Exam 2 Flashcards
What circulatory structures acts as a control valve to regulate flow?
Arterioles and pre capillary sphincters
T/F: Pulmonary blood flow=venous return=cardiac output
True
What 4 histologic materials are vessels made of?
Endothelium
Elastic tissue
Smooth muscle
Fibrous tissue
What tissue is most prominant in the aorta?
Elastic, (then fibrous, then smooth muscle)
In a typical artery, what tissue type dominates?
Smooth muscle (then elastic, then fibrous)
What structure is only made of endothelium?
Capillaries
The volume of blood that passes a certain point per unit time is what?
Flow rate
At a given flow, the velocity is ________ to the cross-sectional area of a vessel.
Inversely proportional
What is the only organ to have flow in excess to the cardiac output (CO)?
Lungs
Flow is ___ to change in pressure but ____ to resistance.
Proportional to chg P, but inversely proportional to resistance
What is considered the driving force of blood movement.?
Pressure gradient
Systemic circulation is predominantly a ____circuit? Series, parallel, or series¶llel?
Parallel
3 advantages of a parallel circuitry?
- Incr/decr flow to tissues independently
- Lowers total peripheral resistance (TPR)
- Oxygen rich blood to every tissue
Slower blood flow is associated with an increase or decrease in blood viscosity?
Increase
What increases the flexibility of RBC’s?
Fibrinogen
What is the normal range for hematocrit?
38%-45%
What disorder is associated with less than 38% hematocrit?
Anemia
T/F: Both EPO and exercise stimulate RBC production
True
What part of a vessel has the fastest velocity?
The center of the vessel
What is the normal, silent, and efficient type of flow called?
Laminar flow
How does Turbulent flow differ from Laminar flow?
Turbulent is less efficient, creates vibrational noise, and is associated with vessel dz
What location in the circulatory system is most likely to have turbulent flow?
Aorta
If the Reynold’s # (R#) is less than 2000 flow is ____, and if the R# is greater than 3000 flow is ___.
3000=turbulent
What is the only factor that is inversely proportional to Reynold’s #: velocity, viscosity, diameter, density
Viscosity, (all others are proportional)
T/F: Broad band Doppler reading is associated with laminar flow
False: Broad=turbulent…Narrow=laminar
T/F: Fick principal is associated with determination of cardiac output
True
What is distensibility?
the ability of a vessel to stretch
How is compliance different from distensibility?
Compliance is the ability of a vessel to stretch AND hold volume
Which is more compliant: arteries or veins?
Veins…arteries can’t store much blood
T/F: In systemic arteries, a small change in volume is associated with a small change in pressure?
False: small change in volume–>large change in pressure
In systemic veins, a large change in volume is associated with a ___ change in pressure
small
Veins are 8 times more ____ and 24 times more ____ than systemic arteries.
Distensible, compliant
T/F: The more wall tone present, the more distensible a vessel will be
False, incr wall tone–> decr in compliance and distensibility
What is the determining factor of local blood flow to tissues?
Metabolic demand by tissues (more active tissues, more blood flow)
T/F: A method of short term control of blood flow includes vasodilation/vasoconstriction of arterioles
True
What is the long-term control of blood flow solution?
Change tissue vascularity via angiogenesis
Two factors important in long term control of blood flow?
- Vascular Endothelial Growth Factor
2. Angiogenin
T/F: SNS vasoconstrictors have alpha receptors
True
What is the local vasodilator theory?
Active tissues release local vasodilators that relax vascular smooth muscle
What is the older theory regarding local vasodilation?
Oxygen Demand Theory; tissues use up oxygen and can’t maintain vasoconstriction and defaults to vasodilation
What is the flaw with the Oxygen Demand Theory?
Tissues on the upstream end would theoretically never vasodilate b/c they have a surplus of oxygen
T/F: Adenosine, NO, CO2, and Histamine are all examples of local vasodilators
True
What is the important concept regarding angiogenesis and cancer growth?
If we could block tumors block supply by inhibiting angiogenesis, we could ideally choke off the tumor
What is the up-regulation of monocyte-chemoattractant protein-1 (MCP-1) associated with?
Following stress to endothelium–>attraction of monocytes–>inflammation and eventual angiogenesis
Hypoxia stimulates the release of ______factor, regarding potential angiogenesis.
Vascular Endothelial Growth Factor (VEGF)
T/F: Neuropeptide Y from parasympathetic nervous system is angiogenic
False: NPY is from SNS to enable angiogenesis
What is vasculogenesis?
development of NEW blood vessels from mesenchyme cells
What is the big difference between angiogenesis and arteriogenesis?
Both sprout from pre-existing vessels but arteriogenesis have fully developed tunica media whereas angiogenesis usually lacks the developed tunica media
3 methods of therapeutic angiogenesis?
Protein Therapy (GF proteins) Gene Therapy (manipulate gene expression) Cellular Therapy (cells that produce angiogenic factors introduced to ischemic tissue)
T/F: Prostacyclin promotes platelet aggreggation
False: promotes vasodilation and inhibits platelet aggreggation
In response to shear stress, healthy endothelium releases ___, which acts as a vasodilator.
Nitric Oxide (NO)
What is the vasoconstrictor released by damaged endothelium?
Endothelin
What is the functional unit of the circulatory system?
Capillary
What is the intermittent contraction of metarterioles and pre capillary sphincters called?
Vasomotion
Functional flow is associated with an increased ____?
oxygen uptake
T/F: Non-nutritive flow increases are associated with shunting of blood thru a bed
True
Starling forces consist are responsible for ultrafiltration by the means of which two pressure?
Hydrostatic P and Colloid Osmotic P
What type of molecules do capillaries utilize passive diffusion for?
Gases that meet permeability and concentration gradient standards use passive diffusion
Hydrostatic P gradient favors ___, whiles colloid osmotic P favors ___.
Hydrostatic-filtration (pushes fluid out)
Colloid Osmotic-reabsorption (draw fluid back in)
T/F: Generally filtration rate=reabsorption rate
False: Filtration>Reabsorption
If filtration is more than reabsorption, why do we not end up with permanent edema?
Lymphatics manage the excess fluid pushed out of a vessel
What are the 3 main plasma proteins that assist with colloid osmotic pressure gradient?
Albumin (75%)
Globulins (25%)
Fibrinogen (<1%)
What is the Donnan Effect?
Increases colloid osmotic effect b/c large MW, negatively-charged plasma proteins attracting positive ions
How much does the Donnan Effect increase the osmotic effect?
Increases by about 50%
Where in the body would you find tight junctions on capillary wall? Discontinuous capillary walls? Fenestrated capillary walls?
Tight Junction=blood brain barrier
Discontinuous=liver
Fenestrations=glomerular capillaries of kidneys
T/F: Only proteins that cannot cross the capillary wall can exert osmotic pressure
True
What would a reflection coefficient of 0 mean?
Proteins can readily cross capillary=no colloid effect
Where in the body would the reflection coefficient be equal to 1?
Brain; all proteins reflected in capillary=full colloid effect
T/F: There are no true lymphatics found in the superficial portions of skin
True: also none in CNS, bone, or endomysium of muscle
What portion of the body does the right lymph duct drain? What drains the rest?
Right side of head, neck, and chest, and right arm. All else is thoracic duct’s responsibility
What acts as the functional lymphatic system in CNS?
Perivascular spaces accumulate filtrate and send to dural venous sinuses via the arachnoid villi
Where is 2/3 of all lymph derived from?
Liver and intestines
T/F: Any factor that decreases filtration and increases reabsorption will increase lymph formation
False: INCR filtration and/or DECR reabsorption–>incr lymph formation
What are lymph nodes?
Meshwork of sinuses lined with tissue macrophages serving as a defense function
What is arterial blood pressure equal to?
volume of blood interacting with the wall
or (Art BP=CO-TPR)
T/F: Greater that half of Total Peripheral Resistance (TPR) is at the level of the capillaries
False: …at the level of the systemic arterioles
T/F: During systole, the left ventricular output is greater than peripheral runoff
True
T/F: Falling systolic pressure during exercise is an ominous sign
True
The recoil of arteries during ____ can act as a pump.
Diastole
What is the phenomenon that converts an intermittent output by the heart to a steady delivery to the tissue?
Hydraulic filtering, (stretch of arteries during systole followed by the recoil during diastole)
T/F: As age increases, hydraulic filtering decreases
True–> increased work load on the heart
What is the maximum pressure in the systemic arteries?
Systolic Blood Pressure
What 2 factors does diastolic BP depend on?
Cycle Length (CL) and Total Peripheral Resistance (TPR)
Cycle length is_____ to diastolic BP, and TPR is ____to diastolic BP.
CL inversely proportional to DBP
TPR is proportional to DBP
During exercise, DBP may not change much due to ___CL being offset by ___ in TPR.
Decreased CL, Decreased TPR
If exercising and DBP increases, what factor is dominant?
And if DBP decreases?
Cycle Length dominant if DBP incr
TPR dominant if DBP decr
Most post-ganglionic SNS terminals release what?
Norepinephrine
What’s the primary receptor type for vascular smooth muscle: alpha, beta, gamma, delta?
Alpha
T/F: Constriction of arterioles helps reduce blood flow and raise arteriole blood pressure
True
What does constriction of veins do?
Mobilizes blood volume and increases venous return
SNS stimulation causes widespread vasoconstriction to everywhere except?
Brain, Lungs, Heart
Why does the heart not vasoconstrict upon SNS stimulation?
overridden by local vasodilators such as adenosine
T/F: Brain and lungs receive only PNS stimulation
False: still weakly innervated by SNS
What is the pressure below which flow ceases due to closure of arterioles: mean arterial BP, mean circulatory filling pressure, critical closing pressure?
Critical closing pressure
T/F: An increase in wall tone will increase critical closing pressure
True
If cardiac output stopped, arterial pressure will __, and venous pressure will __.
ABP will fall, VBP will rise
T/F: if MCFP=Central Venous Pressure(CVP), then venous return goes to 0
True
If central venous pressure increases, what happens to cardiac output?
Cardiac output increases
A vascular function curve is comparing what two features?
Venous return to central venous pressure (inversely-proportional relationship)
A cardiac function curve is comparing what two features?
Cardiac output to central venous pressure (proportional relationship)
Where would you measure central venous pressure?
Right atrium
T/F: The pressor center and the depressor center increase and decrease your blood pressure respectively.
True
What does the sensory area of your vasomotor center mediate?
mediates baroreceptor reflex
T/F: The cardioinhibitory area of the vasomotor center stimulates the phrenic nerve exclusively
False: stimulates Vagus Nerve (CNX)
T/F: Increased baroreceptor input, increases SNS output
False: decreases SNS output
Where is the pressor center and what does it cause?
anterolateral portion of upper medulla;
vasoconstriction and incr heart activity
Where is the depressor center?
anterolateral portion of LOWER medulla
Where is the sensory area of the vasomotor center?
Nucleus tractus solitaries of posterolateral portions of pons and medulla
What 2 cranial nerves does the sensory area of the vasomotor center receive input from? Outputs to?
CN IX and CN X=input
pressor and depressor center=output
Where is the cardioinhibitory area?
medially next to dorsal motor nucleus of vagus
What’s considered the long term regulator of blood pressure?
Kidney’s system of renal-body fluid balance
Where are baroreceptors especially abundant?
Carotid sinus
Arch of aorta
Where do you find low pressure baroreceptors?
Atrial wall
Pulmonary arteries
T/F: You could increase urine output as a way of lowering blood pressure
True
What does the Bainbridge reflex do?
Increases heart rate
T/F: Atrial Natriuretic Peptide (ANP) is a dirurectic, natriuretic, and a vasodilator
True
Which arterioles of the kidney supply the glomerular capillaries: afferent or efferent?
Afferent supply GC, efferent drain GC
What is the structure capable of concentrating urine?
Juxtamedullary nephrons
Most autoregulation of the kidney occurs at the ___arterioles.
afferent arterioles
T/F: Constriction of efferent arterioles will decrease both renal filtration and glomerular filtration
False: …will decrease renal F but will INCREASE glomerular F b/c of back pressure
Normally, do we want an acute or a chronic renal output curve?
Chronic
Who is more likely to have an acute renal output curve?
People w/ impaired kidney function
Most elements of the chronic renal output curve work to lower blood pressure except ___ which promotes fluid and sodium loss to raise blood pressure.
Atrial Natriuretic Peptide (ANP)
What 3 ‘hormones’ decrease renal blood flow via vasoconstriction?
Norepinephrine
Epinephrine
Angiotensin II
Prostaglandins do what to renal blood flow?
Increase RBF by vasodilating smooth muscle
Decreased NaCl in macula densa of distal tubule, causes what 2 thing?
- stim renin release from juxtaglomerular cells (constrict efferent arterioles)
- dilation of afferent arterioles
The combination of constricting efferent arterioles yet dilating afferent arterioles promotes what?
Filtration of kidney
What is the major source of renin?
Smooth muscle cells in afferent arteriole
T/F: Thyroid hormone secretion will decrease renin
False: Stimulates renin
Describe Renin-Angiotensin-Aldosterone System?
Angiotensinogen from liver forms Angiotensin I (via renin).
Angiotensin I–> Angiotensin II (via angiotensin converting enzyme)
What does angiotensin II stimulate?
- release of aldosterone from adrenal cortex
- release of ADH/vasopressin from post-pituitary
- stim kidney
(overall effect of increasing BP)
T/F: Angiotensin I stimulates thirst/drinking behavior at the level of they hypothalamus
False: Angiotensin II
T/F: if you tie off 1 renal artery, you will develop systemic hypertension but don’t develop uremia
True
T/F: if you tie off one renal artery and remove kidney, don’t develop hypertension or uremia
True
What would cause one to develop both hypertension and uremia?
Tie off and removal of both kidneys
What is the name for hypertension developed due to the tying off of a renal artery?
Goldblatt hypertensive model
Does slow breathing play a role in BP control?
Yes, slow breathing–> decrease in both syst BP and diast BP
How do antioxidants play a role in lowering BP?
Antioxidants bind to superoxide radical preventing it from inactivating nitric oxide, (a vasodilator)
____ and ____ are humoral substances that promote bradycardia and hypotension by inhibiting SNS activity.
Serotonin and Nitric Oxide
What is the site of gas exchange in a fetus?
Placenta
Blood returns to the fetus from the placenta via what?
Umbilical veins
What are the 2 means of bypassing the lungs in a fetus?
Ductus Arteriosus and Foramen Ovale
The ductus arteriosus shunts blood from the ___ ___ to the ____.
Pulmonary trunk–>DA–>aorta
T/F: The ductus venosus shunts blood from the right atrium to the left atrium
False, that would be the foramen ovale
What is the ductus venosus?
Shunts blood past liver;
Umbilical vein/portal vein–>DV–> Inferior Vena Cava
T/F: Umbilical veins operate at 80% oxygen saturation, a much lower value than normal
True
What causes the closure of the foramen ovale?
reversal of pressure gradient between RA and LA
T/F: Closure of the ductus arteriosus is due to a reversal of flow from aorta to inferior vena cava
False: ..flow from aorta to PULMONARY ARTERY
A left to right shunt, flowing from aorta to pulmonary trunk, creating a machinery murmur is called what?
Patent Ductus Arteriosus
What is a ventricular septal defect?
membranous septum separating ventricles is not fully formed
What is a transposition of great vessels?
RV–>systemic
LV–>lung
How could a transposition of great vessels be fixed?
Create a ventricular septal defect, so blood could flow freely between ventricles
4 factors of Tetrology of Fallot?
- RV hypertrophy
- Large Ventricular Septal Defect
- RV outflow obstruction
- Overriding aorta
2 symptoms seen in children with Tetrology of Fallot?
- Cyanosis
2. Dyspnea relieved by squatting
___ is the greatest stress you can put on the CV system.
Exercise
T/F: During exercise, blood flow is shifted to active skeletal muscle
True
Why would SNS stimulation vasoconstrict veins?
Incr MCFP and incr venous return
T/F: TPR increases due to vasodilation in active muscle during exercise
False: vasodilation causes TPR decrease
T/F: Exercise–> Incr O2 uptake–>decreased VO2–> incr AVO2 difference
True
Does SNS affect both SV and HR or only one of the above?
SNS increases both
What is Pulse Pressure?
Pulse Pressure= Sys BP- Diast BP
What is the “venous pump” utilized during exercise?
Skeletal muscle of lower extremities contract pushing blood upstream and can’t flow back down with gravity b/c of presence of valves
How does active muscle escape system-wide vasoconstriction of SNS?
Local vasodilators like adenosine, CO2, K+, Histamine, and Lactic acid
Conditioning your body results in increased ____ ____.
Stroke volume
Respiration remains high post-exercise; what is this extra O2 used for?
Restore metabolite levels, and metabolize lactate generated by glycolysis
What system is utilized during the first 10 seconds of exercise?
Phosphocreatine-Creatine System
