Unit 7 - Digestion Flashcards
What four molecules do we consume?
Proteins, carbohydrates, fats, and nucleic acids
What is digestion defined as?
The breakdown of nutrients
What are the 7 components of our gastro-intestinal tract?
- Mouth
- Pharynx
- Esophagus
- Stomach
- Small Intestine
- Large Intestine
- Anus
What is the mouths main function?
Mechanical digestion (chewing)
What are the four kinds of teeth
Incisors, canines, premolars, and molars
What are the 3 layers that make up the teeth?
Outer layer of enamel, middle layer of dentin, and inner pulp containing nerves + blood vessels
What’s the only part of our body that decays while we are alive?
Our teeth
Saliva is produced by what three pairs of salivary glands?
- Parotid
- Sublingual
- Mandibular
What are the three components that make up saliva?
Water, mucus, and salivary amylase
What do the water and mucus in the saliva do?
Moisten the food
What is the role of salivary amylase in the saliva?
Breaks down carbohydrates into maltose
Differentiate between the soft and hard palates
Hard palate is the hard part right behind the teeth (roof of the mouth), everything from there to the uvula is the soft palate
What is the role of the uvula?
To keep food from entering the nasal cavity during swallowing
What is the pharynx?
The open space at the back of your mouth where oral cavity and esophagus meet
What is the role of the pharynx?
It’s the site of the swallowing reflex and also a passage for air between the nasal cavity and trachea
Where is the epiglottis and what is its role?
It’s found in the pharynx. It covers the entrance to the trachea during swallowing to prevent food from entering.
What is the ball of food that goes through our body referred to as?
A “bolus”
What is the esophagus?
The long tube through which the bolus moves down into the stomach
What is peristalsis?
The wave-like contractions of muscles pushing food through the digestive system
What is the lumen?
Inner surface of the esophagus, lined with a mucus membrane for lubrication
What is the opening from the esophagus into the stomach called?
The cardiac sphincter
Give 4 characteristics/functions of the stomach
- J-shaped organ
- Composed of 3 layers of smooth muscle
- Site of mechanical and chemical digestion
- Main function is storage
What is the mechanical digestion in the stomach called (the action of it)
Churning
What glands are in the inner mucosal lining of the stomach? What do they produce?
Gastric glands, they produce gastric juice
What are the two kinds of cells in gastric glands? What are their functions?
Parietal cells = release hydrochloride acid
Chief cells = release inactive enzyme Pepsinogen
What is Pepsinogen later converted into? What is its role? Why is it secreted as an inactive enzyme and not at active one?
Converted into pepsin when exposed to HCl, pepsin is a hydrolytic enzyme that breaks proteins into peptides. It’s secreted as an inactive enzyme because if it was active when created in the cell it would break down the cells own proteins
What are HCl’s functions in the stomach?
- Convert Pepsinogen to pepsin
- Lower stomach pH to 2.5-3.0
(this weakens food bonds and kills most bacteria)
What do mucosal glands do? Where are they found?
They produce mucus to protect the stomach from its own gastric juice. Found in the mucosal lining of the stomach
What are the secondary functions of the stomach?
- Partial digestion of protein
- Weakening of food bonds
- Destroying bacteria
Also plays a role in the absorption of water, alcohol, some drugs, and caffeine.
What is the mixture of food and gastric juice called?
Acid Chyme