Exam1Lec1Circulatory System Flashcards
What is the leading cause of death in the U.S.
Cardiovascular Disease (CVD)
- heart disease and stroke rises steeply after age _
- 40% of deaths between age _ to _
- 60% at age _
- 65
- 65-85
- 85 and above
What is more likely to happen to people over 65 compared to younger people
suffer a heart attackm stroke, or develop coronary heart disease and high blood pressure leading to heart failure
What is the highest percentage of deaths in cardiovascular disease
Coronary heart disease
Cardiovascular disease are higher in deaths than _
cancer
The circulatory system can also be called?
cardiovascular system
What is the purpose of ciculatory system
a vital organ system that delivers essential substances to all cells for basic functions to occur
Explain the network of the cardiovascular system
- Heart as the centralised pump
- Blood vessels that distribute blood throughtout the body (highway)
- Blood itself is for transportation of different substances (think cars)
How is the circulartory system divided?
Divided into two separate loops
* the shorter pulmonary circuit that exchanges blood between the heart and the lungs for oxygenation (O2/CO2 EXCHANGE)
* The longer systemic circuit the distributes blood throughout all other systems and tissues of the body (DISTRIBUTION)
* BOTH CIRCUITS BEGIN AND END IN THE HEART
What is the link of the pulmonary and systmic circuit?
HEART
What is the cirulatory system functions?
- Transport essential substances to the tissue (oxygen, electrolytes, nutrients, hormones, etc)
- Remove metabolic waste products (CO2, urea, lactate, heat, etc)
- Homeostasis: temp regulation, fluid maintenance, meeting metabolic demands during different physiological states (ex. excerise)
What is the circulatory system characteristics
- The heart pumps about 1,800 gallons of blood through the circulatory system every day ( one min= pump 1.25 gallons)
- In the avg. lifetime (75 years) the heart pumps approx. 50 million gallons of blood through the circulatory system
- Stretched end to end, the arteries, veins, and other vessels of the human circulatory system would measure about 60,000 milies
What pumps into the RA?
- superior vena cava
- inferior vena cava
Explain the blood flow of the heart
- deox blood from SVC, IVC, Coronary sinus into RA
- Though tricuspid valve to right ventricle
- Deox blood from right vent through the pulm valve to the pulm artery
- oxy blood comes back through the pulm vein into left atrium
- LA to LV through mitral valve
Explain the cardiac cycle
two phases: systole and diastole, which follow each other in sequence
* systole: occurs when the heart contracts to pump blood out
* Diastole: occurs when the heart relaxes after contraction and is filled with returning blood
What is the function of aorta and large artery
distribution
fxn of small artery and arterioles
resistance
fxn of capillaries and venule
exchange
Fxn of vena cava and vein
capacitance
Aorta function (table)
pulse dampening and distribution
large arteries function (table)
distribution of arterial blood
small arteries function (table)
distribution and resistance
modulating blood flood
Arterioles function (table)
major regulator
* resistance (pressure and flow regulation)
capillaries function (table)
exchange
has a single layer of endothelial tissue
venules function (table)
exchange, collection and capacitance
veins function (table)
capacitance function (blood vol)
Vena Cava function (table)
collection of venous blood
bring blood back to the heart
Explain the structure of aorta, artery, vein, vena cava, arteriole, capillary with endotheilum, elastic tissue and smooth muscle
- Aorta: Very little endo, lots of elastic, medium of SmM
- Artery: Very little endo, lots elastic tissue, losts of smooth muscle
- Vein: VL endo, little (30%) elastic, SmM
- Vena Cava: VL endo, med elastic, SmM
- Ateriole: VL endo, med elastic, SmM
- Terminal arteriole: VL endo, elastic tissue, lots of SmS
- Capillary: VL endo and no elastic tissue and SmM
What is imp for regulation?
Elastic tissue and smooth muscle
How many liters of blood do we have
6 liters
How much of our body is blood (%)
8%
Explain the whole blood compansion
- plasma is 55% which contains proteins, whater and other solutes (ions, nutrients, waste products, gases, regulatory substances)
- Buffy coat is 1-2% which contains platelets and leukocytes
- Formed elements is 45% which contains erthrocytes
What are the proteins in the blood
- Albumins: Maintain hydrostatic pressure
- Globulins: Immune System
- Fibrinogen: clotting
- Prothrombin: clotting
What are the blood functions (list them)
- respiratiry
- Nutrition
- excretory
- regulatory
- body temp
- protective
- acid-base balance
- coagulation (fibrinogen)
What is the blood function of respiratory
- Transport O2 from lungs to tissues
- Transport CO2 from tissues to lungs
What is the blood function of nutrition
transport “food” from gut to tissue (cells)
What is the blood function of excretory
transport waste from tissues to kideny and skin (urea, uric acid, water)
What is the blood function of regulatory
- water content of tissues
- water exchanged through vessel walls to tissue
What is the blood function of protective
antibodies, antitoxins, white blood cells (WBC)
What is the blood function of acid-base balacne
pH 7.35-7.45, NaHCO3/H2CO3
Explain blood composition in normal blood, anemia and polycythemia
normal blood:
* female: 37-47% hematocrit
* male: 42-52% hematocrit
Anemia: depressed hematocrit %
Polycythemia: elevated hematocrit %
With anemia and polycythemia, explain how visosity works
Anemia: decrease viscosity so we cannot slow down to get nutrients
Poly: increase viscosity so it is harder to transport
What is our collecting system and what does it allow?
Veins and right heart
* Allows control of blood volume to make up for the fact that cappilaries are not always open
Explain the blood distribution of the systemic circulation (pic)
Explain this picture
Explain Blood Pressure (PB)
- Mean BP is similar throughout aorta and large arteries
- Mean BP falls successively from aorta to vena cava
- Aortic BP is pulsatile but pulsatile, but pulsation decreases in smaller vessels
What is pulse pressure
Difference between systemic and diastastic pressure
What is pulse pressure
Difference between systemic and diastastic pressure
What is hemodynamics (fluid mechanics)
- Flow, pressure, and resistance relationships
- Characterize the functional state of the circulatory system
What is Q
volume flow: flow volume (displacement of blood) per unit time (cm3 or ml/sec)= Q/t)
* It is 3 dimensional
How much blood is moving from point a to b
What is V
flow velocity: linear flow distance per unit time (cm/sec) = d/t
* It is one dimensional
Speed
AExplain the interrelationships of velocity (V) , volume flow (Q) and cross-sectional area (A)
- As A decreases, the V increases so inverse relationship
- Q is constant
What is constant throughout the circuit and what is inversely proportional to cross sectional area
- Q is constant throughout the circuit
- V is inversely proportional to cros-sectional area
Apply V=Q/A with capillaries
- Capillaries has increase SA so a decrease velocity
- Allows time for exchange
Is the total cross-section area low or high? Why?
high because there are a lot of capillaries
Velocity and bf decrease
area surface increase
*best for exchange
What is poiseuille’s law:
measuring blood flow
Will Pin or Pout be higher?
Pin because it is closer to the heart so more pressure
What is resistance determined by
tube radius, length, and fluid viscosity
In posiseuille law, Tube radius is to what power and how does that effect cardiac output?
- r4
- Increase radius and it will increase cardiac output
How does tuble length affect velocity?
increase distance, decrease velocity
What is the equation for BP, BF and resistance
Q=△P/R –> R=nL/r4
Resistance is determined by what?
- tube radius
- length
- fluid viscoity
Resistance varies _ with the tube length
proporionally
* BUT blood vessel length remains relative constant, so it is not a significant factor in controlling vasculat resistance
What happens when we decrease tube radius
small decrease in tube radius produces large change in the resistance to flow
Resistance of a tube varies inversely as…
the 4th power of the radius
Decrease radius then increase resistance
What is the main determinant of resistance?
- tube radius
- blood flow is controlled primarily by regulation vessel radius
What has the highest resistance
capillaries (small radius)
The greatest velocity and pressure drop occurs in the arterioles. Why?
Arterioles are the major regular of bf and it drops because of change in radius
What happens to resistance in a series coupled circuit summate
Rtotal=R1+R2+R3
The larger the number of parallel coupled circulits (e.g. capillies) , _
the smaller the total resistance
* This explains why the pressure drop across capillary circuits is small even though the resistance of individual capilary is very large and flow velocity is very slow across capillary too
much more vessels=more radius=more area
what happens to upstream pressures, downstream pressues and BF when an area of vasculature is contracted?
- Upstream pressures are increased
- Destream pressures are decreased
- Blood flow is decreased
Just know this
What are two imp principles regarding the parallel arrangement of blood vessels
- The Rtotal of a network of parrallel vessels is less than the resistance of the vessel having the lowest resistance. Therefore, a parallel arrangment of vessels greatly reduceds resistance to BF
- When there are many parallel vessels, changing the resistance of a small number of these vessels will have a relatively small effect on Rtotal for the segment (ex. 3 vassels open compared to 10 vessels open does not make much of a change on Rtotal
why is the drop in BP and the smaller change in BP imp in capillaries
imp for maintaining flow across capilaries
What is rheology
science dealing with the deformation and flow of mater
What is the difference of laminar vs turbulent flow
Laminar:
* linear
* smooth parabolic profile of velocity
* energy efficient
* Quiet
Turbulent:
* Irregular, turbulent flow
* more energy required
* harmful to the vessel wall
* generate sound
How much of our body is blood (%)
8%
why is the drop in BP and the smaller change in BP imp in capillaries
imp for maintaining flow across capilaries
Blood is homogeneous/ newtonian or not?
NOT because it has different components with different viscoities (internal resistance
What is a newtonian fluid?
fluid in which the viscous stresses arising from its flow, at every point, are linearly correlated to the local strain rate-rate of change of its deformation over time
Explain effects of viscosity on flow
Poiseuille’s law
* Flow varies inversely with fluid viscosity
* Q~1/n
* Blood viscosity is not constant
* In small vessles, blood n decreases, thereby decreasing the resistance to blood flow
Decrease the tube diameter will do what to the viscosity, resistance and flow?
Deacrease viscosity and resistance and increase flow
Arterioles can be controlled with what else besides resistance
viscosity level too
Where do RBC accumulate?
in the center of small vessels and flow at a faster rate
What fluid is near the capillary wall?
Plasma (slow velocity
When does shear occur?
When adjacent layers of blood travels at different velocities. Shear is the highest at the blood vessel wall
Lower the hematocrit ratio, the _ the viscosity and a _ resistance to flow
What does this cause?
Lower and lower
Bc of this, blood can be pumped through the peripheral circulation at a much reduced perfusion pressure, leading to lower blood flow to benefit efficient nutrient delivery and removal of wastes as well as no requirement for a strong vessle wall–> the load on the heart is reduced
why is the drop in BP and the smaller change in BP imp in capillaries
imp for maintaining flow across capilaries
