What are the layers of the GI tract?
- -Mucosa(innermost layer)
What is the function of the Mucosa layer in the GI tract?
Its the innermost layer, nutrients pass through.
What is the function of the Submucosa layer in the GI tract?
Connctive tissue, lymph and blood vessels, nerves.
What is the function of the Muscularis layer in the GI tract?
Two or three layers of smooth muscle, responsible for motility in GI tract.
What is the function of the Serosa layer in the GI tract?
Outermost layer, connective tissue sheath.
What are the 5 digestive system processes?
- -Mechanical processing and movement
What happens in mechanical processing and movement?
Chewing and mixing.
What happens during secretion?
Fluid, digestive enzymes and hormones, bile, acid, alkali, mucus.
What happens during digestion?
Breaking down food to smallest absorbable units.
What happens during absorption?
Through mucosa, into blood or lymph vessels.
What happens during elimination?
Undigestied material eliminated.
What are the 3 feeding types?
- -Herbivores: Eat plant material
- -Carnivores: Eat other animals
- -Omnivores: Eat both plant and animal materials
Why do skull and tooth patterns vary?
According to feeding types.
Where does digestion begin?
What type of teeth are there?
What is the function of the tongue?
Made of skeletal muscle, moves food in mouth and taste.
What is the function of swallowing?
Delivers food to stomach.
What is the voluntary phase of swallowing?
The tongue pushes bolus of food into pharynx.
What is the involuntary phase/swallowing reflex of swallowing?
- Receptors in pharynx stimulated by presence of food:
- -Soft palae rises
- -Larynx rises slightly
- -Epiglottis closes opening to trachea
- -Tongue pushes food further
- -Food enters esphagus
What is the function of the pharynx?
- -Common passageway for air and food
- -Participates in swallowing
What is the function of Esophagus?
Connects pharynx to stomach, assists passage of food.
What is the function of the stomach?
Food storage, digestion, regulation of delivery.
What is the pH inside the stomach?
What does stomach contraction do?
Blend food and propel forward.
What is the function of the small intestine?
- -Absorption: 95% of food absorbed
What are the accessory organs of the digestive system?
Pancreas, Liver and Gallbladder
What is the function of the pancreas?
- Exocrine function:
- -Secretes digestive enzymes and sodium bicarbonate
What is the function of the Liver?
- -Produce bile
- -Hepatic portal systems: Drains blood from digestive tract
- -Metabolic functions: Storage, synthesis, and chemical processing
What is the function of the Gallbladder?
What is the function of the Large Intestine?
Absorbs nutrients and water and eliminates waste.
How are proteins and carbohydrates absorbed?
Through active transport
How are lipids absorbed?
They are broken down and reassembled.
How is water absorbed?
How is digestion regulated?
Through the endocrine and nervous systems. Regulation dependent on volume and content of food.
What is the required dietary allowances?
- -Protein: 50 grams
- -Carbohydrates: 300 grams
- -Lipids: 40 grams
What is the function of fiber in our diet?
Helps things move quickly through digestive tract.
What is our major energy source?
Comes from simple or complex carbohydrates.