Digestive System Lecture Notes PDF

Dr. Tarig Alarabi MBBS , BSc, MSc- Anatomy, MSc – Embryology. PhD Department of Humana Anatomy Faculty of Medicine - KKU  Objectives: By the end of this lecture we will be able to know: 1- Functions of the digestive system. 2- Different parts of the digestive system. 3- Safety o...

Dr. Tarig Alarabi MBBS , BSc, MSc- Anatomy, MSc – Embryology. PhD Department of Humana Anatomy Faculty of Medicine - KKU  Objectives: By the end of this lecture we will be able to know: 1- Functions of the digestive system. 2- Different parts of the digestive system. 3- Safety of the digestive system. 5- Routs of chemical hazards. 3- Prevention Steps and Strategies of food poisoning.  Introduction The digestive system is used for breaking down food into nutrients which then pass into the circulatory system and are taken to where they are needed in the body.  Functions of the Digestive System Ingest food Break down food into nutrient molecules Absorb molecules into the bloodstream Rid the body of indigestible remains  Introduction There are four stages to food processing: 1. Ingestion: taking in food 2. Digestion: breaking down food into nutrients 3. Absorption: taking in nutrients by cells 4. Egestion: removing any leftover wastes  Mouth Teeth mechanically Epiglottis is a flap-like break down food into structure at the back of small pieces. Tongue the throat that closes mixes food with saliva over the trachea (contains amylase, preventing food from which helps break down entering it. starch).  Parts of the Digestive System Teeth: Grinds your food. Salivary Glands: Produce the saliva in your mouth. Tongue: Helps to push food into your esophagus.  The tongue is not only one muscle. It is a group of muscles used to mix the food and articulate the words, and it is also what we use to taste food  The tongue pushes food around until it forms a ball called a bolus. The bolus is passed to the pharynx (throat) and the epiglottis makes sure the bolus passes into the esophagus and not down the windpipe!  Pharynx is divided into: 1. Nasopharynx 2. Oropharynx 3. Laryngopharynx  Muscular tube through which food passes from the mouth to the stomach The bolus passes down the esophagus by peristalsis. Peristalsis is a wave of muscular contractions pushing the bolus toward Esophagus the stomach. Peristalsis Waves  The Human Digestive System The stomach is a big muscular pouch that turns the bolus and mixes it with gastric juice, a mixture of stomach acid, mucus and enzymes.  Small intestine Function: 90% of absorption occurs here. N.B: The liver and pancreas help the small intestine to maximize absorption. Small intestine is divided into three parts: 1. Duodenum: The tube that runs from the stomach to the small intestine.  Jejunum The jejunum is where the majority of absorption takes place.  Ileum The last portion of the small intestine is the ileum, compacts the leftovers to pass through into the large intestine. Liver and pancrease Function of the liver: Produce the Bile, in the liver but stored in the gall bladder. Bile breaks down fats. Function of pancreas: The pancreas secretes a juice to reduce the acidity of the chyme.  Large intestine Function of large intestine (or colon): is used to Absorb water from the waste material Produce vitamin K and some B vitamins using the helpful bacteria that live here.  The Human Digestive System Divided into: 1. Ascending colon 2. Transverse colon 3. Descending colon 4. Sigmoid colon 5. Rectum 6. Anal canal  Safety of the digestive system Tools of protections: To protect employees in the workplace from ingestion/absorption of harmful substances you have to provide: 1. Use chemical protective clothing. 2. Use gloves. 3. Wear eye protection. 4. Use the face mask Chemical hazard routs: Chemical hazards pass to our bodies through four routes: Through digestive system: 1. Ingestion 2. Inhalation Through integumentary system: 3. Skin contact 4. Skin absorption  Food poisoning Prevention steps and strategies To prevent food poisoning you need to apply four steps: 1. Clean 2. Separate 3. Cook 4. Chill  References Fanning, F., 2003. Basic safety administration: A handbook for the new safety specialist. American Society of Safety Engineers. World Health Organization, 2021. WHO/ILO joint estimates of the work- related burden of disease and injury, 2000-2016: technical report with data sources and methods. Snell, R.S., 2018. Snell’s Clinical Anatomy. Wolters kluwer india Pvt Ltd. Lumley, J.S., 2008. Surface anatomy: the anatomical basis of clinical examination. Elsevier Health Sciences. Martini, F.H., 2009. Anatomy and Physiology'2007 Ed. Rex Bookstore, Inc.. Thank you …