Phys 3 Exam 2 Flashcards
The main function(s) of the system circulation
To deliver adequate oxygen and nutrients to the systemic tissues.
To remove carbon dioxide and other wast products from systemic tissues.
The systemic circulation serves as a ______ for transport of hormones and other substances and allows these substances to potential act at a distant site from their production.
conduit
Designed to carry blood under high pressure out to the tissue beds.
systemic arteries
Act as control valves to regulate local flow
Arterioles and pre-capillary sphincters
Exchange between tissue (cells) and blood and are one cell layer thick.
Capillaries
Collect blood from capillaries
Venules
Return blood to heart/dynamic storage
Systemic veins
Basic Theory of Circulatory Function: Blood flow is proportional to ___________.
metabolic demand
Basic Theory of Circulatory Function: Cardiac output is controlled by ____________.
local tissue flow
Basic Theory of Circulatory Function: Arterial pressure control is independent of ___________.
local flow or cardiac output.
Why is arterial pressure kept relatively constant?
It allows us to regulate flow.
Cardiac output is equal to __________.
Venous return
Components of Vessels
Endothelium
Elastic tissue
Smooth muscle
Fibrous tissue
One layer of this exists in all vessels
Endothelium
Relative composition of the aorta
Elastic Tissue > Fibrous Tissue > Smooth Muscle
Relative composition of a typical artery
Smooth Muscle > Elastic Tissue > Fibrous Tissue
Relative composition of a vein
Elastic tissue = Smooth Muscle = Fibrous Tissue
Relative composition of a capillary
Only Endothelium
Ohm’s Law
V = IR V= voltage I = current flow R = resistance
3 parts of hemodynamics
- Flow (F)
- Pressure Gradient (Change in Pressure)
- Resistance (R)
The volume of blood that passes a certain point per until time (i.e. ml/min)
Flow (F)
When the cross sectional area is increased what happens to the velocity?
decreases
Velocity * Cross Sectional Area = ___________
Flow
Change in Pressure/Resistance = ___________
Flow
Flow is ______ proportional to change in pressure and _______ proportional to resistance (R)
directly, inversely
At a given flow, the velocity is ________ proportional to the tool cross sectional area.
inversely
Driving force of blood
pressure gradient
difference in pressure between two points
pressure gradient
pressure gradient is ____ to flow (F)
proportional
At a given flow the greater the drop in pressure in a segment of compartment the ________ the resistance to flow.
greater
The greatest resistance to flow occurs in the _________.
pre-capillary resistance vessels
Pre-capillary resistance vessels
arterioles, met-arterioles, pre-capillary sphincters
The systemic circulation is predominantly _______ circuit.
parallel
R Total = R1 + R2 + R3……
series circuit
R Total < smallest individual R
parallel circuit
Advantages of Parallel Circuitry
- Independence of local flow control (increase/decrease flow to tissues independently)
- Minimizes toal peripheral resistance (TPR)
- Oxygen rich blood supply to every tissue
Internal friction of a fluid associated with the intermolecular attraction.
Viscosity
Blood is a suspension with of viscosity of ____.
3, most of viscosity due to red blood cells.
Plasma has a viscosity of _____.
1.5
Water is the standard with a viscosity of ____.
1
As velocity decreases viscosity _____ due to elements in blood sticking together.
increases
Cells can get stuck at constriction points momentarily which ____ apparent viscosity.
increases
Fibrinogen _____ flexibility of RBC’s
increases
In small vessels cells line up which decreases viscosity and offsets the above to some degree. This is known as the __________ effect.
Fahaeus-Lindquist
% of packed cell volume
Hematocrit
Normal range of hematocrit is
38-45%
Streamline, Silent, Most Efficient, Normal
Laminar Flow
Cross mixing, vibrational noise, least efficient, frequently associated with vessel disease (bruit)
Turbulent Flow
Probability statement for turbulent flow. The greater the R#, the greater the probability for turbulence
Reynolds Number
If R# < 2000 flow is USUALLY ______.
laminar
If R# > 3000 flow is USUALLY ______.
turbulent
When using a doppler ultrasonic flow meter you see a broad band this is associated with which type of flow?
turbulent flow
When using a doppler ultrasonic flow meter you see a narrow band this is associated with which type of flow?
laminar flow
Doppler Ultrasonic Flow-meter
Ultrasound to determine velocity of flow
The gold standard for determining cardiac output
indicator dilution
The Fick Principal is used to determine
cardiac output
Venous occlusion plesthymography, doppler ultrasonic flowmeter, and vascular flow cuffs are used to determine.
vessel flow
What are the 3 ports when talking about the Fick Principal?
Input blood concentration of substance x
Output blood concentration of substance x
Addition/removal of substance x from tissue
Based on conservation of mass
indicator dilution
The ability of a vessel to stretch
Dispensability
The ability of a vessel to stretch and hold volume
Compliance
Change in Volume/Change Pressure * Initial Volume
Dispensability
As pressure increases the vessel is ____ distensible.
less
Change in Volume/Change in Pressure
Compliance
Distensibility * Initial Volume
Compliance
In systemic arteries a small change in volume is associated with a ________ change in pressure
large
In systemic veins a large change in volume is associated with a _______ change in pressure.
small
Veins are about _____x more distensible than systemic arteries
8
Veins are ____x more compliant that systemic arteries
24
Long term control of blood flow involves changes in ________.
tissue vascularity
Short term control of blood flow invokes
vasodilatation and vasoconstriction of pre-capillary resistance vessels
Arterioles are richly innervated by SNS _______ fibers and have ______ receptors
vasoconstrictor, alpha
Involves vasoconstriction/vasodilatation of pre-capillary resistance vessels
short term local control of flow
Active tissue release local vasodilator (metabolites) which relax vascular smooth muscle
local vasodilator theory
As tissue uses up oxygen, vascular smooth muscle can’t maintain constriction
oxygen demand theory
Adenosine, carbon dioxide, adenosine phosphate compounds, histamine, potassium ions, hydrogen ions, PGE & PGI series prostaglandins are all examples of _________.
local vasodilators
The ability to keep blood flow constant in the face of a changing arterial blood pressure
auto regulation
T/F Most tissue show some degree of auto regulation
true
INt he kidney both renal flow and glomerular filtration rate (GFR) are ___________.
auto regulated
Shear stress caused by enhanced blood flow velocity associated with partial occlusion
arteriogenesis
Small peptides-stimulate growth of new vessels
Angiogenic factors
Stress activated endothelium up-regulates expression of _________.
Monocyte chemoattractant protein-1 (MCP-1)
VEGF
Vascular endothelial growth factor
Hypoxia cause the release of
VEGF
Production of VEGF is partly mediated by ________ in response to hypoxia
adenosine
Stimulates capillary proliferation and may also be invalid in development of collateral arterial vessels
VEGF
Neuropeptide Y from SNS is
angiogenic
Hyperactive SNS may compromise collateral blood flow by
vasoconstriction
Mesenchymal cell differentiate into endothelial cells
vasculogenesis
formation of new blood vessels by sprouting from pre existing small vessels (usually lacking developed tunica media)
angiogenesis
rapid proliferation of pre existing collateral vessels with fully developed tunica media
arteriogenesis
Mechanical Angiogenesis triggers
Hemodynamic, Shear stress
Chemical Angiogenesis triggers
Hypoxia, NO
Molecular angiogenesis triggers
inflammation, decreased glucose –> increased vascular endothelial growth factor, angiogenic growth factors
Angiogenic growth factors
fibroblast growth factor, VEGF, Placenta growth factor, angiopoietin
