osmosis solvent solution diffusion Lungs/alveoliLarge surface area/ volume ratio Stomata/mesophyll Active transport solute I am a transport process that involves the movement of gases and is passive I am the movement of molecules against their concentration gradient I am the movement of water from a high concentration to a low concentration. I am the word used to describe water when sugar has dissolved I am the word used to describe the sugar I am the combination of both the water and the sugar I am the gas exchange site in humans I am the gas exchange site in plants I am a structural adaptation that increases the rate of gas exchange

TITLE: Photosynthesis - making the links Objectives: To know that the lungs are the site of gas exchange in mammals (grade C) Villi and microvilli allow efficient exchange in the small intestine (grade C/B) Gas exchange is efficient due to structural adaptations (Grade B/A) Gas exchange occurs by the process of diffusion (Grade B/A) The diaphragm separates the thorax from the abdomen KEY WORDS: Lungs Alveoli/alveolus Blood vessels Capillaries Exchange Diaphragm Intercostal muscles Internal External Surface area Thin layer Monocellular Moisture Villi Microvilli Outcomes: Complete ‘what am I’ starter Make observations of lung tissue Label a diagram of the lungs and an alveolus Make predictions of gas composition in both inhaled and exhaled air Complete extended writing activity for both alveolus and villi.

Make your observations of the lung tissue Q:What is this diagram showing? What do you notice?

To secure the B grade - What’s the missing term? The lungs are the site of ……………………………. The alveoli has an excellent…………….. supply The cells of the alveoli are …………. cell thick The arrangement of the alveoli produces a large…………… area to volume ………………. Gas exchange surface ratio blood one

In summary - Adaptations for exchanging material Having a large surface area Being thin (monocellular) provides a short diffusion path (A grade) Animal – have an efficient blood supply Animals – being ventilated is essential for gas exchange The size and complexity of an organism increases the difficulty of exchanging materials

Where is this structure found and what is its role?

The small intestine - villi The villi provide a large surface area and provide a network of capillaries to absorb the products of digestion by diffusion and active transport The villi consist of epithelial cells. (unit 2) The villi are sites of nutrient absorption. Nutrients are absorbed by the cells of the villi into the capillaries within them. This absorption makes vitamins and nutrients available to your blood and lymphatic fluid.

The cells of the villi produce enzymes which help digest carbohydrates and protein. Most all of the absorption which occurs in your body takes place in the small intestine through the action of the villi. It is not difficult to see then how vital these body structures are.

Coeliac Disease and Villi Coeliac disease directly impacts the role of the villi in digestion and absorption. This autoimmune disease causes your body to damage the villi whenever you eat foods containing gluten. If villi are damaged, their ability to perform properly is impaired. The effects are two-fold. First, damage or destruction of the villi decreases the amount of surface area in your intestine available for absorption. Second, rather than capturing valuable nutrients from your food, they are excreted, increasing your risk of malnutrition as well as vitamin and mineral deficiencies. This physical damage may be evident if your doctor performs a biopsy of the small intestine in order to confirm the diagnosis of coeliac disease.

Gluten is the protein found in wheat

Task: Complete the extended writing activity – A grade work. Describe and explain how both the alveolus and the villi (microvilli) are adapted to be efficient exchange surfaces.

Ventilation When we breathe in the intercostal muscles contact and the diaphragm contacts. This increases the volume in the thorax and decreases the pressure. Air rushes in. When we breathe out the intercostal muscles relax and the diaphragm relaxes. This decreases the volume and increases pressure. Forcing air out. This is called VENTILATION.

The lungs … (T/F) The diaphragm is a large muscle The lungs are found in the abdomen When you breathe out the diaphragm relaxes When you inhale the intercostal muscles contract The alveoli are the site of exchange in the small intestine True False True False