Veins and Lymphatics

Question 1

is the venous system a low or high pressure system?

Answer 1

low pressure -

Question 2

at any given point, how much of our circulating blood do the veins contain?

Answer 2

they contain 2/3 of the circulating blood volume

Question 3

veins are innervated by what system?

Answer 3

the sympathetic constrictor nerves

Question 4

what is the implication of gravity on venous return?

Answer 4

• When standing, blood pools in lower limb veins, veins require valves to counteract this
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Question 5

if venous return is insufficient, what is the result?

Answer 5

you get oedema/trophic changes or ulceration

Question 6

how do we measure central venous pressure?

Answer 6

with right heart catherization

Question 7

how can we estimate the central venous pressure?

Answer 7

can estimate using jugular venous pulation or using doppler ultrasound

Question 8

jugular venous pressure mirrors what?

Answer 8

mirrors RA pressure

• no valves between IJV and RA, thus JVP has ACY waves and XY descents just like the RA - therefore if the JVP is elevated, it implies an elevated RA pressure

Question 9

how do you measure JVP?

Answer 9

• patient at 45 degrees
• look between heads of SCM
• should not be palpable
• look for hepato-jugular reflux by putting pressure on the abdomen

Question 10

what is the purpose of lymphatics?

Answer 10

they drain fluid to the venous system (8L/day)

drain proteins

regional lymph nodes have an immunological function

Question 11

What duct carries the majority of lymph?

Answer 11

the Thoracic duct

Question 12

do lymphatic vessels contain valves?

Answer 12

Yes! you wouldn’t want lymph draining backwards

Question 13

what is Lymph made of? - potential SNQ

Answer 13

• acronym = PEC
  
  • P= protein
  • E= electrolytes (including cholesterol)
  • C= cells