Chapter 23 Flashcards
(80 cards)
1
Q
cellular respiration equation
A
O2+C6H12O6=CO2+H2O+ENERGY
2
Q
Why do we eat?
A
energy
3
Q
What does digestive system do to food?
A
converts food into raw materials that build and fuel body’s cells
4
Q
When the digestive system takes in food…
A
breaks it down into molecules, absorbs molecules into bloodstream, and rids body of indigestible remains
5
Q
organs of digestion fall into two groups
A
alimentary canal and accessory digestive organs
6
Q
another name for alimentary canal
A
gastrointestinal tract or gut
7
Q
what does the alimentary canal do?
A
- digest food (breaks into smaller pieces)
- absorbs digested fragments thru its lining into the blood
8
Q
alimentary canal organs
A
mouth, pharynx, esophagus, stomach, small intestine, large intestine
9
Q
accessory digestive organs
A
teeth, tongue, gallbladder, salivary glands, liver, pancreas
10
Q
digestive process
A
- ingestion
- propulsion
- mechanical digestion
- chemical digestion
- absorption
- defecation
11
Q
ingestion
A
bring it in
12
Q
propulsion
A
- swallowing (voluntary)
- peristalsis (involuntary)
- so powerful, food/drink reach stomach even if standing on head
13
Q
mechanical digestion
A
- Physically prepares food for chemical digestion by enzymes
- Includes chewing, churning food, segmentation (rhythmic movement of food in small intestine)
- Not every animal goes through this
14
Q
what animals do not go through mechanical digestion?
A
- Snakes/frog - swallow mice whole - have very powerful chemical digestion
- Chickens - gizzards, rocks - breaks down food
15
Q
chemical digestion
A
- Catabolic reactions (breakdown of food) where food is further broken down into chemical building blocks
- Starts in mouth and is usually complete in small intestine
16
Q
absorption
A
- Passage of digested end products (+ vitamins, minerals, water) from lumen of GI tract thru mucosal cells via active/passive transport into the blood
17
Q
what is the major absorption site?
A
small intestine
18
Q
where does carbohydrate digestion start?
A
mouth
19
Q
amalase
A
starts digestion, chemical
20
Q
defecation
A
- Elimination of indigestible substances from the body
- Waste products move to large intestine
- Small absorption of water in large intestine
21
Q
why is fiber important?
A
flows through body as a waste product, nutrient because of its action and not absorption
22
Q
regulatory mechanisms
A
- Mechano- and chemoreceptors
- Taste cells
- Activate or inhibit glands
- Control of digestive activity under both intrinsic and extrinsic control
- Stomach and small intestine
23
Q
Mechano- and chemoreceptors
A
- found in GI tract walls
- Sense stretching, osmolarity, pH, presence of end products
24
Q
taster cells
A
- In GI tract to guide food choices
- Prep system for what is coming
- Can affect digestion /absorption
25
activate or inhibit glands
salivary glands
26
stomach and small intestine
- Endocrine function
| - Hormones deal with digestion
27
segmentation
rhythmic movement of food in small intestine
28
lumen
cavity, in reference to alimentary canal
29
structural plan
peritoneum & circulation
30
peritoneum
Visceral, Parietal, and Messentery (omenta)
31
Messentery (omenta)
double layer
32
parietal
covers body wall
33
visceral
covers most digestive organs
34
circualtion
- Systemic via celiac trunk/mesenteric arteries
| - Hepatic portal system
35
Hepatic portal system
- collects nutrient-rich blood draining from the GI tract and delivers it to the liver
- liver collects absorbed nutrients for metabolic processing or for storage before releasing them back to bloodstream
36
Histology
- from esophagus to anus, same 4 layers or tunics
- mucosa
- submucosa
- muscularis externa
- serosa
37
mucosa
- Epithelium (simple columnar)
- Rich in goblet cells - mucous secretion
- Functions in secretion (various products), absorption (of digestion end products), protection
38
submucosa
Functions in secretion (various products), absorption (of digestion end products), protection
39
muscularis externa
- smooth
- Responsible for segmentation and peristalsis
- Circular and longitudinal layers
- Forms sphincters - smooth muscle
40
serosa
- Forms visceral peritoneum
| - Tough connective tissue
41
Multiple orientation of muscles allow....
for movement down GI tract
42
mouth
- Oral or buccal cavity
| - Mucosal lining produces antimicrobial peptides, defensins
43
tongue
- Interlacing skeletal muscle fibers
- Mixes food with saliva forms mass called a bolus
- Aids speaking
- Filiform papillae (roughness)
44
bolus
food and saliva mixed together with the tongue to form a mass
45
salivary glands
- Saliva cleanses the mouth, dissolves food chemicals so they can be tasted, moistens food to from bolus, contains enzymes that begin digestion
- Saliva is 97-99.5% water, slightly acidic
- Protects via IgA antibodies, lysozymes, defensins
46
amylase
salivary glands contain enzyme to begin digestion of carbohydrates
47
amount of saliva produced per day
1000-1500 mL
48
When we ingest food, chemoreceptors and mechanoreceptors...
send signals to salivary nuclei in brain, e.g. from food and dentist (mechanoreceptor sense movement when someone is working in your mouth)
49
teeth
- Functions to masticate or chew
| - Deciduous and permanent teeth
50
permanent teeth
in by adolescence (except 3rd molars - wisdom teeth, between 17-25 years)
51
enamel
hardest substance in body, heavily mineralized
52
bulimic
stomach acid destroys teeth
53
esophagus
- About 10" long, collapsed when no food
| - Empties into stomach at cardiac sphincter
54
heartburn
- "acid reflux" or gastric reflux disease strong gastric juice regurgitates into esophagus
- Burns mucosal lining of esophagus
55
stomach
- storage trunk
- Protective mucosa barrier so it doesn't digest itself
- Chemical breakdown of proteins begins
- 6-10 inches long, 50 mL empty to 4 L when full
- First part: cardiac region, top dome: fundus, bottom funnel: pyloric region
- Secretes compound required for intestinal absorption of vitamin B12
56
chyme
- stomach
| - food converted to creamy paster
57
rugae
- stomach
| - longitudinal folds
58
greater omentum
- stomach
| - fat deposits covers
59
gastric juice
- stomach
- Microscopically, contains gastric pits which leads to gastric glands producing "gastric juice"
- 3L per day
60
parietal cells
- stomach
- secrete HCl, pH 1.5-3.5 (could dissolve nails)
- HCl needed for pepsin activation, kills bacteria, denatures proteins
61
chief cells
- stomach
- secrete pepsinogen, pepsinogen can only turn into pepsin in an acidic environment, precursor to protein-digesting enzyme pepsin
62
mucosal barrier
- stomach
- Protein-digesting enzymes/acid could digest stomach itself
- protective layer
63
gastric ulcers
- erosions of the stomach wall
| - about 90% of recurrent ulcers involve Helicobacter pylori
64
emesis
vomiting
65
small intestine
- Major digestive organ (is complete here) and most absorption occurs here (food and water)
- Highly adapted for nutrient absorption
- Contains villi to increase surface area absorption
66
3 parts of small intestine
- duodenum
- jejunum
- ileum
67
microvilli
- plasma membrane (columnar)
- increase surface area
- brush border
68
nutrient assimilation
incorporation of nutrients into cellular structure (to build a body)
69
liver
- Has many regulatory and metabolic roles
- Produces bile for export to duodenum, aids in fat digestion
- Converts excess glucose to storage carb glycogen
70
largest gland in body
liver, 3 pounds
71
where is liver located?
under diaphragm, mostly under rib cage
72
hepatitis
inflammation, most often due to viral infection named A-F
73
cirrhosis
permanent damage
74
gall bladder
- storage for bile
- size of kiwi
- bile aides cholesterol secretion
75
pancreas
produces digestive enzymes
76
large intestine/colon
- Reclaims remaining water from indigestible food, store temp, and rid the body of waste
- Cecum and appendix
- Because absorption occurs before reaching, contains no folding villi or major digestive cells
77
areas of large intestine
ascending, transverse, descending, sigmoid, rectum
78
Undigested food, epithelial cells, mucus, bacteria become ...
feces of the 10L food/drink/GI secretions entering system daily, only about 1L reaches the large intestine
79
bacteria in large intestine/colon
- produce gas
- synthesize vitamins B & K
- Contains large (over 700 species) bacterial flora
80
main function of liver
Main function is to filter and process nutrient-rich blood delivered to it; filtered toxins and other drugs broken down and removed at kidneys; breakdown products are what are detected in drug tests
