Chapter 15: Animal Transport and exchange systems

Chapter 15: Animal Transport and exchange systems
Unit 2: Multicellular Organisms Chapter 15: Animal Transport and exchange systems 26/04/2017 Mrs Smith - National 5 Biology

Unit 2: Multicellular Organisms Chapter 15: Animal Transport and exchange systems Lesson 1: Mammalian circulatory system: HEART 26/04/2017 Mrs Smith - National 5 Biology

Learning Intentions: Animal Transport
By the end of this chapter you should: Be able to demonstrate the pathway of oxygenated and deoxygenated blood through heart, lungs and body. Describe the heart structure to include right and left atria and ventricles and location and function of valves (you DO NOT NEED valve names). Blood vessels to include: aorta, vena cava, pulmonary arteries and veins. 26/04/2017 Mrs Smith - National 5 Biology

Mrs Smith - National 5 Biology
Introduction A large multicellular organism has a small surface area in relation to its volume. (See Torrance. ch14 – pg111). Therefore it needs additional absorbing areas to take in oxygen and food. 26/04/2017 Mrs Smith - National 5 Biology

The need for additional absorbing areas in humans
Humans have for example Alveoli in the lungs Villi in the intestine These greatly increase the surface area for the absorption of oxygen and digested food respectively 26/04/2017 Mrs Smith - National 5 Biology

The need for a circulatory system
Once the essential substances have entered the animal’s body, they must be carried to all of it’s living cells at a faster rate than is possible by diffusion. In mammals, this rapid transport of essential materials is achieved by an animal’s circulatory system. 26/04/2017 Mrs Smith - National 5 Biology

Mammalian circulatory system
The circulatory system consists of the Heart (a muscular pump) Blood vessels (a system of tubes) These carry blood to all parts of the body. Nutrients, oxygen, carbon dioxide and hormones are transported in the body. 26/04/2017 Mrs Smith - National 5 Biology

The Heart The heart is a muscular pump located in the centre of our chest. Its job is to pump blood all around the body. Group Task – Study this diagram of a section through a human heart. Try and work out – How many chambers (large spaces) there are in the heart? Why one side is coloured blue and one side coloured red? Why one side has a thicker wall than the other side? 26/04/2017 Mrs Smith - National 5 Biology

The Heart - Chambers The heart is divided into two separate sides. Each side has 2 hollow chambers - an atrium and a ventricle. The upper chambers are the right and left atria these collect blood. The lower chambers are the right and left ventricles, these pump blood. The wall of the heart is made of cardiac muscle. The diagram shows the 4 chambers viewed from the front of a person. The right hand side of a person is therefore on the left of the diagram and vice versa. 26/04/2017 Mrs Smith - National 5 Biology

The function of veins and arteries.
We will look at their structure later! Veins carry blood into the heart while arteries carry blood away from the heart. The veins carry blood into the atria while the arteries carry blood away from the ventricles. vein Pulmonary vein artery Pulmonary Artery artery vein Aorta Vena cava 26/04/2017 Mrs Smith - National 5 Biology

Blood flow This diagram shows the path taken by blood as it flows through the heart and its associated vessels. Let’s look at it in more detail. 26/04/2017 Mrs Smith - National 5 Biology

Blood flow and associated vessels
Our blood flows through three different types of blood vessels is shown below. VEIN HEART ARTERY CAPILLARIES 26/04/2017 Mrs Smith - National 5 Biology

Flow of blood: Summary The flow of blood from the LV back to the LV... As follows. LV> aorta> body> vena cava> RA> RV> pulmonary artery> lungs> pulmonary vein> LA> LV. Pulmonary Artery Pulmonary vein Aorta Vena cava 26/04/2017 Mrs Smith - National 5 Biology

Blood flow – In more detail
Blood passes through the heart twice (each time it passes around the body also called double circulation). The blood firstly is pumped to the lungs where it picks up oxygen, becoming oxygenated. The blood is then pumped around the body where respiring cells remove the oxygen. This deoxygenates the blood. The blood vessels that carry deoxygenated blood to the lungs are pulmonary arteries, while pulmonary veins return oxygenated blood to the heart. The artery that carries oxygenated blood away from the heart and around the body is the aorta. The vena cava is the vein that returns deoxygenated blood to the heart from the body. 26/04/2017 Mrs Smith - National 5 Biology

Rob the Red Blood Cells Journey!
Rob is a new red blood cell and needs direction about where he’s going and what will happen to him on his journey around the body. Can you help advise him? ? 26/04/2017 Mrs Smith - National 5 Biology

26/04/2017 Mrs Smith - National 5 Biology

Review Questions Where did Rob pick up Oxygen? Where did Rob take it to? Why did Rob change colour? What things would be floating around Rob in the blood? What other cells are there in the blood with 26/04/2017 Mrs Smith - National 5 Biology

Thickness of ventricle walls
The muscle wall of the left ventricle is THICKER than the right ventricle. This is because the left ventricle has to pump blood right round the body, whereas the right ventricle only has to pump blood to the lungs. (which are right next to the heart). 26/04/2017 Mrs Smith - National 5 Biology

The Heart - Valves The heart has four valves in it. The job of the valves is to keep blood flowing in one direction through the heart. The valves stop the blood flowing backwards within the heart. Valve 4 Valve 3 Valve 2 Valve 1 26/04/2017 Mrs Smith - National 5 Biology

The Heart – Valves 1 and 2 Valves 1 and 2 are situated between the atria and the ventricles. When they open, blood passes from the atria into the ventricles. When the ventricles contract, the blood, under pressure closes valves 1 and 2. This prevents blood flowing back into the atria. 26/04/2017 Mrs Smith - National 5 Biology

The Heart – Valves 3 and 4 Valves 3 and 4 are situated between the ventricles and the two arteries that leave the heart. Once blood has been pumped through valves 3 and 4 they close, preventing backflow of blood from arteries into ventricles. Blood is therefore only able to travel in one direction through the heart. 26/04/2017 Mrs Smith - National 5 Biology

Our heart beat is caused by the valve opening and closing

Heart valve disease If one or more valves are diseased or damaged, it can affect how blood flows through the heart in two ways: If your valve does not open fully, it will obstruct the flow of blood. If the valve does not close properly, it will allow blood to leak backwards. People with heart valve disease may be advised to have surgery on your valve, which can greatly improve the symptoms and quality of life. 26/04/2017 Mrs Smith - National 5 Biology

Heart valve surgery There are two options for valve surgery: valve repair and valve replacement. Valve repair is often used for mitral valves that become floppy and leak but are not seriously damaged. Valve replacement is when the diseased valve is replaced with a new valve. The most common types of replacement valves are mechanical (artificial) valves or tissue (animal) valves. 26/04/2017 Mrs Smith - National 5 Biology

Consolidation exercise: The Heart
Individual task - collect the diagram which represents a section through a human heart and stick it into the middle of a page in your jotter. Now see if you can complete and label the diagram by - naming the four chambers. drawing and shading in the muscular walls of each ventricle. indicating the positions of the four valves. naming the four blood vessels associated with the heart. drawing arrows to show the flow of blood through the heart. colouring the “correct” side of the heart blue and the other side red. indicating what the red and blue colours represent. 26/04/2017 Mrs Smith - National 5 Biology

The Heart: Watch this Watch the following video clip about the human heart. Heart : Twig 26/04/2017 Mrs Smith - National 5 Biology

Unit 2: Multicellular Organisms Chapter 15: Animal Transport and exchange systems Lesson 2: Mammalian circulatory system: BLOOD VESSELS 26/04/2017 Mrs Smith - National 5 Biology

Learning Intentions: The vessels associated with the heart
By the end of this chapter you should: Be able to compare the structure and function of arteries, veins and capillaries. Specifically that Arteries have thick, muscular walls, a narrow central channel and carry blood under high pressure away from the heart. Veins carry blood under low pressure; have thinner walls and a wide channel. Veins contain valves to prevent backflow of blood and carry blood towards the heart. Capillaries form networks at organs and tissues, are thin walled and have a large surface area, allowing exchange of materials. Describe coronary arteries and their function. 26/04/2017 Mrs Smith - National 5 Biology

There are three types of blood vessels

Task: Comparing Arteries and Veins
Artery Vein Group Task – Study these diagrams of an artery and a vein. Stick copies into your notes. Describe three differences in the structure of arteries and veins. Decide in which blood vessel the pressure will be highest. Give a reason for your choice. 26/04/2017 Mrs Smith - National 5 Biology

Comparing Arteries and Veins
ANSWER: Comparing Arteries and Veins Blood Vessels Arteries have thick, muscular walls and a narrow central channel. Veins have thinner walls and a wide channel. They also contain valves to prevent the backflow of blood. Arteries carry blood at high pressure AWAY from the heart. Veins carry blood under low pressure back to the heart. Vein Artery Individual Task – Study your wrists. Are the blood vessels that you can see near the surface, arteries or veins? Can you find your pulse in your wrist? What do you think your pulse actually is? 26/04/2017 Mrs Smith - National 5 Biology

What is a pulse? Each time the heart beats, blood is forced along the arteries at high pressure and this pressure wave can be felt as a pulse beat. 26/04/2017 Mrs Smith - National 5 Biology

Capillaries fun facts There are an estimated 10 billion capillaries, measuring approximately 25,000 miles, in the average human body. Each capillary has a length of about 1.1 millimeter. Most capillaries are little more than a single cell layer thick. Capillaries are the smallest and most numerous vessels in the body through which blood flows. The thin capillary wall helps to increase the exchange of materials between cells in the tissue and the blood. While a person is resting, approximately 5% of the blood circulating is in the capillaries, 26/04/2017 Mrs Smith - National 5 Biology

Capillary networks 26/04/2017 Mrs Smith - National 5 Biology

Capillaries An artery divides into smaller vessels and finally into a dense network of tiny, thin walled capillaries. Capillaries are the most numerous type of blood vessel in the body. They present a large surface area and are in close contact with all living cells in tissues and organs. This diagram shows the network of capillaries spreading through the skin in a fingertip. The larger blood vessels are small arteries which carry the blood to the capillaries. Individual Task – Press on the tip of your fingernail and watch what happens. Can you explain the change in colour that occurs. 26/04/2017 Mrs Smith - National 5 Biology

Capillaries cont Capillaries are often referred to as exchange vessels since all exchanges of materials between blood and living tissue takes place through their thin walls (only one cell thick). Capillaries unite to form larger vessels that converge to form veins. The diagram shows a simplified version of the human circulatory system. 26/04/2017 Mrs Smith - National 5 Biology

TASK COPY: Capillaries
Blood flows from arteries into capillaries and then back to veins. As the blood flows through capillaries substances are exchanged with the nearby body cells This diagram shows a capillary network in the inner lining of a cheek. Notice how all the cheek lining cells are very close to a blood capillary. Group Task – Decide whether the following substances will be leaving or entering the blood at this capillary network. Oxygen Carbon dioxide Glucose 26/04/2017 Mrs Smith - National 5 Biology

Task: Stick your diagram + complete the task below.
Individual Task – Stick the diagram of a capillary network into your notes. Colour the blood vessels red and the cytoplasm of the body cells yellow. Individual Task - below your diagram draw one enlarged body cell with a capillary beside it. Individual Task – now draw arrows to represent the movement direction (diffusion) of 1) oxygen 2) carbon dioxide 3) glucose 26/04/2017 Mrs Smith - National 5 Biology

Blood Vessels: Summary: Watch this
Watch the following video clip which contains information about blood vessels and the blood that flows around in them. Blood : Twig 26/04/2017 Mrs Smith - National 5 Biology

Coronary Artery This diagram shows the outside of the heart. Small arteries can be seen branching off the aorta. These are called coronary arteries and they are very important as they supply the muscles in the wall of the heart with oxygen. 26/04/2017 Mrs Smith - National 5 Biology

Coronary Heart Attack The coronary arteries can become narrower as we get older. A fatty diet, smoking and lack of exercise all contribute to this. Eventually, a clot can block the artery leading to a heart attack. Muscle cells in the heart wall become starved of oxygen and die. The heart may stop contracting and unless the heart is quickly restarted the individual will die. 26/04/2017 Mrs Smith - National 5 Biology

Unit 2: Multicellular Organisms Chapter 15: Animal Transport and exchange systems Lesson 3: Mammalian circulatory system: BLOOD 26/04/2017 Mrs Smith - National 5 Biology

Learning Intentions: Blood
By the end of this chapter you should: Be able to describe that mammals, nutrients, oxygen and carbon dioxide are transported in the blood. Red blood cells are specialised by being biconcave in shape, having no nucleus and containing haemoglobin. This allows them to transport oxygen efficiently in the form of oxyhaemoglobin. 26/04/2017 Mrs Smith - National 5 Biology

Remember blood is made of different cells

Blood Blood is a liquid tissue consisting of: plasma red blood cells white blood cells platelets One of the functions of blood is to transport materials around the body. White blood cells and platelets are part of the body's immune system, but plasma and red blood cells are involved in transport. 26/04/2017 Mrs Smith - National 5 Biology

Task: Can you name three nutrients that are carried in the blood?
Group Task – Look at this diagram which represents the parts of blood. Decide which part carries oxygen carbon dioxide nutrients. How many did you get correct? 26/04/2017 Mrs Smith - National 5 Biology

The Blood Nutrients such as glucose and amino acids dissolve in the fluid part of the blood – the plasma. Carbon dioxide gas is also carried around the body in blood plasma. Oxygen is transported around the body in red blood cells. Group Task – can you find out what white blood cells and platelets do? 26/04/2017 Mrs Smith - National 5 Biology

Plasma Plasma is a straw-coloured liquid. It transports dissolved substances around the body, including: Hormones, (Remember hormones are chemical substances that help to regulate processes in the body) such as insulin which regulates the level of glucose in the blood. Oestrogen and progesterone are two hormones involved in the female menstrual cycle. Nutrients, such as water, glucose, amino acids, minerals and vitamins Waste substances, such as carbon dioxide and urea 26/04/2017 Mrs Smith - National 5 Biology

Microscopy - Seeing the composition of Blood
This diagram shows a drop of blood as viewed under a microscope. The nuclei of the white blood cells have been stained purple to make them visible. Notice how few white cells there are compared to red cells. 26/04/2017 Mrs Smith - National 5 Biology

Why is blood is red? This diagram represents an image of blood magnified thousands of times using an electron microscope. The bright red colour of the red blood cells comes from the presence of a pigment called haemoglobin. Haem = Containing iron 26/04/2017 Mrs Smith - National 5 Biology

Red blood cells have no nucleus
The absence of a nucleus is an adaptation of the red blood cell for its role. It allows the red blood cell to contain more haemoglobin and, therefore, carry more oxygen molecules. It also allows the cell to have its distinctive bi-concave shape which aids diffusion 26/04/2017 Mrs Smith - National 5 Biology

Red Blood Cells FUN FACT: The average healthy adult has 35 trillion red blood cells in their body. Red blood cells have a biconcave shape which allows them to absorb lots of oxygen as blood passes through the lungs. Red blood cells are very small so they can easily pass through narrow blood vessels. 26/04/2017 Mrs Smith - National 5 Biology

Haemoglobin & Oxyhaemoglobin
As blood passes through the lung capillaries, haemoglobin (a dark red colour) combines with oxygen to form oxyhaemoglobin (bright read colour). When blood reaches the capillaries beside respiring cells. Oxyhaemoglobin quickly releases the oxygen which then diffuses into cells. 26/04/2017 Mrs Smith - National 5 Biology

Consolidation exercise: The Blood
Individual Task – Stick this diagram into your notes. Then underneath your diagram. 1. List all the substances that are carried dissolved in the plasma. 2. Describe three ways that red blood cells are designed to carry oxygen around the body. 26/04/2017 Mrs Smith - National 5 Biology

TYK Torrance pg’s 123/4 Qu’s 1-3

TYK – How did you do? 26/04/2017 Mrs Smith - National 5 Biology

National 5 Biology Unit 2: Multicellular Organisms Chapter 15: Animal Transport and exchange systems Lesson 4: Organs of gaseous exchange 26/04/2017 Mrs Smith - National 5 Biology

Learning Intentions: Structure of the lungs
By the end of this chapter you should: Be able to describe the structure of the lungs This should include... The trachea and its rings of cartilage which keep main airways open. Comparisons can be made between cartilage in airways and lignin in xylem. The cilia and mucus. Specifically that mucus traps dirt and microorganisms and cilia moves this up and away from the lungs. 26/04/2017 Mrs Smith - National 5 Biology

The Lungs The lungs are a mammals gaseous exchange (where gases enter and leave the bloodstream). Can you name the gas that enters the blood and the gas that leaves the blood in the lungs? Inhaled air enters the body through the mouth or nose. It then travels down through a system of tubes decreasing in diameter - the windpipe (trachea) which divides into bronchi (singular bronchus) which enter each lung. Each bronchus then branches into lots of smaller tubes called bronchioles which carry air throughout each lung. windpipe bronchus bronchioles 26/04/2017 Mrs Smith - National 5 Biology

Task Collect a diagram of the lungs and label the various tubes. 26/04/2017 Mrs Smith - National 5 Biology

The Trachea - Windpipe The windpipe and bronchus (larger airways) are surrounded by rings of cartilage. rings of cartilage These rings are not complete. They are c-shaped held together by ligament 26/04/2017 Mrs Smith - National 5 Biology

Is there something in common with rings of cartilage in the trachea and lignin in xylem vessels (plants) ?? Rings or spirals of Lignin reinforces cell walls, keeping them from collapsing. This is particularly important in the xylem, because the column of water in the hollow xylem cells is under tension and without the lignin reinforcement the cells would collapse. 26/04/2017 Mrs Smith - National 5 Biology

The Trachea - Windpipe Individual Task – see if you can feel the rough rings of cartilage in your own throat. You can also feel this “rubbery” material in your ears and at the tip of your nose. Paired Task – decide what you think the function of this cartilage is. Clue – ligament? rings of cartilage The rings of cartilage protect the windpipe by preventing it from collapsing if it is struck. They spring back keeping the windpipe open and air moving into and out of the lungs. 26/04/2017 Mrs Smith - National 5 Biology

The Trachea – Cilia & mucus
The trachea and bronchi are lined with tiny hair-like cilia and cells that secrete sticky mucus Dirt particles and microorganisms that we inhale stick to the mucus lining the windpipe. This traps them and prevents them entering the lungs. The cilia then beat rhythmically back and forward sweeping the dirty mucus away from our lungs, up to our mouth. This mucus is then swallowed and the acid in our stomach kills the microorganisms. 26/04/2017 Mrs Smith - National 5 Biology

Microscopy of the Windpipe
Section through lining layer (epithelium) of windpipe showing cilia and mucus-producing goblet cells Scanning electron micrograph image of cilia in the windpipe. 26/04/2017 Mrs Smith - National 5 Biology

The internal structure of the lung -Alveoli
This diagram shows that the bronchioles in each lung end in groups of tiny air sacs deep in the lungs called alveoli (singular alveolus). These air sacs are the place where oxygen and carbon dioxide are exchanged with the bloodstream. 26/04/2017 Mrs Smith - National 5 Biology

Why are alveoli so numerous?
Alveoli are so numerous that they provide a very large surface area for gas exchange with the blood. There are around 300 million alveoli in each lung (600 million in total). The total internal surface area of the two lungs is about 90m2 If they were flattened and stitched together they would cover an area equal to a tennis court. 26/04/2017 Mrs Smith - National 5 Biology

National 5 Biology Unit 2: Multicellular Organisms Chapter 15: Animal Transport and exchange systems Lesson 5: Gas Exchange 26/04/2017 Mrs Smith - National 5 Biology

Learning Intentions: Gas Exchange
By the end of this chapter you should: Be able to describe the gas exchange in the lungs This should include... Oxygen and carbon dioxide are exchanged through the alveolar walls. Alveoli have a large surface area, thin walls and a good blood supply for more efficient diffusion of gases. 26/04/2017 Mrs Smith - National 5 Biology

Internal structure of the lung - Alveoli and capillary network
Alveoli are well designed for gaseous exchange. They are surrounded by a dense network of capillaries which give a rich blood supply. If the capillaries from a man’s lungs were unwound and laid end to end they would stretch for 600 miles. 26/04/2017 Mrs Smith - National 5 Biology

Alveoli and capillary network – Structure related to function
As discussed the alveolus is surrounded by a dense network of blood capillaries. The lining of an alveolus is very thin and in close proximity to the walls of the blood capillaries, which are themselves only one cell thick. This combination of Large surface area Short distance Thin walls Good blood supply Presents ideal conditions for gas exchange to occur between alveolar air and blood. 26/04/2017 Mrs Smith - National 5 Biology

Task: Alveoli Paired task Study the diagram – Decide which part of the blood oxygen enters and which part carbon dioxide leaves. Suggest why the red blood cells are shown in different colours in the diagram. - SEE ANIMATION 26/04/2017 Mrs Smith - National 5 Biology

Gas Exchange - Getting oxygen from the air into the blood,
Blood arriving at the lungs is described as deoxygenated because it contains a low concentration of oxygen. Since air breathed into an alveolus contains a higher concentration of oxygen, diffusion occurs. Oxygen first dissolves in the moisture on the inner surface of the thin lining of the alveolus and then diffuses into the blood and surrounding capillaries. The blood therefore becomes oxygenated (rich in oxygen) before leaving the lungs and passing to all parts of the body. 26/04/2017 Mrs Smith - National 5 Biology

Gas Exchange - Removing waste carbon dioxide from the blood into the air Deoxygenated blood contains a higher concentration of carbon dioxide than the air entering the alveoli. Therefore carbon dioxide diffuses from the blood into the alveoli from where it is exhaled. 26/04/2017 Mrs Smith - National 5 Biology

Individual consolidation task:
Collect the alveoli diagrams and stick them into your jotter. 2) On the first diagram label the alveoli, blood capillaries and the bronchiole. 3) On the second diagram do the following – Draw in some red blood cells. Label the capillary, alveolus wall and bronchiole. Draw arrows in different colours to show the flow of oxygen and carbon dioxide between the alveolus and the blood. Underneath your diagrams list three ways that alveoli are designed to allow efficient diffusion of gases. 26/04/2017 Mrs Smith - National 5 Biology

The Lungs in Action Individual Task Study the animation which illustrates the flow of gases into and out of the lungs(Multimedia Science School). List all the parts of the body that oxygen passes through from entering the body until it reaches the muscles. Now list all the parts of the body that carbon dioxide passes through from the muscles until it is breathed out. Can you now explain why there is less oxygen and more carbon dioxide in the air we breathe out. Finally, describe what happens to our breathing when we start to run having been resting. Can you now explain why this change in our breathing happens? 26/04/2017 Mrs Smith - National 5 Biology

The Lungs – Watch this Watch the following video clips about the lungs. Lungs : Twig FactPack: Lungs : Twig 26/04/2017 Mrs Smith - National 5 Biology

National 5 Biology Unit 2: Multicellular Organisms Chapter 15: Animal Transport and exchange systems Lesson 6: Food Transport System 26/04/2017 Mrs Smith - National 5 Biology

Learning Intentions: Food Transport System
By the end of this chapter you should: Be able to demonstrate that Food is moved through the digestive system by peristalsis. Understand the structure of villi in the small intestine Specifically they have a large surface area, thin walls and a good blood supply to aid absorption of glucose and amino acids. Understand the structure of villi in relation to the lacteals which absorb fatty acids and glycerol (the products of fat digestion). 26/04/2017 Mrs Smith - National 5 Biology

Food transport system The alimentary canal is our body’s digestive system. As insoluble molecules of food pass along this muscular tube they are broken down to a soluble state by digestive enzymes. The salivary glands, liver and pancreas, which are connected by ducts to the alimentary canal (gut) are described as associated organs. 26/04/2017 Mrs Smith - National 5 Biology

Revision: Digestive System Structure
The digestive system is essentially a continuous tube which runs from the mouth to the anus. The human gut is over 5 meters long! Individual Task – Study this diagram of the digestive system and see how many parts (A-E) that you can identify. A A = Oesophagus (gullet) B = Stomach C = Small Intestine D = Large Intestine E = Rectum B C D E 26/04/2017 Mrs Smith - National 5 Biology

Oesophagus and Peristalsis
The oesophagus (gullet) is a muscular tube that connects the mouth to stomach. Once food had been swallowed, it is moved down the oesophagus by muscular action called peristalsis. 26/04/2017 Mrs Smith - National 5 Biology

Mechanism of Peristalsis
Contraction behind food Relaxation in front of food Part of the gut wall is composed of circular muscles. When this contracts behind a portion of food, the central hole of the tube becomes narrower and the food is pushed along. At the same time the circular muscle in front of the food becomes relaxed allowing the central hole to enlarge and let the food slip along easily 26/04/2017 Mrs Smith - National 5 Biology

Functions of Peristalsis
Peristalsis also squeezes semi-solid food through the stomach and along the intestines. 1. PERISTALSIS OF THE STOMACH This movement helps to mix the food with digestive juices. 26/04/2017 Mrs Smith - National 5 Biology

Functions of Peristalsis
Peristalsis also squeezes semi-solid food through the stomach and along the intestines. 2. PERISTALSIS OF THE INTESTINE This movement helps Following absorption of the end products of digestion in the small intestine peristalsis keeps unwanted wastes on the move through the large intestine on their way to be eliminated. 26/04/2017 Mrs Smith - National 5 Biology

End products of digestion
Imagine the small intestine of a person that has just eaten an egg sandwich. As a result of complete digestion the starch in the bread has been broken down into glucose. The protein in the egg to amino acids The fat in the butter to the products of fat digestion (Fatty acids and glyserol) 26/04/2017 Mrs Smith - National 5 Biology

What happens to the end products of digestion?
So after complete digestion Carbohydrates are broken down into glucose. Proteins are broken down int amino acids Fats are broken down into fatty acid and glycerol All of these different substances must now be absorbed and transported around the body 26/04/2017 Mrs Smith - National 5 Biology

Absorption in the small intestine
Man’s small intestine is around 7 metres in length and 2·5cms in diameter. The main function of the small intestine is to absorb the end products of digestion through its wall and then pass them into the circulatory system. 26/04/2017 Mrs Smith - National 5 Biology

Absorption in the small intestine Structure related to function
The small intestine is very efficient at its job because of its structure. In biology structure is always related to function! It is long and its internal structure is folded. The inner lining of the small intestine is not smooth. Instead, it has thousands microscopic, finger-like, projections called villi (singular villus) protruding from it. 26/04/2017 Mrs Smith - National 5 Biology

Task: Villi Paired task Study this diagram which shows villi on the inner lining of the small intestine. Decide what their function might be. Clue – they contain a rich blood supply. b) Suggest how their shape helps them to function? 26/04/2017 Mrs Smith - National 5 Biology

The role of Villi Villi increase the surface area of the small intestine for the absorption of digested food into the bloodstream. In addition to providing a large surface area villi are ideally suited to the jobs of absorption and transport of digested food because each villus has a special structure 26/04/2017 Mrs Smith - National 5 Biology

Villus Structure This diagram represents a section through one villus. There are three structural features which aid absorption. The surface walls are thin (one cell thick) to allow digested food to easily diffuse (pass) through rapidly. It contains a good blood supply. A dense network of blood capillaries absorb glucose and amino acids. Tubes in the centre called lacteals absorb and transport the products of fat digestion. 26/04/2017 Mrs Smith - National 5 Biology

TASK: Villus Structure
Individual Task Collect the villus diagram and stick it into the centre of your jotter. Draw an arrow onto your diagram to represent the absorption of glucose and amino acids. Now draw another arrow on the diagram to represent the absorption of the products of fat digestion. Note – you will have to distinguish these arrows in some way. glucose and amino acids products of fat digestion 26/04/2017 Mrs Smith - National 5 Biology

The Digestive System Watch the following video clips about digestion and the small intestine. Introduction to Digestion : Twig Small Intestine : Twig 26/04/2017 Mrs Smith - National 5 Biology

TYK Torrance pg’s 128 Qu’s 1-4

TYK – How did you do? 26/04/2017 Mrs Smith - National 5 Biology

Chapter 15: Animal Transport and exchange systems

Similar presentations

Presentation on theme: "Chapter 15: Animal Transport and exchange systems"— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

Chapter 15: Animal Transport and exchange systems

Similar presentations

Presentation on theme: "Chapter 15: Animal Transport and exchange systems"— Presentation transcript:

Similar presentations

About project

Feedback