digestive system review

in order walls of alimentary canal form inside out

1. lumen is where nutrients and water are mixed with secretions 2. the mucosa contains the surface epithelium that allows for absorption of nutrients, as well as glands for secretion 3. the submucosa is composed mostly of connective tissue, nerves, and vessels, which help to nourish surrounding tissues 4. the muscular layer is responsible for the moevement of substances through the alimentary canal 5. the serosa is composed of epithelia and connective tissues thatt reduce friction between organs in the abdominal cavity

IN ordeR

1. the first sphincter of the digestive system is called the orbicularis oris muscle, surrounds the entrance to the oral cavity 2. the inferior constrictor muscles act as a sphincter, preventing air from entering the esophagus but relaxing to allow the entrance of food into the stomach 3. the terminal end of the esophagus is the lower esophageal sphincter which controls the entrance of food into the stomach 4. the pyloric sphincter regulates the movement of food from the stomach to the small intestine 5. the junction of the small and large intestine is the loaction of the ileocecal sphincter, which regulates the movement of intestinal contents into large intestine 6. the involuntary controlled internal anal sphincter is composed of smooth muscle that relaxes at onset of defecation 7. the voluntary relaxation of the external anal sphincter which is composed of skeletal muscle, is the final step in defecation

IN order:

1. the oral cavity provides mechanical digestion of chewing which is called mastication 2. the esophagus moves food fro the pharynx to the stomach with wave like contractions called peristaltic waves 3. the stomach is a hollow storage vat that initiates digestion of proteins 4. the small intestines is where most absorption of nutrients takes place 5. large intestines absorbs a little water and electrolytes, but is mostly for a storing feces.

walls of digestive tract four layers

inner mucosa, submucosa, muscular layer, outer serosa

accessory organs of the GI tract

liver, gallbladder, pancreas, salivary glands, teeth

organs of alimentary tract

mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus

GI tract in order

oral cavity, pharynx, esophagus, stomach, small intestine (duodenum, jejunum, ileum) large intestine (ascending colon, transverse colon, descending colon, sigmoid colon), rectum, anus

sublingual gland

produces 3-5% of saliva

submandibular gland

produces 60-70% of saliva

liver

produces and secretes bile stores glycogen, minerals, and vitamins

pancreas

produces and secretes digestive enzyme, releases insulin into the blood

parotid gland

products 25-30% of saliva

gallbladder

stores and concentrates bile