Need for Transport National 5 Biology

Learning Outcomes Explain why multicellular organisms require transport systems Explain why plants require a transport system for water State the name for the movement of water through a plant State the structures involved in the transport of water in plants Describe the structure and function of xylem Describe the function of guard cells Name environmental factors which increase the rate of transpiration in plants Explain why plants require a transport system for sugar State the structure involved in the transport of sugar in plants

SA : V Ratio The larger the organism, the smaller its SA : V ratio Larger organisms need transport systems to carry raw materials. 6 : 1

Plant Transport Think – What needs to be transported about inside plants? We need to find out more about how it happens and the problems that arise.

Xylem They have no cell contents and no nucleus. They are dead cells. The end walls have broken down and have disintegrated. Side walls are strengthened by lignin to prevent damage by water pressure

Transport of water lignin xylem vessel

Transpiration Plants need water for photosynthesis. It is absorbed in the roots and evaporated out of leaves.

Transpiration Rate Various factors will affect the rate of transpiration. This includes wind humidity temperature light

Potometer Transpiration rate can be measured using a potometer. Changing conditions around the potometer will change the rate of transpiration

Leaf Structure cuticle upper epidermis lower epidermis stomaguard cells moist air space mesophyll layer vein

Leaf Structure PartFunction Upper Epidermis Mesophyll layer Vein Stoma Guard cells Moist air space Large surface area to help gas exchange Pores on surface to allow gas exchange Cells contain chlorophyll for photosynthesis Cells to control gas exchange by opening Protective layer. Transparent to let light in Contains xylem and phloem for transport

Guard Cells Stoma opens Thin outer wall stretches more than thick inner wall Guard cells become turgid Water enters guard cells Water lost from guard cells Guard cells become flaccid Walls not stretched Stoma closes

Plant Transport transport-1187/ transport-1187

Phloem Columns of sieve tubes, with sieve plates at either end. Companion cells sit next to the sieve tubes. sieve plates with pores sieve tube They have a dense cytoplasm and a nucleus. They are living cells. companion cell nearby cell

Stem cross section

Root cross section

Learning Outcomes Describe the structure of the heart - include names of chambers, blood vessels entering and leaving the heart Describe the position and the function of valves in the heart Describe the pathway of blood through the heart, lungs and body Describe the structure and function of arteries, veins and capillaries Explain how the structure of a capillary network is related to its function State what is carried in the blood State the location and function of haemoglobin Explain the need for iron in the diet and health problems when there is a lack of iron

The heart The heart is made of a special type of muscle called cardiac muscle, which doesn’t get tired. The job of the heart is to pump blood around the body. The heart can be thought of as a muscular pump.

left ventricle The heart has four chambers. The heart is shown from the front. Like it is in your body…the left hand side is nearest your left arm etc… Left atrium right ventricle right atrium The heart

Blood contains (as well as many other things) dissolved food, and gases (e.g. oxygen and carbon dioxide. The blood from the heart must reach all cells, so that means the heart needs its own blood supply too. Every cell in the body needs food and oxygen. The coronary artery supplies food and oxygen to the cells of the heart muscle. When these blood vessels get blocked, you can suffer a heart attack. coronary artery

The heart from lungs to lungs to body from body The ventricles have thicker walls than the atria. The left ventricle has a thicker wall than the right ventricle because the left ventricle has to pump blood right around the body and the right ventricle only has to pump blood to the lungs. left ventricle right ventricle left atrium

The heart pulmonary vein pulmonary artery aortavena cava Arteries go away from the heart. Veins return to the heart. A pulse indicates that blood is flowing through an artery. Can you find your own pulse?

Circulation around body Aorta Pulmonary artery Vena Cava Pulmonary vein

Blood flow through the heart Deoxygenated blood i.e. low in oxygen returns to the heart via the vena cava after travelling to all parts of the body. It enters the heart at the right atrium. The right ventricle then pumps blood out through the pulmonary artery to the lungs. In the lungs the blood picks up oxygen and loses carbon dioxide. The oxygenated blood then returns to the heart via the pulmonary vein, entering the left atrium. The left ventricle pumps blood out through the aorta to the body. vena cava atrium ventricle pulmonary aorta lungs oxygen carbon dioxide veinleft

The heart Valves stop blood flowing backwards (ie the wrong way). Valves between atria and ventricles One set of valves are found between the two atria and the ventricles – blood can’t flow back into the atrium. The heart has two sets of valves. Valves can be open or closed (like gates). Valves between ventricles and blood vessels The other set of valves are found between the two ventricles and the blood vessels leaving the heart – blood can’t flow back into the ventricles.

Valves act like a one way street Valves

heart arteriesveins capillaries Veins/arteries

The heart and blood circulation The blood circulation must reach all cells. Every cell in the body needs food and oxygen. blood vessels arteries veins Arteries carry oxygenated blood (high in oxygen) from the heart around the body. Veins carry deoxygenated blood (high in carbon dioxide) back to the heart. The exception is the pulmonary artery, which carries blood high in carbon dioxide from the heart to the lungs.

Arteries have thick walls to withstand the high pressure of the blood being pumped by the heart. Arteries divide into smaller blood vessels and finally into tiny capillaries. Arteries Veins and Capillaries

Capillaries are in close contact with the living cells. They are only one cell thick. They allow water, gases and other substances, to pass to between the blood and the body’s tissues.

Veins have thinner walls than arteries. They carry the deoxygenated blood (high in carbon dioxide) blood back to the heart. Arteries Veins and Capillaries They have thinner walls because the deoxygenated blood is at low pressure. Veins have valves to prevent the backflow of blood. The pulmonary vein, which carries blood high in oxygen from the lungs to the heart is the exception.

Arteries Veins and Capillaries Blood is carried away from the heart in arteries. These arteries carry blood to the body’s organs and tissues. In the organs the arteries split up into a network of tiny tubes called capillaries. Substances are exchanged between the capillaries and the tissues. Blood leaves the tissues in vessels called veins which carry the blood back to the heart. organs veins capillaries arteries

Gas exchange at the tissues Oxygen diffuses from the high concentration in the capillary blood across into the body cells. Carbon dioxide diffuses from the high concentration in the cells into the plasma. diffuses plasma living cell capillary Blood from artery high oxygen low carbon dioxide Blood to vein high carbon dioxide low oxygen oxygen CO 2

More about Capillaries The capillary network allows efficient exchange of gas, food and waste because 1.They are narrow and thi n walled which gives a greater surface area to allow fast diffusion of gases etc. 2.They are very long which also increases the surface area. 3.No cell is ever far away from a capillary thus ensuring easy exchange. thin long surface

Red blood cells and plasma Blood is made up of cells floating in a liquid called plasma. The plasma also carries dissolved substances such as carbon dioxide, digested food and waste products. Red blood cells carry oxygen carbon dioxide food oxygen

Haemoglobin A red pigment called haemoglobin is found in red blood cells. Its function is to combine with oxygen to form oxyhaemoglobin. At the lungs, haemoglobin combines with oxygen to make oxyhaemoglobin. At the tissues, oxyhaemoglobin releases oxygen and becomes haemoglobin again. haemoglobin oxyhaemoglobin oxygenhaemoglobin + at tissues at lungs

Learning Outcomes Describe the structure and function of the lungs Explain the function of the rings of cartilage in the trachea Describe the function of cilia and mucus in the trachea Describe gas exchange within the alveoli Explain how the structure of the lungs is related to their function

Respiratory system To carry out respiration, the body needs a supply of oxygen. It gets this from the air. The respiratory system extracts oxygen form the air to make it available [via the blood] to the respiring cell.

nasal cavity heart diaphragm trachea intercostal muscle air sac bronchus Left lung ribs Respiratory System Structures - Revision

Lung Structure Lungs are spongy organs full of tiny air sacs called alveoli. They have a very large surface area. They are pinky red because they have a good blood supply. Rings of cartilage are found around the trachea and the bronchi to prevent them from collapsing.

The lining of air passages Air contains dust and germs which could damage your lungs. The cells lining the air passages have small hairs or cilia. The cilia move in waves to push upwards and keep the lungs clear. (produce mucus)

Lung Structure

The bronchi divide into smaller and smaller tubes called bronchioles. Gas exchange in the air sacs Oxygen dissolves in moisture and diffuses from lungs into blood because there is a higher concentration in the air sac than in the blood. Carbon dioxide diffuses in opposite direction because there is a higher concentration in the blood than in the air sac. Each bronchiole ends in an air sac, which is lined in moisture.

Oxygen and carbon dioxide are exchanged between the air and blood in the alveoli. There are many thousands of alveoli. The alveoli

Importance in Multicellular Organisms oxygen carbon dioxide

Learning Outcomes State the function of the digestive system Name the parts of the digestive system and give their function Describe the process of peristalsis Explain how the structure of the small intestine is related to its function State where glucose, amino acids, fatty acids and glycerol are absorbed within the villi

The Alimentary Canal The alimentary canal leads from the mouth to the anus. Associated organs are connected to it – the salivary glands, liver and pancreas by ducts. 1.Digestion in the mouth Digestion begins in the mouth with mechanical breakdown of food by teeth and chemical breakdown of starch by the enzyme amylase.( made in salivary glands) Saliva contains mucus so food is easy to swallow.

Oesophagus is a muscular tube - connects the mouth to stomach. It is the start of the alimentary canal, which is a long tube stretching from mouth to anus. When food is swallowed wave-like muscular contractions called peristalsis ensures the food (bolus) moves down in a slow controlled way no matter what position the body is in. The muscle ahead of the food is relaxed while the muscle behind the food contracts. Oesophagus and Peristalsis

Muscles behind food contracted Muscles ahead of food relaxed Food Direction of food movement Peristalsis

The stomach is a muscular sac with longitudinal and circular muscles that contract and relax, churning or mixing food with acid and enzymes. The mucus, lining the stomach protects the wall from being damaged by the acid ( pH 2). Acid provides the correct pH for the protein digesting enzyme pepsin to work. protein pepsin Peptides Stomach

As food leaves the stomach, it enters the small intestine. The first 12 inches make up the duodenum. There are 2 ducts connected to this : a)Pancreatic : enzymes made by the pancreas enter through this. ( lipases,amylases and proteases, an example of a protease is trypsin) b)Bile : bile stored in the gall bladder enters through this. Bile is made in the liver but stored in the gall bladder. Bile emulsifies fats ( gets them to mix with water) and neutralises the acid soaked food coming from the stomach as it is an alkali. Small Intestine

The main job of the small intestine is to absorb the products of digestion. It is well adapted for this by : Long and inner membrane is highly folded. This increases the surface area for absorption Thin inner lining,only one cell thick. Many blood capillaries to absorb and transport products. Lacteals are present to transport fats Small Intestine

Villi in small intestine 100x

Small intestine villus

Glucose, amino acids ( products of carbohydrate and protein digestion) are absorbed into the blood capillaries Fatty acids and glycerol are absorbed into the lacteal. Next Step – Liver ! The liver decides how much sugar is needed in the blood and converts the excess to glycogen and stores it. Fate of Digested Food

The liver decides how much amino acids should be in the blood and converts the excess to urea. This urea is taken to the kidneys for excretion in urine. Fatty acids and glycerol travel in the lymphatic system. Excess is stored as fatty tissue. Liver

Material passing into the large intestine consists of undigested matter ( fibre), bacteria and dead cells. The colon absorbs water from this before eliminating the waste as faeces. Large Intestine