they take blood AWAY from the heart, most carry oxygenated blood and branch off aorta
What are the two exceptions to arteries carrying oxygenated blood?
pulmonary veins: carry deoxygenated blood due to branching off pulmonary trunk
branch off arteries, give rise to arterial end of capillary bed
formed by branches of arterioles and venules
What happens at the capillaries?
they are the site where oxygen and nutrients leave the blood and enter cells, and where carbon dioxide and wastes leave cells and enter the blood
What are venules?
structures that feed into veins from venule end of capillary bed
In what direction do veins take the blood?
toward the heart
Where do most veins drain?
into the superior/inferior vena cava and carry deoxygenated blood from veins
What are two circumstances where veins are not carrying deoxygenated blood?
How much of the body's blood volume do veins hold?
What is the pathway of blood flow, starting with the aorta?
arteries to arterioles to capillaries to venules to veins
What is the job of capillaries?
to allow transport between blood and tissues
Describe location and composition of the tunica externa
outermost layer of blood vessels composed of dense and elastic CT
Describe location and composition of the tunica media
middle layer of blood vessels composed largely of smooth muscle tissue and some elastic
What is the purpose of the tunica media?
vasoconstriction and vasodilation
Describe location and composition of the tunica intima(Interna)
smooth inner layer that repels blood cells and platelets, composed of a simple squamous epithelial layer and a basement membrane
Where is the majority of smooth muscle located in blood vessels
Since veins do not have as much smooth muscle as arteries, how do they move blood?
through surrounding skeletal muscles
How does the tunica media differ in veins and arteries?
arteries have a thicker tunica media than veins
How does the elasticity of blood vessels differ in the tunica externa?
arteries have more elastic CT in the tunica externa
How does the size of arteries compare to the size of veins?
arteries have a rounder and smaller shape and have a smaller lumen
What is pulse?
a wave of expansion and recoild to aorta expanding and recoiling?
Where is pulse detected, in arteries or veins?
How do the walls of veins differ from arteries?
they have thinner, less elastic walls and a thinner tunica media
What does the tunica interna lack in veins that it has in arteries?
Which tunica is thickest in veins?
How does the shape of veins differ from arteries?
they are unround and larger than arteries in cross section, they also have larger lumens
How do veins prevent blood from falling backwards?
through one way valves that function similarly to semi lunar valves, and are most prevalent in the limbs
How does viagra work?
it is a vasodilator that targets arteries and arterioles in the penis, causing smooth muscle to relax and facilitating increased blood flow to penis, while simulatenously vasoconstricting veins and preventing blood from leaving
Which are thicker, arterioles or veins, and what accounts for this thickness?
arterioles, due to a thicker tunica media
What structures of capillaries facilitate blood filtration?
intercellular clefts (gaps) between cells and fenestration (pores) within their cell membranes
What do fenestrations allow?
they allow passage of gasses, nutrients into joining tissue from capillaries
How does the narrow diameter of capillaries affect red blood cell flow?
it forces red blood cells to filter through single file, making diffusion of oxygen more efficient
How many layers are capillaries composed of?
2-basement membrane and endothelium
What is the number one killer of men and women in the U.S?
Heart Disease/Coronary Artery Disease (CAD)
How does coronary heart disease begin?
with lesions/injuries to the tunica interna
What is atherosclerosis?
1st stage of heart disease where cholesterol sticks to tunica interna or enters lesion and forms fatty streaks within tunica media which hardens into plaques
After fatty streaks are formed in the second stage of coronary artery disease, what causes the plaques deposited under the tunica interna?
calcium enters the plaques, bringing about arteriosclerosis.
What is the consequence of arteriosclerosis in arteries?
What does arteriosclerosis cause in coronary arteries?
What causes the increase in blood pressure in arteries with arteriosclerosis?
narrow and inelastic arteries
Why does arteriosclerosis cause heart attack and stroke?
clot formation, total occlusion of blood vessels due to plaque, then plaque breaks off and becomes mobilized, plugging small vessels
What are some treatment options for arteriosclerosis?
coronary bypass, endarectomy (if located in common carotid), balloon angioplasty
How does coronary bypass treat arteriosclerosis?
graft from great saphenous vein to aorta, beyond blockage to allow blood to flow again
How does balloon angioplasty treat arteriosclerosis?
pushes plaque to the sides of the vessel and then drug coated stent insterted into vessel; prevents plaque from returning to the center of the vessel
How does an endarectomy treat arteriosclerosis?
if located in common carotid, incision can be made in vessel and plaque can be removed, also called "stripping"
What are the risk factors for developing heart disease?
hi BP, smoking, hi cholesterol, hi LDLs (litters) and low HDL (highway crew), hi transfat intake, hi sat fat intake, not enough exercise, obesity, family history, diabetes mellitus, depression
Why do trans fats increase the risk of heart disease?
because they raise LDLs and decrease HDLs
Why does diabetes mellitus increase the risk of heart diesease?
they constrict blood vessels
What is the maximum healthy value for cholestrol in the blood?
less than 200 mg/dL
How do genetics impact high cholesterol?
individuals can have a gene that causes excessive production of cholesterol by the liver
What is the term for excessive blood cholesterol?
Which foods increase blood cholesterol?
liver, egg yolks, full fat dairy, fatty meats
What is the flow of blood from aorta to vena cavas?
arteries, arterioles, capillaries, venules, veins
What is the function of the ductus venosus?
Drains liver and umbilical vein into inferior vena cava
Where is the ductus arteriosus and what is its function?
between the pulmonary trunk and aorta, sends blood from right ventricle into systemic circuit
What is the function of the foramen ovale?
its one way valve prevents backflow to the right atrium from the left atrium, bypasses the pulmonary circuit
What are the two possible pathways to fetal circulation once blodo reaches the right atrium?
Right atrium, thru foramen ovale, to left atrium, left ventricle, and aorta
Right atrium to right ventricle to pulmonary trunk through ductus arteriosus to aorta
What is the chorion?
the membrane of fetus that surrounds the amnion
Once nutrients and oxygen are passed from mother to fetus, what is the pathway to the fetal heart?
umbilical vein to liver and ductus venosus, to inferior vena cava to right atrium (fetal heart)
What is the pathway of blood from the fetal aorta to the chorion?
from aorta to thoracic aorta to abdominal aorta to common illiac arteries to internal illiac arteries to umbilical arteries
At what point does fetal blood become deoxygenated?
at the internal iliac arteri
After birth, what causes fetal circulation to change?
activated pulmonary circuit causes foramen ovale to close
After birth, what causes the ductus arteriosus to constrict and close?
rising oxygen levels
What do the umbilical veins, umbilical arteries, ductus venosus and ductus arteriosus form after birth?
umbilical veins-ligamentum teres/round ligament
umbilical arteries-medial umbilical ligaments
ductus venosus-ligamentum venosus
ductus arteriosum-ligamentum arteriosum
What are patent foramen ovale and patent ligamentum arteriosum?
patent foramen ovale means that foramen ovale does not seal at birth and no fossa ovalis is formed, patent ligamentum arteriosum is when the ligamentum arteriosum does not form
Define blood pressure
the force blood exerts against the inner walls of blood vessels
How is blood pressure measured?
sphymomanometer and stethoscope
What is the unit of measurement in blood pressure?
milliliters of mercury (mm/Hg)
What is systolic blood pressure?
highest level of blood pressure in arteries as a result of ventricular contraction/systole
When is systolic and diastolic blood pressure recorded?
Systolic-when first Kortokoff sound is heard, diastolic-when last kortokoff sound heard.
What is diastolic pressure?
the lowest number in a blood pressure reading, lowest blood pressure as a result of ventricular diastole
What are the guidelines for blood pressure in males and females
Males less than 120/80, females less than 110/70
When does prehypertension begin?
Where does stage 1 hypertension begin?
When does stage 2 hypertension begin?
How can high blood pressure cause damage?
can cause lesions in tunica intima which are then infiltrated with cholesterol (plaque formation), stroke can occur when blood vessel bursts in brain, injury to capillaries which filter blood in kidneys (glomeruli)
What steps can be taken to lower blood pressure?
lose weight, increase physical activity, decrease salt intake, quit smoking, eat a heart healthy diet and take diuretics
Why does weight loss or exercise promote a decrease in blood pressure?
because a decrease in adipose tissue causes a decrease in vascularization, less vascularization means less pressure needed to move blood
Why does salt increase blood pressure?
because an increase in water retention increases blood pressure
How does smoking increase blood pressure?
because smoking constricts blood vessels which increases blood pressure
How do diuretics decrease blood pressure?
chemicals decrease blood volume and therefore decrease blood pressure by increasing urinary output
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