1. Nutrition التغذية Nutrition (nourishment) is the need of cells and organisms of the materials (in the form of food) necessary for life. Nutrition (nourishment) is the need of cells and organisms of the materials (in the form of food) necessary for life.cellsorganismslifecellsorganismslife Nutriton is a process of intake of nutrients المواد الغذائية (like carbohydrates, fats, proteins,vitamins, minerals and water) by the organism and the utilisation of these nutrients by the organism. Nutriton is a process of intake of nutrients المواد الغذائية (like carbohydrates, fats, proteins,vitamins, minerals and water) by the organism and the utilisation of these nutrients by the organism.nutrients The diet الوجبة of an organism is what it eats. The diet الوجبة of an organism is what it eats. A poor diet can have a negative impact on health, causing deficiency diseases such as scurvy الإسقربوط, beriberi, health- threatening conditions like metabolic syndrome مشاكل أيضية. A poor diet can have a negative impact on health, causing deficiency diseases such as scurvy الإسقربوط, beriberi, health- threatening conditions like metabolic syndrome مشاكل أيضية.scurvyberiberimetabolic syndromescurvyberiberimetabolic syndrome Lecture 22: Animal physiology

2. Nutrients المواد الغذائية There are seven major classes of nutrients: carbohydrates, fats, fiber, minerals, protein, vitamin, and water. There are seven major classes of nutrients: carbohydrates, fats, fiber, minerals, protein, vitamin, and water. carbohydratesfatsfibermineralsproteinvitaminwater carbohydratesfatsfibermineralsproteinvitaminwater They are classified into two kategories: They are classified into two kategories: I)- Macronutrients مغذيات كبيرة : needed in relatively large amounts. They are carbohydrates, fats, fibers ألياف, proteins, and water. I)- Macronutrients مغذيات كبيرة : needed in relatively large amounts. They are carbohydrates, fats, fibers ألياف, proteins, and water.Macronutrients II)- Micronutrients مغذيات صغيرة : needed in smaller quantities. They are minerals الأملاح المعدنية and vitamins. II)- Micronutrients مغذيات صغيرة : needed in smaller quantities. They are minerals الأملاح المعدنية and vitamins.icronutrients

3. The macronutrients (but not fibers and water) provide structural material مواد بنائية for example (amino acids from which proteins are built) and (lipids from which cell membrane is built). The macronutrients (but not fibers and water) provide structural material مواد بنائية for example (amino acids from which proteins are built) and (lipids from which cell membrane is built). Some of the structural materials can be used to generate energy internally لتوليد الطاقة داخليا, and measured in kilocalories كيلو كالوري (often called "Calories"). Some of the structural materials can be used to generate energy internally لتوليد الطاقة داخليا, and measured in kilocalories كيلو كالوري (often called "Calories"). I- Carbohydrates and proteins provide 4 kcal of energy per gram. I- Carbohydrates and proteins provide 4 kcal of energy per gram. II- while fats provide 9 kcal per gram. II- while fats provide 9 kcal per gram. Vitamins, minerals, and water do not provide energy, but are required for other reasons. Vitamins, minerals, and water do not provide energy, but are required for other reasons. Fibers (i.e., non-digestible materials such as cellulose), seems to be required, for both mechanical and biochemical reasons. Fibers (i.e., non-digestible materials such as cellulose), seems to be required, for both mechanical and biochemical reasons.

4. Fats are triglycerides, made of fatty acid monomers bound to glycerol backbone. Some fatty acids, but not all, are essential in the diet: they cannot be synthesized in the body. Fats are triglycerides, made of fatty acid monomers bound to glycerol backbone. Some fatty acids, but not all, are essential in the diet: they cannot be synthesized in the body. Protein molecules contain amino acids, some of which are essential (the body can not make them internally). Some of the amino acids are convertible to glucose and can be used for energy production just as ordinary glucose during prolonged starvation. Protein molecules contain amino acids, some of which are essential (the body can not make them internally). Some of the amino acids are convertible to glucose and can be used for energy production just as ordinary glucose during prolonged starvation. Most foods contain a mix of some or all of the nutrient classes, together with other substances such as toxins or various sorts. Most foods contain a mix of some or all of the nutrient classes, together with other substances such as toxins or various sorts. Some nutrients can be stored internally (eg, some vitamins), while others are required more or less continuously. Some nutrients can be stored internally (eg, some vitamins), while others are required more or less continuously. Poor health results from a lack of required nutrients or, too much of a required nutrient. For example, both salt and water (both are required) but cause illness (or even death) in too large amounts. Poor health results from a lack of required nutrients or, too much of a required nutrient. For example, both salt and water (both are required) but cause illness (or even death) in too large amounts.

5. Digestion الهضم Digestion: is the mechanical and chemical breaking down تكسير of food into smaller components, to a form that can be absorbed تُمتص. Digestion: is the mechanical and chemical breaking down تكسير of food into smaller components, to a form that can be absorbed تُمتص. Digestion is a form of catabolism that means break down of macro-food molecules أجزاء الطعام الكبيرة to smaller one. Digestion is a form of catabolism that means break down of macro-food molecules أجزاء الطعام الكبيرة to smaller one. a)- Extracellular digestion الهضم خارج الخلية : In mammals, food enters the mouth, being chewed by teeth, and broken down by the saliva اللعاب from the salivary glands. Then it travels down the esophagus البلعوم into the stomach المعدة, where acid begins physical break down of some food. The food go through the small intestine الأمعاء الدقيقة, through the large intestine الأمعاء الغليظة, and are excreted outside. b)- I ntracellular digestion الهضم داخل الخلية : Some other unicellular organisms الكائنات وحيدة الخلية use different mechanisms to digest food inside the cell.

6. Digestive systems الجهاز الهضمي Once food is inside the organism, digestion can be conducted in the cytoplasm, in a vesicle, through a tube, or through specialized organs aimed at making the absorption of nutrients more efficient. Once food is inside the organism, digestion can be conducted in the cytoplasm, in a vesicle, through a tube, or through specialized organs aimed at making the absorption of nutrients more efficient. Diggestive systems are classified into two kategories: Diggestive systems are classified into two kategories: a)- Gastrovascular cavity التجويف الوعائي المعوي : functions as a stomach in both digestion and the distribution of nutrients to all parts of the body. Digestion takes place within this central cavity التجويف المركزي which has only one opening to the outside that functions as both a mouth فم and an anus شرج. So, it is described as an incomplete gut معي غير كامل. b)- Complete gut المعي الكامل : has specialized organs أعضاء متخصصة that aid in the digestion of their food. Here, animals were created with organs such as beaks مناقير, tongues ألسنة, teeth أسنان, a crop حوصلة, gizzard القانصة, and others.

7. 1. Beaks : birds eat primarily seeds, nuts, and fruit, using their beaks to open even the toughest seed البذور الجافة. 2. Tongue : is skeletal muscle on the floor of the mouth that manipulates food for chewing ( المضغ ) and swallowing ( البلع ). The underside of the tongue is covered with a smooth mucous membrane غشاء مخاطي. The tongue is utilized يوظف to transport food down to the esophagus. 3. Teeth : (singular, tooth) are small whitish structures found in the jaws ( الفكوك ) of many vertebrates that are used to chew food مضغ الطعام. They are not made of bone, but rather of tissues of varying density and hardness. - Teeth of carnivores آكلات اللحوم are shaped to kill and tear meat وتمزق اللحم. - Teeth of carnivores آكلات اللحوم are shaped to kill and tear meat وتمزق اللحم. - Teeth of herbivores آكلات العشب are made for grinding طحن plant parts. - Teeth of herbivores آكلات العشب are made for grinding طحن plant parts.

8. 4. Crop : is a thin-walled expanded portion جزء واسع رفيع الجدار of the alimentary canal used for the storage of food prior to digestion تخزين الطعام قبل الهضم. In some birds it is an expanded, muscular pouch كيس near throat قرب الزور. In adult pigeons, the crop can produce crop milk لبن الحوصلة to feed newly hatched birds. Certain insects may have a crop or enlarged oesophagus. Certain insects may have a crop or enlarged oesophagus. 5. Gizzard : is a specialized stomach with thick سميك, muscular walls used for grinding up food طحن الطعام. Birds and cockroaches have developed gizzards to assist in the digestion of tough materials. The gizzard can grind food with stones that have been swallowed and pass it back to the true stomach and vice versa. Birds and cockroaches have developed gizzards to assist in the digestion of tough materials. The gizzard can grind food with stones that have been swallowed and pass it back to the true stomach and vice versa.

9. 6. Abomasum المعدة الحقيقية Herbivores have evolved cecums (or an abomasum in the case of ruminants الحيوانات المجترة ). Ruminants have a fore-stomach معدة أمامية with four chambers. These are the rumen الكرش, reticulum الشبكية, omasum الورقية, and abomasum الأنفحة ( المعدة الحقيقية ): Herbivores have evolved cecums (or an abomasum in the case of ruminants الحيوانات المجترة ). Ruminants have a fore-stomach معدة أمامية with four chambers. These are the rumen الكرش, reticulum الشبكية, omasum الورقية, and abomasum الأنفحة ( المعدة الحقيقية ): In the first two chambers (the rumen & the reticulum) the food is mixed with saliva and separates into solid and liquid materials. The solid is then regurgitated يُسترجع, chewed slowly يمضغ ببطء to completely mix it with saliva and to break down the particle size. In the first two chambers (the rumen & the reticulum) the food is mixed with saliva and separates into solid and liquid materials. The solid is then regurgitated يُسترجع, chewed slowly يمضغ ببطء to completely mix it with saliva and to break down the particle size. In the 3 rd chamber (omasum) water and many of the inorganic mineral elements are absorbed into the blood stream. In the 3 rd chamber (omasum) water and many of the inorganic mineral elements are absorbed into the blood stream. The 4 th chamber (abomasum) which is equivalent of the human stomach. It serves primarily as a site for digestion of microbial and dietary protein. Digesta is finally moved into the small intestine for absorption of nutrients. The 4 th chamber (abomasum) which is equivalent of the human stomach. It serves primarily as a site for digestion of microbial and dietary protein. Digesta is finally moved into the small intestine for absorption of nutrients.