Transcript File - Groby Bio Page

Identifying blood vessels
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Module 2
Exchange and transport
1.2.10 Blood, tissue and lymph
Starter – Osmosis recap
Quick Recap First!
Osmosis is the
diffusion of water
through a partially
permeable
1) In which direction will osmosis occur in these cells?
membrane
2) Between which cells will the net movement of water be the
greatest? Explain why.
3) Which has the higher water potential, the solution of water in
the soil or the root hair cell? Explain your answer.
Answers
1) From C to B to A.
2) Between C and B, because there is a greater
water potential gradient between these
cells.
3) The water in the soil. It has the greater
amount of water in the solution.
Learning Objectives
Success Criteria
• Define the terms tissue fluid,
blood and lymph
(Grade E - D)
• To understand how tissue
fluid is formed and the
• Describe how tissue fluid is
differences between blood,
formed from plasma
tissue fluid and lymph
(Grade C –B)
• Explain the difference between
blood, tissue fluid & lymph
(Grade B – A)
Tissue Fluid and its formation
• What is it? – A watery liquid containing
glucose, amino acids, salts, fatty acids and
oxygen.
• It supplies the materials to cells and receives
carbon dioxide and waste substances from the
cells for removal.
• Formed by blood plasma, provides a constant
environment for the cells it surrounds.
How does it get to the tissues?
• When blood flows into the capillaries, water and other
substances are exchanged between the blood and tissue
fluid.
• Two forces affect this exchange:
– Hydrostatic pressure: caused by pumping action of
heart – forces water out through capillary walls into
tissue fluid
– Water Potential: Due to large protein molecules in
plasma, attracts water back into blood vessels from
tissue fluid
Lymphatic system
Some tissue fluid remains in tissues
It is carried away by lymphatic system
Network of vessels around body
Drains contents back to heart
Lymphatic system
Movement through vessels caused by
Hydrostatic pressure of fluid in tissue
Contraction of body muscles
squeezing the lymph vessels
tissues
arteriole
venule
capillary
artery
vein
Formation of tissue fluid
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Tissue fluid movement
Arterial End
Hydrostatic pressure forcing water out is
greater force than water potential forcing
water back in
NET movement = into tissues
Venous End
Water Potential gradient attracting water
into vessel is greater force than
hydrostatic pressure forcing
water out into tissues.
NET movement = into vessel
tissues
arteriole
venule
capillary
artery
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vein
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Lymph Formation
• Not all tissue fluid returns
to capillaries, some is
drained into the lymphatic
system.
• Lymph has
less oxygen and nutrients than
tissue fluid
more carbon dioxide
more fatty material absorbed
from the intestines.
presence of lymphocytes
produced in lymph nodes
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lymphatic capillaries
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The lymphatic system
The lymphatic system is a secondary circulatory system
and a major part of the immune system. It consists of:

lymphatic capillaries and vein-like
lymph vessels, containing valves

lymph nodes – sac-like organs that
trap pathogens and foreign
substances, and which contain large
numbers of white blood cells

lymphatic tissue in the spleen, thymus
and tonsils – these also contain large
amounts of white blood cells and are
involved in their development.
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Task 1
•Describe how tissue fluid is formed from
plasma
(Grade C –B)
• Complete worksheet describing how tissue fluid
is formed:
• Extension – Albumin is a protein found in the blood.
Hypoalbuminemia is a condition where the level of albumin in
the blood is vey low. It causes an increase in tissue fluid,
which can lead to swelling. Explain how hypoalbuminemia
causes an increase in tissue fluid.
• Water potential of the capillary is higher because there is less
albumin in the blood. This means less water is absorbed by
osmosis back into the capillary at the vein end of the capillary
bed, which leads to an increase in tissue fluid.
Task 2
• In pairs complete the table comparing blood,
tissue fluid and lymph.
• Homework – exam question
•Define the terms tissue fluid, blood and
lymph
(Grade E - D)
Plenary
• Give one difference between blood and tissue
fluid
• Give one difference between tissue fluid and
lymph
•Explain the difference between blood,
tissue fluid & lymph
(Grade B – A)