Motility and Secrection Flashcards
Why is motility in the GI tract important? (4)
- Propel ingesta along tract
- Retain ingesta
- Physical break down
- Circulate ingesta
Motility can be… by nature? (4)
propulsive, retentive, breaking down or mixing
What is the first act of digestion?
Mastication (chewing)
What type of breakdown is mastication?
Mechanical breakdown
The reflex response stimulates what secretions? (4)
- Saliva
- Gastric juices
- Pancreatic juices
- Bile
What 2 body parts work in conjunction to stop food from entering the windpipe?
The Soft Palette and the Epiglottis
What is the name of the tract that food travel down to the stomach?
The Esophagus
What are the main functions of the proximal stomach? (2)
Storage of food and mixing
What is the function of the Pylorus
Constricts and lets through only the smallest particles of food.
What roles do reflexes play in Gastric Emptying?
Reflexes control gastric emptying by regulating stomach motility
Are there different rates of emptying for solid and liquid diets?
Yes! :)
What needs to match the rate of food leaving the stomach? (2)
The rate of absorption and digestion in the Small Intestine
How many phases are there in Small Intestine motility?
Two
1) During the Postprandial period
2) During the Inter-digestive period
In the Digestive phase what are the 2 primary motility patterns?
- Propulsive
* Nonpropulsive or segmentation
What is the Propulsive motility pattern?
Peristaltic contractions that move down gut in phase with
slow waves.
What is the Nonpropulsive or segmentation motility pattern?
Mixes digesta with digestive juices & moves digesta over
absorptive mucosal surfaces.
What does Ruminant mean?
direct translation: Chew the Cud
The Rumen content can take up to… of total live weight?
up to 14%
Types of Rumen/Reticulum Contractions? (3)
Primary contractions
Secondary contractions
Rumination contractions
Where does the primary contractions of the Rumen occur? how often does it happen?
Starts in reticulum, 1-3 per min
What does the Primary Rumen contractions achieve?
Mixing of content
What does the Secondary Rumen contractions achieve?
Eructation of gas
How many steps are there in Rumination? (3)
1) Regurgitate
2) Remasticate
3) Reswallow
What 4 secretions are added during Rumination?
Saliva
Gastric
Mucus
Pancreatic
How many types of salivary secretion are there? what are they?
2 types
- Serous (thin and watery)
- Viscous (mucus-rich)
What makes up the majority of saliva?
water makes up 98% of saliva
Outside of water what else is in saliva?
Mucin Amylase Bicarbonate Lysozyme and antibodies Urea
What produces Gastric Mucus?
crypt & surface epithelial cells
What is contained in Gastric Mucus?
- Glycoproteins
* Small amounts of mucopolysaccharides
What are the main types of pancreatic enzymes? (3)
- Proteolytic enzymes
- Pancreatic amylase & chitinase
- Pancreatic lipase
