10.1. Digestive System
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10.1. Digestive System

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Questions and Answers

Which of the following hormones are produced by the pancreas?

  • Cholecystokinin
  • Insulin (correct)
  • Glucagon (correct)
  • Hemoglobin

    • The large intestine is responsible for the major absorption of nutrients from food.

    False

    What is the primary function of bile?

    Emulsification and promoting absorption by intestinal epithelia.

    The __________ is the last portion of the large intestine, measuring approximately 15 cm.

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

    Match the following parts of the large intestine with their descriptions:

    <p>Cecum = Pouch-like first portion of the large intestine Colon = Largest portion of the large intestine Rectum = Last 15 cm of the large intestine Anus = Exit point for feces from the body</p> Signup and view all the answers

    Which of the following functions is NOT part of the digestive system?

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

    The small intestine is responsible for 90% of nutrient absorption.

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

    What is the food in the stomach known as?

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

    The _____ phase of swallowing is initiated voluntarily.

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

    Match the sections of the small intestine with their functions:

    <p>Duodenum = Mixes chyme with digestive secretions Jejunum = Site of most nutrient absorption Ileum = Uptake of vitamin B12 and bile salts</p> Signup and view all the answers

    Which hormones stimulate the secretion of pancreatic exocrine secretions?

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

    Mechanical processing refers to the chemical breakdown of food.

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

    What is the main role of bicarbonate ions in pancreatic secretions?

    <p>neutralize HCl</p> Signup and view all the answers

    What is one of the primary roles of the liver?

    <p>Synthesis and secretion of bile</p> Signup and view all the answers

    The large intestine plays a major role in the absorption of vitamins produced by bacteria.

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

    What is the primary function of the pancreas in the endocrine system?

    <p>Insulin production</p> Signup and view all the answers

    The large intestine is approximately ______ m long.

    <p>1.5</p> Signup and view all the answers

    Match the following portions of the large intestine with their descriptions:

    <p>Cecum = First pouch-like portion, includes appendix Colon = Largest portion of the large intestine Rectum = Last 15 cm of the large intestine Anus = Terminal opening for excretion</p> Signup and view all the answers

    What is primarily absorbed in the ileum of the small intestine?

    <p>Vitamin B12 and bile salts</p> Signup and view all the answers

    The stomach only digests food without any role in absorption.

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

    List one major function of the pancreas in digestion.

    <p>Secretion of digestive enzymes</p> Signup and view all the answers

    The collapsed state of the stomach is referred to as __________.

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

    Match the following sections of the small intestine with their primary function:

    <p>Duodenum = Mixes chyme with digestive secretions Jejunum = Site of most chemical digestion and absorption Ileum = Uptake of vitamin B12 and bile salts</p> Signup and view all the answers

    What is the first stage of the digestive process?

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

    Chemical breakdown of food is known as ingestion.

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

    Name the three phases of swallowing.

    <p>Buccal phase, pharyngeal phase, esophageal phase</p> Signup and view all the answers

    Study Notes

    Digestive System Functions

    • Ingestion: Taking food into the mouth
    • Mechanical Processing: Crushing and shearing of food
    • Chemical Breakdown: Digestion of food
    • Secretion: Production of water, acids, enzymes, buffers, and salts
    • Absorption: Uptake of nutrients, electrolytes, vitamins, and water
    • Excretion: Removal of waste products

    Digestive System Organs

    • Mouth: Ingestion and initial mechanical processing of food
    • Pharynx: Conducts food from mouth to esophagus
    • Esophagus: Transports food to the stomach
    • Stomach: Stores food, churns it, mixes it with gastric juices, and begins protein digestion
    • Small Intestine: Major site of nutrient absorption, including:
      • Duodenum: Mixes chyme with pancreatic and liver secretions, absorbs iron
      • Jejunum: Main site of chemical digestion and nutrient absorption
      • Ileum: Absorbs vitamin B12 and bile salts
    • Pancreas: Secretes digestive enzymes and hormones, including:
      • Bicarbonate ions: Neutralize stomach acid
      • Digestive enzymes: Digest fats and proteins
      • Insulin, glucagon, and somatostatin: Regulate blood glucose
    • Liver: Performs various metabolic functions, including:
      • Metabolic regulation: Carbohydrate, lipid, and amino acid metabolism, waste removal
      • Haematological regulation: RBC removal, plasma protein synthesis, hormone removal
      • Bile synthesis and secretion: Emulsifies fats and aids in fat absorption
    • Large Intestine: Absorbs water and electrolytes, compacts waste, and stores feces
      • Cecum: Pouch-like first portion, includes the appendix
      • Colon: Largest portion
      • Rectum: Last 15 cm of the large intestine
      • Anus: Opening for waste elimination

    Stomach Anatomy

    • Function: First stage of food processing and breakdown, storage of food
    • Chyme: Food in the stomach after mixing with gastric juices
    • Structure: Folded structure that can expand to accommodate food
    • Acid-secreting cells: Produce hydrochloric acid for digestion
    • Blood supply: Supports the digestive processes within the stomach

    Small Intestine Anatomy

    • Length: Approximately 9 meters
    • Function: Major site of nutrient absorption
    • Blood supply: Delivers nutrients absorbed from the small intestine to the bloodstream

    Pancreas Anatomy

    • Exocrine function: Secretes digestive enzymes and bicarbonate ions into the small intestine
    • Endocrine function: Secretes hormones like insulin, glucagon, and somatostatin into the bloodstream

    Liver Anatomy

    • Structure: Large organ located in the upper right abdomen
    • Functions: Metabolic regulation, haematological regulation, bile production and secretion

    Large Intestine Anatomy

    • Length: Approximately 1.5 meters
    • Functions: Water and electrolyte absorption, waste compaction, fecal storage
    • Blood supply: Delivers absorbed nutrients and electrolytes to the bloodstream

    Peristalsis

    • Function: Muscle contractions that move food through the digestive tract

    Swallowing (Deglutition)

    • Initiation: Can be voluntary or involuntary
    • Phases:
      • Buccal phase: Voluntary movement of food from mouth to pharynx
      • Pharyngeal phase: Involuntary movement of food through pharynx
      • Esophageal phase: Involuntary movement of food through esophagus

    Chemical Processes of Digestion

    • Enzymes: Proteins that catalyze specific chemical reactions in digestion
    • Substrate: The substance that an enzyme acts upon
    • Product: The result of an enzyme-catalyzed reaction

    Water Movement in Digestive System

    • Absorption: Water is absorbed from the digestive tract into the bloodstream
    • Secretion: Water is secreted into the digestive tract to aid in digestion and lubrication

    Key Hormones

    • Gastrin: Stimulates gastric acid production
    • Cholecystokinin: Stimulates bile release from the gallbladder and pancreatic enzyme secretion
    • Secretin: Stimulates bicarbonate release from the pancreas

    Key Facts

    • 90% of nutrient absorption occurs in the small intestine.
    • The pancreas is both an exocrine and endocrine organ.
    • The liver plays a vital role in metabolism, blood regulation, and bile production.
    • The large intestine is responsible for water absorption, waste compaction, and fecal storage.
    • Peristalsis is the rhythmic contraction of muscles that move food through the digestive tract.
    • Swallowing is a complex process involving both voluntary and involuntary muscle movements.
    • Enzymes are essential for chemical digestion.
    • Water movement is crucial for efficient digestion and nutrient absorption.
    • Hormones play a vital role in regulating digestive processes.

    Digestive System Functions

    • Ingestion: Taking in food
    • Mechanical Processing: Crushing and shearing food
    • Chemical Breakdown (Digestion): Breaking down food molecules
    • Secretion: Producing and releasing fluids like water, acids, enzymes, buffers, and salts
    • Absorption: Taking in nutrients, electrolytes, vitamins, and water
    • Excretion: Removing waste products

    Digestive System Organs

    • Oral Cavity: Mouth, teeth, and tongue for food intake and initial breakdown
    • Pharynx: Throat, connects oral cavity to esophagus
    • Esophagus: Muscular tube that transports food from pharynx to stomach
    • Stomach: Storage and mixing of food with gastric juices
    • Small Intestine: Primary site for nutrient absorption (Duodenum, Jejunum, Ileum)
    • Large Intestine: Water absorption, waste compaction, and bacteria-driven digestion (Cecum, Colon, Rectum, Anus)

    Stomach Anatomy and Function

    • Food is called chyme in the stomach
    • Gastric folds allow for expansion and increased surface area
    • Contains acid-secreting cells for chemical breakdown

    Pancreas Role

    • Endocrine function: Secretes hormones like insulin, glucagon, and somatostatin for glucose regulation
    • Exocrine function: Secretes pancreatic juices containing:
      • Bicarbonate ions to neutralize stomach acid
      • Digestive enzymes for fat and protein breakdown

    Liver Roles

    • Metabolic Regulation: Regulates carbohydrates, lipids, amino acids, waste removal, and stores vitamins and minerals
    • Hematological Regulation: Removes old red blood cells, synthesizes plasma proteins, removes hormones, antibodies, and toxins
    • Bile Production: Synthesizes and secretes bile, which helps emulsify fats and promotes absorption in the small intestine

    Small Intestine Sections:

    • Duodenum: 26 cm long, mixes stomach chyme with pancreatic and liver secretions, iron absorption
    • Jejunum: 2.5 meters long, primarily responsible for chemical digestion and nutrient absorption
    • Ileum: 3.5 meters long, absorbs vitamin B12 and bile salts

    Large Intestine Function

    • Houses bacteria that further digest food material
    • Absorbs:
      • Bacteria and their byproducts (including vitamins)
      • Organic wastes
      • Bile salts (returned to liver via blood)
      • Water
    • Compacts and dries intestinal contents to form feces
    • Stores fecal material before defecation

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    Description

    Explore the fascinating functions and organs of the digestive system. This quiz covers the processes from ingestion to excretion, and details the roles of major digestive organs. Test your knowledge on how food is processed in the human body.

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