Unit 2 Circulation Flashcards
What is the purpose of the circulatory system
Deliver O2 to systemic tissue
Deliver nutrients to tissues
Remove CO2 and waste from systemic tissues
Transport hormones
What are the functional parts of the circulatory system
Arteries Arterioles Pre-capillary sphincters Capillaries Venules Systemic veins
What functional part of the circulatory system is under the most pressure
Arteries
T/F: Arterial pressure control is dependent of local flow or cardiac output
False
Arterial pressure control is independent of local or cadiac output
What is cardiac out put controlled by
Local tissue flow
What is blood flow in proportion to
Metabolic rate
What is different between the aorta and a normal artery in tissue composition
Aorta has mainly Elastic and fibrous tissue with some smooth mucle
Arteries have mainly Elastic tissue and smooth muscle with some Fibrous tissue
What is the typical tissue composition of a vein
Equal parts elastic, fibrous and smooth mucle
What type of tissue composes capillaries
Only endothelium
What is the name for the volume of blood that passes a certain point per unit time
Flow
What is the driving force of blood flow
Pressure gradient
Where is the greatest resistance to flow found
In the pre-capillary vessels
T/F: At a given F, if the pressure decreases the resistance decreases
False
At a given F, if the pressure decreases the resistance increases
What are the advantages of Parallel circuitry
Independence of local flow control
Minimize total peripheral resistance
O2 rich blood to all tissue
What is the internal friction of a fluid
Viscosity
What happens to velocity with viscosity incrases
Velocity decreases
What happens to apparent viscosity when cells get stuck
Apparent viscosity increases
What fiber pervents RBC’s from getting stuck
Fibrinogen
How do RBC decreases viscosity in small vessesl
They line up
What is the normal range of RBC’s in blood
38-45%
What type of flow is associated with Vessel disease
Turbulent flow
What is Reynold’s number
Probability statement for turbulent flow
What tool is used to determine velocity of flow
Doppler Ultrasonic Flow-meter
What indicated turbulent flow with a dopler ultraconic flow-meter
Broad band
What indicates Laminar flow with a doppler ultrasonic flow-meter
Narrow band
What determines cardiac output
Flick principal
Indicator dilution
What determines vessel flow
Venous occlusions
Doppler ultrasonic flow meter
Vascular flow cuffs
What is fick principal
Blood flow to a tissue organ
What is the ability of a vessel to stretch
Distensibility
What is the ability of a vessel to stretch and hold volume
Compliance
A small change in volume in an artery will result in what
A large change in pressure
A large change in volume in a vein will result in what
A small change in pressure
How much more distensible and compliant are veins than arteries
Distensible = 8x
Compliant 24x
How is blood controlled in the short term
Vasodilation
Vasoconstriction
What can affect arteriols on whether they constrict of dilate
SNS innervation constriction fibers
Local dilators
What causes arterioles to dilate
Vasodilators
CO, NO
decrease O2
What happens to resistance and flow when an arteriol is dilated
Resistance decreases
Flow Increases
What happens to resistance and flow when an arteriol is Constricted
Resistance Increases
Flow Decreases
What are the two theories involved in Vasodilation
Local Vasocilator theory
Oxygen demand theory
What are Local Vasodilators
Adenosine Carbon dioxide Adenosine phosphate Histamine Potassium Hydrogen Prostaglandins
What is the ability to keep blood flow constant in the face of a changing arterial BP
Autoregulation
What causes Arteriogenesis
Stress caused by enhanced blood flow
What is VEGF
Vascular endothelial growth factor (promotes angiogenesis)
What up regulates expression of MCP-1
Stress activated endothelium
What happens when MCP-1 is expressed in blood vessesl
Increase in the number of Monocytes in vessels
Inflammation
Remodeling/development of arteries
What does Hypoxia cause the release of
VEGF
What is important in development of collateral arterial vessels
VEGF
What was VEGF first isolated from
Tumors
Terms used to describe Mesenchymal cell differentiate into endothelial cells
Vasculogenesis
Term used to describe formation of new blood vessles by sprouting from pre existing small vessels
Angiogenesis
Term used to describe repid proliferation of pre-existing collateral vessels with fully developed tunica media
Arteriogenesis
What are the different methods in therapeutic angiogenesis
Protein therapy
Gene therapy
Cellular therapy
What can endothelium release to affect Blood vessels
Release Prostacylin
Release NO
release Endothelin
What does Prostacyclin do
Inhibit platelet aggregation
Relaxes vascular smooth muscle
What does NO do
Vasodilator
What stimulates the release of NO
Shear stress
Acetylcholine binding to epithelium
What does Endothelin do
Vasoconstrictor
What is the functional unit of circulation
Capillary
What are the mechanisms of exchange in microcirculation
Diffusion
Ultrafiltration
Vesicular transport
What is functional flow
Increased oxygen uptake/utilization
What is non functional flow
Non nutritive flow, associated with shunting of blood through a bed
What is Ultrafiltration
Bulk flow through a capillary wall
What favours filtartion
hydrostatic pressure gradient (high to Low)
What favours reabsorption
Colloid osmotic pressure (low to High)
What impacts the amount of Colloid osmotic pressure
The concentration of proteins in plasma
What is the Donnan Effect
Increases the colloid osmotic effect
What causes the Donnan effect
Large plasma proteins carry negative charges that attract ions, increasing osmotic effect
T/F: ALL plasma proteins account for Osmotic pressure
False
Only protein that can’t cross capillary wall can exert osmotic pressure
What is the reflection coefficient
How readily protein can cross capillary wall
What drains excess fluid from interstitial spaces
Lymph capillaries
Are there true lymphatics in the CNS
no
What acts as a functional lymphatic system in the CNS
Arachnoid vili which empties into dural venous sinuses
Where does most of the lymph come from
Liver and intestines
Factors that increase filtration and/or decrease reabsorption will do what to lymph
Increase lymph formation
What is the rate of lymph flow per hour
120ml/hr (2.9L/day)
every day the volume of lymph is ____ to your Entire plasma volume is filtered
Equal
What are the functions of Lymphatics
Return lost protein in vascular system
Drain excess plasma
Carry nutrients
Filter lymphatics
What creates arterial blood pressure
The interaction of blood with vascular wall
When are arteries distended
During systole = blood pumped out = Systolic BP
What is Diastolic BP
The lowest point that BP falls during diastole
What is Hydraulic Filtering
Phenomenon that converts intermittent output by the heart into a steady flow to tissues using distensibility of arterial tree
When is inflow rate to the LV the fastest
Systole
What determines the Diastolc BP
Cycle length (high CL will decrease DBP) Total peripheral resistance (proportional to DBP)
Does DBP chance during exercise
No because cycle length is offset by total peripheral resistance
What is the predominant Norepinephrine receptor in blood vessels
Alpha receptors
What affect does SNS have on blood flow
Decreases flow
SNS stimulation decreases blood flow exept where
Brain
Lungs
Heart
How does the heart prevent decreased blood flow due to SNS activation
Increase of Cardiac activity, which releases vasodilators (adenosine)
How does the Brain and Lungs avoid the affects of SNS stimulation on Vasoconstriction
They arteriols are weakly innervated by SNS
What is the Critical closing pressure
The pressure that causes arterioles to close
What keeps arterioles from closing
Critical luminal pressure
What is Mean circulatory filling pressure
the point when arterial BP is equal to venous BP
What prevents Equilibration of pressure
Closing of arterioles
What happens as Central venous pressure increases
Venous return decreases
What is Central venous pressure
Pressure in Superior and Inferior vena cava when it enters right atrium
Central venous pressure is equal to what (can also be called)
Right atrial pressure
What is the collection of neurons in the medulla and pons
Vasomotor center
What does the pressor center do in the vasomotor center
Increases blood flow
Vasoconstriction
Increase cardiac activity
What does the depressor center do in the vasomotor center
Decrease blood pressure
Vasodilation
Decrease cardiac activity
What does the Sensory area do in the vasomotor center
Mediates baroreceptor reflex (inhibit pressor center = lower BP)
What does the cadrioinhibitory area do in the vasomotor center
Stimulates CN X to inhibit heart activity
What controls blood pressure
Nervous system effects on smooth muscle
Renal-body fluid balance
Where are baroreceptors abundant
Carotid Sinus
Arch of Aorta
What happens when Baroreceptors are streched
Vasodilation
Decreased Cardiac Output
What CN send Baroreceptive info to the CNS
IX X
Where are Low pressure barorecptors located
Atrial walls
Pulmonary arteries
How do the kidneys control BP, why triggers this
Increased ECF will cause AP to rise
Kidney excrete excess ECF
Will increased total peripheral resistance create a long term elevation of BP assuming no change in fluid intake and renal change
No
What type of arteriols drain glomerular capillaries
Efferent
Where does reabsorption take place
Peritubular Capillaries
Where does filtration take place in the kidneys
Afferent Arterioles
What hormones decrease renal blood flow
Norepinephrine
Epinephrine
Angiotensin II
What hormones increase renal blood flow
Prostaglandins
What monitors NaCl in the distal tubule
Macula densa
What is released when the Macula densa senses a decrease in NaCl
Juxtaglomerular cells release Renin
What does Renin do
Catalyses the formation of angoitensin
What is the function of Angiotensin II
Stimulates adrenal cortex to secrete aldosterone
Stimulate Kidney
Stimulate release of ADH
What is the net effect of angiotensin
decrease Na+H2O secretions = increase BP
What does slow breathing do to the Baroreflex
increase arterial baroreflex sensitivity
What does NO do to smooth muscle
Relaxes it
What inactivates NO
Superoxide redical
What does Increasing Antioxidents do to NO
reduced amount of free radicals, allowing NO to last longer lower BP
What humoral substances can cause hypotension and bradycardia
Serotonin
NO
What are the Three shunts in fetal circulation
Ductus arteriosis
Foramen ovale
Ductus Venosus
What shunts allow fetal blood to bypass the lungs
Ductus arteriosis
Foramen ovale
What shunt allows fetal blood to bypass the liver
Ductus Venosus
What changes happen to circulation after birth
Increase blood flow to liver and lungs
Decrease pulmonary vascular resistance
Decreased RVP
Decreased Pulmonary BP
What causes the closure of the Foramen ovale
Reversal in pressure gradient closes flap
What causes the closure of Ductus Arteriosis
Reversal of flow
increased O2 cause muscle constriction
What causes the closure of the ductus Venosus
Not known
