Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
107 Cards in this Set
- Front
- Back
|
Arteries |
carry blood away from the heart
have thick muscular walls that allow them to be elastic and contractile. allows for passive changes in size of the vessel's diameter as BP varies |
|
|
Arterioles |
smallest arterial branches
|
|
|
capillary beds |
where the exchange between the blood and interstitial fluids take place |
|
|
Venules |
small veins |
|
|
Tunica Intima (interna) |
innermost layer of the vessel
endothelial lining faces the lumen followed by an under layer of connective tissue with elastic fibers |
|
|
Tunica Media |
middle layer of blood vessels that contains concentric sheets of smooth muscle tissue
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 that supply large blood vessels
"blood vessel for blood vessels" |
|
|
Differences between Arteries and Veins |
a. walls of arteries are thicker. arteries have more smooth muscle and elastic fibers in the tunica media than the vein b. Arteries constrict when blood pressure does not distend them. Veins constrict very little. Lumen of an A looks smaller than a vein c. the endothelial lining of the arter does not contract so when the does contract, it ripples into folds d. arteries are more resilient when stretched. Veins can tear e. Veins have valves to prevent backflow |
|
|
Elastic Arteries |
conducting arteries
walls of elastic arteries are resilient w/ a high concentration of elastic fibers and relatively fewer smooth muscle cells in the tunica media. Can tolerate dramatic pressure changes in the cardiac cycle
aorta, pulmonary trunks and major arterial branches (pulmonary, common carotis, subclavian, and iliac arteries) |
|
|
Muscular Arteries |
medium-sized arteries, distribution arteries
distribute blood to the body's skeletal muscles and internal organs. have more smooth muscle in the tunica media than elastic arteries.
external carotid arteries, brachial arteries and femoral arteries |
|
|
Arterioes |
resistant vessels
have little to no tunica externa adn only 1-2 muscle cell layers deep in the tunica media
although they can vasodilate when O2 levels are low, and vasoconstrict when influenced by the sympathetic divsion |
|
|
Aneurysm |
bulge in weakened wall of an artery that can pop
most dangerous located in the brain (strokes) or aorta (bleed out in minutes).
Occur frequently in patients with arteriosclerosis, arterial inflammation or infection and marfan's syndrome.
go undetected until they burst |
|
|
Continuous capillaries |
the capillary endothelium is a complete lining (located in all tissues except cartilage and epithelia)
specialized continuous capillaries with restricted permeability are responsible for the blood brain barrier |
|
|
Fenestrated capilliaries |
contain pores throughout the endothelial lining
pores allow for rapid exchange of water, small solutes up to small peptides.
Found in hypothalamus, pituitary, pineal and thyroid glads and filtration at the kidneys |
|
|
Sinusoids capillaries |
specialized fenestrated capillaries
have gaps in b/t adjacent endothelial cells and thin or abscent basal lamina
water, solutes, and large plasma proteins can pass through
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 anastomes |
direct connections b/w arterioles and venules that bypass a capillary bed |
|
|
arteriosclerosis |
thickening and toughening of artery walls
two forms: focal calcification and atherosclerosis |
|
|
focal calcification |
gradual degeneration of smooth muscle tissue in the tunica media and subsequent deposititon of calcium salts
typically involves arteries of the limbs and genital organs
may be a part of aging or atherosclerosis. Rapid and severe calcification may occur as a complication of diabetes mellitus |
|
|
Atherosclerosis - definition |
damage to endothelial lining and formation of lipid droplets in the tunica media of arteries
more common form of arteriosclerosis |
|
|
Atherosclerosis - mechanisms |
1. high levels of circulating cholesterol not taken up by the tissues contribute to atherosclerosis 2. Circulating monocytes phagocytize cholesterol- rich and triglyceride rich lipoproteins 3. The monocytes (now foam cells) stick to the endothelial lining of arteries and secrete cytokines that attract platelets and stimulate the smooth muscle to divide 4. Monocytes, smooth muscle cells and endothelial cells all start to phagocytize lipids and form a collaborative fatty mass, a plaque |
|
|
Venules |
smallest venous vessels |
|
|
medium-sized veins |
comparable to muscular arteries but have a thin tunica media and few smooth muscle cells
tunica externa is the thickets layer which contains long bundles of collagen and elastic fibers |
|
|
Large veins |
include the superior vena cava and inferior vena cava.
all three tunicas are present |
|
|
Venous Valves |
b/c blood pressure in venules and medium sized veins are low, they contain valves to prevent backflow to the capillary beds
valves point in the direction of blood flow and are an extension of the tunica interna
valves pushed open by the force of blood inferior to the valve. force comes from the surrounding skeletal muscles contracting. |
|
|
Varicose Veins |
sagging, swollen veins that result from venous blood pooling against the venous valve
venous walls become distorter with age, lack of exercise, increased blood volumes (pregnancy) or a career of standing or sitting for long periods
valves are less effective |
|
|
hemorrhoids |
distended veins near anus due to tremendous force put on the abdominal muscles to defecate or deliver a child.
topical medicines (to contract smooth muscle tissues) or surgery are treatments |
|
|
Distribution of Blood |
venous system contains 65-70% of the circulating blood.
approximately 20% of total blood volume is in the liver, skin, and bone marow |
|
|
hydrostatic pressure |
a force exerted against a liquid
heart pumps blood |
|
|
circulatory pressure |
pressure difference between the base of the ascending aorta and the entrance to the R Atrium.
Average is 100 mm hg
this is the force needed to push blood through the arterioles into the capillaries |
|
|
Three components of circulatory pressure |
1. Blood Pressure 2. Capillary hydrostatic Pressure 3. Venous pressure |
|
|
Blood pressure |
BP
Arterial pressure
range 100mm hg to 35 mm hg |
|
|
Capillary Hydrostatic Pressure |
CHP
pressure in the capillary beds pushing into the interstitial fluid
35-18 mm Hg |
|
|
Venous pressure |
pressure in the venous system
18 mm Hg |
|
|
resistance |
any force that resists movement |
|
|
For circulation to occur, what must the pressure gradient overcome? |
The total peripheral resistance
vascular resistance, viscosity and turbulence |
|
|
total peripheral resistance is made of what 3 componets |
1. vascular resistance 2. viscosity 3. turbulence |
|
|
What is the most important determinant of peripheral resistance? |
diameter of the arterioles
smaller the diameter, greater the resistance |
|
|
Aterial blood pressuer |
must be high enough to overcome peripheral resistance
not stable, fluctuation between ventricle systole and diastole |
|
|
Systolic pressure |
peak pressure during ventricle contraction |
|
|
Diastolic pressure |
minimum pressure at the end of ventricle diastole (relaxation) |
|
|
Pulse |
rhythmic pressure oscillation for each heart beat |
|
|
Pulse pressure |
PP = systolic - diastolic pressure |
|
|
Mean Arterial pressure (MAP) |
MAP = diastolic pressure + ( pulse pressure/3) |
|
|
Elastic Rebound |
when diastole begins, BP drops and the arteries recoil to their original dimensions
the recoil pushes blood toward the capillaries.
push of the blood by recoil is the elastic rebound |
|
|
Hypertension |
increases workload on the heart. to compensate, the L Ventricle increases in size and the demand for O2 and nutrients.
coronary circulation can't keep up and areas go ischemic. Increased arterial pressure puts a strain on the arterial walls.
Prone to arteriosclerosis, aneurysms, heart attacks and strokes.
Therapies include calcium channel blockers, beta-blockers, diuretics, and vasodilators to decrease BP |
|
|
Treatments of Hypertension |
life style changes, quit smoking, exercise, lower salt intake, lower caloric and fat intake. drug therapies: 1. Beta Blockers - decrease pulse & how hard the heart works. 2. Ca Channel blockers - heart doesn't beat as strongly 3. Diuretics - decrease blood volume 4. vasodilators - widens vessels and lowers BP 5. ACE inhibitors - inhibits conversion of Angeotension I to Angeotension II |
|
|
Orthostatis |
form of hypotension when the carotid reflex doesn't work properly due to age or you stand too quickly |
|
|
Treatments of Hypotension |
drug therapies that stimulate heart rate and increase cardiac contractions through beta 1 receptors on the heart (mimic E and NE) dopamine (high concentratiosn) and dobutamine stimulate Ca2+ entry into cells |
|
|
how can you check a pulse? |
can be felt in any large to medium artery by compressing the artery against bone
radial artery, external carotid, brachial, temporal, facial, femoral and popliteal |
|
|
Sphygomomaneter |
instrument to measure blood pressure
inflatable cuff with a pressure gauge (mm Hg) |
|
|
What is capillary exchange dependent on? |
1. diffusion 2. filtration 3. reaborsption |
|
|
Reabsorption |
osmotic pressure pushes solutions back into capillaries from the tissues |
|
|
lymphatic system |
lymph fluid and lympathics (lymph vessels) increase exchange b/t tissue and capillaries
material can go through capillaries to the lympathics and filter through a lympoid organ (lymph nodes, spleen, thymus to check for foreign materials such a toxins or pathogens) and go back into the blood stream via the vena cava |
|
|
diffusion |
net movement of ions based on concentration gradient from high to low |
|
|
filtration |
forced by hydrostatic pressure (BP from heart) to push materials through tissues |
|
|
osmotic pressure |
of a solution is based on solute cocnetration
increase solute concentration, increase osmotic pressure, increase water movement into that solution |
|
|
interplay b/w Filtration and reabsorption |
rates of filtration and reabsorption changes as blood travels through the capillary
in the beginning, more filtration & towards the end more reabsorption.
normally more filtration occurs than reabsorption |
|
|
Net Filtration Pressure (NFP) |
is the difference b/w the net hydrostatic pressure and the net osmotic pressure
how much material got through the tissue?
Decrease capillary hydrostatic pressure, then decrease NFP. |
|
|
Recall of Fluids |
occurs when BP drops due to volume changes (hemorrhage and dehydration)
Hemorrhage decreases BP, then decreases CHP, which decreases NFP and reabsorption increases
plasma volume will increase due to increased reabsorption (from the interstitial fluids) due to osmotic pressure exerted by concentrated plasma or a drop in BP
|
|
|
Edema |
abnormal increase volume of interstitial fluid due to the disturbance in balance of hydrostatic pressure vs osmotic pressure |
|
|
what factors affect tissue perfusion? |
1. cardiac output 2. peripheral resistance 3. blood pressure |
|
|
Local Vasodilators |
factors that promote dilation at the precapillary sphincters
these factors dilate capillaries in response to:
1. increased CO2 2. increased lactic acid 3. increased temperature 4. inflammatory response (histamine) |
|
|
Local Vasoconstrictors |
factors that constrict precapillary sphincters
factors such as prostaglandins & thromboxanes (from activated platelets and WBCs) |
|
|
Cardiovascular centers (CV) |
includes cardioacceleratory and cardioinhibitory centers that are part of the sympathetic and parasympathetic innervation and regulation of the heart |
|
|
Vasomotor Centers |
have two populations of neurons: large group involved w/ widespread vasoconstriction and a small group involved with vasodilation of arterioles to the skeletal muscle and brain
|
|
|
Control of vasoconstriction |
neurons release NE which leads to constriction |
|
|
Control of vasodilation |
starts with ACh released which leads to NO release which then dilates smooth muscle around arterioles of skeletal muscles and the brain |
|
|
Vasomotor tone |
vasoconstrictor activity is continuous to keep arterioles partially constricted |
|
|
Cardiovascular centers monitor changes in pressure, O2, CO2, and pH of peripheral tissue through what two receptors? |
Baroreceptors and Chemoreceptors |
|
|
Baroreceptors |
sensitive to STRETCH in the walls of expandable organs |
|
|
Areas of baroreceptors in the cardiovascular region |
1. carotid sinuses 2. aortic sinuses 3. atrial baroreceptors |
|
|
carotid sinuses |
expandable chambers near the base of the internal carotid arteries
ensures adequate blood flow to the brain |
|
|
aortic sinuses |
pockets in the walls of the ascending aorta and monitors the start of system blood flow |
|
|
atrial baroreceptors |
are in the walls of the right atrium
monitors BP at the end of the systemic circuit |
|
|
Aortic reflex |
baroreceptor reflex
adjust pressure to ensure adequate blood flow through the systemic circuit
|
|
|
In what ways does the Aortic reflex work? |
1. when BP climbs, it alters the activity of the cardiovascular centers to DECREASE CO and 2. VASODILATE peripheral vessels
2. when BP drops, it INCREASES CO and peripheral vessels will VASOCONSTRICT |
|
|
Atrial Reflex |
adjust flow based on the pressure stimulation in the R Atrium.
increased stimulation in the R Atrium will lead to stimulation of the cardiovascular center to increase CO output so there isn't a backlog of venous flow
the opposite of the baroreceptors of the carotid and aortic sinuses |
|
|
Chemoreceptors |
sensitive to changes in CO2, O2, pH in blood & CSF
located in the carotid bodies (near carotid sinuses) and aortic bodies (near the arch).
Chemoreceptors in the medulla oblongat monitor CSF and aid in the control of respiratory function and blood flow to the brain |
|
|
What will increasing the levels of CO2 in the CSF do? |
stimulate chemoreceptors in the medulla oblongata to vasodilate cerebral vessels while vasoconstrict occurs in most other vessels and organs and stimulate respiratory centers.
goal is to keep the brain oxgenated |
|
|
Chemoreceptor reflexes |
respond to increased CO2, decreased pH and decreased O2
stimulate cardioacceleratory center, inhibit cardioinhibitory centers, stimulate vasomotor centers and stimulate respiratory centers |
|
|
NE & E |
increases cardiac output and increases vasoconstriction |
|
|
Antidiuretic Hormone (ADH) |
released by posterior pituitary
in response to decreased blood volume and increased solute concentration in plasma
will increase BP through vasoconstriction, conserve H20 at kidneys to increase blood volume |
|
|
Angiotensin II |
secretion stimulated in response to increased renin (kidneys) in blood.
Renin (converts Angiotensionogen to angiotensin I) is secreted in response to decreased blood pressure
|
|
|
What does Angiotensin II do? |
1. stimulates ADH release 2. stimulates aldosterone production which leads to Na+ absorption, increase H2O osmosis in kidneys 3. stimulate thirst 4. stimulates increased CO through vasoconstriction
|
|
|
how does Angiotenionogen converted to Angotensin II |
Angiotensionogen (plasma protein produced by liver) is converted to Angiotensin I by renin.
Angiotenin I is converted to Angiotensin II by ACE - angiotensin-convertion enzyme, in the capillaries in the lung |
|
|
Erythropoitin (EPO) |
released by kidneys in response to decreased BP or decreased O2 levels in kidneys
EPO stimulates RBC production (increase blood volume and viscosity).
increased # of RBCs increase O2 in blood |
|
|
Atrial Natriuertic Peptide (ANP) and brain natriuetic peptide (BNP) |
ANP from R Atrium and BNP from ventricle muscle cells respond to increased stretching during diastole
They will decrease BP, decrease BV by increasing Na excreted at kidneys, increase h2o loss, stimulate vasodilation, decrease thirst, and block release of ADh, Aldosterone, E and NE
Goal of natrietic peptides is to lower BP |
|
|
Cardiovascular Response to heemorrhaging |
cardiovascular system's immediate task is to maintain adequate BP and peripheral blood flow
long term task is to restore blood volume |
|
|
Short Term Elevation of BP due to hemorrhaging |
Neural response by carotid and aortic reflexes increase cardiac output and cause vasoconstriction. Stress and anxiety leads to stimulation of sympathetic headquarters in hypothalamus. The hypothalamus calls for increase vasomotor tone, release venous reserves (liver, skin, bone marrow) which leads to increase venous return therefore ADH, and Angiotensin II restrict water loss and increase blood volume. Short term elevation of blood pressure remedies are good for < 20% blood loss (when you donate blood you give about 10% of blood volume so you can safely recover by short term effects). |
|
|
Long term Restoration of Blood Volume due to hemorrhaging |
increase reabsorption in capillaries from decrease CHP, Aldosterone and ADH promote fluid retention, EPO make more RBCs (increase volume and viscosity of blood) and increased thirsty (by angiotensin II) ingest more H20 absorbed (increase blood volume). |
|
|
Shock |
Acute circulatory crisis marked by low BP and inadequate peripheral blood flow Causes - decrease 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 causes - hemorrhaging - dehydration - third degree burns symptoms - below 90mm Hg systolic pressure - pale, cool, clammy skin - disorientation - increase heart - no urine production - decrease pH (lactic acid build up from O2 starved tissues) - rate rapid, weak pulse |
|
|
circulatory collapse |
capillaries collapse (due to low BP), tissues are starved, and dying tissues release abnormal chemicals. |
|
|
Special circulation - the Brain |
local demands and pressure changes in brain yet blood flow to brain remains constant. Safeguards include blood-brain barrier and 4 major arteries with anastomoses. The brain receives 750 ml oxygenated blood/minute (about 12% of CO)! |
|
|
Special circulation - the Heart |
Coronary arteries are squeezed when heart contracts (decrease blood flow temporarily). Fortunately heart tissues has enough O2 reserves (bound to myoglobin) until the heart relaxes. BP is highest at base of aorta where coronary vessels originate from. Therefore the coronary arteries will have plenty of pressure to move the blood to the heart tissues. If the workload of the heart increases, and O2 levels decrease and lactic acid concentration increases then the coronary arteries will dilate to increase blood flow to the heart. Unlike the general circulation, E from the sympathetic division activation will dilate coronary vessels (E constricts general systemic vessels). |
|
|
Special Circulation - the Lungs |
Our lungs have 300 million alveoli and each one is individually wrapped with a capillary network. High O2 alveolus concentration will cause lung vessels to dilate. Low O2 alveolus concentration will cause lung vessels to constrict so that the blood is shunted to alveoli with higher O2 levels. This shunting of blood to more oxygenated regions makes lungs efficient. Lungs have low CHP (10mm Hg vs. 35mm Hg) because we don’t want fluids pushed into lung tissue and cause pulmonary edema. The right ventricle has far less muscle mass than the left ventricle to facilitate lung low CHP. |
|
|
fetal circulation |
Because the fetus is in the womb, its respiratory and nutrients come from Mom. Fetal circulation is mapped out slightly differently from those of us outside of the womb. Both in womb and out of womb circulatory circuitry are designed for maximum peripheral tissue perfusion for the condition (womb support or no womb support). |
|
|
Foramen ovale |
hole between the atria (blood bypass pulmonary circuit)
closes soon after birth in response to increase blood pressure in left atrium. A valvular flap closes the hole. The remnant depression is renamed the fossa ovalis. |
|
|
ductus arteriosis |
short muscular vessel between the aortic and pulmonary trunks designed to shunt blood flow to systemic circulation and bypass the lungs. Shortly after birth, high level of O2 stimulates the ductus arteriosus to constrict and blood thruways of the aorta and the pulmonary artery become separated. The ductus arteriosus becomes a fibrous cord now named the ligamentum arteriosum. |
|
|
ductus venous |
brings oxygenated blood from Mom’s umbilical vein and links up with baby’s inferior vena cava bypassing the liver. In the unborn fetus oxygenated blood feeds through the inferior vena cava unlike people out of the womb. Ductus venosus becomes the ligamentum venosum. |
|
|
Patent foramen ovalis and ductus arteriosus |
Mixing of blood sends some deoxygenated blood to systemic circulation (‘blue baby’). BP in the pulmonary circulation is too high (from left ventricular force). Develop pulmonary hypertension and pulmonary edema as well as an enlarge heart (heart has to work harder getting more oxygenated blood into systemic circulation). |
|
|
Tetralogy of Fallot |
Group of four heart and circulatory defects. 1. pulmonary trunk narrows 2. interventricular septum incomplete 3. aorta originates where interventricular septum normally ends 4. right ventricle enlarged, both ventricle thick (increase workload) |
|
|
Hypoplastic Left Heart Syndrome |
The left ventricle is underdeveloped and too small. The mitral valve is not formed or is very small. The aortic valve is not formed or is very small. The ascending portion of the aorta is underdeveloped or is too small. Often, babies with hypoplastic left heart syndrome also have an atrial septal defect, which is a hole between the left and right upper chambers (atria) of the heart. |
|
|
Aging and the Cardiovascular system |
1. changes with blood composition: decreased hematocrit 2. increase chances of constricted or blocked veins by thrombus, pooling of 3. changes in the heart: decrease CO, decrease flexibility of fibrous skeleton, 4. changes in blood vessels: decreased elasticity of vessels which leads to blood in veins, venous valves are less efficient increase incidence of atherosclerosis, increase scar tissue in heart to replace damaged heart tissue increase risk of aneurysm with sudden pressure increases, calcium deposits in vessels, and increase incidence of thrombi formation on atherosclerotic plaques. |
