Digestion & Nutrition
Mission 1: Nutrition...We Are What We Eat!
Mission Objectives. You should be able to...
1. Describe the difference between vitamins and minerals.
2. Determine what makes a vitamin or mineral "essential."
3. Describe the effects of a diet that does not include essential vitamins and minerals.
4. Describe the effects of a diet that contains too much essential vitamins and minerals.
5. Explain how appetite is controlled.
To introduce this mission, let's watch this short TedEd video.
Mission Objectives. You should be able to...
1. Describe the difference between vitamins and minerals.
2. Determine what makes a vitamin or mineral "essential."
3. Describe the effects of a diet that does not include essential vitamins and minerals.
4. Describe the effects of a diet that contains too much essential vitamins and minerals.
5. Explain how appetite is controlled.
To introduce this mission, let's watch this short TedEd video.
Essential nutrients are absorbed to give you energy, strengthen your bones and can prevent you from getting certain kinds of diseases. Your body can produce some of what it needs, but not all essential nutrients can be synthesized by the body. Examples include some amino acids, fatty acids, vitamins and minerals.
Minerals. Minerals are inorganic substances that are needed for a healthy diet. Each mineral plays a specific role. Calcium is used for bones and iron for blood. Other minerals are known as electrolytes because they can dissolve in cytoplasm and intercellular fluid. Examples of these electrolytes are calcium, iron II, sodium, magneisum, chloride and potassium. These ions are important in the mechanism behind how action potentials are sent along neurons, synapses and muscle contractions.
Vitamins. Vitamins are organic molecules that are synthesized by living organisms. Many organisms rely on intake from plants. Intake for vitamins and minerals is in small quantities. Vitamins are used to create long-lived substances within the body, such as Vitamin C. In humans, Vit C is necessary and has to be part of our diet. Not enough Vit C can lead to deficiencies and diseases such as scurvy. Vitamin D is another essential nutrient for the proper formation of bones. Without Vit D, children can get rickets. The epidermis contains precursors that can synthesize Vit D when stimulated by sunlight. But too much sunlight can lead to sunburn and skin cancer.
Minerals. Minerals are inorganic substances that are needed for a healthy diet. Each mineral plays a specific role. Calcium is used for bones and iron for blood. Other minerals are known as electrolytes because they can dissolve in cytoplasm and intercellular fluid. Examples of these electrolytes are calcium, iron II, sodium, magneisum, chloride and potassium. These ions are important in the mechanism behind how action potentials are sent along neurons, synapses and muscle contractions.
Vitamins. Vitamins are organic molecules that are synthesized by living organisms. Many organisms rely on intake from plants. Intake for vitamins and minerals is in small quantities. Vitamins are used to create long-lived substances within the body, such as Vitamin C. In humans, Vit C is necessary and has to be part of our diet. Not enough Vit C can lead to deficiencies and diseases such as scurvy. Vitamin D is another essential nutrient for the proper formation of bones. Without Vit D, children can get rickets. The epidermis contains precursors that can synthesize Vit D when stimulated by sunlight. But too much sunlight can lead to sunburn and skin cancer.
Fatty Acids. The identity of the fatty acid is determined by the number of carbon atoms and the location of the double bond. Specifically, we need two fatty acids in our diet: omega-3 and omega-6.
Amino Acids. There are 20 amino acids, and nine of them are essential. A lack of one or more amino acids means certain proteins cannot be synthesized. There are no storage mechanisms for amino acids, so essential aminos need to be a part of our diet. Phenylketonuria (PKU) is a genetically inherited disease caused by an inability to metabolize the amino acid phenylalanine. Too much phenylalanine can cause mental and behavioral developmental problems.
Eating & Nutrition. Appetite is controlled by the hypothalamus. It is the desire to eat. When you have consumed enough food, you have reached a state of satiety and you stop eating (or you should). The mechanisms for appetite and satiety are a combination of feedback loops between the nervous system, the digestive system, and the endocrine system. The pancreas releases hormones that reduce appetite after eating. Adipose tissue produces a hormone called leptin and leptin sends a message to the hypothalamus to suppress appetite.
Consequences of being overweight. The more you weigh, the more blood is needed to supply oxygen and nutrients to your cells. The more blood on the move, the greater the pressure on the internal walls of your arteries. The chances of getting Type II diabetes occurring increases with weight gain. An excess of nutrients can lead to obesity.
When there is a lack of calories in the diet, the body will draw on reserves for substances that are needed. Glycogen stored in the liver will be used up first. Body fat is then used. Because there are no storage mechanisms for proteins, and if there is no protein intake, then the body begins using body tissue for energy. Muscle tissue is used at this point.
What happens when a diet is too rich in essential nutrients?
How is appetite controlled? Find out and submit a short (4-5 sentences) paragraph explaining how to Managebac under the title "Appetite Control."
Amino Acids. There are 20 amino acids, and nine of them are essential. A lack of one or more amino acids means certain proteins cannot be synthesized. There are no storage mechanisms for amino acids, so essential aminos need to be a part of our diet. Phenylketonuria (PKU) is a genetically inherited disease caused by an inability to metabolize the amino acid phenylalanine. Too much phenylalanine can cause mental and behavioral developmental problems.
Eating & Nutrition. Appetite is controlled by the hypothalamus. It is the desire to eat. When you have consumed enough food, you have reached a state of satiety and you stop eating (or you should). The mechanisms for appetite and satiety are a combination of feedback loops between the nervous system, the digestive system, and the endocrine system. The pancreas releases hormones that reduce appetite after eating. Adipose tissue produces a hormone called leptin and leptin sends a message to the hypothalamus to suppress appetite.
Consequences of being overweight. The more you weigh, the more blood is needed to supply oxygen and nutrients to your cells. The more blood on the move, the greater the pressure on the internal walls of your arteries. The chances of getting Type II diabetes occurring increases with weight gain. An excess of nutrients can lead to obesity.
When there is a lack of calories in the diet, the body will draw on reserves for substances that are needed. Glycogen stored in the liver will be used up first. Body fat is then used. Because there are no storage mechanisms for proteins, and if there is no protein intake, then the body begins using body tissue for energy. Muscle tissue is used at this point.
What happens when a diet is too rich in essential nutrients?
How is appetite controlled? Find out and submit a short (4-5 sentences) paragraph explaining how to Managebac under the title "Appetite Control."
Mission 2:
Mission Objectives. You should be able to...
1. Explain the role of exocrine glands in digestion.
2. Describe the role of hydrochloric acid during the digestive process.
3. Determine what causes stomach ulcers.
4. Explain how villi have adapted for efficient absorption.
5. State why fiber is important in one's diet.
Mission Objectives. You should be able to...
1. Explain the role of exocrine glands in digestion.
2. Describe the role of hydrochloric acid during the digestive process.
3. Determine what causes stomach ulcers.
4. Explain how villi have adapted for efficient absorption.
5. State why fiber is important in one's diet.
Exocrine glands produce secretions that are useful in specific locations in the body via ducts. Examples of secretions: tears (lacrimal fluid) from lacrimal glands, perspiration from sweat glands, and breast milk from mammary glands. These are secreted through the skin. The other location is the interior (lumen) of some part of the alimentary canal. Digestive secretions fall into the latter category.
Table provides a detailed list of exocrine digestive secretions. There are four: saliva, gastric juice, bile and pancreatic juice.
In the stomach is where main digestion occurs. The stomach has glands in its inner lining, called gastric pits. When your senses pick up the smell, sight or taste of food, the ANS sends an impulse to your brain (medulla oblongata) and results in an action potential along the vagus nerve to the stomach. The stomach then begins to secrete hydrochloric acid (HCl; pH <2), pepsinogen and gastrin. Gastrin flows into the blood stream and pepsinogen reacts with HCl to make pepsin, a protease enzyme.
When the stomach is full, the vagus nerve sends a signal to the medulla oblongata, and then the medulla oblongata sends a signal to the stomach to increase production of HCl and pepsinogen to increase the rate of digestion.
In time, a valve at the lower end of the stomach opens and releases chyme into the upper small intestine (duodenum). A set of signals terminates the secretion of acid and pepsinogen from the gastric pits. A hormone called secretin enters the blood and lowers the gastric pit activity.
Table provides a detailed list of exocrine digestive secretions. There are four: saliva, gastric juice, bile and pancreatic juice.
In the stomach is where main digestion occurs. The stomach has glands in its inner lining, called gastric pits. When your senses pick up the smell, sight or taste of food, the ANS sends an impulse to your brain (medulla oblongata) and results in an action potential along the vagus nerve to the stomach. The stomach then begins to secrete hydrochloric acid (HCl; pH <2), pepsinogen and gastrin. Gastrin flows into the blood stream and pepsinogen reacts with HCl to make pepsin, a protease enzyme.
When the stomach is full, the vagus nerve sends a signal to the medulla oblongata, and then the medulla oblongata sends a signal to the stomach to increase production of HCl and pepsinogen to increase the rate of digestion.
In time, a valve at the lower end of the stomach opens and releases chyme into the upper small intestine (duodenum). A set of signals terminates the secretion of acid and pepsinogen from the gastric pits. A hormone called secretin enters the blood and lowers the gastric pit activity.
Digestion is a chemical process that converts macromolecules into small parts so that they can be absorbed by the body. Proteins come in 3D shapes and can be denatured in the highly acidic stomach environment. Bonds are broken and the protein becomes “available” and digestive enzymes can access the peptide bonds between amino acids. Pepsinogen turns into pepsin when it reacts with HCl, and the pH of the stomach is ideal for the enzymatic activity of pepsin.
Another function of HCl in the stomach is to help control ingestion of some pathogens. Many foods contain bacteria and fungi, and a small percentage of them are harmful (pathogenic) and the low pH helps to kill most of these before releasing chyme into the small intestine.
Read about H. pylori, a bacteria found in the stomach that can survive the low pH environment. Answer the following questions and submit your answers to Managebac underneath "H. pylori analysis."
What is H pylori?
Symptoms of H pylori
Risk Factors for catching H pylori
Complications associated with H pylori
Another function of HCl in the stomach is to help control ingestion of some pathogens. Many foods contain bacteria and fungi, and a small percentage of them are harmful (pathogenic) and the low pH helps to kill most of these before releasing chyme into the small intestine.
Read about H. pylori, a bacteria found in the stomach that can survive the low pH environment. Answer the following questions and submit your answers to Managebac underneath "H. pylori analysis."
What is H pylori?
Symptoms of H pylori
Risk Factors for catching H pylori
Complications associated with H pylori
The small intestine is lined with villi. Above (slideshare.net) is the structure of a villus. There are millions of villi lining the small intestine and their purpose is absorption of nutrients from chyme. Each villus has millions of microscopic fingerlike projections called microvilli. This allows for a huge amount of surface area necessary for nutrient absorption. Some of the molecules absorbed are absorbed using an active transport mechanism. Pinocytosis is one mechanism by which molecules are absorbed from the lumen into the villi and requires ATP.
Some ingested substances will never be digested and move into the large intestine to be removed as solid waste. Page 510 lists examples. Fiber is essential for a healthy diet. It is "roughage" composed of cellulose and lignin in plant material and helps the digestive system by providing bulk. In order for peristalsis to function at optimal levels, a sufficient amount roughage is required for the muscles to apply pressure to in order to move the material through the intestine. Rate of movement through the intestine has a positive correlation with fiber consumption.
Some ingested substances will never be digested and move into the large intestine to be removed as solid waste. Page 510 lists examples. Fiber is essential for a healthy diet. It is "roughage" composed of cellulose and lignin in plant material and helps the digestive system by providing bulk. In order for peristalsis to function at optimal levels, a sufficient amount roughage is required for the muscles to apply pressure to in order to move the material through the intestine. Rate of movement through the intestine has a positive correlation with fiber consumption.