Blood and Transport Fluids 8.3

Question 1

What does blood consist of?

Answer 1

Its made mainly of plasma which is a straw-coloured liquid. It contains water, minerals, hormones, glucose, proteins used for different functions, erythrocytes, white blood cells, platelets etc…

Question 2

Functions of the blood

Answer 2

Red blood cells transport oxygen to cells that are needed. Carbon dioxide also has to be transported. It carries glucose and amino acids to cells that need it for respiration. Hormones are transmitted, platelets travel to damaged areas for clotting. Antibodies and white blood cells are used for the immune system. Also contributes to a steady body temp and pH.

Question 3

Oncotic Pressure

Answer 3

Plasma proteins like albumin can give osmotic effects. It decreases the water potential in the capillaries so that water is more likely to move into the capillaries by osmosis. The tendency for water to move into the capillaries is the oncotic pressure.

Question 4

Hydrostatic Pressure

Answer 4

When blood flows through the capillaries from the arterioles, it’s still under a lot of pressure from the surge of blood that happens when the heart contracts.

Question 5

Arterial End

Answer 5

At the arterial end of the capillary, the hydrostatic pressure is high compared to the oncotic pressure so it causes tissue fluid to flow out of the capillaries

Question 6

Tissue Fluid

Answer 6

A fluid similar to plasma that will flow in spaces between the cells after it has been released. It doesn’t have red blood cells or big proteins as they cannot go through the capillary wall. Diffusion between the blood and cells takes place in the tissue fluid.

Question 7

Venous End

Answer 7

In the middle of the capillary to the venous end, there is a change in pressures. The hydrostatic pressure will decrease and oncotic pressure will be stronger so tissue fluid will move back into the capillary and increase the hydrostatic pressure again.

Question 8

Filtration Pressure

Answer 8

Hydrostatic pressure - Oncotic Pressure

Question 9

Lymph

Answer 9

Some of the tissue fluid that left the capillaries remains there. It is drained into the lymphatic system composed of tubes that will drain into larger vessels that also have valves to prevent backflow. Lymph is similar to tissue fluid, just it has less oxygen and nutrients as it’s around cells that have taken it. The lymph is transported by the squeezing of muscles until eventually, the lymph will drain back into the veins and be reabsorbed.

Question 10

Lymph Nodes

Answer 10

Lymphocytes will build up in the nodes and produce antibodies needed for an immune response. They also intercept bacteria and other debris and destroy them with phagocytes made in the lymph nodes. The nodes play an important role in the defence mechanisms of the body so if you are ill and fighting off infection, your lymph nodes will be big.