Lab: Digestive system

Two divisions of the digestive system:

Two divisions of the digestive system:

alimentary canal and accessory organs

The alimentary canal includes what structures?

mouth, pharynx, esophagus, stomach, small intestine, and large intestine

What do the accessory organs do?

aid in digestion by secreting digestive enzymes

The accessory organs include what structures?

salivary glands, liver, gallbladder, and pancreas

What is the function of salivary glands?

to moisten food

Salivary glands release:

digestive enzymes

What are the 3 pairs of salivary glands?

parotid, submandibular, and sublingual glands

The mouth has what type of epithelium?

stratified squamous epithelium

Parotid gland

largest gland, anterior to the ear

Sublingual gland

smallest gland, inferior to tongue

Submandibular gland

along mandible

Bolus

mushy food, ready to go down the digestive system

How does mechanical digestion work?

by utilizing the tongue and teeth via mastication

How does chemical digestion work (specifically in the oral cavity)?

by utilizing saliva released from salivary glands

What are the layers of the digestive tract wall?

mucosa, submucosa, muscularis externa, and serosa

Mucosa

innermost layer, lines the inner lining of each one of the digestive organs with columnar epithelium, produces mucus for substances to move through the digestive system

Blood and lymph vessels of the mucosa are found in the

laminapropia connective tissue layer

Submucosa

embedded with vessels, nerves and lymphatics

The built in network of nerve cells in the submucosa is the

submucosal plexus

Muscularis externa

made of smooth muscle, aids in peristalsis and segmentation

The network of neurons in between the two layers of the muscularis externa is called the...

myenteric plexus

Serosa

outermost layer, houses arteries, veins, and lymphatics

Absorption of nutrients occurs through the

mucosal epithelium

A lack of closure of the esophageal sphincter can cause

acid reflux or GURD

What 4 regions make up the stomach?

cardia, fundus, body, and pylorus

The stomach has what 3 sheets of muscle?

circular, longitudinal, and oblique

What is the purpose of the 3 sheets of muscle in the stomach?

to aid in rotational movement, churning the bolus

Gastric folds (rugae)

allows stomach to expand and hold food and liquid contents

What is chyme?

liquified contents, released from pyloric sphinchter

Small intestine is all about

absorption

What are the 3 parts of the small intestine?

duodenum, jejunum, and ileum

What are the 3 modifications of the small intestine wall that increase surface area?

villi, microvilli, and plicae circularis

Each villi has

lacteals that absorb lipids

Each microvilli has

capillaries that absorb carbohydrates and proteins

Mesentery

connecting piece, holds most structures together

Remaining components from the small intestine go into the

large intestine

Tenia coli

aids in holding the large intestine structure together

Ascending colon

located on right side, from cecum to transverse colon

Transverse colon

courses from ascending to descending colon

Descending colon

courses from transverse colon to sigmoid colon

Sigmoid colon

S shaped

Rectum

anterior to sacrum, has nerves and retains feces until defecation

Cecum

blind pouch inferior to ileocecal valve

Appendix

hangs on cecum, considered vestigial structure, aids in immune system by filtering bacteria

Haustram

creates more feces and allows it to be excreted out

Liver

creates bile

Gallbladder

stores bile

Bile from the gallbladder is released into the…

major duodenal papilla

Pancreas is considered what type of gland?

endocrine and exocrine

The pancreas produces

insulin and glucagon

The pancreas has a main pancreatic duct that meets the

minor duodenal papilla

How are carbohydrates broken down?

salivary amylase is released by salivary glands and in the small intestine pancreatic enzymes break them down to monosaccharides

How are proteins broken down?

pepsin in the stomach breaks polypeptides down and pancreatic enzymes break them down to amino acids

How are lipids broken down?

gastric lipase in the stomach breaks down lipids and bile turns into pancreatic lipase and breaks lipids down to monoglycerides and individual fatty acids