Capillary Process

What are flat cells called?

squamous cells

What are capillary cells?

Thin endothelial cells that make up the capillary blood

What is a capillary bed purpose?

Allowing exchange between blood and body tissues

Capillary process

Oxygen from blood to the cells

Nutrients from the blood to the cells

Carbon Dioxide from cells to blood

Waste from cells to blood

What spaces exist between capillary cells?

Small gaps that allow water molecules to move out of the capillary into tissue spaces, forming tissue fluid.

What is tissue fluid?

Fluid that forms in the spaces around cells and helps with exchange of substances between blood and body cells.

How does oxygen get from red blood cells to body cells?

Oxygen first moves from red blood cells → into tissue fluid → then into body cells.

How do wastes leave body cells?

Waste moves from the cells → into tissue fluid → then into the blood in the capillary bed.

Why is tissue fluid called the "medium of exchange"?

Because oxygen, nutrients, and wastes all pass through it between blood and cells.

What stays inside the capillary and cannot leave?

Plasma proteins and red blood cells stay inside the capillary bed.

What do plasma proteins do in capillaries?

They attract water molecules through a force called osmotic (oncotic) pressure.

What happens at the arterial end of a capillary?

Hydrostatic pressure is stronger, so water is pushed out of the capillary into the tissue fluid.

What happens at the venous end of a capillary?

Osmotic pressure becomes stronger, so water is pulled back into the capillary.

What two pressures control movement of water in capillaries?

• Hydrostatic pressure → pushes fluid out

• Osmotic (oncotic) pressure → pulls fluid back in