Stomach Anatomy and Nerve Supply Quiz: Test Your Knowledge

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Questions and Answers

What is the primary function of the upper esophageal sphincter?

To prevent the backflow of food from the stomach into the esophagus

To control the flow of acid from the stomach back into the esophagus

To control the flow of food from the esophagus into the stomach

To allow the passage of food from the pharynx into the esophagus (correct)

What is the approximate volume of the empty human stomach?

Half the size of your fist (correct)

4 liters

1 liter

2 liters

Which type of cell in the gastric glands is responsible for secreting hydrochloric acid?

Mucous neck cells

Chief cells

Parietal cells (correct)

Enteroendocrine cells

What is the purpose of the lower esophageal sphincter?

To prevent the backflow of food from the stomach into the esophagus Signup and view all the answers

What is the name of the final phase of the swallowing process?

Esophageal phase Signup and view all the answers

What is the purpose of the oblique muscle layer in the stomach?

To churn and mix the food in the stomach Signup and view all the answers

What is the main purpose of the regulatory mechanisms in the digestive system?

To control the secretion of digestive juices and activate the muscles of the digestive tract Signup and view all the answers

What is the primary purpose of the short reflex in the digestive system?

To increase the secretion of digestive juices in response to a local stimulus within the digestive tract Signup and view all the answers

Which hormone is responsible for stimulating the release of gastric acid?

Gastrin Signup and view all the answers

What is the primary function of the tongue in the digestive system?

To facilitate ingestion, mechanical and chemical digestion, swallowing, and vocalization Signup and view all the answers

What is the purpose of the soft palate and the uvula in the digestive system?

To stop food from entering the nasal cavity Signup and view all the answers

What is the main function of the long reflex in the digestive system?

To react to stimuli outside the digestive tract, such as the sight or smell of food, and trigger a response within the digestive system Signup and view all the answers

What is the main function of the hepatocytes in the liver?

Produce bile for breakdown of lipids Signup and view all the answers

Which organ is responsible for storing extra bile?

Gallbladder Signup and view all the answers

What can happen if feces are delayed in the colon for too long?

Firmer feces due to more water absorption Signup and view all the answers

Which nutrient breakdown process in the small intestine is comparable to the action of dish soap on fats in water?

Lipid emulsification Signup and view all the answers

What is the role of the Valsalva maneuver in the process of defecation?

Increase intra-abdominal pressure Signup and view all the answers

What is the primary function of the pancreas in digestion?

Produce enzymes for digestion Signup and view all the answers

Which layer of the stomach wall is the most superficial and only present in the region inside the abdominal cavity?

Serosa Signup and view all the answers

What is the primary function of the enteric nervous system?

Regulating the motility and secretions of the digestive tract Signup and view all the answers

What is the function of the hepatic portal system?

Transporting proteins and carbohydrates from the digestive tract to the liver Signup and view all the answers

Which of the following statements about the peritoneum is correct?

Both (a) and (b) Signup and view all the answers

What is the primary function of the mouth in the digestive process?

Ingesting, chewing, and mixing food, as well as initiating chemical breakdown of carbohydrates and lipids Signup and view all the answers

What percentage of the blood pumped by the heart enters the arteries serving the intestines during resting and digesting states?

25% Signup and view all the answers

What is the rate of peristaltic contractions in the duodenum compared to the ileum?

The duodenum has a faster rate at 12 times per minute, while the ileum is slower at 8 times per minute. Signup and view all the answers

Which of the following statements about lipid digestion is true?

Most lipids are undigested and require bile and pancreatic lipase for digestion. Signup and view all the answers

What is the primary function of the cecum in the large intestine?

To continue the absorption of water and salts, and hold the appendix. Signup and view all the answers

What is the primary function of the bacterial flora in the large intestine?

To facilitate digestion, absorption, and synthesis of certain vitamins. Signup and view all the answers

What is the primary function of the rectum in the large intestine?

It has three lateral bends (rectal valves) to prevent simultaneous passage of feces and gas. Signup and view all the answers

What is the primary function of the mass movements in the large intestine?

To force chyme toward the rectum, happening 3 or 4 times per day. Signup and view all the answers

Study Notes

Digestive System Overview

Chemical digestion breaks down complex food molecules into their building blocks (water, acid, enzymes, and salts)
Absorption primarily occurs in the small intestine, where nutrients are taken into the bloodstream or lipids into the lymphatic system
Defecation removes undigested materials from the body

Regulatory Mechanisms

Neural control: sensors in the stomach monitor expansion, food particle breakdown, liquid presence, and nutrient type, and can activate glands and muscle
Two types of reflexes: short reflex (local stimulus and response) and long reflex (ANS and CNS reacting to stimuli outside the digestive tract)
Hormonal control: gastrin stimulates gastric acid release, secretin stimulates bicarbonate release from the pancreas, CCK stimulates pancreatic enzyme and bile secretion, and gastric inhibitory peptide inhibits gastric secretion and slows gastric emptying and motility

Mouth, Pharynx, and Esophagus

Mouth: oral cavity lined by cheeks, tongue, lips, and palate, capable of handling digestion and respiration simultaneously
Tongue: involved in ingestion, mechanical and chemical digestion, swallowing, and vocalization
Pharynx: propels food to the esophagus and lubricates food and passage
Esophagus: propels food to the stomach, with upper and lower esophageal sphincters controlling food entry and acid reflux

Nerve Supply

Enteric nervous system: runs from esophagus to anus, separated into myenteric and submucosal plexuses, responsible for motility and regulating digestive secretions
Autonomic nervous system: extrinsically innervates the alimentary canal, with sympathetic nerves restricting enteric neurons and parasympathetic nerves increasing GI secretion and motility

Blood Supply

Transports protein and carbohydrate to the liver via the hepatic portal system
Delivers nutrients and oxygen to organs of the alimentary canal, with 25% of blood pumped entering arteries serving the intestines during rest and digestion

The Peritoneum

Holds digestive organs in place, with parietal and visceral peritoneum regions
Peritoneal cavity: space between parietal and visceral peritoneum

Digestive System Processes and Regulation

Mouth: ingests, chews, and mixes food, beginning chemical breakdown of carbs and lipids
Pharynx: propels food to the esophagus, lubricating food and passage
Esophagus: propels food to the stomach, with upper and lower esophageal sphincters controlling food entry and acid reflux
Deglutition (swallowing): movement of food to the stomach, with 4-8 seconds for solid food and 1 second for soft food and liquid, involving voluntary, pharyngeal, and esophageal phases

The Stomach

Links the esophagus to the small intestine, responsible for digestion, contractions, and changing position and size
Empty stomach is about half the size of a fist, can stretch to hold 4 liters, and has an additional oblique muscle to churn food
Cardia, fundus, body, and pylorus regions, with gastric glands producing hydrochloric acid, pepsinogen, and mucous

Gastric Secretion

Three phases: cephalic, gastric, and intestinal
Cephalic phase: brief, stimulated by sight, smell, taste, or thought of food, with chemical secretion of mucous and no digestive enzymes

Feces and Defecation

Feces: undigested food residue, unabsorbed substances, bacteria, old cells from GI mucosa, inorganic salts, and some water
Valsalva maneuver: voluntary procedure to remove feces, increasing intra-abdominal pressure
Feces in the anal canal opens the internal sphincter, giving the choice to open the external sphincter

Accessory Organs

Liver: receives nutrients from the small intestine, processes nutrients, drugs, and toxins, and produces bile for emulsification of lipids in the small intestine
Pancreas: exocrine and endocrine functions, producing bile and pancreatic lipase for digestion

Large Intestine

Finishes absorption, forms feces, and eliminates it, with four regions: cecum, colon, rectum, and anal canal
Bacterial flora: trillions of nonpathogenic bacteria live in the large intestine, facilitating digestion, absorption, and synthesis of certain vitamins

Digestion and Absorption

Chemical digestion finishes carb and protein digestion in the small intestine
Most lipids are undigested and require bile and pancreatic lipase
Most water is absorbed through osmosis
Mechanical digestion: haustral contractions, peristalsis, and mass movement in the large intestine

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Description

Test your knowledge on the anatomy of the stomach and its nerve supply. Learn about the layers of the stomach muscles, the enteric nervous system, and the role of the autonomic nervous system in innervating the alimentary canal.

Stomach Anatomy and Nerve Supply Quiz

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