NUT 150 Nutrient Absorption and Delivery 4.4

Facilitated diffusion

-absorbed by moving from high to low concentration -NO ENERGY -YES TRANSPORTER

The Lymphatic or Immune System

-body's drainage system -tubes, vessels, and other lymphatic organs that transport a fluid called lymph -Lymph is made up of whatever needs to be drained or moved from one place in the body to another THREE PARTS: 1) returns excess fluid from the tissues to the blood. 2) Next, it defends the body against attacking microorganisms and disease. 3) Finally, and most important in our discussion of digestion, it transports most fats and fat-soluble vitamins before they enter into the blood stream. -fat soluble nutrient •packaged into fat transporters and pulled into lacteals and not into the blood capillaries. •The lacteals are tiny lymph vessels which are also found in the middle of each small intestine villi •nutrients enter the general circulation of the blood prior to passing through the liver

The Circulatory System

-circulates blood throughout the body -The blood transports nutrients and oxygen to organs and tissue cells of the body removing carbon dioxide and waste products. -heart, blood, and blood vessels -Arteries are vessels that transport blood away from the heart -Veins are vessels that transport blood towards the heart. -Arteries become smaller and smaller on their way to cells, by the time blood reaches a cell, the vessel is now called a capillary. -exchange oxygen, nutrients, and wastes between the blood and body tissues

Passive diffusion

-moved across the intestinal cell membrane due to the concentration gradient that exists. -NO ENERGY -NO TRANSPORTER

Active transport

-moves digested nutrients from a low to a high concentration -YES ENERGY -YES TRANSPORTER

Waste Removal

After digestion, any of the nutrients or other food material not absorbed into the body, such as fiber, will be eliminated through the feces Waste products also accumulate inside the body and must also be removed such as carbon dioxide, minerals, and nitrogen-containing materials *Kidney plays the main role in this waste elimination by filtering water and other waste materials from the blood and then concentrating the waste in the urine and excreting it.

Anabolism and Building

Energy released by catabolic pathways powers anabolic pathways in the building of macromolecules, cells, and tissues also build energy-storage molecules, such as glycogen, the glucose-storage molecule

Adsorption

For the nutrients to be used by the body cells they have to first leave the GI tract being absorbed through the intestinal wall and then delivered to one of the body's two transport systems: the circulatory (blood) or lymphatic systems.

Metabolism

Once our food is digested and absorbed, the blood transports the nutrients to the cells where they are used in processes of metabolism. ◘The sum of all chemical reactions required to support life. -Break down and release energy from Carbohydrates, fats, proteins, and alcohol -Others allow us to build and make new substances

Water-soluable

glucose and amino acids are transported from the small intestine to the liver through the body's network of blood vessels and veins Water-soluble nutrients absorbed in the small intestine travel mainly to the liver through the hepatic portal vein. The liver regulates the use of nutrients.

Fat-soluable

transported through the lymphatic system, before ever entering the blood

Metabolic Pathway

◘ group of chemical reactions in the body that progresses as a sequence from start to finish Catabolism or Anabolism

Catabolism and Energy Production

◘cellular respiration which is a process that transforms the food macronutrient energy into cellular energy. -Cellular ENERGY adenosine triphosphate (ATP) -broken down and released can be used to perform cellular work such as active transport, muscle contractions, growth, and repair of tissues

Cellular Respiration

◘glucose, fatty acids, and proteins are converted into carbon dioxide, water, and ATP when oxygen is present. 1) First the macronutrients are broken down to form acetyl-CoA, a two-carbon molecule 2) Acetyl-CoA enters the citric acid cycle, a multi-step circular pathway which produces ATP, carbon dioxide (CO2), and high energy (e-)'s. 3)(e-)'s carried by molecules into the inner membrane of the mitochondria in preparation for the next stage 4) Energy is released in the form of ATP as electrons are sequentially transferred between multiple proteins. At the same time, oxygen combines with electrons and hydrogen to form water.

Catabolism

◘process of breaking down materials -RELEASE ENERGY

Anabolism

◘process of building larger materials from smaller components. -CONSUME ENERGY