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Preparados de Lengua - Esófago y Glándula Mamaria

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Preparados de Lengua - Esófago y Glándula Mamaria

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Preparados de Hígado, Páncreas y Glándulas Salivales

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Preparados de Hígado, Páncreas y Glándulas Salivales

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Chapter 14 - Gastrointestinal Tract

The digestive system takes in food, digests and absorbs nutrients, and eliminates the remaining waste material. The digestive system can be divided into the digestive tract (oral cavity, esophagus, stomach, small intestine, and large intestine) and associated digestive organs (salivary glands, pancreas, liver, and gallbladder).

Hard Palate

The hard palate is a thin horizontal bony plate located in the roof of the mouth that separates the oral and nasal cavities.

Tongue

The tongue is a moveable muscular process in the mouth that manipulates food for mastication and is used in the act of swallowing. The tongue's upper surface is covered by taste buds housed in numerous papillae.

Esophagus

The esophagus is a muscular tube through which food passes from the mouth (pharynx) to the stomach. The muscular layer of the esophagus wall is composed of skeletal muscle in the upper part, smooth muscle in the lower part, and a mixture of the two in the middle.

Gastroesophageal Junction

The gastroesophageal junction is the point where the distal esophagus joins the proximal stomach (cardia). It is the key defense against gastroesophageal reflux (GERD).

Stomach

The stomach digests food by acidification and the breakdown of proteins. It is divided into three histological regions (cardiac, body/fundus and pyloric) based on their anatomical location and appearance of their glands.

Cardiac stomach is the closest to the esophagus and contains mucus-secreting glands.

Fundic stomach is the largest part of the stomach (body/fundus) and contains fundic (gastric) glands.

Tissue sections from the fundic stomach stained with hematoxylin and eosin H&E.

Pyloric stomach is closet to the small intestine and contains mucus-secreting glands.

Vasculature of the Gastric Mucosa

The blood supply to the stomach wall can be seen after perfusion with a colored dye.

Gastroduodenal Junction

The gastroduodenal junction is the point where the distal stomach (pyloric) joins the proximal duodenum of the small intestine. The pyloric sphincter controls the passage of partially digested food ( i.e., chyme) from the stomach into the duodenum

Small Intestine

The small intestine is involved in the continued digestion of food and the absorption of nutrients. It is divided into three segments: duodenum, jejunum, and ileum.

Vasculature of the Small Intestine

The blood supply to the small intestine can be seen after perfusion with a colored dye.

Large Intestine

The large intestine absorbs water and consolidates waste material into feces. It is divided into the cecum, appendix, colon, rectum and anal canal.

Rectum

The rectum is the final portion of the large intestine that acts as a temporary storage site for feces. Feces pass out of the rectum, through the anus, and out of the body.

Copyright © 2005-2023. T. Clark Brelje and Robert L. Sorenson. All rights reserved.

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Virtual microscope slides of the gastrointestinal tract - oral cavity, esophagus, stomach, small intestine, and large intestine.

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Chapter 14 - Gastrointestinal Tract

The digestive system takes in food, digests and absorbs nutrients, and eliminates the remaining waste material. The digestive system can be divided into the digestive tract (oral cavity, esophagus, stomach, small intestine, and large intestine) and associated digestive organs (salivary glands, pancreas, liver, and gallbladder).

STOMACH

The stomach digests food by acidification and the breakdown of proteins. It is divided into three histological regions (cardiac, body/fundus and pyloric) based on their anatomical location and appearance of their glands.

Fundic Stomach

Gastric glands are found in the fundus/body of the stomach and produce stomach acid (HCl) and secrete proteolytic enzymes.

Mucous neck cells are found in the upper parts (isthmus and neck) of the gastric glands. They are smaller than surface mucous cells and produce mucins. This mucus protects the epithelium from digesting itself.

Parietal cells are found in gastric glands and secrete hydrochloric acid and intrinsic factor (enables absorption of vitamin B12 in the small intestine).

Chief cells are found at the base of gastric glands and secrete proteolytic enzymes (pepsinogen, chymosin, and gastric lipases)

Enteroendocrine cells are specialized secretory cells found in the simple columnar epithelium of the gastrointestinal tract. They release hormones from their basal surface that diffuse to nearby cells (paracrine) or into the bloodstream (endocrine).

Pyloric Stomach

Pyloric glands are located in the antrum of the pylorus.

GASTRODUODENAL JUNCTION

The gastroduodenal junction is the point where the distal stomach (pyloric) joins the proximal duodenum of the small intestine. The pyloric sphincter controls the passage of partially digested food ( i.e., chyme) from the stomach into the duodenum

SMALL INTESTINE

The small intestine is where most of the digestion and absorption of nutrients occurs. It is divided into the duodenum, jejunum and ileum.

The surface area for absorption is increased 30-fold by broad, finger-like projections into the lumen of the small intestine.

The small intestine is lined with a simple columnar epithelium with goblet cells.

Intestinal Glands

The intestinal epithelium extends into the lamina propria to form intestinal glands (or intestinal crypts, crypts of Lieberkühn).

Blood Supply

The villi of the small intestine is richly supplied with blood to aid in the adsorption of nutrients.

Lacteals

Lacteals are blunt-ended lymphatic capillaries located at the center of villi in the small intestine.

Mucosa-Associated Lymphoid Tissue (MALT)

Lymphoid nodules become increasingly numerous in the ileum and form bulges called Peyer's patches. The epithelium that covers Peyer's patches contain specialized epithelial cells (M cells) that transport antigens to immune cells to initiate an immune response.

ILEOCECAL JUNCTION

The ileocecal junction is the boundary between the small intestine and the large intestine.

LARGE INTESTINE

The large intestine absorbs water and consolidates the fecal mass. It is divided into the cecum, appendix, colon, rectum and anal canal.

Copyright © 2005-2023. T. Clark Brelje and Robert L. Sorenson. All rights reserved.

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Electron microscopy of the digestive system - oral cavity, esophagus, stomach, small and large intestine.

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Hígado, vesícula biliar y páncreas - 2025