Foundation - The Lymphatic System

Question 1

Functions of the lymphatic system

Answer 1

2nd circulatory system essential for life

Supports 3 other systems in your body:

1. Cardiovascular – unilaterally returning interstitial fluid (ISF) to the vascular system
2. Immune – providing the environment that allows for initiation of an adaptive immune response
3. Digestive – absorption of fat-soluble vitamins and fatty substance from the gastrointestinal tract

Question 2

without lymphatic system

Answer 2

blood gets thicker
orgons swell

Question 3

lymphatic system is parallel to

Answer 3

blood vessels
almost every microcapulary is intermixed with lympatic vessels (excpetion - BBB)

lymph - open system
blood - closed system

Question 4

lymph from gut

Answer 4

chyle
milky because increased fat content

(contents of lymp changes with position in body)

Question 5

lymph consolidates and drains back into

Answer 5

blood right before jugular (good place)
[function of the subclavian is to collect lymph fluid from the lymphatic system from the internal jugular vein.]

here and not aortia b/c high pressure at aorta would cause blood to go into lymph
jugular - low pressure

Question 6

The fluid collected by the lymphatic vessels is called lymph and it contains

Answer 6

• Mostly molecules derived from blood - but NO red blood cells
• Immune cells
• Cholesterol, fatty acids, and other fat and large products

Question 7

movement of lymph at microcapilaries

Answer 7

special endothelial cells - close and water (also PAMPs and DAMPs) builds up - causing pressure increase - valve opens and drains - water comes back in (how moves in absence of pump)

opposite side - blind ended - open

Question 8

Lymphocytes (T and B cells) constantly ___

Innate immune cells (macrophages, neutrophils, etc.) constantly ___

Answer 8

move between the blood and the lymph

survey tissues

Question 9

Lymph collects ALL sort of molecules from blood and tissues including ____

All of these come together at lymph nodes where ____

Answer 9

pathogen-associated molecular patterns (PAMPs)
danger-associated molecular patterns (DAMPs)
Lymphocytes (T and B cells)
Innate immune cells (macrophages, neutrophils, etc.)

an adaptive response starts - activated
lymphocytes return to blood to target infection

Question 10

lymph in blood is filtered by

Answer 10

node so (ex.) not spread bacteria

Question 11

CNS lymphatics is imbedded

Answer 11

in dura matter - where large synuses vessles are
where B - menengial barrier is

Question 12

In dura matter blood is

Answer 12

fenestrated
(Intradural vessels are leaky)

Question 13

Direct mechanism of movement between layers (CSF, Dura matter) is

Answer 13

unknown

Indirect evidence indicate cells and large molecules do move between layers

Question 14

How is CSF transported within the large cavity of the SAS?

Answer 14

SLYM (sub-arachnoid lymphatic-like membrane)

monolayer that covers the whole brain - separates areas

can only sample CSF on one side of the SLYM

Question 15

SLYM (achronim) =

Answer 15

sub-arachnoid lymphatic-like membrane

Question 16

SLYM is the

Answer 16

monolater dividing SAS

Phenotypically distinct from dura, arachnoid, and pia maters

Act as a barrier for molecules 3kDa and bigger

works with glymphatic system to organize SAS

Question 17

The glymphatic-lymphatic connection

Answer 17

Anatomically-continuous and functionally-related system (one works after the other)
(Glymphatic -> lymphatic)

Waste removal (into veins) / fluid removal (into lymph nodes)

Question 18

how does the The glymphatic-lymphatic connection compartmentalize waste

Answer 18

waste cannot be removed (via sinus/ arachnoid villi) because of SLYM speration

waste on that side is then removed by lympatics - sampled for PAMPs and DAMPs

Question 19

what regulates CSF to go to lymph

Answer 19

SLYM - waste compartmentalization

Question 20

Immune cells go in and out of
the brain through the

Answer 20

vasculature and the lymphatics

lymphatics (ONLY out - into nodes - cannot go into brain with lymphatics)

Question 21

CSF/ISF constantly absorbed by ____ and monitored at _____

Answer 21

lymphatics and monitored at
cervical lymph nodes

Question 22

if antigens are found at cervical lymph nodes

Answer 22

an immune response can be mounted

(antigens made because filter at nodes and SLYM ?)

Question 23

SLYM can support the role of dural lymphatics in CNS immunity b/c

Answer 23

Act as an immune hub

• Closer to brain surfaces
• Large number of resident immune cells
• Can regulate influx of immune cells from dura/skull bone marrow

Question 24

CNS lymphatics role in autoimmune disease

Answer 24

If they control immune responses in the brain, then controlling that gate could hold promise to treat autoimmune diseases

open/activate - immune hub - more specific response

MS - dec regulation immune response - kill/attack olig. dec. # of olig.

Question 25

CNS lymphatic role in brain cancers

Answer 25

VEGF-C (Vascular endothelial growth factor C) promotes lymphogenesis - treat with - inc lymph vessiles and nodes Increased lymphatics results in increased number of T cells and surveillance inc. chance immune sees new/different protein expression in cancer cells - target cancer

Question 26

Why is brain cancer hard to treat?

Answer 26

1) Side effect of the brain barriers - protect the cancer (hard to survey, hard for immune cells to get in, hard for treatments to get in) 2) Cancers are not inflammatory - cancer is own cells - so many changes - eventually have different proteins that will be visible but cannot see. 3) Steal nutrients and blood away from normal cells