| Term | Definition |
|---|
| Arteries | Carry blood away from the heart, thick muscular walls make arteries elastic and contractile. elasticity allows for passive changes in the size of the vessel's diameter as blood pressure varies. |
| Arterioles | Are the smallest arterial branches, have little to no tunica externa and only 1-2 smooth muscle cell layers deep in the tunica media. |
| Capillary beds | where exchange between the blood and interstitial fluid takes place |
| Venules | small veins |
| Tunica interna | inner most layer of the vessel. The endothelial lining faces the lumen followed by an under layer of connective tissue with elastic fibers. |
| Tunica media | middle layer that contains concentric sheets of smooth muscle tissue. It is usually the thickest layer of the blood vessel. |
| tunica externa | the outermost layer that forms a connective tissue sheath around the vessel |
| vasa vasorum | small arteries and veins in the walls of small arteries and veins that supply smooth muscle cells and fibroblast of the tunica media and tunica externa |
| The differences b/w arteries and veins are: | arteries have more smooth muscle and elastic fibers in the tunica media and are thicker than veins |
| Vasodilation | occurs when arteries relax |
| elastic arteries | walls of arteries are more resilient with a high concentration of elastic fibers and fewer smooth muscle cells. Can tolerate dramatic pressure changes in the cardiac cycle |
| Where are elastic arteries found? | the aorta and pulmonary trunks, major arterial branches such as pulmonary, common carotid, subclavian, and iliac arteries |
| muscular arteries | medium sized arteries distribute blood to the body's skeletal muscles and internal organs. Have more smooth muscle tissue in the tunica media than elastic arteries. |
| Where are muscular arteries found? | in the external carotid arteries, brachial arteries, and femoral arteries. |
| Aneurysm | a bulge in the weakened wall of an artery that can pop. the most dangerous are in the brain (strokes) or aorta (bleed out in minutes). Occurs frequently in patients with arterial inflammation or infection, arteriosclerosis, and Marfans syndrome |
| Capillaries | an endothelial tube with a basal lamina |
| Two types of capillaries are? | continuous and fenestrated |
| Continuous capillaries | Most abundant capillaries located in all tissues except cartilage and epithelia. they are specialized continuous with restricted permeability responsible for the blood brain barrier |
| fenestrated capillaries | contain pores throughout the endothelial lining. Allow for rapid exchange of water, small solutes up to small peptides. |
| Where are fenestrated capillaries found? | In the hypothalamus, pituitary, pineal and thyroid glands. |
| Sinusoids | Are like fenestrated capillaries but they have gaps between adjacent endothelial cells and thin or absent basal lamina. |
| Examples of sinusoids are: | liver, spleen, bone marrow, and endocrine organs |
| precapillary sphincter | a band of smooth muscle tissue around the entrance of each capillary to control the diameter of the capillary lumen |
| collateral | two arteries that fuse and empty into an arteriole |
| arteriovenous anastomoses | direct connections between arterioles and venules that bypass a capillary bed. |
| Arteriosclerosis | thickening and toughening of the artery walls. Can lead to coronary artery disease (CAD) or strokes |
| Two forms of arteriosclerosis | focal calcification and atherosclerosis |
| focal calcification | gradual degeneration of smooth muscle tissue in the tunica media and the subsequent deposition of calcium salts. Typicall involves arteries of the limbs and genital organs. Can be a complication of diabetes mellitus |
| atherosclerosis | damage to the endothelial lining and the formation of lipid droplets in the tunica media of arteries. More common form of arteriosclerosis. High levels of circulating cholesterol, not taken up by the tissue, contribute. |
| medium sized veins | comparable size to muscular arteries but have a thin tunica media and a few smooth muscle cells. Tunica externa is thickest layer and contains long bundles of collagen and elastic fibers |
| Large veins | include the inferior and superior venae cavae and their tributaries. All three tunicas are present |
| Venous valves | because the blood pressure in venules and medium size veins is low they contain valves to prevent backflow to the capillary beds. Valves point to the direction of blood flow and are really an extension of the tunica interna. |
| varicose veins | sagging swollen veins that result from venous blood pooling against the venous valve. Venous walls become distorted with age, lack of exercise, increase blood volumes (preg.) or a career of sitting or standing for extended periods |
| hemorrhoids | distended veins near anus due to tremendous force put on the abdominal muscles to defecate or deliver a child. |
| How much circulating blood does the venous system contain? | 65-70%. Almost 20% of total blood is located in bone marrow, liver, and skin |
| Hydrostatic pressure | a force exerted against its osmotic will (heart pumps blood) |
| Circulatory pressure | the pressure difference b/w the base of the ascending aorta and the entrance to the right atrium. The force is needed to push blood through the arterioles into the capillaries |
| 3 components of circulatory pressure | Blood pressure, Capillary hydrostatic pressure and venous pressure. |
| blood pressure | arterial pressure (range 100mm Hg to 35mm Hg) |
| Capillary hydrostatic pressure (CHP) | the pressure in the capillary beds (35-18 mm Hg) |
| Venous pressure | pressure in the venous system (18mm Hg) |
| Resistance | any force that opposes movement. For circulation to occur the pressure gradient must overcome the total peripheral resistance. |
| The most important determinant of total peripheral resistance is? | The diameter of the arterioles (the smaller, the greater the resistance) |
| arterial blood pressure | must be high enough to to overcome the peripheral resistance. It is not stable because it fluctuates b/w ventricle systole and ventricle diastole |
| systolic pressure | peak pressure during ventricle contraction |
| diastolic pressure | minimum pressure at the end of ventricle diastole |
| pulse | rhythmic pressure oscillation for each heart beat |
| pulse pressure | systolic minus diastolic pressure |
| mean arterial pressure (MAP) | diastolic pressure + pulse pressure/ 3 |
| elastic rebound | when diastole begins, blood pressure drops, and the arteries recoil to their original dimensions. |
| hypertension | high blood pressure (BP> 150/90). It increases the workload of the heart. Prone to aneurysms, heart attacks, and strokes. |
| Drug therapy for hypertension are? | calcium channel blockers, beta-blockers, diuretics, and vasodilators to reduce blood pressure |
| Treatments of hypertension | drug therapy, lifestyle changes, quit smoking, exercise, lower salt intake |
| Hypotension | low blood pressure |
| orthostasis | a form of hypotension when the carotid reflex doesn't work properly |
| treatments of hypotension | drug therapies that stimulate heart rate and increase cardiac contractions through beta receptors on heart |
| sphygomomanometer | instrument to measure blood pressure |
| capillary exchange | is dependent on diffusion, filtration, and reabsorption. Hydrostatic pressure pushes materials out of capillaries and into tissues. Osmotic pressures pushes solutions back into capillaries |
| Lymph | fluid |
| lymphatics | lymph vessels |
| lymphatic system | lymph and lymphatics increase exchange between tissues and capillaries. Material can go through capillaries to lymphatics and filter through a lymphoid organ and go back into the blood stream via the vena cava |
| The interplay b/w filtration and reabsorbtion | changes as blood travels through capillary. beginning there is more filtration and towards the end more reabsorbption |
| Net filtration pressure (NFP) | the difference b/w the net hydrostatic pressure and the net osmotic pressure |
| recall of fluids | occurs when blood pressure drops due to volume changes(hemorrhage and dehydration). Hemorrhage decreased BP, decreases CHP, decreases NFP and increases reabsorption |
| edema | abnormal increase volume of interstitial fluid due to the disturbance in balance of hydrostatic pressure vs. osmotic pressure. |
| muscular compression | contraction of surrounding muscles around veins push blood to heart |
| fainting | temporary loss of consiousness because you can't get enough blood to your brain. |
| respiratory pump | just by breathing you assist blood flow into the inferior vena cava by adjusting thoracic cavity pressures. |
| tissue perfusion | blood flow through the tissues. |
| Factors affecting tissue perfusion | cardiac output, peripheral resistance, blood pressure |
| local vasodilators | factors that promote dialation at the precapillary sphincters. These factors dilate capillaries in response to increase CO2, increase lactic acid, increase temperature, or an inflammatory response (histamine) |
| cardiovascular centers (CV) | includes cardioacceleratory and cardioinhibitory centers that are part of sympathetic and parasympathetic innervation and regulation of the heart |
| Vasomotor centers | have two populations of neurons 1)large group involved with widespread vasoconstriction and 2) a small group involved with vasodilation of arterioles to the skeletal muscles and brain |
| Control of vasoconstriction | neurons release norepinephrine(NE)-adrenergic neurons which lead to constriction |
| Control of vasodialition | starts with ACh released which leads to NO release which then dilates smooth muscle around arterioles of skeletal muscles and brain |
| vasomotor tone | vasoconstrictor activity is continuous to keep arterioles partially constricted |
| baroreceptors | sensitive to stretch stimulus in the walls of expandable organs |
| 3 areas where baroreceptors are involved with cardiovascular regulation | Carotid sinuses, aortic sinuses, and atrial baroreceptors |
| barorecptor reflexes | responses to pressure changes to adjust cardiovascular activity through cardiac output and vascular resistence to maintain normal arterial pressure |
| aortic reflex | adjust pressure to ensure adequate blood flow through systemic circuit |
| When blood pressure climbs the barorrecptors alter activity of the cardiovascular centers to: | 1. decrease cardiac output (stimulate parasympathetic, decrease sympathetic) and 2. vasodilate peripheral vessels |
| atrial reflexes | adjust flow based on pressure stimulation in right atrium |
| chemoreceptors | sensitive to changes in CO2, pH in blood, O2 and CSF. Located in carotid bodies and aortic bodies |
| Chemoreceptors in medulla oblongata monitor? | CSF and aid in the control of respiratory function and hellp regulate blood flow to the brain. |
| Chemoreceptor reflexes | respond to increase CO2, decrease pH, decrease O2, stimulate cardioacceleratory center, inhibit cardioinhibitory centers, vasomotor centers, and stimulate respiratory centers |
| NE & E | hormones that increases cardiac output and increases vasoconstriction |
| Antidiuretic Hormone (ADH) | released by pituitary gland in response to decrease blood volume and increase solute concentration in plasma |
| Angiotensin II | secretion stimulated in response increase renin (kidneys) in blood. |
| Angiotensin II does what? | stimulates ADH release, stimulates Aldosterone production which leads to increase Na absorption, increase H20 by osmosis in kidneys, stimulates thirst, stimulates increase cardiac output, has 4-8x greater effect on BP than NE |
| Erythropoitin(EPO) | released by kidneys in response to decreased BP or decreased O2 levels in kidneys. Stimulates RBC production |
| Atrial Natriuretic Peptide (ANP) and Brain Natriueretic Peptide (BNP) | opposite of Angiotensin II, respond to increase stretching during diastole. Decreased BP, decreases blood volume by increased Na excreted by kidneys, increase H20 loss, decrease thirst |
| Exercise and the cardiovascular system | dramatic rise of cardiac output from rest to exercise in trained athletes vs. couch potatoes. Heart and blood vessels are better conditioned if exercised regularly. |
| Cardiovascular response to hemorrhage is? | immediate task is to maintain adequate blood pressure and peripheral blood flow. Long term task is to restore blood volume. |
| shock | acute circulatory crisis marked by low BP and inadequate peripheral blood flow. |
| What causes shock? | decreased cardiac output after hemorrhage or fluid loss, damage heart, external pressure on heart, extensive peripheral vasodilation |
| circulatory shock | occurs with fluid loss of greater or equal to 30% total blood volume |
| What causes circulatory shock? | hemorrhaging, dehydration, 3rd degree burns |
| Symptoms of circulatory shock? | below 90mm Hg systolic pressure, pale, cool clammy skin, disorientation, increase heart, weak pulse, no urine production, decrease pH |
| circulatory collapse | capillaries collapse due to low BP, tissues are starved, and dying tissues release abnormal chemicals |
| special circulation | circulation through certain organs is controlled by different mechanisms that control the general circulation |
| brain circulation | local demands and pressure changes in brain yet blood flow to brain remains constant. Safeguards blood brain barrier, and 4 major arteries w/anastomoses. |
| Heart circulation | coronary arteries are squeezed when heart contracts. Heart has O2 reserves until heart relaxes. |
| Lung circulation | Has 300 million alveoli and each one is individually wrapped with a capillary network. |
| Fetal circulation | because in the womb its respiratory and nutrients come from mom. |
| Foramen ovale | hole b/w the atria and closes soon after birth in response to increase blood pressure in left atrium. |
| ductus arteriosus | short muscular vessel b/w the aortic and pulmonary trunks designed to shunt blood flow to systemic circulation and bypass the lungs. After birth becomes the ligamentum arteriosum |
| ductus venosus | brings oxygenated blood from MOm's umbilical vein and links up with baby's inferior vena cava bypassing the liver. |
| Patent foramen ovalis and ductus arteriosus | mixing of blood sends some deoxygenated blood to systemic circulation (blue baby). |
| Ventricular septal defects | openings in interventricular septum increase BP to pulmonary circulation and therefore develop pulmonary hypertension and pulmonary edema |
| Tetralogy of fallot | group of 4 heart and circulatory defects 1. pulmonary trunk narrows 2. interventricular septum incomplete 3. aorta orginates where interventricular septum normally ends 4. right ventricle enlarged, both ventricle thick |
| transposition of the great vessels | plumbing is switched b/w aorta and pulmonary artery |
| atrioventricular septal defect | the atria and ventricles are incompletely separated. Common defect with trisomy 21 |
| How can circulatory shock be fatal? | If circulatory shock persists, then irreversible damage to the heart and brain occur. Precapillary sphincters and arterioles vasodilate can cause a fatal decline in BP |
| List four ways natriuretic peptides decrease BP | decrease blood volume by increased Na excreted at kidneys, stimulate vasodilation, decrease thirst, and block release of ADH, Aldosterone, E, and NE |
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