Ch 41 questions Flashcards
(28 cards)
- Essential Nutrients and Their Importance:
The six essential nutrients are carbohydrates (energy source), proteins (tissue repair and enzyme production), fats (energy storage and cell structure), vitamins (regulate body processes), minerals (support bodily functions like bone health), and water (hydration and metabolic processes). Each plays a unique and crucial role in maintaining health and supporting bodily functions.
- Undernourishment vs. Malnourishment:
Undernourishment is when a person doesn’t get enough calories to meet energy needs. Malnourishment refers to an imbalance or lack of specific nutrients, regardless of calorie intake. A person can be overweight and still be malnourished if lacking essential nutrients.
- Main Stages of Food Processing:
The stages are ingestion (eating food), digestion (breaking food into absorbable molecules), absorption (nutrients enter the bloodstream), and elimination (removal of undigested waste). Each step ensures nutrients are properly processed and utilized.
- Sphincters in the Human Digestive Canal:
There are four main sphincters: upper esophageal (controls swallowing), lower esophageal (prevents acid reflux), pyloric (regulates food entry into the small intestine), and anal sphincter (controls waste expulsion). They ensure proper one-way flow and timing in digestion.
- Explain the role of mechanical digestion in humans and how it takes place:
Mechanical digestion involves physically breaking down food into smaller pieces without altering its chemical structure. It begins in the mouth, where teeth chew food, increasing surface area for enzymes to act. The tongue and saliva help form a bolus for easier swallowing. In the stomach, muscles churn the food, mixing it with digestive juices to further break it down before it moves to the small intestine.
- Explain the process of chemical digestion in the stomach:
Chemical digestion in the stomach starts when food mixes with gastric juices, which include acid and enzymes. The acid helps break down food and kills germs. An enzyme called pepsin begins breaking proteins into smaller pieces. This makes the food easier to digest later in the small intestine.
- What are the pancreatic juices which help in digestion?
Pancreatic juices are fluids made by the pancreas to help break down food in the small intestine. They contain enzymes like amylase (for breaking down carbs), lipase (for fats), and proteases (for proteins). These juices also have bicarbonate, which helps neutralize stomach acid. This makes digestion easier and protects the intestine.
- Explain how enzymatic hydrolysis works in the digestive system: carbohydrates, protein, nucleic acid, and fats:
Enzymatic hydrolysis involves breaking down complex food molecules using enzymes and water. Carbohydrates are hydrolyzed by amylase into simple sugars like glucose. Proteins are broken down by proteases such as pepsin and trypsin into amino acids. Nucleic acids are digested by nucleases into nucleotides, while fats are broken down by lipases into fatty acids and glycerol.
- Explain the role of the duodenum:
The duodenum is the first part of the small intestine, right after the stomach. It helps break down food using digestive juices from the pancreas and bile from the liver. This is where most chemical digestion happens. It also absorbs some nutrients and signals other parts of the digestive system to work.
- Where is bile produced and what is its importance?
Bile is produced in the liver and stored in the gallbladder until needed. It contains bile salts, which are essential for emulsifying fats in the small intestine. This increases the surface area of fat droplets, making it easier for lipase enzymes to break them down. Bile also helps in the absorption of fat-soluble vitamins like A, D, E, and K.
- Explain the role of the small intestine in the process of digestion:
The small intestine is the primary site for digestion and nutrient absorption. Enzymes from the pancreas and intestinal walls continue breaking down proteins, carbohydrates, and fats. Its inner surface is lined with villi and microvilli, which increase surface area for maximum absorption. Nutrients pass through these structures into the bloodstream or lymphatic system.
- What are chylomicrons?
Chylomicrons are tiny fat-carrying particles made in the small intestine after you eat fatty foods. They transport fats (like triglycerides and cholesterol) through the lymphatic system and into the bloodstream. Their job is to deliver these fats to body tissues for energy or storage. Think of them as little delivery trucks for fat in your body.
- Explain the process of absorption of fat shown in Figure 41.16:
Fats are first emulsified by bile in the small intestine, breaking them into smaller droplets. Pancreatic lipase then breaks these down into monoglycerides and free fatty acids. These molecules are absorbed by intestinal epithelial cells, where they are reassembled into triglycerides. The triglycerides are packaged into chylomicrons and transported through the lymphatic system into the bloodstream.
- What are the different parts of the large intestine and explain their function:
The large intestine includes the cecum, colon (ascending, transverse, descending, sigmoid), rectum, and anus. The cecum connects to the small intestine and starts the absorption of water and salts. The colon absorbs remaining water and forms solid waste (feces). The rectum stores feces until it’s expelled through the anus during defecation.
- What conditions cause diarrhea and constipation?
Diarrhea is caused when the large intestine fails to absorb enough water, often due to infections, irritation, or certain medications. This results in loose, watery stools. Constipation occurs when stool moves too slowly through the colon, allowing too much water to be absorbed. Causes include low fiber intake, dehydration, and lack of physical activity.
- Explain how people can become obese, even if their intake of dietary fat is relatively low compared with carbohydrate intake:
Excess carbohydrate intake can lead to obesity because unused carbs are converted into fat by the liver and stored in the body. High consumption of sugars and refined carbs causes insulin spikes, promoting fat storage. If caloric intake consistently exceeds what is burned through activity, weight gain occurs regardless of fat content. A low-fat diet doesn’t guarantee weight control if total calorie intake is too high.
- How is obesity responsible for causing diabetes?
Obesity, especially abdominal fat, leads to increased inflammation and insulin resistance in the body. Insulin resistance means cells don’t respond properly to insulin, causing blood sugar levels to rise. Over time, the pancreas can’t produce enough insulin to compensate, resulting in type 2 diabetes. Managing weight through diet and exercise is key to preventing or controlling the disease.
- What is the role of leptin in our body?
Leptin is a hormone produced by fat cells that helps regulate energy balance by signaling the brain to reduce hunger. When fat stores increase, leptin levels rise, curbing appetite and increasing metabolism. In some obese individuals, leptin resistance develops, meaning the brain doesn’t respond to leptin signals. This can lead to continued overeating despite sufficient energy reserves.
What is the importance of chemical energy, organic molecules, and essential nutrients in an animal’s diet?
Chemical energy from food fuels cellular activities and bodily functions like movement, growth, and repair. Organic molecules such as carbohydrates, proteins, and fats are used to build body structures and produce energy. Essential nutrients, including amino acids, fatty acids, vitamins, and minerals, must be obtained from food because the body cannot synthesize them. A balanced diet ensures all these components are available to maintain health and support life processes.
What is the effect of a diet with insufficient amounts of one or more essential amino acids?
Without enough essential amino acids, the body cannot build proteins effectively. This can lead to muscle wasting, weakened immunity, and delayed growth and development, especially in children. Over time, protein deficiency can cause serious health issues like edema or organ damage. Since the body cannot store amino acids like fats or carbs, continuous intake is necessary.
Give a reason to explain if animals can or cannot make essential fatty acids in their body. Why is the deficiency of this nutrient rare?
Animals cannot synthesize essential fatty acids, such as omega-3 and omega-6, because they lack the necessary enzymes to create certain double bonds in fatty acid chains. These must be obtained from dietary sources like seeds, nuts, and fish oils. However, deficiencies are rare because even small amounts of common foods contain sufficient essential fatty acids. Most balanced diets naturally include these fats.
What is epidemiology? How can epidemiologists prevent and control diseases and disorders?
Epidemiology is the study of how diseases spread, who they affect, and how to control them in populations. Epidemiologists collect and analyze data to identify patterns and causes of diseases. They help design public health policies, vaccination programs, and education campaigns. Through surveillance and research, they prevent outbreaks and improve health outcomes.
Where is mucin found and what is its function?
Mucin is found in mucus secreted by epithelial tissues, especially in the mouth, stomach, and intestines. It helps lubricate food for easier swallowing and protects the lining of the digestive tract from mechanical and chemical damage. In the stomach, mucin prevents the acidic gastric juices from eroding the stomach wall. It also traps pathogens and particles, playing a role in immune defense.
How many kinds of muscles are present in the esophagus? Write their names and functions.
The esophagus contains two types of muscles: skeletal and smooth. Skeletal muscle is found in the upper third and allows voluntary control of swallowing. Smooth muscle in the lower two-thirds performs involuntary contractions (peristalsis) to push food toward the stomach. This muscle coordination ensures food moves efficiently down the esophagus.
