Arterial, veinous and lymphatic systems

Question 1

What is vascular compliance?

Answer 1

=Increase in volume/ increase in pressure
= distensibility X original volume
Total quantity that can be stored in a given portion

Question 2

Relation between capacitance, volume and pressure

Answer 2

Capacitance directly proportional to volume

Capacitance inversely proportional to pressure and to elastance

Question 3

Compliance between veins and arteries

Answer 3

Greater for veins than arteries

Capacitance of arteries decrease with age

Question 4

What is elastance?

Answer 4

Measure of the tendency of a hollow viscus to recoil towards original dimensions after removal of a distending or collapsing force

Question 5

Major factors that affect pulse pressure

Answer 5

Pulse pressure= stroke volume/arterial compliance
Stroke volume output of the heart
Compliance

Question 6

Conditions causing abnormal contours

Answer 6

Aortic valve stenosis
Atherosclerosis
Patent ductus arteriosis
Aortic regurgitation

Question 7

Characteristics of Aortic valve stenosis

Answer 7

Diameter of aortic valve reduced
Aortic pressure reduced
Less blood flow

Question 8

Characteristics of patent ductus arteriosis

Answer 8

Half or more of the cardiac output flow back into pulmonary artery and lung
Diastole pressure falls very low before next heartbeat

Question 9

Characteristics of aortic regurgitation

Answer 9

Aortic valve absent or not completely close

Aortic pressure might fall to 0 between heartbeats

Question 10

What is damping of the pressure?

Answer 10

Pressure lessen as blood moves through arteries due to compliance and resistance

Question 11

What is mean arterial pressure ?

Answer 11

Average arterial pressure with respect to time
Closer to diastolic pressure
=diastolic pressure + 1/3 pulse pressure

Question 12

What is central venous pressure

Answer 12

Pressure in the right atrium
Regulated by:
Ability of the heart to pump blood out of the right atrium/ventricle
Tendency of blood to flow into the right atrium

Question 13

Factors that increase veinous return(increase right atrial pressure)

Answer 13

Increased blood volume
Increased peripheral venous pressure due to increased large vessel tone
Dilation of arterioles

Question 14

Microcirculation and capillary system

Answer 14

Main control system to autoregulate blood flow
Small arterioles control blood flow to each tissue
Local conditions in tissues control diameter of arterioles
arterioles are highly muscular
Muscularity lost in metarterioles

Question 15

What is vasomotion?

Answer 15

Cyclical opening and closing of precapillary sphincters

Regulated by concentration of oxygen in tissues

Question 16

Role of diffusion in exchange of substances between blood and interstitial fluid

Answer 16

Lipid soluble diffuse through capillary cell membranes (O2, CO2)
Non lipid soluble diffuse through pores
Rate of water diffusion faster than flow of plasma

Question 17

What is interstitium?

Answer 17

Spaces between cells (1/6 total volume of body)
Contain collagen fibers which provide most of tensional strenghts
Proteoglycan filaments thin coiled (98% hyaluronic acid, 2% protein), can not be seen in light microscope

Question 18

What are the Starling forces?

Answer 18

Forces that determine direction of diffusion into or out of capillary
Papillary pressure (Pc)–>outward force
Capillary plasma colloid osmotic pressure(Pip)–>Inward force
Interstial fluid pressure (Pif)–>Inward force
Interstial fluid colloid osmotic pressure (pi if)–>outward force

Question 19

What is net filtration pressure?

Answer 19

Sum of all Starling forces

=Pc+PIif-Pip-Pif

Question 20

What is filtration?

Answer 20

=coefficient of filtration X net filtration pressure

Negative pressure in interstitial space due to lymph vessels contracting and pumping fluid into circulation

Question 21

Filtration at end of capillaries

Answer 21

At arterial end plasma filters into the interstitial space

At venous end absorption is favored

Question 22

Lymphatic system

Answer 22

Salvage proteins in the interstitial fluid into circulation

Without it oncotic pressure will increase and cause blood loss from capillaries

Question 23

Lymphatic return

Answer 23

One way valve
Reaches maximum when interstitial pressure above atmospheric pressure
Increase lymph flow also increases interstitial fluid pressure

Question 24

Factors that increase lymph flow

Answer 24

Elevated capillary hydrostatic pressure
Decreased capillary plasma colloid osmotic pressure
Increased interstitial fluid colloid osmotic pressure
Increased permeability of capillaries

Question 25

rate of lymph flow

Answer 25

=Interstitial fluid pressure X activity of lymphatic pump

Question 26

What is vascular distensibility?

Answer 26

Increase in volume/(increase in pressure X original volume)