Formation of Lymph Flashcards Preview

ESA 4 - Head and Neck > Formation of Lymph > Flashcards

Flashcards in Formation of Lymph Deck (29):
1

Describe the balance of hydrostatic and oncotic pressure at the arteriole end of the capillary bed? 

Hydrostatic pressure is much higher than oncotic pressure 

2

What is the result of the hydrostatic pressure being much higher than the oncotic pressure at the arteriole end of the capillary bed? 

Get movement of fluid from arteriole end of capillary into interstitial space

3

What is the function of the movement of fluid from arteriole end of capillary to interstitial space? 

Bathes cells, delivering glucose etc. that the cells need 

4

What macromolecules leak through the capillary wall into interstitial space? 

  • Smaller proteins
  • Cell debris
  • Bacteria 

 

5

What happens to the balance between hydrostatic pressure and oncotic pressure as you pass across the capillary bed? 

  • Hydrostatic pressure has dropped due to the loss of fluid
  • Oncotic pressure remains almost the same 

 

6

What is the result of the decrease in hydrostatic pressure across the capillary bed? 

There is a higher pull into the capillary than push out, so at the venule end you get fluid going back into the capillary 

7

Is the net filtration of fluid the same as the net reabsorption of fluid at the capillary bed? 

No, about 9/10 of what is filtered is reabsorbed 

8

What happens to the 1/10 of fluid that is not reabsorbed at the venule end of the capillary bed? 

It remains in interstitial space along with proteins, bits of cellular debris, and bacteria, and is drained by lymph

9

Why do proteins, bits of cellular debris, and bacteria remain in the interstitial space? 

They can't get back through the capillary pores 

10

What would happen if we didn't have a lymphatic system? 

Would get lots of fluid pooling in the interstital space, and so become very oedematous 

11

When is fluid called lymph? 

As soon as tissue fluid and the things it contains pass into the lymphatic capillaries 

12

What does lymph consist of? 

  • Tissue fluid
  • Small proteins
  • Lipids (chylomicrons from gut lymphatics) 
  • Damaged cells
  • Bacteria
  • Cancer cells

 

13

How much lymphatic fluid is produced each day? 

3-4L

14

What does the lymphatic system do? 

Continuously removes remaining tissue fluid (and macromolecules such as proteins) from extracellular space back to blood circulation 

15

What is the clinical relevance of the lymphatic system? 

Provides route for spread of infection and malignant disease

16

What are the features of lymphatic flow? 

  • One directional 
  • Low pressure system
  • No central pump 

 

17

What allows the one directional flow in the lymphatic system? 

  • Endothelial cells in the lymphatic capillary act as one way valves to the entry of lymph
  • Valves prevent backflow
  • Passive and intrinsic constriction 

 

18

What is passive constriction of lymphatic vessels? 

Something from outside helping to squeeze the tubes of lymph vessels 

19

What outside forces contribute to passive contriction? 

  • External constriction of the muscle that the lymphatic vessel is running through
  • Pulsation of an artery running next to lymph vessel 

 

20

What vessels can perform intrinsic compression? 

Larger lymphatic vessels 

21

What happens in intrisinic compression of lymph vessels? 

As lymphatic vessels stretch, they contract due to smooth muscle in their walls, therefore as they start to fill with fluid, autonominously contract 

22

Describe the pathway of lymph fluid

  1. Lymphatic capillary (small to large)
  2. Afferent lymphatic vessel
  3. Lymph node
  4. Efferent lymphatic vessel 
  5. Lymphatic ducts 
  6. Venous circulation 

 

23

What is the result of their being multiple points of entry from a single lymphatic duct, but only one exit? 

Slows down flow

24

What is the advantage of slowed flow in lymph nodes? 

So that whatever is in the lymph node can start to do its roles and functions 

25

What does the lymphatic system drain into? 

Venous circulation 

26

Where does the lymphatic system drain into the venous circulation on the left? 

The junction between left internal jugular and left subclavian 

27

Where does the lymphatic system drain into the venous circulation on the right? 

Between right internal jugular vein and right subclavian vein 

28

Where does the right lymphatic duct drain? 

  • Right side of face
  • Right arm 
  • Right hemithorax

Everything else drained by left 

29

Why is lymph not returned to the artery? 

Because the pressure difference is too great