Digestive System: 8-23-13 (Biology 181) Flashcards
1
Q
all organisms must acquire ___ from the environment in order to survive
A
nutrients
2
Q
two mechanisms for acquiring nutrients
A
anabolism
catabolism
3
Q
- uses raw materials to synthesize essential compounds
- Requires energy
A
anabolism
4
Q
- decomposes (breaks down) substanes to provide energy in order for cells to function
- releases energy
A
catabolism
5
Q
digestion is a ____ reaction
A
catabolic
6
Q
digestion requires two essential ingredients
A
oxygen
organic molecules
7
Q
- broken down by intracellular enzymes (carbs, fats, and proteins)
- provided by the digestive system
A
organic molecules
8
Q
steps in digestion
A
- ingestion
- mechanical processing
- digestion
- secretion
- absorption
- excretion (elimination)
9
Q
-occurs when material enter digestive tract via the mouth
A
ingestion
10
Q
- crushing and shearing
- makes materials easier to propel along the digestive tract
A
mechanical processing (chewing)
11
Q
the chemical breakdown of food into small organic fragments that can be absorbed by the digestive epithelium
A
digestion
12
Q
- the release of water, acids, enzymes, buffers, and salts
- by epithelium digestive tract
- by glandular organs
A
secretion
13
Q
- movement of organic substrates, electrolytes, vitamins, and water
- across digestive epithelium
- into interstitial fluid of digestive tract
A
absorption
14
Q
removal of waste products from body fluids
A
excretion (elimination)
15
Q
digestive tract consists of
A
muscular tube
accessory organs
16
Q
muscular tube extends from
A
oral cavity to anus
17
Q
muscular tube passes through
A
pharynx, esophagus, stomach, and small and large intestines
18
Q
accessory organs (attached to GI tract)
A
salivary glands, liver, pancreas
19
Q
lining of digestive tract protects surrounding tissues against
A
- corrosive effects of digestive acids and enzymes
- mechanical stresses, such as abrasion
- bacteria either ingested with food or that reside in digestive tract
20
Q
lined with ___ membrane consisting of a superficial ____ covering a layer of ____ tissue
A
serous
mesothelium
areolar
21
Q
visceral peritoneum (serosa) covers organs within ____ cavity
A
peritoneal
22
Q
____ peritoneum lines inner surfaces of body wall
A
parietal
23
Q
- produces by serous membrane lining
- provides essential lubrication
- seperates parietal and visceral surfaces
- allows sliding without friction or irritation
A
peritoneal fluid
24
Q
-sheets of serous membrane that connect the parietal peritoneum with the visceral peritoneum that act to suspend portions of digestive tract within peritoneal cavity
A
mesenteries
25
- stabilize internal organs and prevent intestines from becoming entangled
- provide an access route to and from the digestive tract (important fro the passage of blood vessels, nerves, and lymphatic vessels)
mesenteries
26
four types of mesentaries in adult digestive system
ventral mesentery
dosral mesentery
mesentery proper
mesocolon
27
during embryonic development digestive tract and accessory organs are suspended in peritoneal cavity by
dorsal and ventral mesenteries
28
ventral mesentery persists in adults at only two locations (and are derived from the ventral mesentery)
falciform ligament
| lesser omentum
29
falciform ligament
helps stabilize position of live relative to diaphragm and abdominal wall
30
lesser omentum
- stabilizes position of stomach
| - provides access route for blood vessels and other structures entering or leaving liver
31
dorsal mesentery enlarges to form enormous pouch, called the
greater omentum
32
- entends inferiorly between the body wall and the anterior surface of small intestine
- hangs like an apron from lateral and inferior borders of stomach
greater omentum
33
- made up of adipose tissue (fat)
- pads and protects surfaces of abdomen
- provides insulation to reduce heat loss
- stores lipid energy reserves
greater omentum
34
- a mesentery associated with initial portion of small intestine and pancreas
- fuses with posterior abdominal wall, locking structures in place
mesentery proper
35
a mesentery associated with a portion of the large intertine
mesocolon
36
_____ mesocolon supports transverse colon
transverse
37
____ mesocolon supports sigmoid colon
sigmoid
38
mesocolon fuses to the dorsal body wall and stablizes ___, ____, ____.
ascending colon
descending colon
rectum
39
- consists of many folds which increase surface area for absorption
- longitudinal folds disappear as it fills
- permanent transverse folds (pilcae circulares) don't flatten out
lining of the digestive tract
40
four major layers of the digestive tract
mucosa
submucosa
muscularis externa
serosa
41
- thin inner lining of digestive tract
| - mucous membrane consisting of epithelium and lamina proproa
mucosa
42
epithelium moistened by ____ secretions
glandular
43
- layer of dense, irregular connective tissue
- surrounds muscularis mucosae
- has large blood vessels and lymphatic vessels
- may contain exocrine glands
- secrete buffers and enzymes into digestive tract
submucosa
44
- dominated by smooth muscle cells that are arranged in inner circular later and outer longitudinal layer
- involved in processing and movement of materials along digestive tract
muscularis externa
45
- comprised of serous membrane covering muscilaris externa
| - exists throughout the tract except in oral cavity, pharynx, esophagus, and rectum
serosa
46
once food enters your mouth, it is called a
bolus
47
two mechanisms for moving material through digestive tract
peristalsis
| segmentation
48
peristalsis
consists of waves of muscular contractions
49
- thin inner lining of digestive tract
| - mucous membrane consisting of epithelium and lamina proproa
mucosa
50
epithelium moistened by ____ secretions
glandular
51
- layer of dense, irregular connective tissue
- surrounds muscularis mucosae
- has large blood vessels and lymphatic vessels
- may contain exocrine glands
- secrete buffers and enzymes into digestive tract
submucosa
52
- dominated by smooth muscle cells that are arranged in inner circular later and outer longitudinal layer
- involved in processing and movement of materials along digestive tract
muscularis externa
53
- comprised of serous membrane covering muscilaris externa
| - exists throughout the tract except in oral cavity, pharynx, esophagus, and rectum
serosa
54
once food enters your mouth, it is called a
bolus
55
two mechanisms for moving material through digestive tract
peristalsis
| segmentation
56
peristalsis
consists of waves of muscular contraction
57
segmentation
the mixing of contents with intestinal secretions
58
-three steps of peristaltic motion
| circular muscles contract behind bolus while circular muscles ahead of bolus _____.
contract
59
-three steps of peristaltic motion
| longitudinal muscles ahead of bolus contract, ____ the adjacent segments
shortening
60
wave of contraction in circular muscles forces bolus ____.
forward
61
does not push materials of bolus in any one direction
segmentation
62
cycles of contraction in the small intestine and some portions of the large intestine ___ and ___ the bolus and ___ the contents with intestinal secretions
churn and fragment; mix
63
digestive functions are regulated by
neural mechanisms
hormonal control
local control
64
two reflexed involved in the neural control of digestion
short and long reflexes
65
short reflexes control ___ segments of the digestive tract
small (few cm.)
66
- involve higher level of control of digestive and glandular activities
- control large scale peristaltic waves (move material from one region of the tract to another)
long reflexes
67
hormonal control
- at least 18 peptide hormones that affect digestive function
- are produced by enteroendocrine cells in digestive tract
- reach target organ after distribution in bloodstream
68
- affect only a portion of the tract
- prostaglandins, histamine and other chemicals released into interstitial fluid, and affect a small segment of digestive tract
- function in coordinating responses to changing conditions
local control
69
the initial sensory analysis of material before swallowing
oral cavity
70
through actions of teeth, tongue, and palatal surfaces
mechanical processing
71
bolus mixing with mucus and salivary glad secretions
lubrication
72
limited digestion of _____ and _____.
carbohydrates and lipids
73
components of the oral cavity
oral mucosa
labia (lips)
vestibule
gingivae (gums)
74
- lining of oral cavity
- composed of stratified squamos epithelium
- makes up the epithelial lining of cheeks, lips, and inferior surface of tongue
- thin, non-keratinized, and delicate
oral mucosa
75
continuous with mucosa of each cheek
labia (lips)
76
space between the lips and teeth
vestibule
77
- ridges of oral mucosa
| - surround the base of each tooth
gingivae (gums)
78
manipulates material inside the mouth
tongue
79
functions of the tongue
- mechanical processing
- manipulation
- sensory analysis
- secretion of mucins (protiens) and the enzyme lingual lipase
80
compression, abrasion, and distortion
mechanical processing
81
assist in chewing and to prepare material for swallowing
manipulation
82
touch, temperature, and taste receptors
sensory analysis
83
- each pair has distinctive cellular organization
| - and each produces saliva with different properties
pairs of salivary glands
84
three pairs of salivary glands
- parotid salivary glands
- sublingual salivary glands
- submandibular salivary glands
85
- inferior to zygomatic arch (cheek bone)
- produce secretions containing the enzyme salivary amylase (breaks down starches)
- secretions eventually drain into parotid duct
parotid salivary glands
86
- located in floor of the mouth
- produce mucous secretions that act as buffers and lubricants
- secretions drain into sublingual ducts
sublingual salivary glands
87
- in floor of the mouth within mandibular groove
- secrete buffers, glycoprotiens (mucins), and salivary amylase
- drain into submandibular glands
submandibular salivary glands
88
produce 1.0 to 1.5 L of saliva each day
___% by submandibular glands
___% by parotids
___% by sublingual glands
70
25
5
89
saliva made up of ___% water and ___% electrolytes, buffers, ect.
99. 4
| 0. 6
90
functions of saliva
- lubricating
- moistening
- stimulate taste buds
- initiating digestion of complex carbohydrates by the enzyme salivary amylase
91
salivary secretions:
| parasympathetic stimulation is to
accelerate secretions by all salivary glands
92
basic structure of teeth
dentin
pulp cavity
root
crown
93
dentin
- a mineralized matrix similar to that of bone
| - does not contain cells
94
-received blood vessels and nerved through the root canal
pulp cavity
95
- of each tooth sits in a bony socket (alveolus)
| - a layer of cementum covers the dentin of it providing protection and anchoring periodontal ligament
root
96
- exposed portion of the tooth
| - includes the dentin covered by layer of enamel
crown
97
four types of teeth
incisors
cuspids (canines)
bicuspids (premolars)
molars
98
- blade shaped teeth
- located at front of mouth
- used for clipping, cutting
- have a single root
incisors
99
- conical
- pointed tip
- used for tearing and slashing
- have a single root
cuspids (canines)
100
- flattened crowns
- prominent ridges
- used to crush, mash, and grind
- have one or two roots
bicuspids (premolars)
101
- very large, flat crowns
- prominent ridges
- used for crushing, grinding
- have three or more roots
molars
102
- 2 incisors
- 1 cuspid
- 2 deciduous molars
primary dentition or deciduous teeth
103
-32 total
2 incisors
1 cuspid
5 molars
secondary dentition or permanent dentition
104
- an anatomical space that serves as a passageway for solid food, liquid, and air
- main function is to initiate swallowing
the pharynx
105
3 muscles involved in the swallowing process
- pharyngeal constrictor muscles
- palatopharyngeus and stylopharyngeus muscles
- palatal muscles
106
pushes food toward the esophagus
pharyngeal constrictor muscles
107
elevates the larynx
palatopharyngeus and stylopharyngeus muscles
108
elevate the soft palate and adjacent portions of the pharyngeal wall
palatal muscles
109
- hollow, muscular tube
- about 25 cm long and 2 cm wide
- conveys solid food and liquids to the stomach
the esophagus
110
wall of esophagus has three layers
mucosal
submucosal
muscularis (muscularis mucosae and externa)
111
three phases of swallowing
buccal
pharyngeal
esophageal
112
- bolus is compressed against hard palate
- tongue retracts and forces bolus into oropharynx
- soft palate is elevated, thereby sealing off the nasopharynx
- strictly voluntary
buccal phase
113
- bolus stimulates tactile receptors in palate and uvula
- receptors sent information to swallowing center in brain
- motor neurons signal pharyngeal muscles to contract
- larynx elevated, epiglottis folds (closing off glottis)
- bolus passes the closed glottis
- uvula and soft palate block nasopharynx
pharyngeal phase
114
- pharyngeal muscles force bolus into the esophagus
- peristaltic waves push the bolus toward the stomach
- lower esophageal sphincter opens to allows bolus into the stomach
esophageal phase
115
at end of swallowing, the bolus enters the ____ and becomes very ___ and is now referred to as Chyme
stomach; acidic
