1
Q
What are the main fuels of the body?
A
Protein, Fats and carbohydrates.
2
Q
Protein carohydrates and fats are then broken down into what?
A
absorbable units (simple sugars, fatty acids and amino acids)
3
Q
Intracellular digestion occurs by
A
endocytosis.
4
Q
What type of animals does intraceullular digestion take place?
A
Mostly sponges
5
Q
What is an advantage to extraceullular digestion?
A
- Expands the range of available food sources by allowing animals to deal with much larger food items.
- Also allows the animal to eat large batches of food that can be stored and digested while the animal continues other activites.
6
Q
In hydras, coreal and sea anemones the digestion system is called what?
A
gastrovascular cavity as well as a blind-end sac.
7
Q
What are some features of the batch reactor:
A
- Only has one opening
- Pulsed fashion of work
- One batch is processed and eliminated before other
8
Q
Features of the Continuous flow stirred-tank reactor:
A
- Hollow tubular cavity
- 2 passages (input and output)
- Continous proessing allows food to come in all day long.
9
Q
What type of animal uses batch reactor and what kind of animal uses Continuous flow stirred-tank reactor?
A
Batch reactor: Hydra
Continuous flow stirred-tank reactor: Humans
10
Q
Features of the plug-flow reactor:
A
- Bolus of food passes along a tube-like structure
- Continuous digestion
- The composition varies according to position in tube (Different from stirred-tank)
11
Q
What is the advantage of continous flow stirred-tank reactor to batch reactor?
A
you can eat a tremendous amount of food and can digest it over a period of time.
12
Q
The gut tube is divided into 3 main regions:
A
- ) Foregut
- Midgut
- Hindgut
13
Q
What are the 7 main parts of the digestive tract of vertebrates?
A
- Mouth
- Pharynx
- Esophagus
- Stomach (and rumen in ruminants) or proventriculus-gizzard complex in birds
- Small Intestine
- Large intestine
- Anus
14
Q
What are the three accessory organs?
A
- Salivary glands
- Exocrine pancreas
- Biliary system (liver and gallbladder)
15
Q
What are the 5 main processes that occur from ingestion of food to expulsion of wastes:
A
- Mechanical processing
- Secretion of enzymes and other digestive aids
- Enzymatic hydrolysis
- Absorption
- Elimination
16
Q
The digestive system is under the control of the?
A
nervous and endocrine system
17
Q
The foregut has these 2 important activites at the start of the digestive system:
A
- Feeding
and - Swallowing
18
Q
What are the 3 parts of the body that are strongly used in the forgut for the activites of feeding and swallowing?
A
- Teeth
- Tongue
- Salivary glands: for lubrication
19
Q
Swallowing (deglutition) is the process of
A
moving food from the mouth through the esophagus into the stomach.
20
Q
What muscle pushes the bolus of food in the pharynx?
A
The tongue
21
Q
What initiates the swallowing reflex?
A
When the bolus reaches the pharynx
22
Q
Pharyngeal pressure receptors send afferent impulses to the
A
medulla oblongata
23
Q
Swallowing reflex has two phases:
A
Oropharyngeal phase(from chewing to push it to pharynx) and esophageal phase (esophagus to stomach)
24
Q
Three things that happen in the oropharyngeal stage:
A
- Uvula is elevated and seals off the nasal passage
- Glottis is closed and covered by the epiglottis to prevent food from entering the respiratory airways
- Pharyngeal muscles contract to force bolus into esophagus
25
Two things that happen in the esophageal stage:
1. Peristaltic wave sweeps down the esophagus
| 2. Gastroesophageal sphincter relaxes to allow bolus into stomach
26
What causes heartburn?
Inappropriate opening of the gastroesophageal sphincter leads to heartburn. Or if it does not close all the way after the food has entered the stomach.
27
What is peristalsis:
Peristalsis is ringlike contractions of the circular smooth muscle that move progressively forward
28
Kim Kardashian drinks beer from a keg…. While being upside down. What allows her to drink upside down?
Because of peristalsis!! If you didn't have this you couldn't do this because then the fluid would not go up to your stomach! When we swallow it is not gravity it is the peristalsis.
29
Esophagus:
Conducts food from headgut to stomach
30
What happens in the stomach?
Chemical digestion of proteins, fats and carbohydrates
| Absorption of products
31
Do carnivores have shorter midguts than herbivores? True or False!
True! Meat is less difficult to digest than plants.
32
Bile from liver:
emulsifies fats, neutralizes acids.
33
The stomach is divided into 3 regions:
Fundus
body (corpus)
and antrum (more muscular)
34
What separates the stomach from the duodenum?
Pyloric sphincter
35
What are the three major functions of the stomach:
1. Storage of food
2. Digestion of proteins
3. Formation of chyme
36
What is chyme?
is a thick, liquid mixture of food and gastric secretions
37
What are the four steps of Gastric emptying?
1. A peristaltic contraction originates in the upper fundus and sweeps down toward the pyloric sphincter.
2. The contraction becomes more vigorous as it reaches the thick-muscled antrum.
3. The strong antral peristaltic contraction propels the chyme forward.
4. A small portion of chyme is pushed through the partially open sphincter into the duodenum. The stronger the antral contraction, the more chyme is emptied with each contractive wave.
38
What are the two steps of Gastric mixing?
5. When the peristaltic contraction reaches the pyloric sphincter the sphincter is tightly closed and no further emptying takes place.
6. When chyme that was being propelled forward hits the closed sphincter, it is tossed back into the antrum. Mixing of chyme is accomplished as chyme is propelled forward and tossed back into the antrum with each peristaltic contraction.
39
Why is there a high pH in the stomach?
This is crucial for production of enzymes that break down proteins and stuff.
40
How can the stomach contain acid without injuring itself?
The components of the gastric mucosal barrier. The mucus pH is 7 while the stomach is 2 therefore it acts as a buffer.
41
What are some 'adapatations' to the mucosal barrier that allows it to be so awesome at buffering the stomach's strong acid?
1. Impermeable to H so the HCL cannot penetrate the cells.
2. Have tight junctions so cannot HCL cannot penetrate between cells.
3. Mucus coating over the mucosal barrier.
4. The rich mucus acts as a chemical barrier that neautralizes the acid in the vicinity of the mucus barrier.
42
What does the ruminant stomach have that allows them to be able to break down plant material so well?
anaerobic microbes
43
What type of stomach does human have?
Monogastric stomach
44
What type of stomach do cows have?
Digastric stomach.
45
What are the four parts to a cows stomach?
1. Rumen
2. Reticulum
3. Omasum
4. abomasum
46
Rumen:
1. Anaerobic fermentation of plant material
2. Absorption of nutrients and simple molecules
3. Divided into internal compartments by pillars
4. Finger-like papillae increase the surface area
47
Omasum:
1. Provides a channel for passage of ingesta from the reticulum into the abomasum
2. Absorbs water and nutrients
48
The abomasum resembles the stomach of monogastric vertebrates. Therefore what two things does it do?
1. Acid-secreting region of the stomach
| 2. Digests proteins and lyses rumen microbes
49
Where does most of the digestion and absorption occur? How is it able to absorb so well?
In the small intestine. It has a very large surface area which allows it to absorb well.
50
What two features of the small intestine increases its surface area by 600 fold?
Villi and Microvilli
51
Within the small intestine where does majority of the absorption take place?
In the dueodenum and the jejunum
52
How do we absorb fats?
Diffuse across the luminal membrane
53
How do we absorb carbohydrates?
Monosaccharides absorbed by secondary active transport with Na+ as a co-transporter
54
How do we absorb protein?
Amino acids absorbed by secondary active transport similar to glucose transport
55
What is hindgut most responsible for?
storage and for absorbing water and ions.
56
The vertebrate hindgut consists of....
Consists of the colon, cecum and rectum or cloaca(birds)
57
The colon is made up of three regions:
Ascending, transverse and descending colon
58
Do carnivores have longer colons than omnivores and herbivores? True or false
False! They have shorter colons!
59
Where does fermentation take place?
In the hindgut
60
What region of the digestive system is totally controlled by the central nervous system?
Esophagus
61
What does the sympathetic and parasympathetic systems control the gut?
Sympathetic is inhibitory to gut and parasympathetic is stimulatory.
62
What type of nervous system controls the GI Tract
The enteric nervous system. Sometimes thought as seperate of the autonomic nervous system due to the fact it has its own reflexes (gastro colic reflex)
63
Endocrine glands secerete hormones into what?
Into the circulatory system
64
Exocrine glands secerete digestive enzymes, water, mucus and electrolytes where?
into the lumen of the GI tract
65
Is the mammalian salivary gland an endocrine or exocrine gland?
Exocrine gland!
66
What are the three phases of the major gastric secretions ?
1. Cephalic phase: Production of this secretion when you know your going to eat (smell BBQ)
2. Gastric phase: Triggered by the presence of food inside your gut
3. Intestinale phase: When the food enters the duoedenum it will shut down the previous stage.
67
Gastrin stimulates the release of what two hormones:
1. HCL
| 2. pepsinogen secretion
68
In the intestinal phase in repsonse to fatty acids what is released?
GIP (gastric inhibtory peptide)
69
The hormone secretion stimulates ---- and inhibits -----?
Pancrease/ stomach
70
Where is gastrin released?
It is released by G cells in the pyloric antrum of the stomach, duodenum, and the pancreas.
71
Glucose will be absorbed through transporters, such as sodium transporter, this requires....
Active Transport.
72
What are essential amino acids?
Those that cannot be synthesized?
73
What are the sources of carbohydrates?
Sugars, starches, cellulose, glycogen are the sources
74
Carbohydrates are stored as ?
Glycogen
75
What are lipids important for?
Important as constituents of membranes
76
Nucelic acids are for essential for....
DNA and RNA
77
Do we need to uptake nucleic acids?
nope
78
Do we have to take up electrolytes?
Yes
79
Saliva is made up of what?
It is 99% water, also contains a mucus which helps the food go down, bicarbonate ions (HCO3) which helps neuralize acids in the food to keep the pH of the mouth between 6.5 and 7.5. Aslo contains lysozyme which kills bacteria.
