The pharynx provides what 2 functions?
Digestive & Respiratory functions
What is the esophageal hiatus?
What are the two sphincters in the esophagus and their respective location?
1. Hole in diaphram were esophagus travels through
2a. pharyngoesophangeal sphincter = upper
2b. gastroesophageal sphincter = lower
What 2 main layers compose the esophagus?
1. Protective Epithelial layers (stratified squamous)
2. Peristalitic muscular layers
Deglutition is what?
Involuntary deglutition begins where?
1. The process of swallowing
What are the 3 processes of deglutition?
1. soft palate pushes up against the back of the throat
2. epiglottis drops down to cover larynx
3. larynx rises
What is paristalsis?
synchronous muscular contraction pushing food along digestive tract
What is the most distendible part of the GI tract?
What are the 5 main functions of the stomach?
1. stores food
2. churns food w/gastric juices
3. initiate chemical digestion of proteins
4. forms chyme (called this once it leaves the stomach)
5. production of intrinsic factor
Intrinsic factor is required for what?
As people age they make less __________ _______.
1. Absorption of VB12 in the ileum of the small intestine
2. intrinsic factor
The muscular layers of the stomach contain circular, longitudinal and ____________ .
Oblique (deeper than circular)
The folds that create more surface area in the stomach are called what?
What are the holes on the stomach's inner mucosa called?
The gastric pit contains _____________ _______ that secrete various gastric substances.
What are the 5 cells that produce various substances throughout the inner mucosa?
1. Gatric pits
2. Gastric Glands
3a. Golblet cells
3b. Parietal cells
3c. Chief Cells
1. What type of cells will you find at the top region of the gastric pit? What do they secrete?
2. What cells would you expect to find in the middle portion? What do they secrete?
3.What cells would you find just below/deeper than parietal cells or lower portion of the gastric pit? What do they secrete?
4. Which 2 cells lack a specific location? What do they both secrete?
1. Goblet cells = Mucous cells
2. Parietal cells = Hydrochloric acif (HCL) and Intrinsic Factor
3. Chief cells = pepsinogen
4a. G-cells = gastrin hormone
4b. D-cells = somatostatin hormone
Pepsinogen is an ____________ substance.
What is step 1 in the chemical digestion of protein?
What is "the chemical digestor of protein"?
1. HCL + Pepsinogen = Pepsin
What is step 2 in the chemical digestion of protein? (2)
1. Additinal HCL is released to lower pH <2
2. Therefore, Increasing activity of Pepsin
The small intestine does what to Pepsin?
Increases pH to make Pepsin inert (so it will not digest the small intestine)
Mucous has what 2 functions in the Stomach?
When is it secreted?
1a. Provides seal to Pepsin from entering the gastric pits
1b. prevents ulcers
2. AFTER parietal and chief cells send out their products (creating pepsin)