exercise 21 blood vessels & circulation portland community college bi 232
TRANSCRIPT
Exercise 21
Blood Vessels & Circulation
Portland Community CollegeBI 232
Blood vessels
• Conduits that carry oxygen and nutrients to cells and remove wastes
• Arteries transport blood away from the heart.
• Deliver blood to capillary beds where gas and nutrient exchange occurs.
• Veins transport blood toward the heart.
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Martinipg. 711
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General Circulatory Patterns
• Two main circuits:• Pulmonary circulation: Blood goes from the heart to
the lungs and returns to the heart. The pulmonary trunk and its branches; leave the right ventricle of the heart and contain deoxygenated blood.
• Systemic Circulation: Blood goes from the heart to rest of the body. The aorta and its branches; leave the left ventricle of the heart and contain oxygenated blood.
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Artery and VeinHistology
• Walls have 3 layers:
• Tunica intima
• Tunica media
• Tunica externa
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Tunica Intima
• Is the innermost layer near the lumen
• Includes:• The endothelial lining• Connective tissue layer
• Internal Elastic Membrane: In arteries, is a thick layer of elastic fibers in the outer margin of the tunica intima
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Tunica Media
• Is the middle layer
• Contains concentric sheets of smooth muscle in loose connective tissue
• Binds to inner and outer layers
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Tunica Externa (aka: Tunica Adventitia)
• Is outer layer• Contains connective tissue sheath• Anchors vessel to adjacent tissues• In arteries:
• Contain collagen• Elastic fibers
• In veins:• Contain elastic fibers• Smooth muscle cells
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Elastic Arteries• Also called conducting arteries, these are the
largest arteries• Tunica media has many elastic fibers and few
muscle cells• Elasticity evens out pulse force • Examples:
• Pulmonary trunk• Aorta• Common carotid arteries• Subclavian arteries• Common iliac arteries
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n = smooth muscle cellTA = tunica adventitia
TI = tunica intimaTM = tunica media
el = elastic fibersend = endothelial cells
Aorta
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Vasa Vasorum
• “Vessels of Vessels”• Small arteries and
veins in the walls of large arteries and veins
• Supply cells of tunica media and tunica externa
Aorta
Vasa Vasorum
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Muscular Arteries
• Also called distribution arteries, are medium-sized (most arteries)
• Tunica media has many muscle cells• Examples:
• External carotid arteries• Brachial arteries• Femoral arteries
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Muscular Arteries
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Arterioles
• The smallest branches of arteries
• Feed into capillaries
• Have little or no tunica externa
• Have thin or incomplete tunica media
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Arteriole
end = endothelial cell nucleus
n = smooth muscle nucleus
rbc = red blood cells
end = endothelial cell nucleusn = smooth muscle nucleusrbc = red blood cells
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Capillaries
• The smallest vessels • Structure: Simple squamous epithelium tube
• Lumen side has a thin basal lamina• No tunica media, No tunica externa
• Location of exchange between blood and interstitial fluid.• Gasses and chemicals diffuse across their walls
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Veins
• Carry blood to the heart• Are larger in diameter than arteries• Have thinner walls • Contain valves
• Folds of tunica intima that prevent blood from flowing backward
• Venules: The smallest veins that carry blood away from the capillaries
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Veins
• Medium-sized veins:• Thin tunica media and few smooth muscle cells• Tunica externa with longitudinal bundles of
elastic fibers
• Large veins:• Have all 3 tunica layers• Thick tunica externa• Thin tunica media
• Example: Inferior and Superior vena cava
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Venous Valve in Medium Vein
ad = adipose tissueTA = tunica adventitiaTM = tunica mediav = valve
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Large Vein
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Arteries Vs. Veins
• Arteries and veins run side-by-side
• Arteries have thicker walls and higher blood pressure
• Collapsed artery has small, round lumen
• Vein has a large, flat lumen
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Vein
Artery
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Ascending Aorta
Aortic Arch
Right Coronary A.
Left Coronary A.
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AorticArch External carotid
Internal Carotid
R. Vertebral
Common Carotid
Brachiocephalic Trunk
R. Axillary a.
R.Subclavian a. L.Subclavian a.
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Brachiocephalic Trunk
Left Common Carotid
L..Subclavian
R.Subclavian
Right Common Carotid
Vertebral
Descending aorta
• Thoracic aorta: above the diaphragm• Includes the intercostal
arteries which run between the ribs
• Abdominal aorta: below the diaphragm
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Axillary Artery
R. Axillary a.
Brachial a.
Radial a. Ulnar a.
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External carotid
Internal Carotid
Vertebral
Circle of Willis
Arteries of the head and neck
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Circle of Willis
R. Vertebral L. Vertebral
Basilar
Internal Carotid (cut)Anterior cerebral
Anterior communicating
Middle cerebral
Posterior cerebral
Posterior communicating
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Middle cerebral
Posterior cerebral
Anterior cerebral
Internal Carotid
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AbdominalAorta Celiac Trunk
Superior Mesenteric
Gonadal
Renal A.
Inferior MesentericCommon Iliac
External IliacInternal Iliac
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Abdominal Aorta
Celiac Trunk
Common HepaticLeft Gastric
Splenic
Inferior Mesenteric
Superior Mesenteric
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Renal a.
Spleen
Splenic a.
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Thigh
External Iliac
Femoral
Deep Femoral
Anterior Posterior
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LowerLeg
Femoral
Popliteal
Anterior tibial
Posterior tibial
Fibular
Dorsalis Pedis
Fibular
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Axillary vein Cephalic vein
Basilic veinBrachial vein
Median Cubital vein Radial vein
Ulnar vein
Basilic vein
Cephalic vein
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Azygos Hemiazygos
Brachiocephalic
Right Left Subclavian vein
Axillary vein
Cephalic vein
Brachial vein
Basilic vein
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Superior Sagittal sinus
Petrosal sinus
Straight sinus
Cavernous sinus
Transverse sinus
Sigmoid sinus
Vertebral Vein
Internal Jugular
External Jugular
Subclavian vein
Brachiocephalic
RightLeft
Superior Vena Cava
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Anterior Tibial
Small Saphenous
Great Saphenous
Popliteal
Small Saphenous
Femoral
Anterior Tibial
Posterior Tibial
Fibular
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Femoral
Deep Femoral
Great Saphenous
Small Saphenous
Small Saphenous
Popliteal
Posterior Tibial
Fibular
Anterior Tibial
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Hepatic veins
Renal veinInferior Vena Cava
Common iliac vein
External iliac vein
Internal iliac vein
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Inferior Vena Cava
Hepatic veins
Hepatic Portal vein
Inferior Mesenteric
Superior Mesenteric
Splenic vein
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Hepatic Portal Circulation
• Veins that flow into the liver before returning to the heart
• Blood from digestive organs and spleen travel to capillaries of the liver.
• The liver processes the blood before sending it through the hepatic vein.
• Blood then travels to the inferior Vena Cava
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Thoracic Veins
• Intercostal veins which drain the intercostal muscles
• Azygos and hemiazygos veins which drain blood from the thoracic region
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Fetal Circulation
• Lungs of fetus are non functional.
• Oxygen and nutrients move from the maternal side of the placenta to the fetal bloodstream and CO2 and wastes moves from the fetal blood to the placenta
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Fetal Circulation
• Blood flow• From the umbilical
cord blood travels through the ductus venosus which shunts the blood to the inferior vena cava
• From the VC blood travels to the right atrium of the heart
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Fetal Circulation
• Blood can then move either to the right ventricle or through a hole in the right atrium called the foramen ovale (bypass route)
• Blood in the right ventricle moves into the pulmonary trunk where another shunt vessel, the ductus arteriosus carries blood to the aortic arch, bypassing the lungs.
• Closing to the foramen ovale leaves the fossa ovalis which we learned about in the heart lab.
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Blood Pressure• Maintenance of bp is important
for the health of the heart and proper functioning of various organs
• The force exerted by blood on the walls of blood vessels.
• A function of the pumping action of the heart and the resistance to flow as blood moves through the blood vessels.
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Blood Pressure
• In large elastic arteries, the BP fluctuates between a max. and min. value
• Systolic pressure is the maximum pressure exerted on bv walls.
• Diastolic pressure is the minimum level
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Blood Pressure
• Measured in units called millimeters of mercury (mmHg)
• If the pressure in a bv is 95mm Hg, it means that the force exerted by the blood will cause a column of mercury to rise 95mm
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Blood Pressure Cuffs
• BP cuffs come in different sizes.
• Be sure to choose the one that is appropriate for the patient
Large Adult
Infant
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Measuring Blood Pressure
• Most cuffs are marked with an O or an arrow. This should be placed near the artery.
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Measuring Blood Pressure
• Place the BP cuff snugly on the patient's arm.
• Check to make sure you have found the artery.
• Line the mark on the cuff up with the artery
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Measuring Blood Pressure
• Stethoscope: Note how the ear pieces slant slightly in one direction.
• Make sure the ear pieces on the stethoscope are point away from you when you put them on.
• Place stethoscope on the artery, tucked slightly under the cuff
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Measuring Blood Pressure
• The cuff should be placed at the level of the heart.
• The patients arm (or leg) should be completely relaxed.• Resting on the
table or in their lab is helpful
WRONG TECHNIQUE
CORRECT TECHNIQUE
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Inflate the Cuff
• A Grasp the bulb so that your thumb can easily access the valve.
• Turn the valve to the right to tighten it and pump up the cuff, turn it to the left to loosen it and deflate the cuff.
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Measuring Blood Pressure
• Pump up the cuff until the sphygmomanometer reads 180 to 200.
• Loosen the valve to let a little of the air out. • Listen for the first heartbeat, that is the top
number (systolic BP)• Continue to listen until there are no more
heartbeats. The last beat you hear is the bottom number (diastolic BP)
• Let the air all the way out and remove the cuff.
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Video Demonstration for Measuring Blood Pressure
• http://www.uams.edu/csc/programs/orientation/bloodPressure/TakingBP1.mov
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Normal Blood Pressure• Reference:
• August 2004, National Heart Lung and Blood Institute – Diseases and Conditions Index
• http://www.nhlbi.nih.gov/health/dci/Diseases/Hbp/HBP_WhatIs.html
• For adults 18 and older who: • Are not on medicine for high blood pressure
• Are not having a short-term serious illness
• Do not have other conditions such as diabetes and kidney disease
• Systolic BP: Less than 120• Diastolic BP: Less than 80
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Pre-Hypertension
• Systolic BP: between 120-139• Diastolic BP: between 80-89
• Examples: 118/82, 128/89, or 130/86
• If your blood pressure is in the pre-hypertension range, it is more likely that you will end up with high blood pressure unless you take action to prevent it.
• Note: When systolic and diastolic blood pressures fall into different categories, the higher category should be used to classify blood pressure level.
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Hypertension
• Stage 1
• Systolic BP: between 140-159
• Diastolic BP: between 90-99
• Stage 2
• Systolic BP: 160 or higher
• Diastolic BP: 100 or higher
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Hypotension
• Hypotension is a subnormal arterial pressure. • There is not enough pressure to adequately perfuse
the tissues. • There is usually a mean arterial pressure (MAP)
below 60 mmHg. • MAP= diastolic + 1/3(systolic-diastolic)
Example: BP= 120/70 MAP= 70 + 1/3(120-70)= 86.6
• People who are chronically hypertensive may feel symptoms of hypotension if their mean arterial pressure drops by 40 mmHg, even if the absolute value is still over 60.
Pulse
• The rhythmic expansion and recoil of the arteries is known as the pulse.
• Can be found in various locations
• Diminish in smaller arteries and are absent in capillaries and veins
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Pulse
Carotid Pulse
Radial Pulse
Brachial Pulse
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Pulse
Dorsalis Pedis Pulse
Posterior Tibial Pulse
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The End