4.8 Human Digestive system Flashcards
1
Q
Food in different steps of digestive system
A
Food Bolus Chyme Stool Feces
2
Q
Where does it all begin?
- sharp incisors do?
- molars do?
- Salivary glands do?
A
- Mouth/Oral cavity
- Food broken down mechanically by chewing
- Sharp incisors > slice
- Molars > grind food in pulpy mass
-Salivary glands > produce saliva
3
Q
What is the purpose of saliva?
A
- attacks bacteria with enzymes
- Dissolves substances so that food can be tasted.
- Breaks down starch with an enzyme:
“salivary amylase” - Cleanses teeth.
-Liquefies food so it is easier to swallow.
4
Q
Tongue
- structure
- fuction
A
- covered with papillae “bumby surface”, which contains taste buds
- pushes the Bolus (the ball of moist food) in the pharynx
5
Q
Uvula
-where?
- function
A
- Hangs at the back of the soft palate
- prevent food from entering the nasopharynx
- a role in speech
6
Q
Pharynx
A
- common passageway for food and air
7
Q
Esophagus
- phys desc.
- function
- peristalsis?
- esophageal spincters / cardiac spincters
A
- Floppy tube-like structure
- transports food to stomach
- Moves food through peristalsis: a wave of muscular contractions
- Ends with a ring of muscle called the esophageal sphincter (or cardiac sphincter)
8
Q
Waht happens if pancreas stops working?
A
- pancrease produces enzymes, which helps break down carbohydrates, proteins, and fats in the samll intestine. It also produces insulin.
-if pancrease stops producing enough enzymes -> malabsorption of nutrients -> deficiencies & weight loss.
-if not enough insulin -> diabetes & high sugar levels
9
Q
Stomach (Outside structure)
- phys desc.
- function
A
- A sac-like organ with layers of smooth muscles going in every direction.
- muscles contract so that the food can be mixed and churned via mechanical digestion.
10
Q
Stomach (Inside Structure)
- Phys desc.
A
- layer is made up of an extremely folded lining called rugae
- has glands that produces acidic gastric juices to continue chemical digestion.
- Gastric juices include hydrochloric acid (HCl) and pepsinogen (enzyme to break down protein)
11
Q
Stomach
- function
- absorbs what?
- phyloric sphincter?
A
- After chemical digestion the food becomes a watery paste called CHYME
- does NOT absorb most nutrients
- alcohol is absorbed across the stomach lining, directly into the bloodstream.
- pyloric sphincter is a ring of muscles that controls the movement of food out of the stomach.
12
Q
Small Intestine
- made up of ?
- why lined with vili/microvilli?
- lacteal vessel?
- Receives secretions from?
A
- Made up of three segments; Duodenum, Jejunum, Ileum
- Main site of chemical digestion
- Lined with villi/microvilli to increase the surface area to optimize absorption of nutrients.
> In the center of the villus, there is a lacteal vessel that takes in the larger fat particles absorbed from the intestine. - Receives secretions from the liver, gall bladder and the pancreas to assist in digestion
13
Q
Duodenum
- position compared to stomach , liver, pancrease
recieves ?
A
- Closest to the stomach
- So, recieves the acidic chyme, that needs to be neutalized.
- Connected to liver and pancreas via common bile duct.
14
Q
Jejunum
A
- Digestion of the chyme continue
15
Q
Ileum
A
- Main site of nutrients absorption
