Chapter 14 Digestive System - Gross Anatomy

What are the components of the digestive system

alimentary canal, pharynx, esophagus, and stomach

What is the component of the alimentary canal

Oral cavity (mouth)

What is the mouth the site of

site of mastication (chewing)

What is in the mouth

salivary glands and tongue

what do the salivary glands do

secrete saliva that lubricates the bolus (chewed food) easing swallowing

what does saliva contain

salivary amylase which initiates chemical digestion of carbs

What does the tongue do

moves the bolus around the mouth so it contacts the teeth

What is the tongue covered in

taste buds which makes eating enjoyable and helps identify spoiled food

what is the pharynx

bolus passes through the oropharynx after swallowing

What is the esophagus

tube (25cm) connects the pharynx with the stomach

What is the esophagus covered with

by the epiglottis for breathing

What starts in the esophagus

the common layers of the alimentary canal

What are the common layers of the alimentary canal

muscosa, submucosa, muscularis externa, and serosa

What is the muscosa layer

innerrmost layer, lining of the tube

What is the submucosa layer

mostly connective tissue, location of blood vessels, nerves, and lymph nodes

What is the muscularis externa layer

layer of stomach muscles

What is the serosa layer

external surface/visceral peritoneum which will interact with the parietal peritoneum/inner walls of the abdominal cavity

Where is the stomach located

in the left side of the peritoneal cavity, inferior to the diaphragm

What are the 4 regions of the stomach

cardiac region, fundus region, body, pylorus

What is the cardiac region

top portion, separated from the esophagus by the cardioesophageal sphincter

What is the fundus region

expands when we eat and swallow

What is the body region

inferior portion, expands and mixes the bolus with the gastric juices

What is the pylorus region

funnel shaped portion that leads to the small intestine via the pyloric sphincter

What is the function of the stomach

stores and digests the bolus by churning it with the gastric juices

What are the different gastric juices

HCl, pepsinogens, and mucus

What is HCl secreted by

secreted by parietal cells

What is pepsinogen secreted by and what does it do

secreted by chief cells and breaks down proteins

What is mucus secreted by and what does it do

secreted by neck cells and maintains a protective coating to the mucosa of the stomach

What is chyme

food stuffs leaving the stomach

What is the small intestine

long narrow tube divided into 3 sections

What are the 3 sections of the small intestine

duodenum (25cm), jejunum (2.5 m), and Ileum (3m)

How does chemical digestion occur in the small intestine

chemical digestion continues with the addition of enzymes secreted by the small intestine, pancreas, and bile from the liver via the gall bladder (continues physical digestion of lipids)

where are all enzymes secreted

all enzymes are secreted into the duodenum

What lives in the small intestine

E. Coli bacteria lives in our intestine and aids in digestions

What occurs in the small intestine

most of the absorption of nutrients

What does the mucosa have

has folds called plicae circulares which are covered with William with microvilli

What does the plicae circulares do

increases surface area for absorption

What is the muscosa spotted with

lymph tissues called peyer’s patches

What is the large intestine

larger in diameter (1.5 m) extends from the ileocecal valve to the external anal sphincter

What are the sections of the large intestine

cecum, ascending colon, transverse colon, descending colon, sigmoid colon, anal canal (rectum), appendix (extdns from the cecum but has no apparent function)

What are the functions of the large intestine

reabsorption of water and the consolidation and elimination of solid waste

What do goblet cells in the large intestine do

secrete mucus into the lumen to ease defecation

What are the accessory organs of the digestive system

salivary