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101 Cards in this Set
- Front
- Back
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Carry blood away from the heart
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Arteries
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Places where things are exchanged
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Capillaries
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Returns blood back to the heart
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Venus system
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Flat cells that join together to form the inner lining of arteries and veins
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Endothelium
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The muscle that is concentric to the blood vessels (wrapped around)
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Smooth Muscle
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Has the largest diameter in a blood vessel
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Aorta
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Distributing vessels
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Muscular arteries
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Has a smallest diameter
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Arterioles
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Arteries that are closest to the heart, thick walls; aorta and its major branches
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Elastic (conducting arteries)
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The brachiocephalic is an__________ artery
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Elastic
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Characteristics of elastic arteries (4)
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1. Have a large lumen to allow low-resistance conduction of blood
2. Contain elastin 3. Withstand and smooth out large blood pressure fluctuations 4. Are pressure reservoirs |
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Are able to absorb pressure and give back
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Pressure reservoirs
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Distal to elastic arteries; deliver blood to body organs
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Muscular arteries
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Two characteristics of muscular (distributing) arteries
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1. Have thich tunica media (muscle in the middle)
2. Active in vasoconstriction (smooth muscle) |
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Smallest arteries that lead to capillary beds
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Arterioles
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Arterioles control flow into capillary beds via ________ and _________
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Vasodilation and constriction
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Smallest blood vessels
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Capillaries
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3 Characteristics of capillaries
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1. Thin tunica interna, one cell thick
2. Allow only 1 RBC to pass at a time 3. Pericytes on the outer surface stabilize their walls |
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What are the 3 structural types of capillaries?
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1. Continuous
2. Fenestrated 3. Sinusoids |
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Where are continuous capilaries found?
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Skin and muscles
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Continous layer of endothelium, prevents RBC's and other cells from moving out
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Continous capillaries
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What capillaries make the blood-brain barrier?
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Continous
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A hole-y, pore-like capillary that runs across the cell membrane, movement occurs here and they have extreme permeability (like swiss cheese)
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Fenestrated Capillaries
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Where are fenestrated capillaries found?
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Small intestines, kidneys, endocrine glands (Wherever aborption and filtration formation occurs)
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Most permeable capillary; makes it possible for all RBC's to move in and out. Leaky with large lumens, makes the blood flow sluggishly, allowing for modifications
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Sinusoid Capillaries
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Close off the flow of blood when needed, made of smooth muscle
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Sphincters
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The middle part of a cappilary bed that runs through to both sides
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Shunt
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Blood flows from _______ to ________ through capillary beds
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Left to right
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Form when capillary beds unite, allow fluids and WBC's to pass from the bloodstream to tissues
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Venules
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Smallest venules, composed of endothelium and a few pericytes
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Postcapillary venules
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Large venlules have one or two layers of ______ _______
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Smooth muscle (tunica Media)
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Formed when venules converge, composed of three tunics, consisting of collagen fibers and elastic networks
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Veins
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Contain 65% of the blood supply on the venus side
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Capacitance vessels
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Gives muscles strength
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Collagen
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Have thin walls because the blood pressure is lower, and have longer diameters
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Veins
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2 Characteristics veins have
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1. Large-diameter lumens (offer little resistance to flow
2. Valves to prevent backflow |
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Specialized, flattened veins with extremely thin walls (Coronary sinus of the heart and dural sinuses of the brain)
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Venus Sinuses
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Actual volume of blood flow through a vessel, an organ, or the entire circulation in a given period (ml per min)
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Blood flow
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F=
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Pressure
F= -------------- = Cardiac output Resistance |
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Force per unit area exerted on the wall of a blood vessel by its contained blood
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Blood pressure
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Created by the force of blood coming from contraction of the ventricles in the cardiac muscle
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Blood pressure
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Opposition to flow, measures the amound of friction blood encounters, generally encountered in the systemic circulation. Sometimes referred to as the peripheral resistance
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Resistance
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The 3 ways resistance is created
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1. Viscosity
2. Length 3. Diameter |
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Thickness or stickiness of blood
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Viscosity
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The longer the vessel, the greater the ____________
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resistance
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Smaller the diameter, the higher the ______________
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resistance
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Major determinants of peripheral resistance
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Small-diameter arterioles
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How is blood vessel diameter regulated?
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Via vasoconstriction and vasodilation
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What are the 2 factors in a vascular disease
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1. Fatty Plaques
2. Atherosclerosis |
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How does flow relate to osmosis and diffusion?
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Flow occurs down a pressure gradient like osmosis and diffusion
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When is the pressure the highest?
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At the exit of the heart
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When is the pressure the lowest?
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Coming back to the heart
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Blood flow is ________ proportional to resistance
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Inversely
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Blood flow is ________ proportional to the difference in blood pressure
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Directly
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If resistance increases, what decreases?
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Blood flow
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Why does blood pressure go up and down?
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Because it is driven by the heart contracting and relaxing.
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TRUE OR FALSE: In the cardiac cycle, more time is spent in diastole than systole
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True
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Because venous BP by itself is too low to get adequate blood return, what two things aid it?
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1. Respiratory "Pump"
2. Muscular "Pump" |
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What does the respiratory "pump" do to aid venous return of blood?
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Pressure changes made during breathing suck blood toward the heart by squeezing local veins.
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What does the muscular "pump" do to aid venous return of blood?
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The contraction of skeletal muscles bring blood towards the heart
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What prevents blackflow during venous return?
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Valves. (Without valves, blood would pool in your feet)
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A sign of your veins not working right is what condition?
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Varicose veins
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What are the three main factors that influence blood pressure?
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1. Cardiac output
2. Peripheral Resistance 3. Blood Volume |
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Blood pressure=
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COxPR=SVxHRxPR
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Another term for artery constriction
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Vasoconstriction
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Another term for vein constriction
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Venoconstriction
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What organ decides when to eliminate or retain water?
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Kidneys
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How does retaining water help the body?
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It helps control blood volume by raising it
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How does water elimination help the body?
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It decreases blood volume
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Short term blood pressure controls are mediated by which two things?
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Nervous system and bloodborne chemicals
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Long term blood pressure controls regulate ____________?
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Blood volume
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What is the one thing you need in order to regulate something?
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A sensor
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Sensor that regulates BP in the carotid artery
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Baroreceptors
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A cluster of sympathetic neurons in the medulla the oversees change in blood vessel diameter
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Vasomotor center
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Vasomotor center+the cardiac centers that integrate blood pressure control by altering cardiac output and blood vessel diameter as BP fluctuates
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Cardiovascular center
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High blood pressure stimulates the cardioinhibitory to do what two things?
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1. Increase vessel diameter
2. Decrease heart rate, cardiac output, peripheral resistance and BP |
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Low blood pressure stimulates the cardioacceleratory center to:
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1. Increase CO and PR
2. Stimulate the vasomotor center to constrict blood vessels |
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Group of cells close to the heart that senses BP change and converts a neural signal.
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Baroreceptors
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What two hormones in the adrenal medulla increase blood pressure?
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Epinephrin and norepinephrin
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What hormone causes intense vasoconstriction in cases of extremely low BP by making the body retain water and increase blood.
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ADH
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The kidneys release angiotensin II which causes what because of high aldestrone levels?
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Vasoconstriction
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What are the four chemicals that INCREASE blood pressure
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1. Epinephrin
2. Norepinephrin 3. ADH 4. Aldesterone |
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If theres more sodium, there is more water which helps bring blood pressure:
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Down
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Which chemical causes BP to drop by inhibiting ADH? It also causes urination.
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Alcohol
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Inflammatory chemicals such as a _________, are vasodilators caused by bacteria. EX: Runny nose
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Histamine
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A brief but potent gas vasodilator that enhances blood flow to the skeletal muscle, penis, clitoris and coronary muscle.
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Nitric Oxide
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Causes blood volume and pressure to decline
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Atrial Natriuretic Peptide
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What are the four chemicals that decrease blood pressure?
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1. Alcohol
2. Histamines 3. Nitric Oxide 4. Atrial Natriuretic Peptide |
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Long term mechanisms control BP by altering ____________
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Blood volume
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High blood pressure stimulates kidneys to eliminate water which does what to BP?
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lowers BP
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Low blood pressure stimulates the kidneys to raise what two things?
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Blood volume and BP
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TRUE OR FALSE: The kidney also has baroreceptors
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True
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Direct renal mechanisms alters what?
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Blood volume
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Indirect renal mechanisms involves what?
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Reinangiotensin mechanisms
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Why would you need to increase BP?
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If you were sweating or hemorhaging
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Low BP in which systolic pressure is blow 100
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Hypotension
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Condition of sustained elevaated arterial pressure of 140/90 or higher
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Hypertension
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Temporary low BP and dizziness when suddenly rising from a sitting or reclining position
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Orthostatic Hypotension
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Hint of poor nutrition and warning sign for addisons disease
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Chronic hypotension
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Important sign of circulatory shock
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Acute hypotension
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Risk factors in primary hypertension (7)
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1. Diet
2. Obesity 3. Age 4. Race 5. Hereditary 6. Stress 7. Smoking |
