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Ch. 21 Blood Vessels and Hemodynamics
Anatomy
71
Anatomy
Undergraduate 3
02/25/2014

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Term
What is the structure and function of arteries? Capillaries? Veins?
Definition

Arteries: carry blood away from heart

Capillaries: site of nutrient and gas exchange

Veins: carry blood towards the heart

Term
What are the 3 walls of the blood vessel?
Definition

Tunica interna: consists of endothelium/elastic lamina

Tunica media: consists of elastic fibers/smooth muscle

Tunica externa: consists of elastin/collagen fibers

Term
What are elastic arteries?
Definition
Largest arteries, thin-walled compared to lumen diameter, carry large volumes of blood quickly.
Term
What are muscular arteries?
Definition
Intermediate size, thicker wall compared to lumen, help adjust rate of blood flow.
Term
What is anastamoses?
Definition
Union of branches of 2 or more vessels serving same body area, allows collateral circulation for an alternate blood route.
Term
What are arterioles?
Definition
Nearly microscopic, major site of BP regulation through vasoconstriction or vasodilation.
Term
What are capillaries?
Definition
Connection between arterioles and venules, site of gas/nutrient/waste exchange, blood flow is regulated by metarterioles and precapillary sphincter.
Term
What are the 3 types of capillaries?
Definition

Continuous: medium, muscle, CT, lungs

Fenestrated: small, kidneys, SI villi, endocrine glands

Sinusoids: large, red bone marrow, liver, spleen

Term
What are venules?
Definition
Small veins, receive blood from capillaries, drain into veins.
Term
What are veins? (function/structure)
Definition
Return blood to heart, walls have thin tunica interna and media and thick tunica externa and aren't as strong/thick as arteries and are flexible, valves prevent backflow and are for the veins of the limbs and if valves leak can lead to varicose veins.
Term
What is a venous sinus?
Definition
Thin, no smooth muscle to alter diameter, receive blood then empty it out.
Term
How is the blood distributed throughout the body?
Definition
Systemic veins and venules contain a large percentage of blood volume, function as blood reservoirs.
Term
How does diffusion occur in capillary exchange?
Definition
Lipid-soluble materials diffuse across cell membranes, water-soluble materials diffuse via fenestrations/intercellular clefts.
Term
How does transcytosis occur in capillary exchange?
Definition

Endocytosis: large non-lipid soluble substances enter cells enclosed in vesicles

Exocytosis: substances exit cells

Term
What is bulk flow in capillary exchange?
Definition
Movement of large numbers of ions, molecules in same direction from high to low pressure areas.
Term
What is starling's law of capillaries and what is filtration and reabsorption?
Definition

Starling's law: capillary filtration and reabsorption are balanced

Filtration: movement of fluid/solutes from capillaries into interstitial fluid

Reabsorption: movement of fluid/solutes from interstitial fluid into capillaries

Term
Describe the two major hydrostatic pressures.
Definition

Blood hydrostatic pressure: pushes fluids into interstitial fluid, promotes flitration

Interstitial fluid hydrostatic pressure: pushes fluids into blood, promotes reabsorption, usually is less than BHP

Term
Describe the two major osmotic pressures.
Definition

Blood colloid osmotic pressure: albumin molecules pull water into blood, promotes reabsorption

Interstitial fluid osmotic pressure: pulls water into interestitial fluid, IFOP usually less than BCOP, promotes filtration

Term
What is the formula for net filtration pressure and what is it?
Definition

NFP = (BHP + IFOP) - (BCOP + IFHP)

Shows direction of fluid movement, positive NFP means fluid moves out of the blood, negative NFP means fluid moves into the blood.

Term
How does CO affect blood flow?
Definition
Higher CO = faster velocity, lower volume reduces CO and BP, water retention increases BP.
Term
Describe/define blood pressure.
Definition
Contraction of ventricles generates blood pressure, pressure against vessel wall, measured with sphygmomanometer.
Term
What is vascular resistance?
Definition
Friction slowing blood flow, the smaller radius of the vessel the greater the resistance, the longer the vessel the greater the resistance.
Term
What is venous return and what factors influence it?
Definition
Volume of blood returning to heart through veins, cardiac chamber pressures, low vein resistance, functional heart valves, skeletal muscle pump and respiratory pump aid venous return.
Term
How is the velocity of blood flow related to the cross-sectional area of the vessel?
Definition
Velocity is lower with higher cross-sectional area.
Term
What is circulation time?
Definition
Time for blood to make complete circuit through body, normal time is 1 min at rest, shorter if higher velocity.
Term
How is blood pressure and blood flow controlled?
Definition
Cardiovascular center in the medulla oblongata, receives input from higher brain regions and sensory receptors.
Term
What pathway is cardiostimulatory?
Definition
Sympathetic ANS which activates NE.
Term
What path is cardioinhibitory?
Definition
Parasympathetic ANS which release ACh.
Term
What are baroreceptors and how do they go about neural regulation?
Definition
Found in walls of carotid arteries and aorta, negative feedback loop, if BP low HR increases to cause increase of BP, stimulation of baroreceptors can slow HR in tachycardia in carotid arteries.
Term
How do chemoreceptors help with neural regulation?
Definition
Chemoreceptors found close to baroreceptors in carotid and aortic bodies, detect H+/CO2/O2 levels.
Term
What is the renin-angiotensin-aldosterone (RAA) system?
Definition
Releases renin from kidneys when blood volume falls or blood flow to kidneys decreases, renin converted which causes vasoconstriction, stimulates aldosterone secretion in adrenal glands, reabsorbs Na+ and H2O which causes increase in BP.
Term
How do norepinephrine and epinephrine hormonally regulate?
Definition
Increase CO and BP by increasing rate of force of contractions, cause vasoconstriction or vasodilation.
Term
How does antidiuretic hormone hormonally regulate?
Definition
Released when dehydrated or decreased blood volume, vasoconstriction upon hemorrhage which raises BP, inhibited by alcohol.
Term
How does atrial natriuretic peptide (ANP) hormonally regulate?
Definition
Released by atrial cells, vasodilation, promotes excretion of Na+/H2O which lowers blood volume and lowers BP.
Term
What are the two ways the body autoregulates BP?
Definition
Physical and chemical.
Term
How does the body physically autoregulate BP?
Definition
Warming through vasodilation, cooling through vasoconstriction, myogenic response is when arteriole stretches and smooth muscle contracts cause constriction.
Term
How does the body chemically autoregulate BP?
Definition
Chemicals released from blood cells to tissues adjacent to blood, stimuli that cause release are O2/CO2 levels, tissue stretching, and hormones.
Term
What are two vasodilating chemicals?
Definition
Histamines and kinins.
Term
What are two vasoconstricting chemicals?
Definition
Thromboxane A2 and serotonin.
Term
What is tachycardia?
Definition
BPM over 100.
Term
What is bradycardia?
Definition
BPM below 50.
Term
What is a bounding pulse?
Definition
Very strong, fluid overload.
Term
What is a thready pulse?
Definition
Weak, rapid.
Term
What are the 3 types of hypertension?
Definition

Prehypertension: systolic b/w 120-139 or diastolic b/w 80-89

Stage 1: systolic b/w 140-159 or diastolic b/w 90-99

Stage 2: systolic above 160 or diastolic above 100

Term
What is shock and what are the 4 types?
Definition

Failure of cardiovascular system to deliver enough O2 and nutrients to meet cellular metabolic needs.

1. Hypovolemic = decreased blood volume

2. Cardiogenic = poor heart function/ischemia/MI

3. Vascular = inappropriate vasodilation

4. Obstructive = obstruction of blood flow

Term
What homeostatic response occur when 10% of total fluid is lost due to shock?
Definition
Homeostasis compensates if up to 10% total fluid loss, RAA system activates, secretes ADH, ANS activated, release of local vasodilators, CO/BP is raised, can last 30 sec to 48 hr.
Term
What homeostatic responses occur when 10-20% of body fluid is lost due to schock?
Definition
Homeostatic responses often cannot compensate, drastic decrease of CO/BP, capillary leakage, acidosis, heart/liver use up ATP reserves, DEAD.
Term
What are sign/symptoms of shock?
Definition
Skin pale/cool/clammy, systolic BP lower than 90 mm Hg, sweating, tachycardia, weak pulse, rapid pulse, altered mental state, decreased urine output, thirst, acidosis.
Term
Describe the systemic circulatory routes.
Definition
Carries oxygenated blood from left ventricle to body and returns deoxygenated blood from body to right atrium.
Term
Describe the pulmonary circulatory route.
Definition
Carries deoxygenated blood from right ventricle to lungs and returns oxygenated blood to left atrium.
Term
Describe the hepatic portal in blood circulation.
Definition
Carries nutrient-rich, deoxygenated blood from GI tract and spleen to liver.
Term
Describe the fetal circulatory route.
Definition
Two umbilical arteries carry deoxygenated blood with wastes to placenta and one umbilical vein carries nutrient-rich, oxygenated vein back to fetus.
Term
How does aging affect the blood circulation?
Definition
Less blood in aorta, atrophy of cardiac myofibers, reduced CO, HR maximum is reduced, increase systolic BP, increase blood cholesterol, increased CAD, increased CHF, reduced blood flow.
Term
Between primary and secondary hypertension which is idiopathic and which is not?
Definition

Primary: 90-95% idiopathic

Secondary: can identify the cause

Term
What are the effects of hypertension?
Definition
Thickened tunica media, atherosclerosis and coronary artery disease, forces heart to work harder, myocardial hypertrophy leading to heart attack, strokes, kidney damage.
Term
What are lifestyle changes to reduce hypertension?
Definition
Lose excess weight, limit alcohol, exercise more, reduce Na+ intake, increase K/Ca/Mg intake, don't smoke, manage stress.
Term
What are treatments for hypertension?
Definition
Diuretics to increase urine output and decrease blood volume and BP, ACE inhibitors to promote vasodilation and decrease aldosterone secretion, beta blockers to inhibit renin and decrease HR and force of contraction, vasodilators which are Ca channel blockers which decrease HR.
Term
What is an aneurysm?
Definition
Bulging of thin/weakened artery or vein, massive hemorrhage if it ruptures.
Term
What is angiogenesis?
Definition
Formation of new blood vessels.
Term
What is an aortography?
Definition
X-ray exam of aorta with injected dyes.
Term
What is a carotid endarterectomy?
Definition
Removal of plaque to restore blood flow to brain.
Term
What is claudication?
Definition
Pain/lameness in limbs due to poor circulation.
Term
What is deep venous thrombosis?
Definition
Blood clot in leg veins that can cause pulmonary embolism and damage vein valves.
Term
What is hypotension?
Definition
Low BP.
Term
What is normotensive?
Definition
Normal BP.
Term
What is an occlusion?
Definition
Obstruction of blood vessel.
Term
What is orthostatic hypotension?
Definition
Excessive blood pressure drop when standing, sign of disease.
Term
What is phlebitis?
Definition
Inflammation of vein.
Term
What is a thrombectomy?
Definition
Removal of clot from blood vessel.
Term
What is a thrombophlebitis?
Definition
Inflammation of vein due to blood clot.
Term
What is white coat hypertension?
Definition
Elevated BP when examined by physician, otherwise normal.
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