9.3 Absorption in the Ileum

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What feature of the villus primarily aids in accelerating nutrient absorption?

A large surface area covered in mucus

A thick epithelial layer

An epithelial layer that is one cell thick (correct)

A network of lymphatic vessels

Which of the following is NOT a function of the villi in the ileum?

Transport of digestive products

Production of bile (correct)

Secretion of digestive enzymes

Secretion of mucus

Why is the length of the ileum beneficial for absorption?

It allows for more efficient breakdown of nutrients.

It increases the surface area for absorption. (correct)

It reduces the time food spends in the intestine.

It facilitates faster passage of food through the digestive tract.

What purpose do microvilli serve on the surface of the villus?

To increase the surface area for absorption Signup and view all the answers

What role do lacteals play in the absorption process?

They carry absorbed fatty acids and fat-soluble vitamins. Signup and view all the answers

What substances are absorbed in the large intestine?

Water, mineral salts, and metabolic byproducts of bacteria Signup and view all the answers

Which of the following correctly describes the function of faeces?

Contains dead cells, waste products, and bacteria Signup and view all the answers

What role do bacteria in the colon play?

They decompose food waste and synthesize certain vitamins. Signup and view all the answers

What triggers the need to expel faeces from the body?

Increased pressure in the rectum Signup and view all the answers

What effect can the consumption of antibiotics have on the colon?

Decrease the microbial population in the colon Signup and view all the answers

What is the primary function of the liver in the assimilation of digested food?

To convert excess glucose to glycogen Signup and view all the answers

During the deamination process in the liver, what is excess amino acids converted into?

Urea Signup and view all the answers

What does the hepatic portal vein primarily transport?

Nutrients from the small intestine Signup and view all the answers

Which of the following substances does the liver expel during detoxification?

Toxic substances Signup and view all the answers

What is liver cirrhosis primarily caused by?

Alcoholic drinks and toxic substances Signup and view all the answers

Which structure collects lymph from the lymphatic system before it enters the bloodstream?

Thoracic duct Signup and view all the answers

What role do amino acids play in liver function?

They are synthesized into plasma proteins and enzymes Signup and view all the answers

Which of the following functions is NOT performed by the liver?

Production of insulin Signup and view all the answers

What happens to excess amino acids in the body?

They undergo deamination to form urea. Signup and view all the answers

What is the primary function of glucose in the liver?

Cellular respiration and conversion to glycogen. Signup and view all the answers

When glucose levels decrease in the blood, what process occurs?

Glycogen is converted to glucose for energy. Signup and view all the answers

Which of the following describes the role of lipids in the body?

They are building blocks of plasma membranes. Signup and view all the answers

What is the main consequence of a maximum glycogen supply?

Conversion of excess glucose into fats. Signup and view all the answers

What components are mixed together when food enters the colon?

Water, undigested food, bacteria, and fiber. Signup and view all the answers

Which process describes the movement of digested food through the colon?

Peristalsis. Signup and view all the answers

Which of these statements about amino acids is incorrect?

They can be stored for future energy use. Signup and view all the answers

What is the primary function of microvilli in the small intestine?

Increases surface area for nutrient absorption Signup and view all the answers

Which nutrients are absorbed directly into the blood capillaries from the ileum?

Glucose, amino acids, and water Signup and view all the answers

How are fatty acids and glycerol absorbed in the small intestine?

Simple diffusion into lacteals Signup and view all the answers

What mechanism is used for the absorption of glucose in the ileum?

Active transport Signup and view all the answers

Which vitamins are absorbed through the lacteals of the small intestine?

Vitamin A, D, E, and K Signup and view all the answers

Which nutrient is transported to the liver via the hepatic portal vein?

Amino acids Signup and view all the answers

What process allows water to be absorbed in the ileum?

Osmosis Signup and view all the answers

What is the role of the lymphatic system in nutrient absorption?

Transports absorbed fats to the bloodstream Signup and view all the answers

Which of the following nutrients is NOT absorbed into the blood capillaries from the ileum?

Fatty acids Signup and view all the answers

Where do the nutrients absorbed into the lacteals eventually enter the bloodstream?

Through the thoracic duct Signup and view all the answers

Study Notes

Absorption of Digested Food

Absorption occurs primarily in the ileum of the small intestine, where simple molecules from digested food are taken up.
The ileum is long with a highly folded inner layer, featuring villi and microvilli that significantly increase surface area for nutrient absorption.

Adaptations of Villi

The epithelial layer of each villus is only one cell thick, enhancing absorption rates.
Goblet cells within the villi secrete mucus, facilitating digestion.
Blood capillaries transport absorbed nutrients throughout the body, while lacteals carry fatty acids and fat-soluble vitamins.
Intestinal glands secrete digestive enzymes via intestinal juices; microvilli further expand the surface area for absorption.

Nutrient Absorption Pathways

Nutrients absorbed into blood capillaries: Water, glucose, amino acids, vitamins B and C.
Nutrients absorbed into lacteals: Fatty acids, glycerol, vitamins A, D, E, and K.
Glucose, galactose, fructose, amino acids, vitamins B and C, and water are absorbed through ileum epithelial cells into blood capillaries, then transported to the liver via the hepatic portal vein.
Fatty acids and glycerol enter the lacteals by simple diffusion, recombine into lipids within epithelial cells, and are transported through the lymphatic system into the bloodstream.

Mechanisms of Nutrient Absorption

Fructose: Facilitated diffusion.
Glucose and Galactose: Active transport.
Amino Acids: Active transport.
Vitamins B and C, Water: Absorbed with water and via osmosis.
Fatty Acids and Glycerol: Simple diffusion.
Vitamins A, D, E, K: Also absorbed by simple diffusion as they dissolve in lipids.

Role of the Circulatory System

The circulatory system comprises blood circulation and lymphatic systems to transport absorbed nutrients for assimilation.
Blood capillaries in the small intestine converge to form the hepatic portal vein, directing blood to the liver.
Lymphatic vessels collect from lacteals and transport lipids through the thoracic duct to the left subclavian vein.

Functions of the Liver in Assimilation

Metabolism: Converts glucose for respiration, and amino acids into plasma proteins; excess amino acids undergo deamination to form urea.
Detoxification: Eliminates toxic substances like drugs and alcohol from the blood.
Storage: Stores excess glucose as glycogen, along with vitamins and mineral salts.

Liver Health and Diseases

Liver cirrhosis results from alcohol, toxins, or hepatitis, leading to scar tissue formation and impaired liver function.
Hepatitis is an inflammation of the liver caused by infections or toxins.

Assimilation Process

Amino acids are used to synthesize proteins and enzymes or converted to urea in the liver.
Glucose is utilized for energy through respiration and excess is stored as glycogen or converted to fats.
Lipids contribute to cellular structures like membranes and are stored as energy reserves.

Functions of the Large Intestine

Absorbs remaining water, vitamins, and metabolic byproducts, resulting in feces formation.
Feces comprise water, dead cells, waste, and bacteria, exiting the body via the anus during defecation.

Bacteria in the Colon

The large intestine hosts a diverse microbial community, crucial for decomposing food waste and synthesizing vitamins B12 and K.
Maintaining a balance between beneficial and harmful bacteria is vital for health; antibiotics can disrupt this balance.

Studying That Suits You

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

Description

Explore the adaptations of the ileum in the small intestine for the absorption of digested food. This quiz covers key details about how the structure of the ileum enhances its efficiency in nutrient absorption. Test your understanding of the absorption process and its significance.