Digestive System Flashcards
The Digestive System
The systems and organs in the body that help with…
→ taking in and breaking down food into smaller pieces
→ Absorption of Nutrients
→ Excretion of Waste
Basically wants to reduce all different kinds of molecules in the food to their most basic forms.
→ Lipids, Carbohydrates, Nucleic acids and proteins
get converted into
→ Fatty acids, Amino acids, sugars and nucleotides
Mechanical Digestion
Food is broken down by grinding action of teeth and squeezing of muscles.
Chemical Digestion
Broken down by the action of chemicals like Hydrochloric acid and enzymes like saliva.
Enzymes are proteins that living things use as catalysts to speed up reactions.
The steps of Digestion
1) Ingestion
2) Propulsion
3) Mechanical breakdown
4) Chemical Digestion
5) Absorption
6) Defecation
Mouth (Ingestion) [Oral Cavity]
→ Stratified Squamous Epithelial tissue (can withstand a lot of friction )
Teeth start to break down the food physically by chewing (with teeth and tongue) and chemically with our salivary glands producing saliva
→ Saliva also kills harmful bacteria and keeps the mouth somewhat clean.
Pharynx (Ingestion)
The connection between the mouth and esophagus. Is uses Parastolsis to propel the food to the esophagus.
→ Made of squamous epithelial
Esophagus (Propulsion)
→ Stratified Squamous Epithelial tissue
→ Connects mouth to the stomach
The esophagus propels (thus “propulsion”) the food to the stomach using times contraction in a movement called “Peristalsis”
Stomach (Propulsion, Mechanical Breakdown and Chemical Digestion)
→ Columnar Epithelial tissue
↑ Secretes mucus to line the organ so that it does not get digested by its own enzymes
→ Can hold 2-4 litres of material
→ The stomach uses Hydrochloric acid and enzymes to break down the food to smaller sizes (Chemical Digestion)
→ It contracts and expands to move the food to the intestines (Propulsion)
→ Muscles contract and expand to “churn” the food (Mechanical Breakdown)
→ Kills a lot of harmful viruses and bacteria
We are breaking down the food to increase its surface area so that it can encounter more enzymes.
Small Intestine (Propulsion, Mechanical Breakdown, Chemical Digestion and Absorption)
→ Columnar Epithelial tissue
↑ Secretes mucus to line the organ so that it does not get digested by its own enzymes
→ Smooth muscle segments in the small intestine contract and relax in a process called segmentation (Mechanical Breakdown and Propulsion)
→ Chemically breakdown the food with enzymes from the liver, gallbladder and pancreas (Chemical Digestion)
→ The Small intestines are lined with villi and microvilli which are hair-like projections responsible for collecting nutrients. Once absorbed they can get put into the blood stream and go to any cell (Absorption)
Large Intestine (Defecation)
→ Columnar Epithelial tissue
↑ Secretes mucus to line the organ so that it does not get digested by its own enzymes
→ Absorbs the water and turns the food into feces (Defecation)
→ Has good bacteria that digest anything your body could not. (These are responsible for producing gas as well).
→ Breaks down your feces with contractions and expansions (Mechanical breakdown)\
→ Peristalsis is used to transport the feces to your anus.
Anus (Defecation)
→ Stratified Squamous Epithelial tissue
→ The organ responsible for excreting feces.
Supporting Organs: Liver
The main role is to make Bile for the digestive system
→ This solution stops fat from clumping so that it can be broken down
Supporting Organs: Gallbladder
Holds the bile and controls its flow based on cues.
Supporting Organs: Pancreas
Makes an enzyme cocktail called pancreatic juice which can break down a lot of things, like a lot.
Stomach Controls: Cephalic Phase
This is when the brain sends a signal to the stomach to prepare for digestion. This is triggered when you see, hear, smell or think about food.
