Anatomy - Digestion

What are 2 types of Digestion

Chemical and Mechanical

Mechanical Digestion

Physically breaking about food which increases surface area for enzymes.

Chemical Digestion

Uses enzymes to break down food which increases speed of reaction, pH and temperature sensitve

GI Tract

Long tube on outside of body where food is broguht in and digested. Nutrients and water are brought back into the body.

Alimentary canal

COntinous holow tube that winds throguh mouth and ends at anus. Mouth, pharnyx, esophafus, stomach, small intestine, large intestines, anus.

Peristalisis

Moving food from esophagus to anus with muscle tube that contracts in wave-like motion moving food throguh digestive tract.

Mouth Mechanicals- Teeth

Gring and cut food up. Made up of dentin pulp, enamel nerves, and blood vessels.

Mouth Mechanicals- Tounge

Moves food

Mouth Mechanical: Palate

Seperates oral and nasal cavity.

Mouth Chemical

Salivary glands produce saliva

Saliva

Consists of water, mucus, and enzyme called Salivary Amylase

Salivary Amylase

Digests startch(polysaccharides) to maltose (diasaccharides)

Esophagus

• Not digestion

• Muscular tube runs throguh diaphram and connects pharnyx and stomach

• Peristalis is when muscular contractions force food throguh esophagus to stomach

Bolus

Ball of food forced inot pharnyx when you swallow.

Epiglottis

Prevents bous from entering Trachea (voice box)

Heartburn

Stomach aci backs up into tube that carries food from mouth to stomach.

Stomach: Mechanical Digestion

• Lower Eophageal/Cardiac spincter

• Pyloric spincter

• 3 layers of muscles to churn food contents

Lower Eophageal/Cardiac spincter

Controls entering stomach

Pyloric spincter

Controls exiting of stomach

Stomach Chemical Digesiton: Gastric pi

The stomach's inner layer has gastric pits(open end glands).

Gastric glands

secrete mucus, enzymes, and HCL

Pepsin

Enzyme breaks down complex proteins(pepsides) into amino acids

HCL

Ensures low pH and also kills bacteria.

Function of Mucus

It coats and protects lining of stomach from HCI and prevents pepsin from digesting proteins in stomach tissue

What happens after food enters stomach?

It stays in the stomach churning and mixing with gastric juices for 3-4 hours, then forms chyme. A smoother substance.

What does chyme contain?

Simple suars, startches, vitamins, minerals, peptides, and large proteins that don’t get broken down.

What produces the mucus lining in the stomach?

Surface mucous cells(foveolar cells) which are made to protect stomach from harsh additive acids.

Chamical DIgetstion: Dehydration synthesis

Forming polymers from monomers by loss of water moecule(growth)

Chemical Digestion: Hydrolysis

Adding a water molecule to break polymers into monomers(diegestion)

Stomach Issues: Heartburn

Acidic jucies from stomach reflux back into esophagus

Ulcer

Pepsin starts eating away at protiens in stomach lining due to mucus eaten away by bacteria H….

Vomiting(emesis)

Bacterial food poisoning irrtates stomach, activates emetic center in brain(disrupts equilibrium of inner ear) causing reverse peristalisis.

4 Tunics of GI Tract(from inside to outside)

1. Mucosa

2. Submucosa

3. Muscularis exerna

4. Serosa

Mucosa

Secretes mucus, digestive enzymes (HCI and pepsin) and hormones

Submucosa

Contains blood vessels, lymph vessels, and nerves

Muscularis externa

Muscles for peristalitc contractions

Serosa

Outercovering

How many lobes does the liver have?

4

Function of liver

Store glycogen, break down toxins, secretes bile

What does bile do?

Bile assists in fat digestion, throguh emulsfication, breaks down lare fat flobules into smaller droplets.

Where does bile go?

It goes to gallbladder and is stored there and then released. Once chyme moves into small intestine, bile is released into the intestine to emulsify lipids.

Function of Pancreas

• Involved in Chemical Diesiton in small intestine

• Secretes enzymes called pancreases (amylase, lipase, protease)

What does pancreases do?

Breaks down disaccharides into monosaccharids, fats into glycerol and fatty acids, and proteins into amino acids.

What are the 2 hormones that the pancreases secertes?

Insulin and glucagon

Insulin

Released when blood sugar is too high

Glucagon

Released when blood sugar is too low

Phyloric spincter

Controls opening or small intestine

3 parts of Small Intestine

1. Duodenum: Takes pancreases bile, and more enzymes to help break down food

2. Jejunum

3. Ileum

What are the end products of Small Intestine Absorption?

AMino acids, glycerol, fatty acids, monosaccharides. ALl absorbed intothe blood vessels in the small intestine lining.

What is small intestine lined with?

Covered by millions of villi which contain more microvilli to increase surface area of intestine.

Lacteal

Modified lymphatic capillaries that absorb fats.

4 Parts of Large Intestine

ascending colon, transverse colon, descending colon, sigmoid colon 

Appendix

Twisted spot where bacteira can accumulate causing appendicitis.

Goblet cells

Produce mucus to lubricate hehe boy

Process of large Intestine

Water is absorbed to solidfy waste into feces. Feces exits though y botty whole. External and spincter controls opening of anus.

Gastroparesis (stomach paralysis)

Delayed Gastric emptying

SIBO

Small Intestine Bacteiral Growth

• Cause of Diahreha and malabsorption

Celiac Disease

Illness caused by immune system reaction to eating gluten

Crohn’s Disease

Chronic disease causing inflammation of the lining of the digestive tract;

Ulcerative colitis

Inflamtaion in Large Intestine and Rectum

Diverticulitis

Small bulging pouches develop in digestive tract and become inflamed/infected

Appendicitis

appendix gets filled with something that causes it to swell, such as mucus, stool, or parasites

Cirrhosis

Chronic(continuous) inflammation of the liver

Hepatitis

Inflammation of liver caused by viral infection

Gallstones

Bile stored in gallbladder for too long or too much water is removed

Digestive Symptoms (Common signs of vitamin and mineral deficiencies) 

• Brittle hair/nails 

• Mouth ulcers/cracks in corners of mouth 

• Bleeding gums 

• Poor night vision 

• Scaly patches and dandruff

• Hair loss

• Red/white bumps on skin