Before Test 1, Part 2 Flashcards
What are the two ways that we classify animals in terms of feeding?
Digestive anatomy/ physiology (Monogastric? Ruminate?)
Normal food preference (Carnivore, omnivore…?)
Describe the three main food preferences
Carnivore: eats meat
Omnivore: Eats meat and plants
Herbivore: Eats plants. (Often the leafy part)
What is one stipulation that is important in food preference?
It is what the animal would eat when given a choice! Ex: A dog forced into a vegan diet by its owner.
What kind of system do we use when classifying animals into eating patterns?
A dual system!
Ex: dogs are monogastric carnivores.
Monogastrics can be ____, ____, and ______
Ruminants can be _____ and maybe _____?
Carnivores, omnivores, herbivores.
Herbivores, omnivores?
In talking about plants, what is a cereal?
Generally the seed portion of a plant
What are some characteristics of cereals
High in energy (oil content in grain,) low fiber and no cellulose!
What are some examples of feed cereals?
Oat, corn, rice, wheat, barley, ect.
What is a roughage or forage?
Generally the leaves or stems of plants.
What are some characteristics of roughages?
Low in energy, high in fiber, contain a lot of cellulose and or lignin.
What are some examples of common roughages?
Grass, hay, silages, ect…
What is the simple, working definition of digestion?
The process by which feed particles are reduced to molecules so that they can enter the body.
Absorbtion is the same as digestion.
False! Digestion ONLY includes breaking down food.
What are the three types of digestion?
Mechanical action: Chewing and gut motility
Chemical action: Acidic breakdown of food.
Enzymatic action: Biological cleavage of food.
What is the definition of absorption?
The process by which molecules are transported from the digestive tract, through intestinal cells, and enter the vascular or lymph systems.
Can you have digestion without absorption?
What about absorption without digestion?
Yes to both!
Ex: Digestion without absorption: diarrhea
Ex: Absorption without digestion: energy drinks.
What are the two types of absorption?
Passive diffusion
Active transport.
Define passive diffusion in absorption.
Molecules enter body without using energy.
Define active transport in absorption.
Molecules are transported into the body against the concentration gradient. This requires energy!
In monogastric, herbivores carnivores, and omnivores, all have different systems and organs.
False! The organs are the same regardless
What is the order of the organs in a monogastric digestive system?
Mouth, esophagus, stomach, pyloric sphincter, small intestines, cecum, large intestines, rectum.
The cecum is a _______ _____. What does this mean?
Blind pouch. Food goes in and then back out through the same entrance.
Where is the cecum located?
In between the small intestine and the large intestine.
Describe the function of the mouth in digestion.
Mechanical digestion. Reduces particle size by chewing.
In some species (humans included) enzymatic digestion! Amylase breaks down starches into sugars.
In the very beginning of the digestive system, how do avians differ from other monogastics?
Very little mechanical digestion in the mouth.
Explain the role of the esophagus in digestion.
Transports food from mouth to stomach via peristalsis.
No digestion or absorption happens here!
what is chyme?
The mix of partially digested food with stomach secretions (yum)
Explain the role of the stomach in digestion.
Chemical, Enzymatic, and Mechanical!
Chemical: HCI secretions break down proteins.
Mechanical: Churning, anatomical folds increase surface area of chyme.
Enzymatic: Gastrin and pepsin. Break down proteins into polypeptides.
Does absorption happen in the stomach?
NO!
Why do you want most of your chemical and mechanical digestion to be done before enzymatic digestion starts?
So that the enzymes have a bigger surface area to work!!
Enzymes work on the surface of chyme. It needs to be small pieces for enzymes to be effective.
What is the function of the small intestine in digestion and absorption?
Major site of enzymatic digestion in monogastric animals that are NOT herbivores.
Also includes chemical digestion via bile.
Most efficient site of absorption of nutrients in ALL animals.
Why is the small intestine perfect for enzymatic digestion and absorption?
It is long and skinny! Increases surface area for enzymes to work.
It is highly vascular to aid in absorption.
Why is the small intestine red and the large intestine is not?
The small intestine is highly vascular to aid in absorption! The large intestine does less absorption.
What does the liver do in the digestive process?
Produces bile. This breaks down fat.
What organ stores bile?
The gallbladder.
Describe the cecum
A blind pouch in the junction of the small and large intestine.
In monogastrics, what is the function of the cecum?
To break down complex sugars and cellulose. Using microbes and protozoa
This allows monogastric to consume leafy plants.
Animals don’t produce ____ on their own. _____ that live in the cecum produce it instead. This is an example of a perfect _________ relationship.
Cellulase. Microbes. Symbiotic.
What breaks down cellulose?
Cellulase.
Why can plant material not be digested and absorbed without passing through the cecum or rumen?
Cellulose creates a plant cell wall and must be broken down with cellulase.
What does the large intestine do in digestion and absorption?
water reabsorption, concentrates undigested feed into waste.
Very little digestion and nutrient absorption happens here.