Digestive System and Digestion Quiz
29 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Describe the role of the hepatic portal vein in the assimilation process.

The hepatic portal vein carries blood rich in nutrients absorbed from the small intestine to the liver. This allows the liver to regulate the amount of nutrients entering the bloodstream and to process them further.

Explain the process of deamination and its significance in the assimilation of amino acids.

Deamination is the process of removing the amino group (-NH2) from excess amino acids. This converts them into ammonia, which is then converted into urea by the liver and excreted through urine. Deamination prevents the build-up of toxic ammonia in the body.

How does the liver act as a storage organ for nutrients?

When excess glucose is present in the bloodstream, the liver converts it into glycogen and stores it. This stored glycogen can be later converted back into glucose when energy is needed by the body.

What are the two main functions of the large intestine in the digestive process?

<p>The large intestine is responsible for the absorption of water and certain vitamins, and the formation of faeces.</p> Signup and view all the answers

What are the specific substances absorbed by the large intestine?

<p>The large intestine absorbs water, mineral salts, and certain vitamins produced by bacteria, including vitamin B, vitamin K, and folic acid.</p> Signup and view all the answers

Explain the composition of faeces and how it is formed.

<p>Faeces consist of undigested food, dead cells from the intestinal lining, waste products like bile pigments, bacteria, and toxic substances. As water is absorbed from the remaining waste in the large intestine, the semi-solid faeces is formed.</p> Signup and view all the answers

Describe the role of mucus in the movement of faeces through the large intestine.

<p>The mucus secreted by the walls of the large intestine lubricates the faeces, facilitating its smooth passage through the intestines to the anus.</p> Signup and view all the answers

What triggers the need to defecate?

<p>As faeces accumulates in the rectum, the pressure within the rectum increases, triggering the urge to defecate and expulsion of faeces from the body.</p> Signup and view all the answers

What role does water intake play in the health of the large intestine?

<p>Water intake helps to keep feces soft and facilitates their movement along the large intestine.</p> Signup and view all the answers

Identify two health issues related to poor eating habits and briefly describe one.

<p>Two health issues are anorexia nervosa and bulimia nervosa. Anorexia nervosa involves an obsession with body weight, leading individuals to avoid food and suffer from nutrient deficiencies.</p> Signup and view all the answers

What can untreated gastritis lead to, and what are its primary causes?

<p>Untreated gastritis can result in gastric ulcers. Its primary causes include irregular eating patterns and excessive consumption of alcohol or painkillers.</p> Signup and view all the answers

How does bulimia nervosa affect a person's physical health over time?

<p>Bulimia nervosa can lead to dehydration, nutritional deficiencies, and severely impact cardiovascular health or lead to kidney failure.</p> Signup and view all the answers

Describe muscle dysmorphia and its potential impact on an individual.

<p>Muscle dysmorphia is characterized by an obsession with body size, often leading to extreme weightlifting and steroid use. This can result in serious health risks, including hormonal imbalances and dependency on harmful substances.</p> Signup and view all the answers

What is the process called when the rectum muscles contract to expel faeces?

<p>Defaecation</p> Signup and view all the answers

What are the seven food classes that make up a balanced diet?

<p>Carbohydrates, lipids, proteins, vitamins, mineral salts, fibre, and water.</p> Signup and view all the answers

What unit is commonly used to measure the energy value of food?

<p>Kilojoule per gram (kJ g<sup>-1</sup>) or calorie.</p> Signup and view all the answers

How does fibre contribute to the defaecation process?

<p>Fibre stimulates peristalsis and smoothens bowel movements.</p> Signup and view all the answers

What are some short-term side effects of gastric bypass surgery?

<p>Acid reflux, nausea, vomiting, and risk of infection.</p> Signup and view all the answers

What health issues can arise from insufficient dietary fibre?

<p>Constipation, colon cancer, rectum cancer, and haemorrhoids.</p> Signup and view all the answers

What is the role of vitamin C in fruits and vegetables?

<p>Vitamin C is an essential nutrient that varies in content among different fruits and vegetables.</p> Signup and view all the answers

Why is obesity considered a health issue, and how can it be managed?

<p>Obesity can lead to numerous health problems and can be managed through diet, exercise, and sometimes medical treatment.</p> Signup and view all the answers

What are the main parts of the alimentary canal in the human digestive system?

<p>The main parts of the alimentary canal are the mouth, oesophagus, stomach, small intestine, large intestine, and anus.</p> Signup and view all the answers

Distinguish between physical digestion and chemical digestion.

<p>Physical digestion involves the mechanical breakdown of food, while chemical digestion involves the decomposition of complex molecules into simpler ones through enzyme reactions.</p> Signup and view all the answers

How does saliva contribute to the digestion of carbohydrates in the mouth?

<p>Saliva contains salivary amylase, which hydrolyses starch into maltose, aiding in the digestion of carbohydrates.</p> Signup and view all the answers

What adaptations does the ileum have for nutrient absorption?

<p>The ileum has a long structure with folded internal layers and is covered with tiny projections called villi to facilitate nutrient absorption.</p> Signup and view all the answers

Describe the role of villi in nutrient absorption.

<p>Villi are adapted for nutrient absorption with a one-cell-thick epithelial layer, a network of blood capillaries, and goblet cells that secrete mucus.</p> Signup and view all the answers

What enzyme is responsible for the breakdown of starch in the mouth, and what is its optimal pH range?

<p>Salivary amylase is the enzyme that breaks down starch in the mouth, with an optimal pH range of 6.5-7.5.</p> Signup and view all the answers

What is the function of lacteals in the villi?

<p>Lacteals transport droplets of fatty acids and glycerol from the digested food into the lymphatic system.</p> Signup and view all the answers

Explain the significance of microvilli in the villus structure.

<p>Microvilli increase the surface area of the villus, enhancing the rate of nutrient absorption in the small intestine.</p> Signup and view all the answers

Study Notes

Digestive System

  • The human digestive system is a long muscular tube, starting at the mouth and ending at the anus.
  • It includes the mouth, esophagus, stomach, small intestine, large intestine, and anus.
  • Other organs like the liver, gallbladder, and pancreas also aid in digestion.
  • Glands in the digestive system secrete digestive juices into the alimentary canal.

Digestion

  • Digestion breaks down large, complex food pieces into smaller, simpler, absorbable pieces.
  • This process has two components: physical and chemical digestion.
  • Physical digestion involves mechanical breakdown of food, such as chewing and peristalsis.
  • Chemical digestion uses enzymes to break down complex molecules like proteins into simpler molecules for absorption.
  • Digestion begins in the mouth with the breakdown of carbohydrates through saliva amylase.

Digestion of Carbohydrates in the Mouth

  • Food in the mouth stimulates saliva secretion from salivary glands.
  • Saliva contains salivary amylase that hydrolyzes starch to maltose.
  • The optimum pH range for amylase is 6.5-7.5.
  • Saliva also helps form a bolus for easier swallowing.

Digestion of Protein in the Stomach

  • The stomach lining has gastric glands with chief cells, parietal cells, and mucous cells.
  • Chief cells make pepsinogen, which is activated to pepsin by hydrochloric acid from parietal cells.
  • Pepsin hydrolyzes proteins into polypeptides.
  • Mucous cells produce mucus to protect the stomach wall from acid.

Digestion in the Small Intestine

  • The small intestine includes the duodenum, jejunum, and ileum. It receives chyme from the stomach.
  • Duodenum also receives bile from the liver and pancreatic juice.
  • Pancreatic amylase hydrolyzes starch to maltose.
  • Trypsin hydrolyzes polypeptides into shorter peptides.
  • Lipase hydrolyzes lipids into fatty acids and glycerol.

Carbohydrate Digestion (in the small intestine)

  • Maltase hydrolyzes maltose into glucose.
  • Sucrase hydrolyzes sucrose into glucose and fructose.
  • Lactase hydrolyzes lactose into glucose and galactose.

Lipid Digestion (in the small intestine)

  • Lipase hydrolyzes lipids into fatty acids and glycerol.

Protein Digestion (in the small intestine)

  • Erepsin hydrolyzes peptides into amino acids.

Absorption

  • The ileum is adapted to absorb nutrients due to its folded inner layer covered by villi.
  • Villi have a one-cell-thick epithelial layer, goblet cells to secrete mucus and a network of blood capillaries.
  • Microvilli further increase the surface area for absorption.
  • Lacteals transport fatty acids and glycerol.
  • Different nutrients are absorbed via different mechanisms (active transport, facilitated diffusion, osmosis, simple diffusion).

Assimilation

  • The circulatory system transports absorbed nutrients.
  • Blood capillaries in the small intestine form the hepatic portal vein, transporting blood to the liver.
  • The liver controls the quantity of nutrients entering the blood circulation. Functions include metabolism of glucose, amino acids & lipids; detoxification, and storage of nutrients.

Defaecation

  • Undigested food, dead cells, and fiber enter the large intestine, moving slowly through peristalsis.
  • The large intestine absorbs water and vitamins.
  • Waste products form feces.
  • Feces moves to the rectum and are expelled through the anus.
  • Fiber stimulates peristalsis, absorbs toxins and helps regulate glucose absorption in diabetics.

Balanced Diet

  • A balanced diet includes all seven food groups in appropriate proportions.
  • Energy value is the total energy released from the complete oxidation of 1 gm of food.
  • Energy is measured in kilojoules (kJ) or calories (cal).
  • Obesity, a significant health concern, arises from imbalanced food intake and energy use.
  • Issues like gastritis (stomach inflammation), anorexia nervosa (eating disorder characterized by food avoidance), bulimia nervosa (cycle of binge eating and purging), and muscle dysmorphia (extreme dissatisfaction with body image), are all related to eating habits.
  • Other issues include problems during defaecation (e.g constipation, colon cancer, rectum cancer and haemorrhoids) and poor healthy habits.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Digestive System PDF

Description

Test your knowledge on the human digestive system and its processes. This quiz covers the anatomy of the digestive tract, the stages of digestion, and the specific breakdown of carbohydrates in the mouth. Challenge yourself to understand how food is processed from intake to absorption.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser