Download The Human Digestive System

The Human Digestive System
Watch the video “The Human Body: Digestion and Nutirition”
http://www.youtube.com/watch?v=JN0bFd5J7UY
The overview of the digestive system starts about 10 minutes into the video (if you want a great
overview of the biochemistry chapter we did, watch all of the video!)
From the video, answer the following questions:
1.
2.
What is digestion? Gradual breaking down of food to allow it to enter into the body
Why digest food? To break down food into nutrients/monomers and absorb into cells.
3.
When is the food considered to be inside the body? Never in digestive system – only when
absorbed which is the circulatory system.
4.
What are the roles of the different layers of tissue?
1. absorbs nutrients and release mucus
2. lined with capillaries to connect to bloodstream
3. muscle for movement
5.
What is peristalsis? Muscle contractions used to move food through the body
6.
The first place where digestion occurs is the mouth. The mechanical digestion that
takes place is tearing, chewing & grinding caused by the teeth. The
chemical digestion that takes place is the release of saliva from the
salivary glands then travels to the esophagus.
8.
After swallowing, the bolus of food travels to the stomach . The mechanical digestion
that takes place is churning caused by 3 layer of muscle. The
chemical digestion that takes place is from HCl (hydrochloric acid) being secreted.
Mucus secretion helps line and protect the stomach from being destroyed by its own digestive
juices.
9.
What is the name of the food now as it passes out of the stomach? chyme
10.
The longest part of the digestive system is the
small intestine.
It is lined with small protrusions called villi and microvilli.
What is their role?
Absorb materials into the bloodstream (into the body)
How does their structure aid in this?
Lined with capillaries, have a large surface area to absorb lots of materials!
11.
There are 3 accessory organs that aid in digestion in the small intestine. They are:
1. liver which helps by producing bile
2. gallbladder which helps by storing bile
3. pancreas which helps by releasing hormones, digestive juices
A lot of
water
is also added at this stage.
9.
The remains of the food then pass through to large intestine.
What is missing by the time food reaches here?
Most of the usable nutrients
What is there more of?
Mucous (since water is being reabsorbed)
10.
What is the main role of this organ?
Reabsorb the water
11.
What is the role of the appendix in digestion?
None!
12.
The mechanical digestion that takes place is
peristalsis
13.
The chemical digestion that takes place is carried out by
bacteria
.
It is important since it gives you
vitamins
14.
What are the last stages of digestion- where does it go?
rectumand anus
15.
What are two health concerns mentioned that can be caused by what we eat?
diabetesand Cardiovascular disease
16.
Where in the digestive system does most of the digestion and absorption occur?
Small intestine