Circulatory System Flashcards
What are the three methods of exchange between capillaries and the body cells?
- Diffusion (Concentration)
- Transcytosis (Awkward molecule movement)
- Bulk flow (Pressure gradient)*
S# 89
How does the rate of diffusion compare to the rate of bulk flow.
Diffusion is slower due to its delicate and particular nature.
S#90
_________ is usually present in arterial blood in higher concentrations and ________ is usually found in higher concentrations in the interstitial fluid.
Oxygen , Carbon Dioxide
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What qualities of capillaries found in the brain block many substances from passing through the BBB?
- Very tight junctions
- Endothelial cells very closely packed together
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Which parts of the brain lack BBB and allow capillary exchange to occur more freely?
- Hypothalamus
- Pineal gland
- Pituitary gland
S#91
Method of movement used to transport large lipid insoluble molecules across capillary walls.
Transcytosis
- Insulin
- Antibodies
S#93
Passive process by which large amount of fluid moves into and out of capillaries rapidly
Bulk Flow
S#95
What are the two pressure driven mechanisms of Bulk Flow
- Filtration
- Reabsorption
S#95
Pressure driven movement of fluid and solutes from blood within the capillaries into interstitial fluid
Filtration
- Blood hydrostatic pressure (BHP)
- Interstitial fluid osmotic pressure (IFOP)
S#96
Pressure driven movement of fluids and solutes from the interstitial fluid/space into blood
Reabsorption
Blood colloid osmotic pressure (BCOP)
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Balance of the filtration and reabsorption pressures
Net filtration Pressure (NFP)
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What does the NFP measure?
Determines whether volumes of blood and interstitial fluid remain steady or change on BOTH the arterial and venous end of the capillary
S#97
Volume of fluid and solutes reabsorbed is near the volume of fluid and solutes filtered.
Frank Starling’s law of the capillaries
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NFP Formula
S98
(BHP + IFOP) Promotes filt. minus (BCOP + IFHP) Promotes reab.
What value will a NFP that promotes filtration have?
S98
Positive
What does a negative NFP promote?
S98
Reabsorption
Pressure blood exerts against blood vessel walls.
“pushes” fluid/certain solutes out of capillaries into interstitial space
S99
Blood Hydrostatic Pressure.
Usually 35mmHg at arterial end
Usually 16mmHg at venous end
Where is fluid pulled due to IFOP?
Out of capillaries into interstitial fluid.
Normally small pressure, 1mmHg
small amounts of protein in interstitial fluid
S#99
“Pull” fluid/certain solutes from interstitial spaces into capillaries
S100
Blood Colloid Osmotic Pressure
Usually 26mmHg
“Pushes” fluid/certain solutes out of interstitial spaces back into capillaries
Interstitial Fluid Hydrostatic Pressure
S#100
What is indicative of a IFHP > 0 mmHg?
Pathological process
S#100
Fluid moves out of capillary and into interstitial spaces
Arterial end
Filtration
S#101
Fluid moves from interstitial fluid into capillaries
Venous end
Reabsorption
S#101
Concerning bulk flow, what percentage of fluids/solutes filtered out of the capillaries are reabsorbed?
On average ~ 85%
S#103
What percentage of fluids/solutes escape from the blood and enter the lymphatic capillaries?
~ 15% (That eventually returns to the blood.)
S#103
Plays large part in returning nutrients from gastrointestinal tract back into circulation.
The lymphatic system
S#104
What do superficial portions of the skin, the CNS,
endomysium, and bones have in common?
They all lack nearby lymphatic drainage.
S# 104
Where do the lower portion of the body, left side of the head/neck, left arm and left side of the thorax all drain into?
The large thoracic lymphatic duct.
S# 105
What venous junction does lymph from the large thoracic duct empty into?
the junction of the left internal jugular vein and left subclavian vein
S#105
A mathematical equation describing blood flow and its relationship to known parameters.
Poiseuille’s equation.
S#113
Which five variables influence blood flow and pressure?
- Cardiac Output
- Compliance
- Volume of blood
- Viscosity of blood
- Blood Vessel length and diameter
2(C) 3(V)
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Measurement of blood flow from the heart through the ventricles.
Cardiac Output
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What is the formula for cardiac output?
CO=Stroke Volume (SV) x Heart Rate (HR)
Usually measured in milliliters per minute.
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The ability of any compartment to expand to accommodate increased content
Compliance
S#116
Of the two types of circulation which can expand to hold more volume, making them more compliant? (Arteries or veins)
Veins
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What results from the reduction of compliance due to the hardening of arteries?
- Increase resistance to blood flow
- Increase Blood pressure
- Decrease flow rate
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What is directly proportionate to pressure and flow?
Blood volume
S#117
What effect on blood volume are expected with the following conditions and why?
heart failure, liver cirrhosis, kidney disease
Hypervolemia ; due to retention of salt and water.
S#117
Define Blood viscosity.
Thickness of fluid
S#118
What are the 4 main components of blood?
RBC’s (Solid)
WBC’s (Solid)
Platelets (Solid)
Plasma (Fluid)
S#118
Blood viscosity is directly proportional to ___________ and inversely proportional to ___________.
Resistance / Flow
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Vessel length is directly proportional to _____________
Resistance ; Increased vessel length = increased resistance and therefore decreased flow rate
S#119
What must remain constant in order for diameter to be inversely proportional to resistance?
Volume
S#120
If an artery or arteriole constricts to 1/2 its original radius, how much will resistance increase?
16x’s
S# 120
What can flow (Q) be related to?
- Cross-sectional area (A)
- Linear velocity of flow (V)
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Where is velocity the slowest?
Capillaries ; have the greatest aggregate cross-sectional area but the smallest diameter
S# 122
Which type of vessel has the greatest surface area if laid out and dissected length-wise?
123
Capillaries
Arrange the following vessels from greatest to least cross sectional area.
Aorta, vena Cava, and capillaries.
- Capillaries (4500-6000cm2)
- Vena Cava (14cm2)
- Aorta (3-5cm2)
Velocity (#3,2,1)
S#124
Where is greatest velocity and least greatest velocity of flow found in a vessel?
- Greatest velocity of flow is in the center of the vessel
- Lowest velocity is near the vascular wall
S#126
Caused by shear stress produced as blood flows past stationary wall
Streamlining
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What are Whorls, Vortices, Eddies all characteristics of?
Turbulent blood flow.
S#126