A&P Chapter 19 Notes PDF

Cardiovascular System: Blood vessels -- Chapter 19: Part 1: 1. Blood vessels a. Delivery system that begins and ends at the heart i. Arteries -- carry blood away from the heart; oxygenated except for pulmonary artery ii. Capillaries -- contact tissue cells and...

Cardiovascular System: Blood vessels -- Chapter 19: Part 1: 1. Blood vessels a. Delivery system that begins and ends at the heart i. Arteries -- carry blood away from the heart; oxygenated except for pulmonary artery ii. Capillaries -- contact tissue cells and directly serve cellular needs -- business center of the heart iii. Veins -- carry blood towards the heart 1. Deoxygenated except for pulmonary vein 2. Structure of Blood vessel walls b. Arteries and veins iv. Tunica intima, tunica media, and tunica externa c. Lumen v. Central blood-containing space d. Capillaries vi. Endothelium with sparse basal lamina e. 3. Tunics f. Tunica intima vii. Endothelium lines the lumen of all vessels g. Tunica media viii. Smooth muscle ix. Sympathetic vasomotor nerve fibers control vasoconstriction and vasodilation of vessels 2. Vasoconstriction -- decreased lumen diameter 3. Vasodilation -- increased lumen diameter h. Tunica externa (tunica adventitia) 4. Elastic (conducting) arteries i. Large thick-walled arteries j. Act as pressure reservoirs -- expand and recoil as blood is ejected from the heart k. Ex. aorta and its major branches 5. Muscular (Distributing) Arteries and Arterioles l. Distal to elastic arteries =\> deliver blood to body organs m. Active in vasoconstriction n. Ex. renal artery 6. Arterioles o. Smallest arteries p. Lead to capillary beds q. Control flow into capillary beds via vasodilation and vasoconstriction 7. Capillaries r. Microscopic blood vessels s. Walls of tunica intima, one cell thick t. In all tissues except for cartilage, epithelia, cornea, and lens of eye u. Functions: exchange of gases, nutrients, wastes, hormones, etc. v. Three structural types x. Continuous capillaries xi. Fenestrated capillaries xii. Sinusoidal capillaries (sinusoids) 8. Capillary beds w. Interwoven network of capillaries between arterioles and venules x. Microcirculation -- flow of blood through bed y. Capillary beds consist of two types of vessels xiii. Vascular shunt -- channel that connects arteriole directly with venule (metarteriole through fare channel) xiv. True capillaries -- actual vessels involved in exchange 9. Veins z. Carry blood toward the heart a. Have thinner walls that arteries, but larger lumen b. Capillary beds =\> postcapillary venules =\> merge into larger and larger veins c. Have all tunics, but thinner walls with large lumens compared with corresponding arteries d. Large lumen and thin walls make veins good storage vessels xv. Called capacitance vessels (blood reservoirs) because they contain up to 65% of blood supply e. Blood pressure lower than in arteries, so adaptations ensure return of blood to heart xvi. Large-diameter lumens offer little resistance 4. Smaller diameter means more resistance because more of the blood volume is touching the wall xvii. Venous valves 5. Prevent backflow of blood 6. Most abundant in veins of limbs xviii. Venous sinuses 7. Flattened veins with extremely thin walls 8. Examples -- coronary sinus of the heart and dural sinuses of the brain 10. Anastomoses f. Vascular anastomoses -- interconnections of blood vessels g. Arterial anastomoses -- provide alternate pathways (collateral channels) to ensure continuous flow, even if one artery is blocked xix. Common in joints, abdominal organs, brain and heart xx. None in retina, kidneys, spleen h. Arteriovenous anastomoses xxi. Shunts in capillaries xxii. Example -- metarteriole -- thoroughfare channel i. Venous anastomoses xxiii. So abundant that occluded veins rarely block blood flow j. Blood flow xxiv. Volume of blood flowing through vessel, organ, or entire circulation in given period xxv. Measured in ml/min, it is equivalent to cardiac output (CO) for entire vascular system xxvi. Overall is relatively constant when at rest, but varies at individual organ level, based on needs 11. Physiology of circulation -- definition of terms k. Blood pressure (BP) xxvii. Force per unit area exerted on the wall of a blood vessel by the blood 9. Expressed in mm Hg 10. Measured as systemic arterial BP in large arteries near the heart xxviii. High to low pressure gradient =\> driving force that keeps blood moving l. Resistance (peripheral resistance) xxix. Opposition to flow xxx. Measure of the amount of friction blood encounters m. Three important sources of resistance xxxi. Blood viscosity 11. Viscosity -- thickness of blood xxxii. Total blood vessel length 12. The shorter the blood vessel the less resistance xxxiii. Blood vessel diameter 13. The smaller the diameter the more resistance (inversely proportional) 12. Resistance n. Blood viscosity xxxiv. The "stickiness" of the blood due to formed elements and plasma proteins 14. Higher viscosity, higher resistance xxxv. Blood vessel length 15. The longer the vessel, the greater the resistance encountered a. Lower length lower resistance b. Longer length higher resistance xxxvi. Blood vessel diameter 16. Varies inversely with the fourth power of vessel radius c. Higher diameter less resistance d. Lower diameter higher resistance e. Less resistance = higher blood flow 17. Small diameter arterioles are the major determinants of peripheral resistance 18. What happens when there are changes in diameter or fatty plaques from atherosclerosis? f. When diameter decreases, resistance increases, and there is reduced blood flow 13. Systemic blood pressure o. The pumping action of the heart generates blood flow p. Pressure results when flow is opposed by resistance q. Systemic pressure xxxvii. Is highest in the aorta xxxviii. Declines throughout the pathway xxxix. Is 0 mm Hg in the right atrium r. The steepest drop occurs in arterioles 14. Arterial blood pressure s. Systolic pressure -- pressure exerted during ventricular contraction t. Diastolic pressure -- lowest level of arterial pressure u. Pulse pressure -- difference between systolic and diastolic pressure v. Mean arterial pressure (MAP) -- pressure that propels the blood to the tissues xl. MAP = diastolic pressure + 1/3 pulse pressure w. Pulse pressure and MAP both decline with increasing distance from the heart x.  y. Clinical monitoring of circulatory efficiency xli. Vital signs 19. Pulse and blood pressure 20. Respiratory rate 21. Body temperature xlii. Taking a pulse 22. Radial pulse (taken at the wrist) -- most routinely used, but there are other clinically important pulse points 23. Pressure points -- areas where arteries are close to body surface g. Can be compressed to stop blood flow in event of hemorrhaging 15. Capillary blood pressure z. Ranges from 15 to 35 mmHg a. Low capillary pressure is desirable xliii. High BP would rupture failure, thin-walled capillaries xliv. Most are very permeable, so low pressure forces filtrate into interstitial spaces 16. Venous blood pressure b. Changes little during the cardiac cycle c. Small pressure gradient, about 15 mm Hg d. Low pressure due to cumulative effects of peripheral resistance 17. Factors aiding venous return e. Respiratory "pump" -- pressure changes created during breathing move blood toward the heart by squeezing abdominal veins as thoracic veins expand f. Muscular "pump" -- contraction of skeletal muscles "milk" blood toward the heart and valves prevent backflow g. Vasoconstriction of veins under sympathetic control 18. Regulation of blood pressure h. Three main factors regulating blood pressure xlv. Cardiac output (CO) xlvi. Peripheral resistance (PR) xlvii. Blood volume i. Factors can be affected by xlviii. Short-term regulation -- neural controls xlix. Short-term regulation -- hormonal controls l. Long-term regulation -- renal controls 19. TBW Part 2: 1. Blood vessels -- aorta a. Aorta i. Ascending aorta ii. Arch of aorta iii. Descending aorta b. Arch of the aorta branches iv. B -- brachiocephalic trunk v. C -- common carotid vi. S -- left subclavian 2. Branches of aorta c. Brachiocephalic (1^st^) vii. Right subclavian -- arm viii. Right common carotid 1. Right internal carotid -- to the brain 2. Left external carotid -- to the head and neck d. Left common carotid (2^nd^) ix. Left internal carotid x. Left external carotid e. Left subclavian (3^rd^) -- arm 3. Blood vessels -- arm f. Subclavian -- toward shoulder g. Axillary -- armpit (axilla) h. Brachial -- arm xi. Forearm 3. Medial -- ulna 4. Lateral -- radial 4. Blood vessels -- brain i. A diagram of a diagram Description automatically generated j.  5. Abdominal aorta -- 3 single arteries k. Celiac trunk xii. Common hepatic artery -- 3 branches 5. Hepatic artery proper -- liver 6. Right gastric artery -- stomach 7. Gastroduodenal artery -- stomach/duodenum xiii. Splenic xiv. Left gastric l. Superior mesenteric xv. Intestinal -- small intestines m. Inferior mesenteric xvi. Intestinal -- large intestine 6. Abdominal aorta -- paired branches n. Renal -- R and L o. Gonadal -- R and L p. Common iliac -- R and L iliac xvii. Internal iliac -- supply the pelvis xviii. External iliac -- supply the lower limbs 7. 8.  9. 10. Arteries of the lower limb q. External iliac r. Femoral -- thigh s. Popliteal -- back of knee t. Tibial -- dorsal pedis xix. Anterior & posterior u. Fibular 11.  12. Diagram of a diagram of a human body Description automatically generated 13.  14. 15.  16. Veins of the arm v. Superficial veins xx. Basilic -- medial side -- axillary xxi. Cephalic -- lateral side -- subclavian w. Deep veins xxii. Ulna & radial -- forearm xxiii. Brachial (arm) -- axillary x. Axillary -- subclavian y. A diagram of veins and veins Description automatically generated 17. Lower limb veins z. Superficial xxiv. Small saphenous -- popliteal -- back of knee xxv. Great saphenous -- femoral -- in the thigh a. Deep xxvi. Tibial & Fibular -- popliteal -- femoral -- external iliac (pelvis) -- common iliac -- inferior vena cava b.  18. Abdominal veins c. External + internal iliac veins -- common iliac (L and R) d. 2 common iliac -- IVC (inferior vena cava) e. Renal -- IVC f. Gonadal -- IVC 19.