1. Absorption of materials

2. SQA Summary
Oxygen and nutrients from food must be absorbed into the bloodstream to be delivered to cells for respiration. Waste materials, such as carbon dioxide, must be removed from cells into the bloodstream.
Tissues contain capillary networks to allow the exchange of materials at cellular
level.
Surfaces involved in the absorption of materials have certain features in common: large surface area, thin walls, extensive blood supply. These increase the efficiency of absorption.
Lungs are gas exchange organs. They consist of a large number of alveoli providing a large surface area. Oxygen and carbon dioxide are absorbed through the thin alveolar walls to or from the many blood capillaries.
Nutrients from food are absorbed into the villi in the small intestine. The large number of thin walled villi provides a large surface area. Each villus contains a network of capillaries to absorb glucose and amino acids and a lacteal to absorb fatty acids and glycerol.

3. Lesson starter What 4 things make up the blood?
What part of the heart pumps blood to the lungs?
What parts of the body are involved in the respiratory system?
What structure in the lungs has a large surface area for maximum gas exchange?
Give one difference between arteries and veins?
What are capillaries?

4. Today we are learning about the structure and function of the lungs.

5. HUMAN LUNGS

6. Larynx (voice box) Trachea Bronchus Rib Bronchioles Alveoli Diaphragm
Rings of cartilage
Bronchus
Rib
Bronchioles
Alveoli
Diaphragm

7. Air enters the body via the
Respiratory System
Air enters the body via the
nose and mouth,
then passes to the
trachea,
then to the
2 bronchi,
bronchioles,
and finally to the tiny
alveoli.
Singular of
bronchi is
bronchus

8. Structures of the Lungs
The trachea and bronchi are held open by rings of cartilage.
They are also lined with tiny hair-like structures called cilia and have glandular cells that secrete sticky mucus.
Mucus traps dirt and microorganisms
cilia moves this up and away from the lungs.

9. Lesson starter Which line describes features of veins?
Which line describes features of arteries?
Direction of
blood flow
Detection of
pulse
Presence of
valves A
towards the heart
yes no B
away from the heart C D
3.Haemoglobin combines with oxygen to form oxy-haemoglobin.
 Which of the following statements is correct? 
A At low oxygen levels oxy-haemoglobin releases oxygen in the lungs.
B At high oxygen levels oxy-haemoglobin releases oxygen in the tissues.
C At low oxygen levels oxy-haemoglobin releases oxygen in the tissues.
D At high oxygen levels oxy-haemoglobin releases oxygen in the lungs.

10. Questions 4 and 5 refer to the diagram below which shows a section through a mammalian heart.
4. Which arrow identifies the vena cava?
A 1
B 2
C 3
D 4
5. Which heart chamber pumps blood to the lungs?
6. Which number represents the:
Pulmonary vein
Aorta

11. Unscramble the words Threa Ungls Rtoaa Vprunomyalnie Acveacanv
ypehteonp

12. Lesson starter Label the 4 chambers A-D
And the four arteries/veins 1-4
Also state whether blood is going in or out and if it is oxygenated or deoxygenated

14. Absorption of materials
Oxygen and nutrients from food must be absorbed into the bloodstream to be delivered to cells for respiration.
Waste materials, such as carbon dioxide, must be removed from cells into the bloodstream

15. Alveoli http://www. bbc. co
air sac
The alveoli are the functional unit of the lungs.
There are millions of alveoli in each lung.
They provide a large surface area for exchange of Carbon dioxide and oxygen.
They are well supplied with blood.
blood capillary

17. All surfaces involved in absorption of materials have:
Large surface area
Very thin walls
Surrounded by blood capillaries
Moist

18. Capillary networks
Tissues contain capillary networks to allow the exchange of materials at cellular level.

19. Diffusion gas exchange in lungs
O2 Breathe in  Alveoli = high conc of oxygen  Diffusion occurs from alveoli  blood capillaries (low conc) Blood capillaries now have high O2 conc Cells have low O2 conc Diffusion occurs from blood capillaries  cells
CO2
Cells have high CO2
Capillaries have low CO2
Diffusion occurs from cells  blood capillaries
Blood capillaries now have high CO2 conc
Alveoli have low CO2 conc
Diffusion occurs from blood capillaries  alveoli
Breathe out!

20. Digestion Structure and function of the villi

21. Starter Quiz . . . Name the subunits of proteins?
Name the chemical elements present in fats?
Describe what is happening in digestion?
What is the test for identifying glucose?
What is the test for identifying starch?

22. These can now be absorbed into the bloodstream
What is Digestion?
Breaking down:
LARGE INSOLUBLE molecules
SMALL SOLUBLE molecules
These can now be absorbed into the bloodstream

23. Alimentary Canal
Can you describe the journey food takes starting with the mouth?
Mouth  oesophagus  stomach  small intestine  large intestine  rectum  anus

25. Digestion starts in the mouth . . .
Food is mechanically broken by the teeth.
Food is then mixed up with saliva from the salivary glands.
Saliva contains the digestive enzyme AMYLASE which promotes the breakdown of ___________ to __________

26. OESOPHAGUS Then food is swallowed . . .
Food is then transported from the mouth to the stomach by the:
OESOPHAGUS

27. Movement in the digestive system: Peristalsis
Muscles contract here
Food moves this way
Muscles relax here

28. The Stomach
The stomach muscles churn food and mix it with digestive juices and the enzyme PEPSIN to completely break it down.

29. Lesson starter Digestive Enzymes . . .
Write the enzyme word equations for:
CARBOHYDRATES
PROTEINS
FATS
State where in the digestive system these enzymes are active?

30. After the stomach…
The broken down food travels to the small intestine where useful substances are absorbed into the blood.
Small intestine – reabsorbs nutrients from food
Large intestine – reabsorbs water

31. *Villi notes*
Nutrients from food are absorbed into the villi in the small intestine.
The large number of thin walled villi provides a large surface area.
Each villus contains a network of capillaries to absorb glucose and amino acids and a lacteal to absorb fatty acids and glycerol.

32. Structure of Small Intestine
The structure of the small intestine is suited to the function of food absorption:
Long, highly folded and having thousands of fingerlike villi – there is a large surface area for absorption of digested food.
The lining of the villi is only one cell thick – this allows nutrients to pass through easily.

33. Small Intestine - Villus
Internal structure of
Small Intestine - Villus
Each villus contains a blood capillary network and a central lacteal .

34. Absorption through the Villus
1. Glucose and amino acids (soluble) are absorbed into the blood capillaries.
Glucose from carbohydrates
Amino acids from protein
2. Fatty acids and glycerol pass into the central lacteal and then to the lymphatic system.

35. Large surface area – folded structure
So how is the structure of the villi suited to its function?
Large surface area – folded structure
1 cell thick – to allow for easy absorption
Next to a dense network of blood capillaries – easy absorption and exchange of materials