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If I decrease the radius by a factor of 2, the resistance increase and _______ flow by a factor of _____ .
Decreases flow!
R = 1/(2)4 = 1/16 = 0.06 (by a factor of 16x)
Explain the metabolic theory of autoregulation.
If tissue is inadequately perfused, wastes accumulate, stimulating vasodilation which increases perfusion (more blood flow/vol. tissue/min.) Decrease in local BP
What are the 3 types of capillaries (list from least permeable to most)
1. Continuous capillaries (least)
2. Fenestrated capillaries
3. Sinusoids (most)
How do RBC produce ATP? Why do they use this method?
Anaerobic fermentation because they lack a mitochondria.
What is agglutination?
Clumping of red blood cells caused by the antibodies binding to antigens. Can interrupt blood flow in smaller blood vessels.
Explain vasomotion and how is it regulated.
Collective term for both vasoconstriction and vasodilation, quick and powerful way of alterting blood pressure and flow.
Controlled in part by vasomotor center in medulla oblongata (neural), local, and hormonal.
Histamine, bradykinin, and prostaglandins are examples of ________ .
Superoxide radicals, thromboxane A2, and serotonin are examples of ________ .
Vasodilators
Vasoconstrictors.
What are the three routes of fluid exchange across the capillary wall?
1. Diffusion (most important!)- Glucose, O2 blood to tissue/CO2 & waste tissue to blood.
2. Transcytosis – vesicle-mediated, pinocytosis or receptor-mediated endocytosis; ferried across cell then exocytosis; minor mechanism but important for hormones.
3. Filtration and Reabsorption- Fluid filters out of arterial end of capillary and osmotically reenters venous end; delivers materials to the cell & removes metabolic wastes.
How does your body correct hypoxemia?
Liver and kidneys secrete erythropoietin, which stimulates the red bone marrow to accelerate erythropoiesis and increased RBC, which increases the O2 transport.
A person has chickenpox, what would you expect to see in increase in?
Basophils.
From aorta to capillaries, blood velocity decrease, due to what three reasons?
1. As blood traveled encountered friction against vessel walls.
2. Smaller radii of arterioles and capillaries.
3. Farther from heart (number of vessels and their total cross-sectional area becomes greater and greater).
What is angiogenesis and what is the result of it?
Growth of new blood vessels, increased perfusion.
What are the formed elements of the blood?
Ethryocytes, platelets, leukocytes, granulocytes, agranulocytes.
How many oxygen binding sites per hemoglobin?
4 O2 binding sites.
These increase in viral infections and eventually transform into macrophages and act as antigen presenting cells.
Monocytes
What has the most control over peripheral resistance and flow? Why?
Arterioles.
1. On proximal side of capillary beds and best positioned to regulate flow into the capillaries
2. Outnumber any other type of artery, providing the most numerous control points
3. More muscular in proportion to their diameter
What is a baroreflex? What is chemoreflex?
Baroreflex: Automatic, negative feedback response to change in blood pressure. Govern short-term regulation of BP
Chemoreflex: Primary role of chemoreflexes is to adjust respiration to changes in blood chemistry ([O2], [CO2], pH), cause widespread vasoconstriction (increase BP and lung perfusion)
This substance is identical to blood plasma without fibrinogen.
Serum.
Do men or women have a higher hematocrit percentage?
Men (42-52%) androgens stimulate RBC production.
Women (37-48%). blood loss with menstruation
List the prevalence of WBCs.
1. Never (Neutrophils)
2. Let (Lymphocytes)
3. Monkeys (Monocytes)
4. Eat (Eosinophils)
5. Bananas (Basophils)
How does the atrial natriuretic peptide work?
When the atria feels an increased BP (stretching), atrial cells release ANP, which lowers BP by increasing Na+ excretion by the kidneys (water follows sodium!) which reduces blood vol. --> Overall decreased BP
Explain the RAAS Pathway.
1. The kidney's detect low BP and release renin.
2. Renin converts angiotensinogen (from liver) to angiotensin I .
3. Angiotensin I is converted to angiotensin II by ACE (from lungs).
4. Angiotensin II stimulates vasocontriction, thirst (ADH), and Aldosterone.
4. BP increased!!!
If blood osmolarity is too low, what will happen?
Too much water stays in the tissue, blood pressure drops, and edema occurs.
Fe3+ gets transported in the body by what?
Transferrin
1. Vascular Spasm: Platelets secrete vasoconstrictors that help reduce blood loss.
2. Platelet plug formation: Platelet Adhesion – stick to damaged blood vessel (exposed collagen fibers)
Activated platelets release: Serotonin (vasoconstr.); ADP – attracts more platelets, makes them sticky; Thromboxane A2 – promotes all of the above.
3. Coagulation: Cascading series of enzymatic reactions via activated plasma proteins/clotting factors resulting in fibrin clot.