Exam 3 (Lecture 1) - Structure and Function of Oral Cavity 1 Flashcards
Compare and contrast digestive tract structure and function of unicellular with multicellular organisms.
Unicellular:
- Intracellular digestion
- Endocytosis
- Exocytosis and elimination
Multicellular:
- Extracellular digestion
- One-way tubular digestive tract
- Proteosomes and deuterosomes
Environment directly impacts ________, which directly impacts _______.
1) Structure
2) Function
Describe steps 1-3 of prehension mechanism development in water.
1) Suspension feeding in water:
- Ciliary/mucous (passive)
- Amphioxus
- Sea squirt
2) Suspension feeding in water:
- Muscular pharyngeal pump (active)
3) Jaws (gnathostome)
- Directly procure larger prey from water
- More active, predaceous lifestyle (Bruce; Finding Nemo) :)
List the 4 types of food chemistry content that influence structural and functional features of GI tract.
1) CHOs
2) Proteins
3) Fats
4) Plant fibers (contain cellulose = refractory to rapid digestion)
List the food types that can be ranked according to the lowest, intermediate, and highest amounts of refractory material.
Lowest:
- Nectar
- Vertebrate flesh
- Whole vertebrates
- Whole invertebrates
Intermediate:
- Seeds
- Fruits
Highest:
- Vegetation (grass, dicot leaves, twigs)
- Detritus (garbage)
Digestive efficiency of a food type decreases with _________ amount of refractory material in food.
Increased
What are the common digestive system functions vertebrates share?
1) Prehension of food and water
2) Digestion and absorption of nutrients
3) Elimination of wastes
4) Acid-base balance
5) Microbiome homeostasis
Describe how carnivores and omnivores digest/absorb nutrients.
Monogastric digestive system is designed for efficient digestion and absorption.
- Digestive and absorptive capacities are equal to the relative
amounts of dietary carbohydrates, proteins, and fats
- Expression of digestive enzymes and nutrient transporters
approximately matches the amount of respective substrates
- Consume foods with low amounts of refractory material
Describe how herbivores digest/absorb nutrients.
- Adjustments in digestive compartment size to decrease the flow of digesta through the GI tract
- Participate in foregut (rumen) or hindgut (colon and/or cecum) fermentation to obtain nutrients
- Consume plant-based diets/foods with high amounts of refractory material
Describe foregut fermentation.
Rumen:
- Cattle, sheep, goats, giraffes
- Fermentative symbioses with microbes and fungi are important
for cellulose degradation in the rumen
- slow rate of degradation
- If herbivores retain digesta in the rumen for < 4 - 8 hours
- cellulose digestion is incomplete
- if incomplete, VFAs are not produces by microbes
VFAs = 70% of energy for cows
Describe hindgut fermentation.
Cecum Fermentation
- Rabbits, guinea pigs, and rats
Cecum and Colon Fermentation
- Horses, zebras, donkeys, and rhinos
** Fermentative symbioses with microbes and fungi are important
for cellulose degradation in the cecum and/or colon.
List the oral cavity structures and functions.
Structures:
- Lips and cheeks
- Hard and soft palate
- Dental pad
- Tongue and taste buds
- Jaws and teeth
- Salivary glands
Functions:
- Prehension of food and water
- Taste sensation
- Mastication
- Deglutition
- Behavioral display
- Defense
List the oral cavity boundaries. What is the oral vestibule?
Boundaries:
- Lateral and rostral: cheeks and lips
- Dorsal: hard and soft palate
- Ventral: tongue and underlying mucosa
Oral Vestibule:
- Real and potential space lateral to the teeth and inside the
cheeks
What are the functions of lips and cheeks?
Functions:
- Provide a lateral and rostral barrier to the oral vestibule - Expression of emotions such as anger and fear - Retention of food prior to deglutition - Storage compartment (hamsters) - Retention of saliva
Salivary gland ducts and secretions associated with PM4 and M1?
Zygomatic and Parotid salivary gland ducts
- associated with calculus (tartar) build-up
