BIO digestive system

What are the parts of the digestive system?

1. Gastrointestinal tract

2. Accessory organs

zygote

fertilized egg

blastula

hollow ball of cells that keep dividing

protostomes

mouth first, animals whose mouth develops from the blastopore (the initial opening in an embryo's developing gut) during embryonic development

deuterosomes

butt first, animals in which the anus develops before the mouth during embryonic development

What is the primary function of the digestive system?

process food, food-> macros

What are the levels of food processing?

1. Ingestion

2. Digesting- chem vs mech

3. Absorption

4. Elimination

lumen

the inner space or opening within the tubular organs, like the intestines, where food and digested material pass through

How many layers are there in the digestive tract?

4 muscular smooth layers

What are all the accessory organs in the digestive system?

liver, gallbladder, pancreas, mouth, teeth, tongue

mouth

• Primary Function= mechanical & chemical digestion

• Bolus @ swallowing, the technical name for getting ready to swallow spit

teeth

• 20 deciduous (baby) teeth & 32 adult teeth

• 3 salivary glands

  • saliva= amylase, an enzyme that cuts starch into sugar

• Hard palate-> soft palate-> uvula

tongue

food manipulator

What is the pharynx protected by?

epiglottis

What is the esophagus protected by?

sphincter

swallowing

the act of passing something from the mouth to the pharynx & into the esophagus

Peristalsis

 rhythmic contraction/relaxation of GI tract muscle, moves food

stomach

• Primary Function: chemical & mechanical digestion

• Secondary Function: food storage, protein digestion

• Tertiary Function: absorption

  • Some H2O

  • Some meds

  • Alcohol

  • Caffeine

• “J” shape

• Extra muscular layer, oblique

• Controlled slow emptying

• 1 tsp at a time

• Empties in 2-6 hrs

chyme

the pulpy acidic fluid which passes from the stomach to the small intestine, consisting of gastric juices and partly digested food

Stomach structures

• Acid+ digestive juice

• Digestive hormones

• Rugae & fundus

• Sphincter

Gastric pits

• Gastric glands

• Exocrine

• Make stomach juices

gastric glands

• Mucus (protection)

• pepsinogen-> pepsin

• HCI= pH2, activates pepsin, pepsin digests protein

Gastroesophageal Reflux Disease (GERD)

small intestine

• 18-20 ft

• folds, willi w/ microvilli

• Primary Function: digestion & absorption

• Digestion of protein, carbs, & fat

• Gastric HCI in chyme= duodenum-> secretin

• Protein & fat= jejenum-> CCk

• Secretin+ CCK in blood-> pancreas to increase the output of pancreatic juices

• CCK= liver to increase bile production

• CCK= GB to release stored bile

What are the 3 parts of the small intestine?

• duodenum, jejunum, ileum

Segmentation

Mixing of foodstuffs and digestive secretions

Liver

• The largest organ in the body

• Location= under diaphragm

• Can regenerate

• Primary Function= detox

• Secondary Function: storage, Fe, vitamins: A, D, E, K & B12

What is does the liver produce?

• glycerol & amino acids-> glucose when hangry

• Cholesterol

• Bile surrounds all the fat droplets

Gallbladder

• Primary Function: stores bile

• Location: under the liver

gallstones

stones formed within the gallbladder/bile duct

• cholesterol/decrease bile salts= stone

• Crampy pain in the right upper part of the abdomen, fever, yellowish skin, vomiting, tea-colored urine

• surgery/shock waves

• Ppl w/ estrogen, +40 years, weight & diet

Pancreas

• Primary Function: exocrine= pancreatic juices

• Location: behind the stomach

• Dump digestive juices into the small intestine

• Pancreatic juicies+ buffer

• Pancreatic juice contains sodium bicarbonate, which is acidic chyme

Large intestine

• Primary Function: absorption & storage 

• Location: around the small intestine

• 4-5 ft long

• subparts-> in lab

• Absorbs water, vitamins made by bacteria

Rectum

• last 20 cm of large intestine

  • Storage area

  • Internal sphincter: involuntary

  • External sphincter: voluntary

    • Anal canal= site of defecation, voluntary

brown poop

Bilirubin processing+ oxidized iron

Appendicitis

• inflammation of the appendix

  • caused by blockage

  • Right/lower abdominal pain Nausea, vomiting, & decreased appetite

  • Sepsis

  • Removal

Lactose Intolerance

• inability to digest milk sugars

  • If no lactase enzyme can't digest lactose

  • Bacteria break down lactose anaerobically, producing gas, bloating, and diarrhea

  • Cheese & yogurt OK, heavy cream & butter too

  • Diet & lactase supplement