blood vessels are arranged in parallel?

Delivers blood with the same composition to all the tissues (O2 & CO2)




Adequate perfusion pressure for each tissue, while allowing organs and tissues to adjust their own blood flow.

What has to be true in steady state blood flow?

Output from the RV & LV are equal




CO=Venous Return

What type of tissue is blood?

Connective Tissue

What percent of the body weight is blood?

8% of body weight.




1 Liter of blood ~ 1 Kg




Can estimate Total Blood Volume (TBV) by multiplying weight by 8%

What is the composition of Plasma?

Plasma proteins-7%




Other Solutes-1% (electrolytes, organic nutrients and wastes) Contribute to Osmotic Pressure




Water-92%

What are the four Plasma Proteins?

Albumin- made in liver, major contributor to Colloid pressure (7%)


Globulins-made in liver, transport ions & immune function (35%)


Fibrinogens-Made in liver, Clotting (4%)


Regulatory Proteins-enzymes, proenzymes, & hormones (<1%)

What are the only solutes important in fluid exchange across capillaries?

Plasma Proteins




There is a continuous bulk flow of protein-free ECF across capillaries, proteins exert colloid osmotic pressure.

What are the types of WBCs?

Neutrophils


lymphocytes


monocytes


eosinophils


basophils

Blood consists of plasma and formed elements, what are the formed elements and their percentages?

RBCs-99.9%




Platelets and WBCs-0.1%

What are the characteristics of WBCs?


What is the most plentiful cell type in the body?

RBCs ~25 trillion in the body

Describe the structures and functions of the RBCs?

Biconcave disc providing large membrane surface area (Fick's Law)



No nucleus or Organelles-short lifespan & no O2 consumption



Contains enzyme Carbonic Anhydrase for the transport of CO2

What forms the different formed elements of the blood?

All elements are derived from the same type of stem cell in the red bone marrow (hemocytoblasts).



What happens at the end of the RBCs lifespan?

Macrophages (mostly in spleen) detect worn out membranes and engulfs the RBC (phagocytosis)


Globin is digested into component amino acids


Iron of heme is recycled (transported by transferrin)


Non-iron portion of heme is converted into bilirubin released into blood and cleared by liver



What controls the production of RBCs?

Regulated by erythropoietin-produced in Kidneys




Low O2 concentrations cause endocrine cells to release erythropoietin




Must have amino acids (globin), iron (heme), B12, folic acid, and other nutrients

What is the hematocrit level for: Normal, anemia, polycythemia, and dehydration?

Normal-45%




Anemia<30%




Polycythemia-70%




Dehydration-70%

What are seven types of anemia?

Nutritional-deficient in Fe, B12, Folic Acid, etc


Pernicious-Lacking intrinsic factor in stomach to absorb B12


Renal-insufficient EPO from kidneys


Aplastic-failure of hematopoietic stem cells (toxins, radiation, chemo)


Hemorrhagic- acute or chronic


Hemolytic-rupture of RBCs


Sickle Cell

What are the three phases of Hemostasis?

Vascular spasm




Platelet Plug formation




Coagulation

What are the three layers of the vessels?

Tunica Interna-single layer of simple squamous endothelium (elastic connective tissue just outside which allows for stretch & recoil)




Tunica Media-smooth muscle cells arranged in circle around lumen




Tunica Externa-collagen and elastin fibers

What causes vasospasm in hemostasis?

Seratonin and Thromboxin A2 released by damaged endothelial cells and platelets causing constriction.




May possibly have a sympathetic response to pain

What happens in platelet plug formation?

When a vessel wall is damaged and collagen fibers become exposed plts. adhere to the damaged collagen fibers triggering the plt. to release serotonin, thromboxane A2, and ADP. Thromboxane A2 and serotonin induce vasoconstriction. ADP and thromboxane A2 induce plt. aggregation. After enough plts. have adhered the leak will be temporarily sealed. Prostacyclin, normally excreted by healthy endothelium, inhibits plts. from adhering. Aspirin inhibits thromboxane A2 (a type of prostaglandin). Released chemicals trigger coagulation cascade.

Describe the intrinsic, extrinsic, and common pathways.


What is Clot retraction?


How is a clot brokendown (Fibrinolysis)?

Steptokinase is a thrombolytic drug (aka clot buster) used to convert plasminogen to plasmin

What are blood type antigens and antibodies?

Antigens are on the surface of the cell and trigger immune responses. (Type A has A antigens, O has no antigens)


Antibodies are proteins that bind to foreign antigens.



When does a baby develop antigens and what is likely the cause?

At 6 months of age, likely in response to gut bacteria with similar CHO groups.

What are the percentages of Rh antigens, and when are they an issue?


How do you prevent Hemolytic Disease of the Newborn (HDN)?

Give the mother RhoGam (antibodies that destroy Rh+ fetal RBCs) at 28th week and after delivery.

How can a change in the membrane potential be made?


What are the two general types of Cardiac Action Potentials?



What is happening at each of the phases of the fast action cardiac potentials?


How are slow action potentials different?


How is the conduction velocity of fast and slow response potentials different (which type of tissue do they conduct through)?

Fast-purkinje fibers and atrial/ventricular muscle cells


Slow-AV and SA nodes




Different fiber diameter, rate of activation, and difference in amplitude of AP (greater amplitude the greater spread of Local current)

What is automaticity?

Cells in the heart that have unstable membrane potential causing an AP.




Occurs in total absence of any ANS or hormonal stimulation.


SA 90-100 bpm


AV 40-60 bpm


purkinje fibers 14-40 bpm

What is the mechanism of the changes in membrane potential that stimulates the AP?


What is the histology of Cardiac Muscle Cells?

Connected in series




Connected end to end by intercalated discs




Intercalated discs have gap junctions for quick propagation of APs.



What is the function of the AV node?

It is the only electrical connection between the atria and the ventricles.

How does the AV node slow the conduction of an AP?


What are other features that affect AV conduction?


How does an AP conduct through the ventricles?


What is the normal axis of the heart conduction?


What are specifics of cardiac muscle that is specific to cardiac muscle?

Has a high capillary density (dependent of aerobic metabolism)




Layers that wrap around atria & spiral within the ventricles




Many mitochondria



What is the cross-bridge cycle of cardiac muscle?


What is responsible for activation in cardiac muscle?


What is different between cardiac muscle when compared to skeletal muscle?

In skeletal Enough Ca++ is released to bind to every single troponin activating every tropomysin.



In skeletal muscle every Ca++ comes from the sarcoplasmic Reticulum while in Cardiac ECF Ca++ is also involved.



How is Ca++ removed after an AP?

Most reabsorbed by active transport back into the SR.




Some Ca++ is transported out of the cell by secondary active transport

How is contraction of heart affected by ANS?

in Absence of ANS stimulation not enough Ca++ is available to activate all cross bridges.




ANS affects Ca++ availability.

Can you have summation of APs in cardiac muscle?


Describe the phases of the Wiggers Diagram.


What are the big picture points of blood flow?



What two factors affect aortic pressure?

Compliance (constant)




Volume of blood (major factor from beat to beat)

What causes the a wave on the Wiggers Diagram?

Atrial Muscle contraction causing a small increase in the left atrial pressure.

What causes the c wave in the Wiggers Diagram that occurs during isovolumic contraction?

The cusps of the semilunar valves bulge into the atria causing a slight increase in atrial pressure.

When is the most rapid filling of the ventricle?

as soon as the AV valves open.

What are the volumes of blood during :


End Diastolic Volume (EDV)


End Systolic Volume (ESV)


Stroke Volume (SV)


Ejection Fraction (EF)

EDV-110-120 ml


ESV-40-50 ml


SV- (EDV-ESV)-70 ml/bt


EF- (SV/EDV)-60%

What are factors that affect heart volumes?


What is charted on the X & Y axis of the pressure volume loop?

X-volume of blood in the LV




y-ventricular pressure



What is the cause of heart sounds?

First-AV valves closing, Ventricular systole




Second-Semilunar valves closing, ventricular diastole



What causes a murmur and what does it symbolize?

Turbulent blood flow


Murmur heard during systole over right AV valve caused by regurgitation


Murmur heard over pulmonary semilunar valves caused by pulmonic stenosis

When does the heart receive its perfusion?

Coronary arteries receive perfusion during diastole.

How is cardiac output measured (steady State) using the Fick method?




CO is volume of blood pumped by each ventricle per minute (L/min).


How do you calculate Cardiac Reserve?

Cardiac Reserve=Max CO-Resting CO

What determines Cardiac Output?

CO=HRxSV




Ultimately venous return (VR) determines CO

How is the ANS innervating the heart?


Where does sympathetic nervous system innervation start?

Originate in the lateral horn from T1-T6




Affects mainly heart rate and force of contraction.




Right side SNS mainly pacemaker and conduction system, left to myocardium

Where does parasympathetic nervous system innervation start?

Vagus Nerve to medulla




Right side of PNS innervation goes to the SA node, Left side goes to the AV node




Affects mainly heart rate and conduction velocity