Question

Discuss how the changes in taste and smell can contribute to malnutrition during illness and how these perceptions diminish with age.

Discuss the importance of the intestinal microbiome to overall health.

Describe the functions of the accessory organs of digestion in the digestive process.

List and discuss the many important functions of the liver.

Explain how it is possible for gastrointestinal function to continue without the gallbladder, but life itself cannot continue without the liver or the pancreas

Answer 1

1.Discuss how the changes in taste and smell can contribute to malnutrition during illness and how these perceptions diminish with age.

          The elderly population is extremely diverse, ranging from fit, active, and healthy octogenarians to extremely frail, totally dependent people with chronic disease and severe disabilities

Malnutrition can be defined as the state of being poorly nourished. It may be caused by the lack of one or more nutrients (under‐nutrition), or an excess of nutrients (over‐nutrition).

In the ageing population malnutrition is an important problem that has been seen in hospitals, residential care, and in the community.

Malnutrition is not an inevitable side effect of ageing, but many changes associated with the process of ageing can promote malnutrition.

For example, ageing is frequently associated with decreases in taste acuity and smell, deteriorating dental health, and decreases in physical activity, which may all affect nutrient intake.

Any change in nutrient intake can lead to malnutrition with its potentially serious consequences. Many studies have found a direct relation between the degree of malnutrition and increased length of stay, treatment costs, return to usual life, and re‐admission to hospital rates.

Therefore the treatment and prevention of malnutrition, which is most common in the older age group, is an important challenge for the health care system.

CHANGES IN TASTE AND SMELL CONTRIBUTING TO MALNUTRITION

Taste and smell are also implicated in the loss of appetite through a perceived decline in the pleasantness of food. Taste is also an important part of the cephalic phase response that prepares the body for digestion. It helps modulate food choice and meal size by increasing satiety and the pleasure of eating.

Loss of taste and smell is common in the elderly and can be exacerbated by disease and drugs. The cause of taste loss is not fully understood but possible theories include a reduction in the number of taste buds, or a decrease in the functioning of receptors in cell membranes involved in the taste sensation.

Many drugs can change taste and smell, including drugs in the following groups: lipid lowering drugs, antihistamines, antibiotics, anti‐inflammatories, bronchodilators and other asthma drugs, antihypertensives, Parkinson's disease treatments, and antidepressants. The mechanism by which these drugs affect taste or smell remains unknown.

Improving the flavour of the foods, can improve nutritional intake and increase body weight in hospital and nursing home patients, as well as the healthy elderly.

HOW THESE PERCEPTIONS DIMINISH WITH AGE:

The senses of taste and smell work together. Most tastes are linked with odors. The sense of smell begins at the nerve endings high in the lining of the nose. There are about 9,000 taste buds. Taste buds sense sweet, salty, sour, bitter, and umami flavors.

SMELL

As we get older, our olfactory function declines . Not only do we lose our sense of smell, we lose our ability to discriminate between smells. The sense of smell can also diminish, especially after age 70. This may be related to a loss of nerve endings and less mucus production in the nose. Mucus helps odors stay in the nose long enough to be detected by the nerve endings. It also helps clear odors from the nerve endings.

Both the number of fibres in the olfactory bulb, along with olfactory receptors decrease noticeably with age. The bulb losses may well be secondary to sensory cell loss in the olfactory mucosa, along with a general deterioration in central nervous system cognitive processing functions olfactory receptor neurones undergo apoptosis at a baseline rate in each person.

Mammals have the ability to replace these cells, however this process degenerates with ageing. This results in a reduction in the surface area of olfactory epithelium, along with reduced numbers of olfactory receptor neurones.

TASTE:

Between the ages of 40 and 50, the number of taste buds decreases, and the rest begin to shrink, losing mass vital to their operation. After age 60, you may begin to lose the ability to distinguish the taste of sweet, salty, sour, and bitter foods.

Gustatory dysfunction may be related to the normal ageing process. Normal ageing produces taste loss because of changes in taste cell membranes involving altered function of ion channels and receptors.

Taste bud loss is thought to contribute less to this problem with no relation between taste acuity and number of papillae. Rather than whole mouth gustatory dysfunction, regional deficits are much more common.

Most elderly people are unaware of regional taste deficits. In addition, the mouth produces less saliva with ageing. This can cause dry mouth, which can affect the sense of taste.

Certain things can speed up the loss of taste and smell. These include diseases, smoking, and exposure to harmful particles in the air.Decreased taste and smell can lessen the interest and enjoyment in eating.

2.DISCUSS THE IMPORTANCE OF THE INTESTINAL MICROBIOME TO OVERALL HEALTH.

Our body is full of trillions of bacteria, viruses and fungi. They are collectively known as the microbiome. While some bacteria are associated with disease, others are actually extremely important for your immune system, heart, weight and many other aspects of health.

Trillions of these microbes exist mainly inside the intestines. There are a number of different ways in which the gut microbiome can affect key bodily functions and influence your health

• Digesting breast milk: Some of the bacteria that first begin to grow inside babies' intestines are called Bifidobacteria. They digest the healthy sugars in breast milk that are important for growth.

• Digesting fiber: Certain bacteria digest fiber, producing short-chain fatty acids, which are important for gut health. Fiber may help prevent weight gain, diabetes, heart disease and the risk of cancer
• Helping control your immune system: The gut microbiome also controls how your immune system works. By communicating with immune cells, the gut microbiome can control how your body responds to infection .
• Helping control brain health: The gut microbiome may also affect the central nervous system, which controls brain function.

3.DESCRIBE THE FUNCTIONS OF THE ACCESSORY ORGANS OF DIGESTION IN THE DIGESTIVE PROCESS.

The salivary glands, liver, gallbladder, and pancreas are not part of the digestive tract, but they have a role in digestive activities and are considered accessory organs.

Salivary Glands

Three pairs of major salivary glands (parotid, submandibular, and sublingual glands) and numerous smaller ones secrete saliva into the oral cavity, where it is mixed with food during mastication. Saliva contains water, mucus, and enzyme amylase. Functions of saliva include the following:

• It has a cleansing action on the teeth.
• It moistens and lubricates food during mastication and swallowing.
• It dissolves certain molecules so that food can be tasted.
• It begins the chemical digestion of starches through the action of amylase, which breaks down polysaccharides into disaccharides.

Liver

The liver is located primarily in the right hypochondriac and epigastric regions of the abdomen, just beneath the diaphragm. It is the largest gland in the body. On the surface, the liver is divided into two major lobes and two smaller lobes. The functional units of the liver are lobules with sinusoids that carry blood from the periphery to the central vein of the lobule.

The liver receives blood from two sources. Freshly oxygenated blood is brought to the liver by the common hepatic artery, a branch of the celiac trunk from the abdominal aorta. Blood that is rich in nutrients from the digestive tract is carried to the liver by the hepatic portal vein.

The liver has a wide variety of functions and many of these are vital to life. Hepatocytes perform most of the functions attributed to the liver, but the phagocytic Kupffer cells that line the sinusoids are responsible for cleansing the blood.

Liver functions include the following:

• secretion
• synthesis of bile salts
• synthesis of plasma protein
• storage
• detoxification
• excretion
• carbohyrate metabolism
• lipid metabolism
• protein metabolism
• filtering

Gallbladder

The gallbladder is a pear-shaped sac that is attached to the visceral surface of the liver by the cystic duct. The principal function of the gallbladder is to serve as a storage reservoir for bile. Bile is a yellowish-green fluid produced by liver cells. The main components of bile are water, bile salts, bile pigments, and cholesterol.

Bile salts act as emulsifying agents in the digestion and absorption of fats. Cholesterol and bile pigments from the breakdown of hemoglobin are excreted from the body in the bile.

Pancreas

The pancreas has both endocrine and exocrine functions. The endocrine portion consists of the scattered islets of Langerhans, which secrete the hormones insulin and glucagon into the blood. The exocrine portion is the major part of the gland. It consists of pancreatic acinar cells that secrete digestive enzymes into tiny ducts interwoven between the cells.

Pancreatic enzymes include anylase, trypsin, peptidase, and lipase. Pancreatic secretions are controlled by the hormones secretin and cholecystokinin.

In short,the functions of the the accessory organs of digestion in the digestive process can be summarized as:.

Salivary gland - Produce salvia, moistens food to bind it into a rounded bolus, begins the chemical breakdown of starch using the enzyme amylase.

Pancreas -Exocrine glands produce pancreatic juice and enzymes in alkaline fluid to digest food.

Gallbladder-Stores and concentrates bile

Liver-Monitors blood from digestive organs, processes the absorbed nutrients, removes toxins, phagocytize bacteria, produces blood proteins, stores fat-soluble vitamins, produces and secretes bile.

4. LIST AND DISCUSS THE MANY IMPORTANT FUNCTIONS OF THE LIVER.

The liver is a four-lobed, triangular-shaped organ weighing a little more than 3 pounds. It is the largest gland in the human body. The liver is part of the gastrointestinal system and is located in the upper abdomen to the right of the stomach. The liver carries out many functions necessary for survival, including processes of metabolism, digestion and cleansing of the blood.The functions of the liver are

• Detoxification
• Nutrient Processing
• Cholesterol Production
• Protein Synthesis
• Bile Production
• Storage
• Blood Sugar Regulation

Detoxification

The cells of the liver contain thousands of enzymes for use in the chemical reactions of metabolism. People consume various toxins from foods, drugs and water daily. A healthy liver is capable of transforming potentially harmful substances, such as drugs and alcohol, into harmless products to be eliminated in the bile or urine.

Nutrient Processing

Nutrients consumed in the diet travel from the intestine to the liver and are processed into substances that the body's tissues can use. The liver synthesizes, stores and releases nutrients into the blood based on the body's needs.

Cholesterol Production

Each day, the liver makes about 1,000 milligrams of cholesterol, which is used for production of hormones, Vitamin D and bile.

Protein Synthesis

The liver makes certain proteins necessary for blood clotting and for transporting nutrients such as iron. Many blood proteins are also needed for water balance in the body. Additionally, the liver produces proteins involved in the functioning of the immune system.

Bile Production

The liver produces bile, which is stored in the gall bladder. Bile aids in the digestion of fats and assists with elimination of toxins from the body.

Storage

Many nutrients are stored in the liver, including certain fats, Vitamin B12, iron, copper and the fat-soluble vitamins A, D and K. The liver also stores glycogen, the storage form of glucose.

Blood Sugar Regulation

The body must maintain blood glucose within a particular range. When blood glucose falls too far, the liver can convert stored glycogen back to glucose, or it can make glucose from amino acids to raise blood glucose to a normal level.

5.EXPLAIN HOW IT IS POSSIBLE FOR GASTROINTESTINAL FUNCTION TO CONTINUE WITHOUT THE GALLBLADDER

The gallbladder is a small storage organ located inferior and posterior to the liver. Though small in size, the gallbladder plays an important role in our digestion of food. The gallbladder holds bile produced in the liver until it is needed for digesting fatty foods in the duodenum of the small intestine.

Bile is important because it helps with the digestion of fat and its transfer from the intestine into the body. When the gallbladder is removed, bile made by the liver can no longer be stored between meals. Instead, the bile flows directly into the intestine anytime the liver produces it.

          Most people have no real change in digestion in the absence of gall bladder.

Obviously, without a gallbladder, it can no longer store bile. Bile is a liquid that helps to digest fatty foods. The gallbladder releases it into the small intestine.

When a person is not eating for a long period of time, such as at night during sleep,the gallbladder stores the bile.

However, when the gallbladder is removed, (removal of the reservoir), the person will have the same amount of bile in the body. Here, the bile is constantly being delivered into the intestine instead of being stored, which means that the person will not have problem in digesting food.

And hence gallbladder is an organ one can live without.

HOW LIFE CANNOT CONTINUE WITHOUT THE LIVER OR THE PANCREAS

Among other functions, the liver produces bile, an alkaline juice that helps the gut to dissolve and digest fatty foods.

The liver has a number of other life-sustaining roles, and its function is critical and irreplaceable. The bile duct stores bile for controlled release into the small intestine.

          Among other functions, the pancreas secretes digestive juices into the small intestine, in this case with enzymes that help to break down carbohydrates, proteins and fats. Hence, life cannot continue without the liver or the pancreas.