Thanks to Mrs. Saxe for going over BMI with you. Here is a site for you to explore more on BMI. You also went over how the liver is involved in digestion.
How is the liver involved - produces bile (an emulsifier) stored in the gall bladder and moved into the small intestine. The bile increases the surface area of fats by mechanical digestion. Here is a website with an animation on bile and fats (Bile site)
We continued on our journey through the digestive system. We are still in the small intestine.
What is the function of the small intestine? = breakdown of food and absorption of simple sugars, amino acids, fatty acids, nucleic acids, vitamins, and minerals?
Pancreas enzymes (amylase, lipase, protease) and: (where are these used?)
DNAse breaks down DNA into nucleic acids (where does the DNA come from in your food?)
Where are the nutrients then absorbed into? The plasma! since there are capillaries within the Villi in the small intestine.
What are villi? Finger like projections that help increase the surface area to increase nutrient absorption into the blood. Villi have capillaries within them.
Villi have microvilli on them - to increase the surface area even more for nutrient absorption.
How does the digested food move through the small intestine?
Monday we delved further into structure and function of the parts of the digestive system.
To start with structure and function, we began with:
Mouth - teeth, tongue, salivary glands. Teeth increase surface area by mechanical digestion, while the tongue moves food to the pharynx. The salivary glands (are they alimentary canal or accessory organs?) produce saliva which has amylase (what does this break down?) by chemical digestion.
Epiglottis - skin flap made of cartilage that closes off the trachea temporarily when you eat to prevent food from entering.
Pharynx - upper part of the throat. the junction between the alimentary canal and airway.
Esophagus - muscular tube -transfers food (bolus) to the stomach from the mouth by a series of muscle contractions called peristalsis. tube is closed unless food is inside.
Stomach - muscular sac which has an elastic mucus lining. function - to aid digestion. Mucus lining - helps protect the stomach does not digest itself, lining cells are quickly replaced.
1. Mechanical - churning of the layers of muscle (which go in different directions).
2. Chemical - 2 major chemicals involved. a)HCl-breaks down everything. b) Pepsin - breaks down proteins.
We will talk more about Rugae on Thursday!
Small Intestine - muscular tube that contains and moves chyme (liquefied food) where the food is broken down even more and the majority of absorption takes place. We will continue the structure of the SI on Thursday!
Pancreatic Enzymes, made by the pancreas and put into the beginning of the SI
1. Pancreatic Amylase - substrate (what enzyme works on) starches and medium size sugars into the products = Simple Sugars (such as glucose!)
2. Lipase - substrate = fats (lipids) into product = fatty acids (with help from bile (where is this made then stored?)
3. Protease - subsrate = proteins into product = amino acids
4. DNAse - substrate = DNA into product = nucleic acids
Where do the nutrients that are the products absorbed into and by what structure?
Here is a video that may help. (reminder: the enzymes are not discussed in the video, but you should know them!)
