human digestion “who has the guts?”. swallowing digestive anatomy
TRANSCRIPT
Human Digestion
“Who has the Guts?”
Swallowing
Digestive Anatomy
Digestion
There are 2 types of digestion:
Mechanical Digestion – breaks food into smaller pieces to increase surface area exposure to digestive enzymes
Chemical Digestion – breaks organic compounds into their building blocks
Mechanical/ Chemical Digestion
Chewing Salivary glands release saliva which
moistens the chewed food, now called a Bolus.
The tongue pushes the bolus to the back of the throat, called the Pharynx.
A flap of skin called the Epiglottis flips down and covers the entrance to the Trachea during swallowing
Swallowing Digestion Overview
Peristalsis/Alimentary Canal
The bolus passes through the esophagus by peristalsis
Peristalsis Food continues to pass through the
Alimentary Canal (any part that food passes through)
Mouth-Pharynx-Esophagus-Stomach-Small Intestine-Large Intestine-Anus
Accessory organs play a role in digestion, but food never enters them
Salivary glands-Pancreas-Gall Bladder-Liver
Anatomy of Digestion
Chemical Digestion
Enzymes break down the organic compounds (polymers) into their building blocks (monomers) so they can be absorbed into the blood stream and transported to all cells
Carbohydrates – Simple sugars Protein – Amino acids Lipids – Glycerol and 3 Fatty acids Nucleic acids - Nucleotides
Look in your textbook Chapter 38-2
Compare the digestion of Carbohydrates and Protein.
Follow the digestion of Carbs from the time they enter your mouth until the end products are absorbed into your blood.
Do the same for Protein.
Do you know your guts?
Try the quiz.
Digestion of Carbohydrates
Mouth – Mechanical digestion breaks the carbs into smaller pieces to increase the surface area exposure to enzymes.
Saliva lubricates the bolus. It contains the enzyme Amylase which begins the Chemical digestion of Carbs.
Polysaccharides are broken into shorter chains.
Swallowing pushes the bolus into the esophagus
Carbs in the Stomach
Peristalsis moves the bolus to the stomach. Cardiac sphincter opens and bolus enters
the stomach Bolus now mixes with the gastric juices of
the stomach. This acidic mixture is now called Chyme Mechanical digestion (churning) continues No chemical digestion of Carbs here
because of the acidity of the chyme Protein is digested here
Carbs in the Duodenum
Pyloric sphincter opens and chyme moves into the duodenum.
Pancreas secretes: Alkaline secretion that neutralizes the
acidic chyme Pancreatic amylase and disaccharase
continue the breakdown of carbs into simple sugars
Absorption of Simple Sugars
Small intestine is about 6 meters long!
The lumen of the small intestine is lined with Villi.
Absorption of Carbs
Each villi has microvilli on it’s surface
The infolds increase surface area contact so the simple sugars can pass into the blood by diffusion.
Small Intestine
Absorption is complete here. Peristalsis moves the digested food
mass to the Large Intestine (Colon)
Large Intestine Main function is to absorb water from the
unusable waste that remains. Too much water absorption –
constipation! Not enough water absorption – diarrhea! Bacteria in colon produce Vitamin K Feces passes from descending colon to
rectum and then is excreted through the anus (anal sphincter)
Accessory organs and their Functions
Salivary glands – Amylase Pancreas – Amylase
- DisacharaseLiver – produces bile which is stored in the Gall Bladder and secreted into the duodenum through the Common Bile Duct
- Bile emulsifies fats
Digestion
Human Digestion
Have another look
Digestion Animation
Digestive Problems
Heart burn – acidic gastric juice enters the esophagus
Gastric ulcer – mucus lining of the stomach deteriorates and the gastric juice of the stomach begins to digest the stomach wall
Pig Dissection