Accessory Digestive Organs and Pancreas Overview
46 Questions
1 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

What is the primary function of enteropeptidase in digestion?

  • To digest carbohydrates
  • To absorb amino acids
  • To activate trypsin (correct)
  • To activate lipase enzymes

Which enzymes are released by pancreatic secretion to aid in digestion?

  • Trypsin and sucrase
  • Lactase and maltase
  • Pancreatic amylase and lipase (correct)
  • Enteropeptidase and maltase

What type of transport is primarily used for the absorption of monosaccharides?

  • Active transport
  • Facilitated diffusion (correct)
  • Simple diffusion
  • Osmosis

What is the final route to the bloodstream for carbohydrates and amino acids?

<p>They are transported by intestinal capillaries. (D)</p> Signup and view all the answers

What form do lipids take before entering the bloodstream?

<p>Chylomicrons (D)</p> Signup and view all the answers

What role do amino acids play in the body?

<p>They can be broken down for energy or used for synthesis. (D)</p> Signup and view all the answers

Which enzyme is released in the stomach and activated by HCl?

<p>Pepsinogen (C)</p> Signup and view all the answers

What triggers the release of the hormone Gastrin in the stomach?

<p>Anticipation or arrival of food (A)</p> Signup and view all the answers

Which enzyme is released by the pancreas in the small intestine?

<p>Alpha-amylase (B)</p> Signup and view all the answers

What is the stimulus for the release of CCK in the small intestine?

<p>Arrival of chyme in the duodenum (D)</p> Signup and view all the answers

What is the primary hormone released by G cells of the stomach in response to the arrival of food?

<p>Gastrin (A)</p> Signup and view all the answers

Which enzyme is activated by hydrochloric acid (HCl) in the stomach?

<p>Pepsin (B)</p> Signup and view all the answers

Which of the following enzymes is NOT released from the pancreas into the small intestine?

<p>Lactase (B)</p> Signup and view all the answers

What activates trypsin in the duodenum?

<p>Enteropeptidase (D)</p> Signup and view all the answers

What type of transport mechanism is primarily used for the absorption of amino acids in the intestinal mucosa?

<p>Facilitated diffusion and cotransport (A)</p> Signup and view all the answers

What happens to lipids after absorption in the intestines?

<p>They form chylomicrons and diffuse into lacteals. (C)</p> Signup and view all the answers

Which pancreatic enzyme specifically digests polypeptides into short peptides?

<p>Chymotrypsin (C)</p> Signup and view all the answers

Where do carbohydrates and amino acids enter the bloodstream after absorption?

<p>Through intestinal capillaries (C)</p> Signup and view all the answers

What hormone is released in response to the anticipation or arrival of food in the stomach?

<p>Gastrin (A)</p> Signup and view all the answers

Which enzyme is activated from pepsinogen in the stomach?

<p>Pepsin (B)</p> Signup and view all the answers

What triggers the release of CCK in the small intestine?

<p>Arrival of chyme (B)</p> Signup and view all the answers

Which of the following enzymes is NOT released by the pancreas?

<p>Trypsin (C)</p> Signup and view all the answers

How are lipids absorbed into the bloodstream?

<p>Forming chylomicrons and entering the lacteals (D)</p> Signup and view all the answers

What structure do lipids primarily use to travel to the left subclavian vein?

<p>Thoracic duct (A)</p> Signup and view all the answers

What is activated by enteropeptidase in the small intestine?

<p>Trypsinogen (C)</p> Signup and view all the answers

Which of the following is the end product of lipid digestion that can diffuse into the intestinal mucosa?

<p>Monoglycerides and fatty acids (A)</p> Signup and view all the answers

What is one of the main digestive functions of the liver?

<p>Production of bile for fat digestion (C)</p> Signup and view all the answers

What role do bile salts play in fat digestion?

<p>They physically separate large fat globules. (B)</p> Signup and view all the answers

What are micelles primarily made of?

<p>Lecithin and bile acids (D)</p> Signup and view all the answers

What role does the gallbladder serve in digestion?

<p>It stores bile until needed. (A)</p> Signup and view all the answers

What is produced by hepatocytes in the liver?

<p>Bile (A)</p> Signup and view all the answers

Where do chylomicrons transport fat-soluble substances?

<p>To the lacteals of the lymphatic system (D)</p> Signup and view all the answers

How much bile does the liver secrete roughly per day?

<p>1 liter (B)</p> Signup and view all the answers

What are hepatocytes primarily involved in?

<p>Storing glucose (C)</p> Signup and view all the answers

Which duct connects the liver and duodenum for bile flow?

<p>Common bile duct (A)</p> Signup and view all the answers

How do Kupffer cells relate to liver function?

<p>They detoxify blood. (C)</p> Signup and view all the answers

What is the primary exocrine function of the pancreas?

<p>Secreting pancreatic juice into the duodenum (A)</p> Signup and view all the answers

What is one role of secretin in the digestive process?

<p>Neutralizing acidic chyme in the duodenum (B)</p> Signup and view all the answers

Which pancreatic enzyme is specifically responsible for digesting carbohydrates?

<p>Pancreatic amylase (D)</p> Signup and view all the answers

What substance is secreted by the pancreas to neutralize acidic chyme?

<p>Sodium bicarbonate (C)</p> Signup and view all the answers

How are protein-digesting enzymes released from the pancreas?

<p>As inactive precursors to prevent damage (C)</p> Signup and view all the answers

Which cells in the pancreas are responsible for hormone production?

<p>Pancreatic islets (A)</p> Signup and view all the answers

What is the primary function of bile produced by the liver?

<p>Fat emulsification (D)</p> Signup and view all the answers

Where do pancreatic juices enter the digestive system?

<p>Duodenum (B)</p> Signup and view all the answers

Which of the following substances is NOT produced by the pancreas?

<p>HCl (hydrochloric acid) (D)</p> Signup and view all the answers

What type of fluid do pancreatic duct cells secrete?

<p>Aqueous NaHCO3 solution (C)</p> Signup and view all the answers

Flashcards

Proteins

Large molecules made up of amino acids that are broken down to provide energy for ATP synthesis or used to synthesize carbohydrates, proteins, and lipids.

Amino acids

The building blocks of proteins, released into the bloodstream after protein digestion.

Carbohydrates

Sugars and starches that are broken down into monosaccharides.

Salivary Amylase

An enzyme produced in the salivary glands that breaks down starch into disaccharides.

Signup and view all the flashcards

Pancreatic Alpha-Amylase

An enzyme produced in the pancreas that breaks down starch into disaccharides.

Signup and view all the flashcards

Enteropeptidase

An enzyme secreted by the small intestine that activates trypsin, which in turn activates other digestive enzymes.

Signup and view all the flashcards

Disaccharides

Sugars made up of two simple sugar units, like lactose, maltose, and sucrose.

Signup and view all the flashcards

Brush border

The lining of the small intestine covered with microscopic projections called microvilli, increasing surface area for absorption.

Signup and view all the flashcards

Facilitated diffusion

The movement of a substance across a cell membrane with the help of a protein, without requiring energy.

Signup and view all the flashcards

Chylomicrons

Lipid-protein complexes formed in the small intestine that transport dietary fats through the lymphatic system.

Signup and view all the flashcards

Accessory Digestive Organs

Organs not directly part of the alimentary canal, but contribute to digestion by secreting substances or performing specific functions.

Signup and view all the flashcards

Pancreas location

The pancreas is located behind the stomach, in the abdominal cavity, and is considered retroperitoneal, meaning it lies behind the peritoneum.

Signup and view all the flashcards

Pancreatic Juice

A mixture of digestive enzymes and an alkaline fluid secreted by the pancreas into the duodenum.

Signup and view all the flashcards

Pancreatic Digestive Enzymes

Enzymes produced by the pancreas that break down different food components like carbohydrates, lipids (fats), and proteins.

Signup and view all the flashcards

Trypsinogen → Trypsin

Trypsinogen is an inactive form of the protein-digesting enzyme trypsin. It is activated in the duodenum to become trypsin.

Signup and view all the flashcards

Pancreatic Islet

Clusters of endocrine cells within the pancreas that produce hormones like insulin and glucagon.

Signup and view all the flashcards

Insulin & Glucagon

Hormones produced by the pancreatic islets that regulate blood sugar levels.

Signup and view all the flashcards

Secretin

A hormone released by the duodenum in response to acidic chyme, stimulating the pancreas to secrete bicarbonate (NaHCO3) into the duodenum.

Signup and view all the flashcards

Cholecystokinin (CCK)

A hormone released by the duodenum in response to fats and proteins, stimulating the pancreas to release digestive enzymes.

Signup and view all the flashcards

Liver location & size

The liver is a large organ, weighing around 3 pounds, located in the upper right abdomen, below the diaphragm.

Signup and view all the flashcards

Pepsinogen

An inactive enzyme precursor produced by chief cells in the stomach. It is activated into pepsin by hydrochloric acid (HCl).

Signup and view all the flashcards

Pepsin

An active enzyme that breaks down proteins into smaller polypeptides in the stomach. It's activated from pepsinogen by hydrochloric acid.

Signup and view all the flashcards

Trypsinogen

An inactive enzyme precursor produced by the pancreas. It is activated by enteropeptidase in the small intestine.

Signup and view all the flashcards

Trypsin

An active enzyme produced in the small intestine that breaks down proteins into smaller peptides. It is activated from trypsinogen by enteropeptidase.

Signup and view all the flashcards

Chymotrypsinogen

An inactive enzyme precursor produced by the pancreas. It is activated by trypsin in the small intestine.

Signup and view all the flashcards

Chymotrypsin

An active enzyme produced in the small intestine that breaks down proteins into smaller peptides. It is activated from chymotrypsinogen by trypsin.

Signup and view all the flashcards

Carboxypeptidase

An active enzyme produced in the small intestine that removes amino acids from the ends of peptide chains.

Signup and view all the flashcards

Elastase

An active enzyme produced in the small intestine that breaks down the protein elastin.

Signup and view all the flashcards

Liver's Digestive Role

The liver produces bile, a substance crucial for fat digestion. It also detoxifies blood from the digestive system and stores nutrients, regulating blood sugar levels.

Signup and view all the flashcards

Liver's Other Key Function

The liver is responsible for producing essential plasma proteins, such as albumin, which play a vital role in maintaining blood volume and pressure.

Signup and view all the flashcards

Bile Storage

When bile is not actively being secreted, it is stored in the gallbladder, a small sac located near the liver.

Signup and view all the flashcards

Hepatocytes

Hepatocytes are the primary functional cells of the liver. They perform various vital functions, including bile production, detoxification, and nutrient processing.

Signup and view all the flashcards

Sinusoid

Sinusoids are specialized capillaries in the liver that receive blood from both the hepatic portal vein and hepatic artery. They allow for close contact between blood and hepatocytes.

Signup and view all the flashcards

Bile Canaliculi

Bile canaliculi are tiny channels between hepatocytes that collect bile produced by the liver.

Signup and view all the flashcards

Emulsification

Bile salts physically break down large fat globules into smaller droplets, increasing the surface area available for enzymatic breakdown.

Signup and view all the flashcards

Micelles

Micelles are water-soluble transport vesicles formed by bile salts and lecithin. They help transport fat-soluble substances, including triglycerides, fatty acids, and cholesterol, for absorption.

Signup and view all the flashcards

Duodenal Ampulla

The duodenal ampulla is a small opening in the duodenum where bile from the liver and digestive enzymes from the pancreas are released.

Signup and view all the flashcards

Gastrin

A hormone released by G cells in the stomach in response to anticipation or arrival of food. It stimulates the release of pepsinogen from chief cells and HCl, which activates pepsin for protein digestion.

Signup and view all the flashcards

CCK (Cholecystokinin)

A hormone released by the duodenum in response to chyme, triggering the release of pancreatic enzymes and bile.

Signup and view all the flashcards

Pancreatic Enzymes

A group of enzymes released by the pancreas: chymotrypsinogen, procarboxypeptidase, proelastase, and trypsinogen. These enzymes break down proteins into smaller peptides.

Signup and view all the flashcards

Bile Salts

Substances produced by the liver and stored in the gallbladder, released into the small intestine. They emulsify fats, breaking large fat droplets into smaller ones for easier digestion by lipase.

Signup and view all the flashcards

Study Notes

Accessory Digestive Organs

  • Accessory digestive organs are not part of the alimentary canal
  • They secrete digestive enzymes into the canal, aiding in digestion
  • Include salivary glands, pancreas, liver, and gallbladder

Pancreas: Location and Secretions

  • Lies behind the stomach, retroperitoneal

  • Exocrine function: Acinar cells secrete pancreatic juice into the duodenum

    • Digestive enzymes:
      • Pancreatic amylase (carbohydrates)
      • Pancreatic lipase (lipids)
      • Protein-digesting enzymes (inactive to prevent pancreas damage):
        • Trypsinogen → Trypsin
        • Chymotrypsinogen → Chymotrypsin
        • Procarboxypeptidase → Carboxypeptidase
  • Alkaline fluid (NaHCO3) neutralizes acidic chyme from the stomach

Pancreas Histology

  • Pancreatic acini: Clusters of exocrine cells producing pancreatic juices.
  • Pancreatic islets (Islets of Langerhans): Endocrine cells producing hormones insulin and glucagon

Control of Pancreatic Secretions

  • Secretin: Carried by blood; stimulates pancreatic duct cells to secrete aqueous NaHCO3 into the duodenum.
  • CCK: Carried by blood; stimulates pancreatic acinar cells to secrete digestive enzymes into the duodenum

Liver

  • Large organ (~3 lbs), enclosed in the rib cage, inferior to the diaphragm.
  • Over 200 functions!
    • a) Digestive functions:
      • Produces bile for fat digestion
      • Detoxifies and processes blood from the digestive system.
      • Nutrient storage (blood sugar regulation)
    • b) Other main function:
      • Plasma protein production (e.g., albumin)

Liver Blood Flow

  • Blood coming from the digestive system enters the liver through hepatic portal vein
  • Blood from hepatic portal veins and hepatic arteries enters sinusoids
  • Sinusoids supply hepatocytes
  • Hepatocytes produce bile

Bile Salts and Fat Digestion

  • Bile salts are a component of bile, essential for fat digestion, but do not contain any enzymes.
  • Emulsification: Bile salts physically separate large fat globules into smaller fat droplets suspended in an aqueous solution.
  • Increases lipase's surface area to chemically break down fats.

Micelles and Chylomicrons

  • Micelles: Water-soluble transport vesicles formed by bile salts (and lecithin).
  • Micelles surround lipid-soluble substances like fatty acids, triglycerides, fat-soluble vitamins, and cholesterol, aiding absorption.
  • Chylomicrons: Large fat-soluble particles, formed from micelle contents, which move from the small intestine epithelium to lymphatic vessels (lacteals).

Bile Duct System

  • Right and left hepatic ducts merge to form the common hepatic duct
  • Cystic duct connects the gallbladder to the common bile duct
  • Common bile duct and pancreatic duct merge as they enter the duodenum forming the hepatopancreatic ampulla (Ampulla of Vater).

Duodenal (Hepatopancreatic) Ampulla

  • Enters lumen of duodenum, releasing bile from the liver and digestive enzymes from the pancreas

Role of CCK

  • CCK release in the duodenum causes dilation of the hepatopancreatic sphincter and gallbladder contraction.
  • This releases bile into the duodenum through the duodenal ampulla.

Regions of Large Intestine

  • Cecum: First sac-like part of the large intestine, with the appendix attached.
  • Ascending colon: Travels up the right side of the abdomen.
  • Transverse colon: Travels across the abdominal cavity.
  • Descending colon: Travels down the left side.
  • Sigmoid colon: S-shaped portion, which turns posteriorly into the pelvis.
  • Rectum: Anterior to the sacrum and coccyx.

Haustra & Taenia Coli

  • Taenia coli: Incomplete longitudinal muscularis externa, forming three thin bands.
  • Haustra: Sac-like pouches formed by the bands of taenia coli.
  • Haustral contractions: Ring-like contractions at 1 every 30 minutes, aiding in movement.

Large Intestine Bacteria ("Good" Bacteria)

  • Bacteria accumulate in the large intestine due to slow motility.
  • 500-1000 species estimated in the colon, some beneficial functions:
    • Prevent pathogenic bacterial growth
    • Breakdown dietary fiber (produces gas)
    • Promote motility
    • Maintain mucosa
    • Synthesize vitamin K (for blood clotting and bone health)

Final Water Absorption in Large Intestines

  • Small intestine reabsorbs 7800 mL of water
  • Colon reabsorbs 1250 mL of water
  • 150 mL of water is lost in feces

Anal Canal

  • Anal canal: Last 3 cm of the rectum, opening to the exterior.
  • Internal involuntary sphincter: Smooth muscle
  • External voluntary sphincter: Skeletal muscle

Defecation Reflex

  • Defecation reflex: Rectum wall stretches, internal anal sphincter relaxes.
  • Voluntary control of external anal sphincter to release contents

Digestion Summary

  • Breaks down physical structure of food
  • Disassembles component molecules (e.g., protein to amino acids)
  • Molecules released into bloodstream
  • Absorbed by cells (for energy or building new molecules)

Carbohydrates Digestion

  • Salivary amylase in the oral cavity begins carbohydrate digestion
  • Pancreatic alpha-amylase in the small intestine breaks down carbohydrates into disaccharides and trisaccharides
  • Brush border enzymes (lactase, maltase, sucrase) break down disaccharides and trisaccharides into monosaccharides, which are absorbed.

Lipids Digestion

  • Pancreatic lipase and bile salts break down lipids
  • Lipids broken down into monoglycerides and fatty acids
  • Monoglycerides and fatty acids absorbed into cells, forming triglycerides
  • Triglycerides and other lipids combine to form chylomicrons, which are transported into lymphatic vessels (lacteals).

Proteins Digestion

  • Pepsin in the stomach starts protein breakdown
  • Pancreatic enzymes (trypsin, chymotrypsin, carboxypeptidase, elastase) break down polypeptides into smaller peptides and amino acids
  • Brush border enzyme (dipeptidase) breaks down dipeptides into amino acids
  • Amino acids are absorbed into cells.

Studying That Suits You

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

Quiz Team

Related Documents

Digestive System Part 3 PDF

Description

This quiz explores the accessory digestive organs, focusing specifically on the pancreas. It covers aspects such as location, secretions, and histology, including the roles of pancreatic acini and islets. Test your knowledge on the functions and characteristics of these vital digestive components.

More Like This

The Pancreas
10 questions

The Pancreas

ThrilledCommonsense avatar
ThrilledCommonsense
Pancreas Anatomy and Function
6 questions
The Pancreas and Its Functions
10 questions
Biology of the Pancreas and Mouth
43 questions

Biology of the Pancreas and Mouth

IntriguingSatellite6322 avatar
IntriguingSatellite6322
Use Quizgecko on...
Browser
Browser