Engineering Balances: Respiration and Digestion in BME

1. BIO307- Bioengineering principles SPRING 2019 Lecture 5 Engineering Balances: Respiration and Digestion Lecturer: Jasmin Sutkovic 8.4.2019

2. Content • Introduction • Introduction to mass balances • Respiratory physiology • Digestion and metabolism

3. Introduction • Human nutrition and respiration from the perspective of biomedical engineering (BME). • What are the processes responsible for input of nutrients and raw materials? • How are molecular nutrients extracted from ingested materials? • How are these processes controlled?

4. Mass balance • This section presents another frequent aspect of engineering analysis: the mass balance. • A mass balance is simply a systematic approach to applying a physical principle: • Mass cannot be created or destroyed. • Before illustrating a mass balance, the concept of a system is presented.

5. What do we engineers mean by a System? • Supporting beam under the bridge • Set of components on a computer circuits board • Human body • The cell • Organ in the body

6. So, we first define the system • After we try to examine changes in the system caused by movement of mass, heat, or electrical charge across the system boundaries. • This depend if the system is open or closed? • In a closed system, there is no movement of mass across the system boundaries during the period of observation! • Open systems, in contrast, do allow for exchange of mass across system boundaries

8. Formula for Mass balance We analyze changes in mass within an open or closed system. A mass balance on an open system can be written: • ACC is the rate of accumulation of mass in the system, • IN is the rate of flow of mass into the system, • OUT is the rate of flow of mass out of the system, • GEN is the rate of mass generation within the system • CONS is the rate of mass consumption within the system GEN − CONS is the overall net rate of mass production within the system boundaries

9. Water balance in the body • Consider the human body as system! • Basically the liquid concentration must remain in homeostasis.. in balance! • The intake of water should mot exceed nor be limited to our body ! • Kidney regulates the water balance…

10. Water homeostasis in human body • https://www.youtube.com/watch?v=i7TgTcm1Ziw

11. Kidneys • The kidneys regulates water control in two ways: • by regulation of chemical composition of the body fluids, particularly, concentration of sodium, and 2) by direct elimination of water from the body.

12. Respiratory physiology • Has in general two meanings: • Internal respiration • In cells, where energy is derived from diet. Cells consumes oxygen and produces CO2 • External respiration • Done by the human LUNGs

14. External respiration • The exchange of O2 and CO2 happens in ALVEOLUS (a membrane that separates the blood from gases )

17. Digestion and metabolism • During digestion, solid foods are mechanically pulverized into small pieces, which are further dissolved into molecules. • Large molecules, such as proteins and polysaccharides, are broken down into monomer units to allow for absorption into the body. • The digestive system has a number of functions that are familiar to engineers: storage and controlled emptying, mixing, secretion, digestion, and adsorption.

19. In its simplest description, the digestive tract is 8 m of tubing connecting the mouth to the anus. • One of the most important functions of the digestive tract is to perform digestive actions to break food into its molecular components without harming the tissues inside the body!

21. Organs of the digestive system and their function • Mouth : Chewing breaks the food into pieces that are more easily digested, while saliva mixes with food to begin the process of breaking it down into a form your body can absorb and use. • Esophagus: by means of a series of muscular contractions called peristalsis, the esophagus delivers food to your stomach. • Stomach : The stomach is a hollow organ, or "container," that holds food while it is being mixed with enzymes. The stomach is an expandable vessel, which can hold up to 1 L of material. • Cells of the stomach lining secrete a large volume of fluid into the stomach lumen. These secreted gastric fluids are highly acidic, with pH low as 1. • Low gastric pH protects people from bacteria in the diet because most bacteria cannot survive in low pH.

22. Small intestine-Made up of three segments: the duodenum, jejunum, and ileum  • The small intestine has a rich array of digestive enzymes, many of which are secreted into the intestine by the Pancreas These enzymes include peptidases (such as chymotrypsin and carboxypeptidase) to break down proteins, lipases that break triglycerides into glycerol and fatty acids, amylases to break down carbohydrates, andribonucleasesto break down nucleic acids.. Many of the pancreatic enzymes are zymogens (proteins that are secreted in an inactive form and then converted into an active enzyme)

23. Liver • Liver , has multiple functions, but its main function within the digestive system is to process the nutrients absorbed from the small intestine. Functions: • Cleanses blood • Regulates the supply of body fuel • Manufactures many essential body proteins involved in • Regulates the balance of many hormones • Regulates body cholesterol • Regulates the supply of essential vitamins and minerals such as iron and copper • Produces bile which eliminates toxic substances from the body and aids digestion. http://www.liver.ca/liver-health/how-liver-works.aspx

24. Gallbladder, stores and concentrates bile, and then releases it into the duodenum to help absorb and digest fats. • Colon (large intestine), a 6-foot long muscular tube that connects the small intestine to the rectum. Regulates the disposal of digested and unused nutrients to the rectum • Rectum, a chamber that connects the colon to the anus. When anything (gas or stool) comes into the rectum, sensors send a message to the brain.  • Anus…..the end point of the nutrients journey …

25. The digestive organs…