Digestive System Overview and Functions
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Questions and Answers

What is the primary function of bile acids secreted by the liver?

  • To regulate hormone levels
  • To store glucose
  • To emulsify dietary fats (correct)
  • To secrete digestive enzymes

    • Which component of the digestive system is responsible for holding the anus shut?

  • The internal anal sphincter (correct)
  • The taeniae coli
  • The pelvic cavity
  • The external anal sphincter (correct)

    • What is the major difference between the longitudinal muscles of the colon and those of the rectum?

  • The rectum has a continuous sheet and no haustra (correct)
  • The colon contracts involuntarily
  • The colon has continuous sheets of muscle
  • The rectum also has haustra

    • Which of the following correctly describes the pancreatic islets?

    <p>They have both endocrine and exocrine functions</p> Signup and view all the answers

    What is the role of pancreatic juice in digestion?

    <p>It neutralizes stomach acid</p> Signup and view all the answers

    What is the primary function of the digestive system?

    <p>To break down and absorb nutrients</p> Signup and view all the answers

    Which of the following is NOT a function of the mouth?

    <p>Regulation of body temperature</p> Signup and view all the answers

    Which part of the digestive system is primarily involved in nutrient absorption?

    <p>Small intestine</p> Signup and view all the answers

    Where does digestion of proteins and fats primarily begin?

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

    What are the two anatomical subdivisions of the digestive system?

    <p>Digestive tract and accessory organs</p> Signup and view all the answers

    What is the role of the pyloric sphincter?

    <p>It controls the passage of chyme into the duodenum</p> Signup and view all the answers

    What is the function of the salivary glands?

    <p>To produce saliva for digestion and oral moisture</p> Signup and view all the answers

    Which organ is responsible for compacting indigestible food residue?

    <p>Large intestine</p> Signup and view all the answers

    What is chyme?

    <p>The semi-digested food in the stomach</p> Signup and view all the answers

    What structure connects the oral cavity to the esophagus?

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

    What is the primary purpose of the large intestine?

    <p>To eliminate waste</p> Signup and view all the answers

    Which is not a region of the small intestine?

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

    Which type of salivary gland secretes saliva at a constant rate?

    <p>Intrinsic salivary glands</p> Signup and view all the answers

    Which of the following structures is a part of the accessory organs of the digestive system?

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

    Study Notes

    Digestive System Overview

    • The digestive system is an assembly line, breaking down nutrients for the body to use.
    • Nutrients are broken down to smaller components like amino acids & monosaccharides.
    • Food is processed through ingestion, digestion, absorption, compaction, and defecation.

    Digestive System Functions

    • Ingestion: The selective intake of food.
    • Digestion: Mechanical and chemical breakdown of food into usable forms.
    • Absorption: Uptake of nutrients into the bloodstream and lymph.
    • Compaction: Absorbing water and consolidating indigestible material into feces.
    • Defecation: Elimination of feces.

    Digestive Tract

    • The digestive tract is a muscular tube extending from the mouth to the anus.
    • It includes the mouth, pharynx, esophagus, stomach, small intestine, and large intestine.
    • The gastrointestinal tract (GI tract) comprises the stomach and intestines.
    • Accessory organs to the digestive tract are teeth, tongue, salivary glands, liver, gallbladder, and pancreas.

    The Mouth (Oral Cavity)

    • The mouth is also known as the oral or buccal cavity.
    • Functions: ingestion, taste, sensory responses to food, mastication (chewing), speech, and respiration.
    • Mechanical digestion begins in the mouth with chewing.

    Salivary Glands

    • 3 pairs of salivary glands outside the mucosa
    • Intrinsic salivary glands are numerous and dispersed in oral tissues (e.g., lingual, buccal glands).
    • Extrinsic salivary glands (parotid, submandibular, sublingual): secrete saliva constantly or in response to food.
    • Saliva keeps the mouth moist & inhibits bacterial growth.

    The Pharynx

    • A muscular funnel connecting the oral cavity to the esophagus and nasal cavity to the larynx.
    • Connects the digestive and respiratory tracts.
    • Swallowing begins with the tongue and palate.

    The Esophagus

    • A muscular tube (~25-30 cm) posterior to the trachea.
    • Connects the pharynx to the stomach.
    • Carries swallowed food from pharynx to stomach.
    • Controlled by nerves and brain stem.

    The Stomach

    • Located in the upper left abdominal cavity, inferior to the diaphragm.
    • Primarily a food storage organ.
    • Mechanically mixes and breaks down food.
    • Liquefies food into chyme and begins chemical digestion of proteins & fats.
    • Controlled by smooth muscles.

    The Pylorus

    • The end of the stomach.
    • Surrounded by a thick ring of smooth muscle (pyloric sphincter).
    • Regulates the passage of chyme into the duodenum.

    The Small Intestine

    • A coiled tube filling most of the abdominal cavity inferior to the stomach and liver.
    • Three regions: duodenum, jejunum, and ileum (absorption primarily occurs here).
    • Large surface area due to extensive folding and length.
    • Nearly all chemical digestion and nutrient absorption happen here.
    • Receives secretions from the liver and pancreas.

    The Ileocecal Junction

    • Where the ileum (small intestine) joins the cecum (large intestine).
    • Ileocecal valve regulates the passage of food residue into the large intestine, preventing leakage back to the small intestine.

    The Large Intestine

    • Relatively large diameter, not its length.
    • Receives about 500 mL of indigestible food residue.
    • Absorbs water and salts.
    • Eliminates feces (through defecation).
    • Four regions: cecum, colon, rectum, anal canal.

    The Liver

    • Large, reddish-brown gland, inferior to the diaphragm.
    • Largest gland in body.
    • Important role in digestion (bile production).
    • Detoxifies blood.

    The Pancreas

    • Located posterior to the stomach.
    • Endocrine (hormones) and exocrine (enzymes) gland.
    • Secretes pancreatic juice (digestive enzymes, bicarbonate).
    • Empties into duodenum (small intestine).
    • Aids in digestion of carbohydrates, proteins, and fats.

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    Digestive System Notes PDF

    Description

    Explore the intricate workings of the digestive system, from ingestion to defecation. This quiz covers the essential functions and components of the digestive tract, including the roles of accessory organs. Test your knowledge on how nutrients are processed and absorbed by the body.

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