Hemodynamics Flashcards
What exchanges materials with cells?
Capillaries
Composition of arteries
Endothelium, elastic tissue, smooth muscle (primarily), fibrous tissue
Composition of arterioles
Endothelium, smooth muscle (primarily)
Composition of capillaries
Endothelium only
Composition of venules
Endothelium and fibrous tissue
Composition of veins
Endothelium, elastic tissue, smooth muscle, fibrous tissue
Difference between veins and arteries
Arteries contain thicker layers of smooth muscle and elastic tissue
Why do capillaries lack smooth muscle and elastic tissue?
To allow for exchange with cells
Metarterioles
regulate flow into a capillary bed
Arteriovenous bypass
Connection between an artery and a vein (component of a capillary bed)
Angiogenesis
Development of new blood vessels, involved in wound healing, uterine lining growth, controlled by cytokines
Where is blood pressure highest?
Arteries
Blood pressure decreases as…
it continuously flows through circulatory system
MAP
Mean arterial pressure
MAP=
Diastolic pressure + 1/3 (systolic pressure - diastolic pressure); proportional to cardiac output x resistance
Pulse pressure=
Systolic pressure - diastolic pressure
Factors influencing arteriolar resistance
Local control, sympathetic reflexes, hormones
Myogenic autoregulation
Ability of an artery to control its own state of contraction
Active hyperemia
Increased tissue metabolism, vasodilators released, arterioles dilate, lower resistance, increase blood flow, O2 and nutrient supply to tissue increases (as long as tissue demands)
Hyperemia
Increase in blood flow, increase in metabolic activity
Reactive hyperemia
Decreased tissue blood flow due to occlusion, vasodilators released, arterioles dilate, occlusion removed, decreased resistance increases flow, arterioles constrict as vasodilators wash away
Tonic control of arterioles
Duration of signal from neuron to arteriole changes diameter; decreased signal rate increases diameter, increased signal rate decreases diameter
Precapillary sphincters
Can constrict and prevent blood from traveling across capillary bed from artery to vein
Continuous capillaries
Capillaries with leaky junctions
Fenestrated capillaries
Capillaries with large pores
Transfer of large proteins and solutes through capillaries
Transcytosis
Absorption
Fluid movement into capillaries (net absorption at venous end)
Filtration
Fluid movement out of capillaries (net filtration at arterial end)
Fluid exchange at a capillary is regulated by
Hydrostatic pressure and osmotic pressure
Relationship between lymphatic system and capillaries
Return fluids and proteins to circulatory system, filtering pathogens
Baroreceptors
Monitor blood pressure
Proprioceptors
Monitor joint movements
Chemoreceptor reflex
Detection of blood gas and H+ levels, communicates to respiratory center to adjust breathing rates, adjusts MAP
RAA system
Renin-angiotensin-aldosterone system, increases blood pressure
Effect of epi and norepi on BP
increase
Effect of antidiuretic hormone on BP
increase
Effect of atrial natriuretic peptide on BP
decrease
Blood composition
Plasma + cellular elements
Plasma composition
Water, ions, organic molecules, trace elements/vitamins, gases (CO2, O2)
Cellular elements of blood
RBC, WBC, platelets
White blood cells
Lymphocytes, monocytes, neutrophils, eosinophils, basophils
Lymphocytes
Immunocytes
Monocytes
develop into macrophages (phagocytes)
Neutrophils
Phagocytes, granulocytes
Eosinophils
Granulocytes
Basophils
Mast cells
Erythropoietin
Influences growth or differentiation of RBC
Thrombopoietin
Influences growth or differentiation of megakaryocytes (platelets)
Hematocrit
ratio of RBC to plasma
Shape of RBC
Biconcave disk
Lifespan of RBC
120 days
What happens when an RBC is destroyed?
Some components are recycled (amino acids, some iron, remnants of heme groups converted to bilirubin)
Hemoglobin
Oxygen carrying protein, contained in RBC
RBC lack
a nucleus
Why is the biconcave structure of RBC advantageous?
Increases surface area to enhance diffusion
Agglutination
Occurs when wrong blood type is given in a transfusion, clumping of cells (can cause kidney damage)
Rh blood group
Rh present (+), Rh absent (-)
Hemolytic disease of the newborn
When a negative mother has a positive Rh fetus (or vice versa) and the fetus is incompatible
