Lecture 5 - Cap and Lymph Flashcards
Capillaries
- Function
- Function demands three things - what are they?
- What does large total area of cap bed mean?
-
Pre capillary sphincters
- Composed of?
- What does it do?
-
Three types of caps - what are they (order them)
- Continuous - most wide spread - controlled, tight
- Fenestrated - leaky
- Sinusoidal - V leaky
Continuous caps
- Barrier between…?
- Basement membrane - what is it?
- Example
- What’s the arteriovenous anastomosis?
- Diameter
- Continuous cellular barrier between lumen and interstitial space
- It;s a layer on the basal surface of the endothelial cells. Like a fuzzy coat that the cell rests on so whatever passes through this cap needs to pass through this too.
- Skeletal and cardiac muscle
- Blood goes here when precap spinc tighten
- 5 - 10(m)m
Fenestrated caps (leaky)
- What does it have? Regions of cytoplasm where it has…..and allows freer……
- What does it still have?
- Example
- Diameter
- Regions of cytoplasm where it has openings - allows freer exchange between lumen and underlying interstitial space (but still basement membrane)
- Basement mem - extracellular barrier
- Glomerulus, kidney (it’s a series of fenestrated caps)
- 5 - 10(m)m
Sinusoidal caps (very leaky)
- Bigger….and what about the basement mem?
- Placed where?
- It’s not about what but rather about what?
- Example
- Can RBC fit through holes?
- Bigger fenestrations and gaps in underlying basement membrane (under cell)
- Placed where we want more exchange between lumen and underlying tissue
- Not about gas exchange but rather nutrient exchange and minimising distance
- Liver sinusoids (no barrier obstructing lumen and tissue)
- Nope! So won’t get haemorrhage
What are the three ways you can get exchange in continuous caps?
What about the other two caps?
- Direct diffusion (gradient, gas exchange)
- Diffusion through intracellular cleft (tight junction) but this is still controlled by cell - cell controls how many tight junctions it lays down
- Vesicles - anything that can’t go through diffu goes through this.
= Continuous
*For the other two - have diffusion through pores but for fenestrated, also have to pass through basal lamina (basement mem) too.
Lymph
- Any fluid that leaves blood vascular space gets picked up by what?
- Lymph channel - three things
- By lymph network
- Thin walled, no RBC, has valves (bicuspid - have endothelial cells lining valves so wall of valve is just endo cells on surface and CT in between). Low pressure so need to force fluid back to heart.
Lymph vascular system - open entry drainage system
Functions
- Drains
- Filters
- Screens
- Absorbs
-
The Lymphatic System Structure
Lymph vessels
- Commence as
- From small intestine…
- Larger (thin wall) collecting vessels have numerous….
-
Describe the structure of the fingers of lymph caps
Flaps allow fluid from interstitial to get in (mini valves) tips very porous. Any ish that drains into interstitial space goes to lymph
Regional lymph nodes
1 . Entrance of right lymphatic duct into….
- Entrance of thoracic duct into
- The cisterna chyli looks like a hand (fingers are lacteal) so what’s the arm?
- Most lymph fluid throughout the body drains into the _______ ____ ____ while a minority (from blue shaded) drains into ____ _____
- Where will you definitely find a vale in the above mentioned list?
- Name three nodes and whereabouts they are
- left subclavian vein
- Left Sub vein
- Thoracid duct
- Left Sub vein….right sub vein
- Entrance of thoracic into left sub vein so blood can’t rush into lymph vessel.
- Cervical nodes (neck), axillary nodes (armpit) and inguinal nodes (hip-ish)
Lacteal
- What is it?
- Takes from to and then to
- Finger-like projection that takes up fat laden fluid across gastro mucosa and then goes back to cisterna chyli (white and milky because fat in it)
- From intestinal artieries to portal veins and then to liver (take the nutrients/toxins to liver cells - sinusodial and then goes back to heart)
Lymph node structure
Series of lymphatic channels from periphery to these - fluid comes in and bathes the immune cells
Lymphatic drainage of the breast
Go look at slides
