W6: Vertebrate Physiology (Digestion In Vertebrates) [Dr. Matt] Flashcards
1
Q
Feeding styles? (2)
A
- Autotrophic feeding.
- Heterotrophic feeding.
2
Q
Autotroph?
A
= can produce their own food.
3
Q
Egs of Autotrophs? (3)
A
- Plants.
- Phytoplankton.
- Cyanobacteria.
4
Q
Heterotroph?
A
= consumes autotrophs & heterotrophs.
5
Q
Egs of heterotrophs? (3)
A
- Fungi.
- Most bacteria.
- Animals.
6
Q
Types of heterotrophic feeding? (3)
A
- Parasitic.
- Saprophytic.
- Holozoic.
7
Q
Parasitic heterotrophic feeding?
A
= where organisms live on or in a host organism.
8
Q
Saprophytic heterotrophic feeding?
A
= organism has external digestion & then absorption.
9
Q
Holozoic heterotrophic feeding?
A
= organism has an internal digestive system.
10
Q
Egs of Parasitic heterotrophic feeders? (3)
A
- Helminths.
- Protozoa.
- Ectoparasites.
11
Q
Eg of a Saprophytic heterotrophic feeder?
A
Fungi.
12
Q
Eg of Holozoic heterotrophic feeders?
A
Most animals.
13
Q
Digestion in holozoic heterotrophs attributes? (3)
A
- Breaks food down into smaller nutrient molecules.
- Can then be absorbed into the body cells.
- Used for energy, growth & cell repair.
14
Q
Lay down Increasing complexity of internal digestion? (5)
A
- Intracellular digestion (phagocytosis).
- Extracellular digestion.
- Animals with a simple body plan.
- Invertebrates.
- Vertebrates.
15
Q
Intracellular digestion attributes? (5)
A
- Unicellular organisms.
- Food enters via oral groove.
- Produces a food vacuole.
- Lysosomes break down food.
- Waste products excreted through an anal pore.
16
Q
Lysosomes?
A
= hydrolytic enzymes.
17
Q
Extracellular digestion attributes? (2)
A
- Multicellular organisms.
- Compartments are continuous with outside body.
18
Q
Animals with a simple body plan attributes? (2)
A
- Have a gastrovascular cavity.
- Functions in digestion & absorption.
19
Q
Invertebrates attributes? (2)
A
- Development of two openings & specialised organs.
- Complexity increases from Hyda, Flatworm, Mollusk then Cockroach.
20
Q
Vertebrates attributes? (2)
A
- One basic organisational plan with common elements.
- Complexity increases among taxa from cyclostomes (hagfish), elasmobranchs (shark), teleost fish, amphibians (frog), birds (pigeon), then mammals (human).
21
Q
Commonalities in vertebrate digestive systems? (3)
A
- Digestive tube with two openings (mouth & anus/cloaca).
- Complete digestive tract/alimentary canal.
- Can have specialised regions for digestion & absorption (similar organs with specialised functions).
22
Q
Kinds of digestion that occur in digestion? (2)
A
- Mechanical digestion.
- Chemical digestion.
23
Q
Mechanical digestion attributes? (3)
A
- Breaks food down into smaller parts.
- Occurs in the oral/buccal cavity, which consists of teeth & saliva.
- Variations & exceptions.
24
Q
Why break down food into smaller parts?
A
It’s because it increases surface area for chemical digestion.
25
Function of saliva in the oral cavity?
Lubricates food.
26
Dentition components in mammals? (4)
- Incisors.
- Canines.
- Pre-molars.
- Molars.
27
Incisors?
= for gnawing.
28
Canines?
= for piercing & tearing.
29
Pre-molars?
= for side-to-side grinding.
30
Molars?
= for side-to-side grinding.
31
Egs of organisms that don't chew/have teeth? (3)
- Nectar-feeding bats.
- Birds.
- Reptiles.
32
Nectar-feeding bats?
= some mammals don't chew but feed on nectar as they have elongated incisors & long tongue.
33
Birds?
= in place of teeth, birds have the muscular walls of the gizzard to squeeze the contents, while small stones grind the food (specialised organ for mechanical digestion).
34
Reptiles?
= cannot chew but have specialised teeth (recurved teeth), which function as hyperdermic needles & they rely on chemical digestion.
35
Recap: Digestive systems & mechanical digestion? (3)
- Complexity of digestion systems.
- Digestion: break food down into smaller molecules for absorption.
- Mechanical digestion.
36
Digestion process in order? (7)
- Buccal/Oral cavity.
- Oesaphagus.
- Stomach.
- Small intestine.
- Large intestine.
- Rectum.
- Anus.
37
Chemical digestion attributes? (3)
- Further splits food particles into smaller molecule.
- Enzymatic hydrolysis.
- Occurs in specialised compartments.
38
Enzymatic hydrolysis?
= splits bonds in molecules with the addition of water.
39
Attributes pertaining to chemical digestion occurring in specialised compartments? (2)
- It reduces the risk of digesting own cells & tissues.
- Sphincters (valves) regulates movement.
40
Buccal/Oral cavity attributes? (3)
- Chemical digestion starts.
- Concurrent with mechanical digestion.
- Pharynx/Throat opens to the oesophagus (goes to the stomach) & trachea/windpipe (goes to the lungs).
41
How is the buccal/oral cavity concurrent with mechanical digestion? (2)
By:
- Salivary amylase breaking down carbohydrates.
- Tongue shaping food into a bolus for swallowing.
42
Oesaphagus attributes? (2)
- Swallowing occurs by the epiglottis blocking entry to the trachea.
- Conducts food to the stomach by peristalsis.
43
Swallowing attributes? (3)
- Epiglottis blocks entry to the trachea.
- The food bolus is guided into the oesophagus.
- Coughing occurs when swallowing reflex fails.
44
How does the oesophagus conduct food to the stomach by peristalsis? (2)
Through:
- Rhythmic contractions of oesophagus wall muscles, with
- Sphincter regulates entry into the stomach.
45
Stomach attributes? (2)
- Secretes gastric juice.
- Food converted into acid chyme.
- Have sphincters that regulate entry & exit.
- Mucous protects stomach lining.
46
Gastric juice attributes & constituents? (4)
- pH = 2.
- Kills bacteria & denatures proteins.
- HCl (from parietal cells).
- Pepsin: protease (from chief cells, pepsinogen).
47
Small intestine attributes? (4)
- Major organ of digestion & absorption.
- Longest section of the alimentary canal.
- Peristalsis moves food along.
- Made up of 3 sections: duodenum, jejunum & ileum.
48
Duodenum attributes? (3)
- Most digestion.
- Chyme mixes with digestive juices containing hydrolysing enzymes.
- From pancreas, liver, gall bladder & wall of small intestine.
49
Jejunum & Ileum attributes? (3)
- Mostly absorption of nutrients & water.
- Nutrients are absorbed & transported throughout the body.
- Brush-border of villi & microvilli on the intestinal wall has a high SA exposed to lumen, which increases the rate of nutrient absorption.
50
Large intestine attributes? (4)
- Sectioned into the caecum & colon.
- Has 3 main functions.
- Faeces are stored in the rectum until they are eliminated.
- Regulates bowel movements.
51
Caecum attributes? (3)
- Absorbs water & electrolytes.
- Fermentation of plant materials.
- Enlarged in herbivores.
52
Colon attributes? (3)
- Absorbs water & electrolytes.
- Bacteria feed on waste.
- Some produce vitamins (like E.coli).
53
3 main functions of the large intestine?
- Absorbing water & electrolytes.
- Absorption of vitamins.
- Forming & propelling faeces for elimination.
54
Rectum attributes? (2)
- Sphincters exist between the rectum & anus.
- Stores faeces.
55
Accessory organs of the digestive system?
= digestive organs that aid in digestion but are not part of the digestive tract.
56
List of the accessory organs of the digestive system? (4)
- Salivary glands.
- Gall bladder.
- Liver.
- Pancreas.
57
Salivary glands?
= secretes enzymes for chemical digestion.
58
Gall bladder attributes? (2)
- Stores secretions from the liver (eg, bile).
- Empties into the small intestine.
59
Liver attributes? (5)
- Converts nutrients into useful substances for the body.
- Stores & distributes these substances as needed.
- Detoxifies harmful molecules.
- Secretes bile & other molecules for digestion.
- Processes absorbed nutrients.
60
Pancreas attributes? (3)
- Produces alkaline juices.
- Neutralises acid chyme in the small intestine.
- Contains digestive enzymes.
61
Digestion in natural environments? (3)
- Interface between food supply & demand for energy and nutrients.
- Close relationsip between life history & nutrition.
- Digestive systems vary with diet.
62
How is there a close relationship between life history & nutrition? (2)
- By fluctuations & seasonality in the availability and abundance of food.
- Strategies to adjust/survive fluctuations & seasonality in the availability and abundance of food.
63
What are the strategies to adjust/survive fluctuations & seasonality in the availability and abundance of food (4)?
- Breeding season.
- Animal migration.
- Hibernation.
- Flexibility in digestive systems.
64
How do digestive systems vary with diet?
Through carnivores ingesting tissues that are easily degraded by enzymes (meat) & herbivores having plant diets that are more difficult to digest.
65
Digestive system variations in vertebrates? (3)
- Four-part stomach in foregut fermenters.
- Enlarged caecum in hindgut fermenters.
- Crop & gizzard in birds.
- Most vertebrates have a cloaca.
66
Foregut fermenters attributes? (2)
- 4 part stomach.
- Rumen, reticulum, omasum, abomasum and colon.
67
Egs of Foregut fermenters? (3)
- Cattle.
- Sheep.
- Giraffes.
68
Hindgut fermenters attributes? (2)
- Enlarged caecum & colon.
- Microbial fermentation to break down cellulose in plants.
69
Egs of Hindgut fermenters? (3)
- Horses.
- Rhinos.
- Rabbits.
70
Crop & gizzard attributes? (2)
- Store food.
- 2 chambered stomach.
71
Cloaca attributes? (2)
- Exists in most vertebrates instead of an anus.
- One exit for urinary & faecal waste.
72
Egs of vertebrates with a cloaca? (4)
- Amphibians.
- Birds.
- Reptiles.
- Some mammals.
73
Digestive phenotypic flexibility?
= reversible adjustments of the digestive system within individuals.
74
Egs of Digestive phenotypic flexibility? (4)
- Burmese pythons.
- Red knots.
- Alpine marmots.
- Garden warblers.
75
Burmese pythons as an eg of digestive phenotypic flexibility? (2)
- What happens as they are sit-and-wait foragers?
- What happens when they catch prey?
76
What happens as they are sit-and-wait foragers? (4)
- Weeks to months between meals.
- Stomach doesn't produce acid.
- No secretion from the gall bladder or pancreas.
- Atrophied intestinal walls with short microvilli.
77
What happens when they catch prey? (4)
- Gut rapidly resumes function.
- Within 24hours, the pH drops from 7 to 2 & 4xmicrovilli length.
- Within 48hours, the small intestine is 3x bigger.
- Pancreas mass doubles & 20x enzyme activity.
78
Red knots as an eg of digestive phenotypic flexibility? (2)
- In summer, feed on soft-bodied prey.
- In winter, feed on hard-bodied molluscs & thus have larger muscular gizzards.
79
Alpine marmots as an eg of digestive phenotypic flexibility? (2)
- Atrophy of the digestive system during hibernation, which helps with conserving energy.
- Recovery of digestive system post-hibernation.
80
Garden warblers as an eg of digestive phenotypic flexibility? (2)
- During migration, they decrease body, muscle & organ masses.
- After a 7-day recovery period, small intestine & gizzard still increasing.
81
Recap: Digestive system variations & flexibility in vertebrates? (2)
- Digestve system variation (foregut fermenters, hindgut fermenters, birds, cloaca).
- Phenotypic flexibility in digestion (intermittent feeding, dietary changes, hibernation & migration).
