Digestive System

Mouth Function

Chemical Function: Saliva

Mechanical Function: Chewing

Pharynx/ Esophagus Function

A passageway to the stomach

Has the lower esophageal sphincter

Lower Esophageal Sphincter

Prevents upward flow of stomach acid into the esophagus

Stomach Function

Chemical Breakdown: acidic breakdown

Mechanical Breakdown: violently sloshes food around in stomach

Has Pepsin and lipase

Plyoric Sphincter

Pyloric Sphincter

Controls the amount chyme entering the duodenum

• Opens when the stomach forces small amounts of chyme into the duodenum

• Closes when the duodenum is full or when acidic/fatty chyme triggers hormonal signals

Small Intestine Function

Absorbs nutrients from the chyme (driven by NA+ movement)

• The walls of the intestine has maltase, sucrase, lactase, and pancreatic amylase

• Protein digestion by pancreatic enzymes trypsin, chymotrypsin, and carboxypeptidases

• Pancreatic lipase and bile salts

Illeocecal Valve

Controls how much digested nutrients moves from the small intestine to the large intestine

Small Intestine Structures

Folds in the small intestine = plicae

Finger-like projections for catching nutrients = villi

Bristle-like cells on villi= microvilli

Large Intestine

Has no enyzmes but bacteria that eats undigested food via fermentation (creates gas)

Rectum & Anal Canal

Rectum: absorbs excess water and holds feces

Anal Canal: controls bowel movements via muscles and sphincters

Internal Anal Sphincter

uses smooth muscle to move feces

External Anal Sphincter

uses skeletal muscles to consciously move feces

Liver Function

1. Can make and secrete Bile

2. Detoxification of waste such as drugs, hormones, and alcohol

3. Metabolic processing of nutrients ( cell metabolism)

4. Stores glycogen, fats, vitamins, and minerals

5. Synthesizes blood proteins like albumin

6. Synthesizes clotting factors and angiotensinogen

7. Reconverts lactate into pyruvate

8. filters out microplastics

Liver pathway

Oxygenated arterioles—> gut system—> portal vein & hepatic artery—> liver—> lobules—> interlobular vein—> hepatic veins—> deoxygenated inferior vena cave

Portal Triad

At the corner of each hepatocyte, there are the hepatic artery, portal vein, and bile duct. The hepatic artery and portal vein bring oxygenated and nutrient-rich blood to lit. The bile duct collects bile from hepatocytes.

Blood sinusoid

Is a blood vessel that delivers oxygen and nutrients to hepatocytes and allows for blood proteins to move freely.

Bile Canaliculus

Collects waste or bile in tubes and transport it to bile duct

Gallbladder

stores and releases bile

Bile elements

Bile salts- emulsify fats

Bile pigments- bilirubin

Waste products- remove waste from blood and put it into the digestive tract to poop out

Liver & Bile

So the right and left hepatic ducts take bile from the bile canaliculi and merge into the common hepatic duct

Gall Bladder & Bile

Gall bladder holds bile and releases it into the cystic duct

Bile reaching the Small Intestine

The liver and gallbladder’s respective ducts connect into the common bile duct. The common bile duct and pancreatic juices go through the hepatopancreatic sphincter into the duodenum

Digestive System Pathway

mouth—>pharynx—>esophagus—>esophgeal sphincter—>stomach—>pyloric sphincter—>duodenum—>jejunum—>lleum—>illeocecal valve—>cecum—>ascending colon—>transvere colon—>descending colon—>sigmoid colon—> anal sphincters—> rectum—>anal canal—>anus

Where does protein end up?

• Prtein channels

• tissue repair

• muscle hypertrophy

• cell receptors

• cell membrane kinda

• hormones (-oid)

• enzymes

• blood albumin

Where do carbohydrates end up?

• immediate fuel

• glycogen storage

• cell membrane

Where do fatty acids end up?

• adipose

• myelin sheath

• hormones

• cell membrane

• immediate fuel (maybe)

Hepatitis

Inflammation of the liver

• Hep A—comes from feces contamination and prevention is vaccine/good hygiene

• Hep B—Bodily flid/blood from sexual intercourse, contact with fluids, and childbirth. Prevention is safe sex and good hygiene

• Hep C—comes from sexual intercourse and contact with fluid. Prevention includes not sharing shavers, needles, tooth brushes

• Hep D—contact with fluids from someone who has Hep B. Prevention have Hep B vaccine and avoid sharing stuff

• Hep E- comes from feces contamination and practice good hygiene.