Blood Flow, Pressure, Capillary exchange Flashcards
What is the average cardiac output at rest?
5 L a minute
Blood is about ____% plasma and
_____% erythrocytes 
60, 45
The Buffy coat is about ____% of whole blood volume.
What does the Buffy coat consist of?
1
Leukocytes and platelets
Total cardiac output can go up but same fraction for kidneys. True or false?
True
What is hematocrit?
The percentage of blood that is erythrocytes
Water is ____% of plasma volume 
90
Proteins account for ____% of plasma by weight
8
What are the three layers of the adventitia?
- tunica intima (simple squamous endothelium)
- tunica media (smooth muscle)
- tunica externa (connective tissue)
Recoil of arteries is described as…
Elastic
When a vessel does not expand much it is considered….
Low compliance
What type of vessels are Elastic, low compliance, pressure reservoirs?
Aorta and large arteries
What type of vessels are resistance vessels, highest resistance in the system, radius regulated to control blood pressure or flow
Arterioles
Exchange vessels, individual capillary has highest resistance but so many in parallel that collective resistance is very low
Capillaries
Volume reservoir, high compliance, have valves
Venules and veins
What type of vessel has high compliance and which one has low compliance?
High compliance- veins
Low compliance- arteries
What determines fluid movement?
Starlings forces
What is Pcap and Pif?
Pcap- hydrostatic pressure in the capillary (blood pressure in the capillary)
Pif- hydrostatic pressure in the interstitial fluid
What is Pi(cap)?
Pi(if)?
Pi(cap)-osmotic (oncotic) pressure in the capillary
Pi(if)-osmotic pressure in the interstitial fluid
Pi(cap) and Pi(if) is mainly due to what?
Soluble proteins
What are the four Starling forces?
P(cap)
P(if)
Pi(cap)
Pi(if)
________________ is positive and fluid moves out.
________________ is negative and fluid moves in
Filtration
Absorption
What is net filtration pressure?
NFP = filtering pressures – absorbing pressures
NFP = (Pcap+Pi(if)) – (Pif+Pi(cap))
Overall there is a slight _________ NFP over capillary length. Excess fluid is picked up by lymphatics and returned.
Positive
What is ohms law?
What is the equation for resistance?
Q (flow) = delta P / Resistance
R ≈ ń•l / r^4
 how do you calculate total peripheral resistance (TPR) for vessels in series and parallel?
Series: R(total) = R1 + R2 + R3 +Rn…
Parallel resistances: 1/R(total) 
TPR =
The sum of the resistance of the aorta, arteries, arterial‘s, capillaries, venules, veins, and vena cava
Because organs receive parallel arterial input, organs or even regions within an organ can regulate blood flow ____________ or independent of other organs or regions
Locally
Blood pressure is regulated at the ____________ level whereas blood flow is regulated at the ______________ level.
Both involve controlling arterial __________.
Systemic
Local or tissue
Resistance
MAP (mean arterial pressure) (average pressure in aorta)
MAP= 
= CO + TPR
= diastolic pressure + 1/3(SP-DP) 
CO=
CO = MAP/ TPR
How is blood flow regulated at the local level: regulating arterial resistance
Vasoconstriction or vasodilation
what affects how blood flow is regulated at the local level by vasoconstriction or vasodilation??
- Metabolic regulations
- Active hyperemia
- reactive hyperemia
- Myogenic mechanism
What is included in metabolic regulation of blood flow at the local level?
Local factors like CO2, H+, ADP, AMP, A
a) active hyperemia (increase in blood flow following an increase in metabolism) * very important for brain blood flow
b) increase in blood flow following a period of decrease in blood flow (occlusive blockage)
What is the myogenic mechanism involved in blood flow regulated at the local level?
an increase in blood pressure…
- increase flow
- increase stretch on arteriole
- increase arterial strength triggers arterial to vasoconstrict —-> increases resistance ——-> restores flow
- Q= delta P/ R
- happens in the kidney to keep flow constant
How do you calculate mean arterial blood pressure (MAP)? 
MAP= DP + 1/3(SP-DP)
Q= delta P/ R »_space;> CO= MAP/TPR
Or MAP = CO • TPR
Or MAP = HR • SV • TPR
TPR is controlled by regulating arterial resistance through….
-norepinephrine, Epinephrine, antidiuretic hormone (ADH) or vasopressin, angiotensin II 
What regulates blood pressure in the short term? 
The arterial baroreflex 
Renal functions include….
- urea excretion (nitrogenous waste)
- regulating pH balance
- regulating osmotic balance
- regulating ion concentrations
- regulating volume (blood pressure)
Where are the renal columns located and what do they include?
Between renal pyramids. Contains blood and nerve supply
The space were urine collects
Renal pelvis
What is the functional unit of the kidney?
Nephron.
About 4 million per kidney
Includes (Bowmans capsule, proximal tubule, loop of Henle, distal tubule) 
All of the nephron and collecting duct is what type of tissue?
Simple epithelium
Describe the unique blood supply
Portal circulation (two capillary beds in series)
- Afferent arteriole
- glomerular capillaries
- efferent arteriole 
- Peritubular capillaries (vasa recta ——> loop) 
Urinary excretion = 
Glomerular filtration – tubular reabsorption + tubular secretion
Filtration
Protein free plasma (into Bowmans capsule) 
Salt, water, glucose, and amino acids are reabsorbed
Mechanism of reabsorption
Isosmotic (no change in osmolarity as it goes through) 
Proximal tubule- 80% of reabsorption, non-regulated, 100% of glucose is reabsorbed most amino acids.
Cellular mechanism is secondary active cotransport with Na+ (water follows solute transport) 
What happens in DT and CD?
- only about 20% reabsorption
- regulated process (hormones: aldosterone and ADH) 
Steroid hormone, secreted from adrenal cortex when
- plasma K+ is high
- angiotensin II is high (results from low volume) 
Aldosterone
Aldosterone increases protein synthesis of….
- Na+/K+ pumps
- Na+ channels
- K+ channels
- Secreted from posterior pituitary
- protein hormone secreted when • volume/BP Low • plasma concentration high 
ADH
Action of ADH is to regulate the water permeability of…..
Collecting duct
