Digestive system
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Transcript of Digestive system
Digestive System
Vocabulary
• __________ - life function by which humans use for energy, growth, and repair
• ___________- mouth • ___________- wave of muscular contractions• __________- microscopic parts that help with
absorption in the small intestine• ____________- bile movements (semi solid
stored in rectum)• _____________ - splitting by adding water
(break down od big pieces into smaller ones)
Let’s Review
• One of the Life Process that are similar in ALL Living things is nutrition. – Nutrition is needed for growth, repair, and
energy. – In order for us to us nutrition we need to break
down the nutrients into small enough pieces that they can reach each cell.
– Our bodies need a healthy diet this includes the right amount of protein, carbs, fats, and minerals
So how do we get these nutrients in our bodies?
I Don’t know!!! Let me sleep!
OOOOHHHH. I
know….Digestive System
Digestive System Overview
• There are four parts to digestion
1. __________- taking in food
2. ___________- mechanical and chemical breakdown of food so that it can be absorbed by the cells
3. ______________: cells lining the digestive tract take up (absorb) small nutrient molecules
4. ________________: undigested material passes out of the digestive tract
There are two ways digestion breaks up the food
• 1. Mechanical digestion – physical breakdown of large pieces of food into smaller ones
• 2. Chemical digestion – hydrolysis – the splitting of large molecules into small, molecules with the use of water and enzymes ( in other words; breaking complex molecules into simple ones)
The process of chemical digestion ( hydrolysis) is controlled by enzymes
Examples of Chemical Digestion:
• 1. Carbohydrates+ water -> simple sugars (glucose for instance)
• 2. Proteins+ water -> amino acids
• 3. Lipids+ water -> 3 fatty acids +gylcerol
How Does Our Digestive system
work?
HUMAN DIGESTIVE SYSTEM
• The digestive system is a one way food tube that goes from the Oral Cavity to the rectum.
• This one way track is called the GI track (gastrointestinal)
Oral Cavity
• Oral Cavity is a fancy name for a mouth– Used to ingest (take in
food)
• Teeth - function in mechanical breakdown of food, increases surface area of food for enzyme action
• Tongue -
Teeth &Tongue
• Teeth - function in mechanical breakdown of food, increases surface area of food for enzyme action
• Tongue acts as a plunger to push food back into the throat (pharynx) taste buds are located on the surface of the tongue
• The enzyme reaction is caused by saliva
• Saliva is secreted (let out) by the salivary glands
• The saliva’s job is to begin the Chemical digestion of carbohydrates etc..
Pharynx
• Pharynx is another name for the throat – The tongue pushes
the food to the back of the throat
• This starts the swallowing
• food is now in the form of a bolus
– Epiglottis: flap that prevents choking
Esophagus
• Esophagus: muscular tube that moves food from mouth to the stomach by process of peristalsis: wave of muscular contractions that moves chewed food to stomach
Stomach
• Stomach: J-shaped, sac-like , muscular organ
• mechanically churns food into a liquid and begins chemical digestion
• lining secretes gastric juice,
• stomach empties in about 2-6hrs.,
• food now liquid called chyme
Gastric Juice
• Components of gastric juice:– 1. water-solvent– 2. mucus-lubrication– 3. enzyme that begins chemical digestion of
protein– 4. hydrochloric acid (HCl)
Small Intestine • the major organ of chemical digestion
and nutrient absorption,• long twisted tube with small diameter, • enzymes and fluids needed to
complete chemical digestion come 3 separate sources:
– 1. intestine itself– 2. pancreas-. Small intestine– 3. liver-> gallbladder->small intestine
• Main organ for absorption
• Villi: fingerlike projections that increase surface area of small intestine contain a network of capillaries for absorption of amino acids and simple sugars into blood, center contains lymph vessel called lacteal which absorbs fatty acids
Large Intestine
• The food now goes into the large intestine – It gets the food that has
not been digested – Usually in a liquid state – NO digestion occurs here – Reabsorbs the water and
solidifies the waste – known as feces
• the feces are stored at the lower end of the Long Intestine called the rectum
– Leaves the body through the anus
Accessory Organs to the digestive system
• Even though not part of the food tube there are important organs for digestion
• This includes – Liver – Gallbladder – Pancreas
Liver
• largest internal organ (has many functions outside digestion)– Makes bile ~ bile NOT
an enzyme,) • Bile breaks down
lipids- breaks them into smaller droplets to increase the surface area for enzymes (lipases) to act on fats
Gallbladder
• small storage sac for bile, carries bile to small intestine
Pancreas
• Pancreas: located near small intestine– Produces juices, enzymes,
and fluids• These enzymes are
important to break down complex molecules into soluble end products
– Such as » Glucose » Amino acids » Fatty acids » Glycerol
Digestive Homeostasis Disorders
• 1.Constipation– person has uncomfortable or infrequent bowel movements results from sluggish peristalsis that allows excess water to be removed from feces (fecal matter hardens)- may result from insufficient fiber in diet
• 2. Diarrhea– opposite of constipation– associated with intestinal disturbances caused by infections or stress– prolonged diarrhea may result in severe dehydration
• 3. Gall stones– small hard particles made of cholesterol which form & collect in gall bladder- may block the bile duct and cause pain
• 4. acid reflux -backflow of stomach contents upward into esophagus
• 5. appendicitis- inflammation of appendix