Lecture 33 Flashcards
what is Hydrostatic pressure in the capillaries
refers to the pressure exerted by the blood against the walls of the capillaries
in the case of the capillaries it is the BP
in the case of the interstitial fluid it is water
what is Osmotic pressure in the capillaries
Osmotic pressure in capillaries refers to the pressure exerted by the concentration of solutes in the blood, such as proteins, electrolytes, and other molecules.
These solutes are too large to pass through the walls of the capillaries and therefore remain inside the blood vessels.
As blood flows through the capillaries, the concentration of solutes in the blood creates an osmotic pressure that tends to draw fluid from the surrounding tissues back into the capillaries. This process is called reabsorption and is essential for maintaining proper fluid balance in the body.
The osmotic pressure in the capillaries is generated by the presence of proteins and other solutes that are more concentrated in the blood than in the interstitial fluid surrounding the cells. This concentration gradient creates a force that draws water from the tissues into the capillaries to balance the concentrations of solutes on both sides of the capillary walls.
The balance between the hydrostatic pressure and the osmotic pressure in the capillaries determines the net movement of fluids and solutes across the capillary walls, which is essential for maintaining proper fluid balance and nutrient exchange between the blood and the surrounding tissues.
what is the Net filtration pressure formula(write it out)
(write it out)
Pressures pushing water out of capillary:
capillary hydrostatic pressure and interstitial fluid osmotic pressure
Pressures driving fluid back into the blood:
interstitial fluid hydrostatic pressure and capillary osmotic pressure
By vasodilating the arteriole is there going to be filtration or absorption
vasodilation of the arteriole would result in filtration rather than absorption.
The reason for this is that vasodilation causes an increase in blood flow to the capillaries, which in turn increases the hydrostatic pressure in the capillaries. This increased pressure would overcome the opposing osmotic pressure and drive fluid and solutes out of the capillaries and into the surrounding tissues.
By vasoconstrict the arteriole is there going to be filtration or absorption
vasoconstriction of the arteriole would result in increased reabsorption of fluid and solutes back into the capillaries, rather than filtration.
The reason for this is that vasoconstriction causes a decrease in blood flow to the capillaries, which in turn decreases the hydrostatic pressure in the capillaries. This decreased pressure would allow the opposing osmotic pressure to drive fluid and solutes back into the capillaries, rather than out of the capillaries and into the surrounding tissues.
What Happens to the Fluid that is Filtered and not Reabsorbed?
The fluid that is filtered from the capillaries but not reabsorbed back into the capillaries is collected by the lymphatic system.
what is the lymphatic system
The lymphatic system is a network of vessels and tissues that collect excess fluid, proteins, and waste products from the interstitial spaces and return them to the bloodstream.
how does fluid enter the Lymphatic System
initial lymphatics → lymph nodes → lymph vessel → back into venous system (right side of heart)
what are the important functions of the Lymphatic System
Fluid balance
Immune surveillance
Movement of immune cells
What Happens if the Lymph System isn’t Working Correctly?
can lead to a condition called Edema
or
Elephantiasis: chronic condition; lymph system doesn’t work properly
what is Edema
excess fluid accumulation in the extracellular/interstitial space
Occurs with trauma; sprained ankle (swelling occurs because you can’t reabsorb that much fluid from the interstitial space; swelling will be there until you can reabsorb it back into the blood, or until the lymph system can absorb it and bring it back into the blood; bruising occurs from blood cells escaping to interstitial space from damaged capillaries)
