Bms 508 Exam 3

Front 1

Anabolism

Back 1

Uses raw material to synthesize essential compounds (building up)

Front 2

Catabolism

Back 2

Decomposes substances to provide energy cells need to function (breaking down)

Front 3

The digestive system acquires nutrients from the

Back 3

environment

Front 4

Two essential ingredients required for catabolic reactions

Back 4

1. Oxygen

2. Organic molecules broken down by intracellular enzymes (carb, protein, fat)

Front 5

Other names for the digestive tract

Back 5

Gastrointestinal tract or Alimentary canal

Front 6

Digestive tract extends from

Back 6

Oral cavity to anus

Front 7

Digestive tract passes through

Back 7

Pharynx, esophagus, stomach, small and large intestines

Front 8

Oral cavity (mouth) functions

Back 8

Ingestion, mechanical processing with accessory organs (teeth and tongue), moistening, mixing with salivary secretions

Front 9

Pharynx function

Back 9

Muscular propulsion of materials into esophagus

Front 10

Esophagus function

Back 10

Transport of materials into stomach

Front 11

Stomach functions

Back 11

Chemical breakdown of materials by acid and enzymes; mechanical processing through muscular contractions

Front 12

Small intestine functions

Back 12

Enzymatic digestion and absorption of water, organic substrates, vitamins, and ions

Front 13

Large intestine functions

Back 13

Dehydration and compaction of indigestible materials in preparation for elimination

Front 14

Teeth function

Back 14

Mechanical processing by chewing (mastication)

Front 15

Another word for chewing

Back 15

Mastication

Front 16

Tongue functions

Back 16

Assists mechanical processing with teeth, sensory analysis

Front 17

Salivary glands function

Back 17

Secretion of lubricating fluid containing enzymes that break down carbohydrates

Front 18

Liver functions

Back 18

Secretion of bile, storage of nutrients, many other vital functions

Front 19

Gallbladder function

Back 19

Storage and concentration of bile

Front 20

Pancreas functions

Back 20

Exocrine cells secrete buffers and digestive enzymes; Endocrine cells secrete hormones

Front 21

6 functions of the digestive system

Back 21

1. Ingestion
   
2. Mechanical processing
3. Digestion
   
4. Secretion
5. Absorption
6. Excretion

Front 22

Ingestion

Back 22

Occurs when materials enter digestive tract via the mouth (eating)

Front 23

Mechanical processing

Back 23

• Crushing and shearing
  
• Makes materials easier to propel along digestive tract
  

Front 24

Digestion

Back 24

The chemical breakdown of food into small organic fragments for absorption by digestive epithelium

Front 25

Secretion

Back 25

Is the release of water, acids, enzymes, buffers, and salts by epithelium of digestive tract and glandular organs

Front 26

Absorption

Back 26

Movement of organic substrates, electrolytes, vitamins, and water across digestive epithelium into interstitial fluid of digestive tract

Front 27

Excretion

Back 27

Removal of waste products from body fluids

Front 28

Lining of digestive tract safeguards surrounding tissues against

Back 28

1. Corrosive effects of digestive acids and enzymes
2. Mechanical stresses, such as abrasion
3. Bacteria either ingested with food or that reside in digestive tract

Front 29

Digestive organs and peritoneum are lined with serous membrane consisting of

Back 29

• Superficial mesothelium covering a layer of areolar tissue
• Serosa (or visceral peritoneum)
• Parietal peritoneum

Front 30

Serosa (visceral peritoneum)

Back 30

Covers organs with peritoneal cavity

Front 31

Parietal peritoneum

Back 31

Lines inner surfaces of body wall

Front 32

Mesenteries

Back 32

Double sheets of peritoneal membrane

Front 33

Mesenteries function

Back 33

• Suspend portions of digestive tract within peritoneal cavity by sheets of serous membrane that connect parietal peritoneum with visceral peritoneum
  
• Stabilize positions of attached organs
• Prevent intestines from becoming entangled

Front 34

Areolar tissue between mesothelial surfaces

Back 34

Provides an access route to and from the digestive tract for passage of blood vessels, nerves, and lymphatic vessels

Front 35

During embryonic development digestive tract and accessory organs are suspended in peritoneal cavity by

Back 35

Dorsal mesentery

Ventral mesentery

Front 36

What happens to the ventral mesentery

Back 36

It disappears along most of the digestive tract

Front 37

Where is the ventral mesentery remain in adults

Back 37

lesser omentum and falciform ligament

Front 38

The Lesser Omentum

Back 38

• Stabilizes position of stomach
• Provides access route for blood vessels and other structures entering or leaving liver

Front 39

The Falciform Ligament

Back 39

Helps stabilize portion of liver relative to diaphragm and abdominal wall

Front 40

The Dorsal Mesentery

Back 40

• Enlarges to form enormous pouch, called greater omentum
  
• Extends infeiorly between body wall and anterior surface of small intestine
• Hangs like an apron from lateral and infeior borders of stomach

Front 41

Greater omentum

Back 41

• A large fold of the dorsal mesentery of the stomach
  
• Hangs anterior to the intestines

Front 42

Adipose tissue in greater omentum

Back 42

• Conforms to shapes of surrounding organs
• Pads and protects surfaces of abdomen
• Provides insulation to reduce heat loss
• Stores lipid energy reserves

Front 43

The Mesentery Proper

Back 43

• Thick mesenterial sheet
• Provides stability
• Permits some independent movement
• Suspends all but first 25 cm (10 in) of small intestine
• Associated with initial portion of small intestine (duodenum) and pancreas
• Fuses with posterior abdominal wall, locking structures in position

Front 44

The Mesocolon

Back 44

A mesentery associated with a portion of the large intestine

Front 45

Major organs of digestive tract

Back 45

• Oral cavity (mouth)
  
• Pharynx
• Esophagus
• Stomach
• Small intestine
• Large intestine

Front 46

Accessory organs of digestive tract

Back 46

• Teeth
  
• Tongue
• Salivary glands
• Liver
• Gallbladder
• Pancreas

Front 47

Peritoneal fluid is produced by

Back 47

Serous membrane lining

Front 48

Peritoneal fluid functions

Back 48

• Provides essential lubrication
• Separates parietal and visceral surfaces
• Allows sliding without friction or irritation

Front 49

How much peritoneal fluid is absorbed daily

Back 49

~ 7 liters

Front 50

Ascites

Back 50

Excess peritoneal fluid causing abdominal swelling

Front 51

During development, mesocolon of ascending colon, descending colon, and the rectum:

Back 51

• Fuse to dorsal body wall
  
• Lock regions in place

Front 52

4 major layers of digestive tract

Back 52

1. Mucosa
2. Submucosa
3. Muscularis externa
4. Serosa

Front 53

The Mucosa

Back 53

• Inner lining of digestive tract
• Mucous membrane consisting of epithelium moistened by glandular secretions

Front 54

Mucosal epithelium

Back 54

Simple or stratified depending on location, function, and stresses

Front 55

Oral cavity, pharynx, and esophagus histology

Back 55

• Mechanical stresses

• Lined by stratified squamous ephithelium

Front 56

Stomach, small intestine, and most of large intestine histology

Back 56

• Absorption
• Simple columnar epithelium with mucous cells

Front 57

Where are enteroendocrine cells

Back 57

Scattered among columnar cells of digestive epithelium

Front 58

What do enteroendocrine cells do?

Back 58

Secrete hormones that coordinate activities of the digestive tract and accessory glands

Front 59

What does folding do for the digestive tract?

Back 59

Increases surface area for absorption

Front 60

What types of folds are in the digestive tract?

Back 60

• Longitudinal folds (disappear as digestive tract fills)
  
• Permanent transverse folds

Front 61

Lamina Propria

Back 61

A layer of areolar tissue that contains:

• Blood vessels
• Sensory nerve endings
• Lymphatic vessels
• Smooth muscle cells
• Scattered areas of lymphatic tissue

Front 62

Muscularis mucosae

Back 62

Narrow band of smooth muscle and elastic fibers in lamina propria

Front 63

Smooth muscle cells of muscularis mucosae arranged in two concentric layers

Back 63

• Inner layer encircles lumen (circular muscle)

• Outer layer contains muscle cells parallel to tract (longitudinal layer)

Front 64

Submucosa

Back 64

• 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)

Front 65

Submucosa surrounds

Back 65

Muscularis mucosae

Front 66

Submucosal Plexus also called

Back 66

Meissner's plexus

Front 67

Submucosal plexus

Back 67

• Innervates the mucosa and submucosa
• Contains sensory neurons, parasympathetic ganglionic neurons, sympathetic postganglionic fibers

Front 68

Muscularis externa

Back 68

Dominated by smooth muscle cells arranged in inner circular layer and outer longitudinal layer

Front 69

Muscularis externa is involved in

Back 69

• Mechanical processing
• Movement of materials along digestive tract

Front 70

Muscularis externa movements are coordinated by

Back 70

Enteric nervous system (ENS)

Front 71

Enteric nervous system (ENS)

Back 71

Automatic - works on its own

Primarily innervated by parasympathetic division of ANS

Front 72

Serosa

Back 72

Serous membrane that covers the muscularis externa

(except in oral cavity, pharynx, esophagus, and rectum)

Front 73

Adventitia

Back 73

Fibrous sheath that firmly attaches the digestive tract to adjacent structures

Front 74

The muscular layers of the digestive tract consist of

Back 74

visceral smooth muscle tissue

Front 75

Pacesetter cells function

Back 75

Control rhythmic cycles along digestive tract

Front 76

Smooth muscle cells in digestive tract undergo

Back 76

spontaneous depolarization, triggering a wave of contraction through entire muscular sheet

Front 77

How is a wave of contraction triggered through the muscular sheet

Back 77

spontaneous depolarization by pacesetter cells along digestive tract

Front 78

Where are pacesetter cells located

Back 78

In muscularis mucosae and muscularis externa, surrounding the lumen of the digestive tract

Front 79

Peristalsis

Back 79

• Waves of muscular contractions
  
• Moves a bolus along the length of the digestive tract

Front 80

Steps of peristaltic motion

Back 80

1. Contraction of circular muscles behind bolus
2. Contraction of longitudinal muscles ahead of bolus
3. Wave of contraction in circular muscles forces bolus forward

Front 81

Segmentation

Back 81

• Cycles of contraction that churn and fragment the bolus, mixing the contents with intestinal secretions
  
• Does not follow a set pattern, does not push materials in any one direction
• * Mixing the food, pushing enzymes to outside

Front 82

Control of digestive functions

Back 82

• Local factors
• Neural mechanisms
• Hormonal mechanisms

Front 83

Local factors

Back 83

• Prostaglandins, histamine, and other chemicals released into interstitial fluid
  
• May affect adjacent cells within small segment of digestive tract
• Coordinate response to changing conditions (for example: variations in local pH, chemical, or physical stimuli)
• Affect only a portion of tract (*local*)

Front 84

Neural mechanisms

Back 84

• Control movement of materials along digestive tract and secretory functions
• Motor neurons control smooth muscle contraction and glandular secretion located in myenteric plexus

Front 85

Neural mechanisms - short reflexes

Back 85

• Responsible for local reflexes
• Control small segments of digestive tract
• Operate entirely outside of CNS control (sensory neurons, motor neurons, interneurons)

Front 86

Neural mechanisms - long reflexes

Back 86

• Higher level control of digestive and glandular activities

• Control large-scale peristaltic waves

• Involve interneurons and motor neurons in CNS

• May involve parasympathetic motor fibers that synapse in the myenteric plexus

Front 87

Hormonal mechanisms

Back 87

• At least 18 peptide hormones that affect most aspects of digestive function and activities of other systems
  
• Are produced by enteroendocrine cells in digestive tract
• Reach target organs after distribution in bloodstream

Front 88

Functions of the oral cavity

Back 88

1. Sensory analysis of material before swallowing
2. Mechanical processing through actions of teeth, tongue, and palatal surfaces
3. Lubrication (mixing with mucus and salivary gland secretions)
4. Limited digestion of carbs and lipids

Front 89

Oral mucosa epithelium

Back 89

stratified squamous epithelium

Front 90

Oral mucosa

Back 90

• Lining of oral cavity
• Inferior to tongue is thin and vascular enough to rapidly absorb lipid-soluble drugs
• Cheeks are supported by pads of fat and the buccinator muscles

Front 91

Epithelial lining of cheeks, lips, and inferior surface of tongue

Back 91

Is relatively thin, nonkeratinized, and delicate

Front 92

Labia

Back 92

• Also called lips
  
• Anteriorly, the mucosa of each cheek is continuous with that of the lips

Front 93

Vestibule

Back 93

Space between the cheeks (or lips) and the teeth

Front 94

Gingivae

Back 94

Gums

• Ridges of oral mucosa
• Surround base of each tooth on alveolar processes of maxillary bones and mandible

Front 95

Functions of the tongue

Back 95

1. Mechanical processing by compression, abrasion, and distortion
2. Manipulation to assist in chewing and to prepare material for swallowing
3. Sensory analysis by touch, temperature, and taste receptors
4. Secretion of mucins and the enzyme lingual lipase

Front 96

3 pairs of salivary glands secrete into oral cavity

Back 96

1. Parotid salivary glands
2. Sublingual salivary glands
3. Submandibular salivary glands

Front 97

Each pair of salivary glands has

Back 97

distinctive cellular organization and produces saliva with different properties

Front 98

Parotid salivary glands

Back 98

• Inferior to zygomatic arch
• Produce serous secretion (enzyme salivary amylase - breaks down starches)
• Drained by parotid duct which empties into vestibule at second molar

Front 99

Sublingual salivary glands

Back 99

"sub" = under
"lingual" = tongue

• Covered by mucous membrane of floor of mouth
  
• Produce mucous secretion
  
• Acts as buffer and lubricant
  
• Sublingual ducts on either side of lingual frenulum
  

Front 100

Submandibular salivary glands

Back 100

• In floor of mouth
• Within mandibular groove
• Secretes buffers, glycoproteins, and salivary amylase
• Submandibular ducts open immediately posterior to teeth, either side of lingual frenulum

Front 101

Saliva

Back 101

Glands produce 1.0-1.5 liters of saliva each day

99.4% water

Front 102

Saliva functions

Back 102

• Lubricating the mouth
  
• Moistening and lubricating materials in the mouth
• Dissolving chemicals that stimulate taste buds and provide sensory information
• Initiating digestion of complex carbohydrates by the enzyme salivary amylase

Front 103

Control of salivary secretions

Back 103

Autonomic nervous system

Parasympathetic - increases

Sympathetic - decreases

Front 104

Dentin

Back 104

A mineralized matrix similar to that of bone, does not contain cells

Front 105

Pulp cavity

Back 105

Receives blood vessels and nerves through the root canal

Front 106

Root

Back 106

• Of each tooth sits in a bony socket
• A layer of cementum covers dentin of root providing protection and anchoring periodontal ligament

Front 107

Crown

Back 107

• Exposed portion of tooth
• Projects beyond soft tissue of gingiva
• Dentin covered by layer of enamel
  

Front 108

Alveolar processes of the maxillae

Back 108

Form maxillary arcade (upper dental arch)

Front 109

Alveolar processes of the mandible

Back 109

Form mandibular arcade (lower dental arch)

Front 110

Primary dentition (deciduous teeth)

Back 110

• Also called primary teeth, milk teeth, or baby teeth
• 20 temporary teeth

Front 111

Secondary dentition

Back 111

• Also called permanent dentition
• Replaces deciduous teeth
• 32 permanent teeth

Front 112

Pharynx (throat)

Back 112

• Common passageway for solid food, liquids, and air
  
• Food passes through oropharynx and laryngopharynx to the esophagus

Front 113

Regions of the pharynx

Back 113

• Nasopharynx
  
• Oropharynx
  
• Laryngopharynx
  

Front 114

Esophagus

Back 114

• Hollow muscular tube
• Conveys solid food and liquids to the stomach
• Contracts with muscles to push food into stomach

Front 115

Resting muscle tone

Back 115

Esophagus prevents air from entering

Front 116

3 layers of wall of esophagus

Back 116

1. Mucosal

2. Submucosal

3. Muscularis

Front 117

Mucosa histology

Back 117

Nonkeratinized and stratified squamous epithelium

Front 118

Mucosa and submucosa form

Back 118

Large folds that extend the length of the esophagus

Front 119

Another word for swallowing

Back 119

Deglutition

Front 120

Swallowing

Back 120

• Can be initiated voluntarily
• Proceeds automatically
• Divided into 3 phases

Front 121

3 phases of swallowing

Back 121

1. Buccal phase

2. Pharyngeal phase

3. Esophageal phase

Front 122

Buccal phase of swallowing

Back 122

• Compression of bolus against hard palate
  
• Retraction of tongue forces bolus into oropharynx

Front 123

Pharyngeal phase of swallowing

Back 123

• Begins as bolus comes into contact with palatoglossal and palatopharyngeal arches and posterior pharyngeal wall

Front 124

Esophageal phase of swallowing

Back 124

• Begins as the contraction of pharyngeal muscles forces bolus through entrance of esophagus
  
• Bolus is pushed toward stomach by peristalsis

Front 125

The approach of the bolus to the stomach triggers the

Back 125

Opening of the lower esophageal sphincter

Front 126

Major functions of the stomach

Back 126

1. Storage of ingested food

2. Mechanical breakdown of ingested food

3. Disruption of chemical bonds in food material by acid and enzymes

4. Production of intrinsic factor

Front 127

Intrinsic factor

Back 127

Glycoprotein required for absorption of vitamin B12 in small intestine

Front 128

Stomach shape

Back 128

Like an expanded J

Front 129

Regions of the stomach

Back 129

1. Cardia

2. Fundus

3. Body

4. Pylorus

Front 130

Histology of the stomach

Back 130

Simple columnar epithelium lines all portions of stomach

Front 131

Gastric pits

Back 131

Shallow depressions in stomach that open onto gastric surface

Front 132

Gastric glands

Back 132

• In fundus and body of stomach, extend deep into underlying lamina propria
  
• Each gastric pit communicates with several gastric glands - Parietal cells & Chief cells

Front 133

Parietal cells

Back 133

Secrete intrinsic factor and hydrochloric acid (HCl)

Front 134

Chief cells

Back 134

Are most abundant near base of gastric gland that secrete pepsinogen

Front 135

Pepsinogen

Back 135

Is converted by HCl in the gastric lumen to pepsin

Front 136

Pyloric glands

Back 136

• Located in pylorus
  
• Produce mucous secretions scattered with enteroendocrine cells

Front 137

Mucous secretions of pyloric glands

Back 137

• G cells produce gastrin
  
• D cells release somatostatin

Front 138

Somatostatin

Back 138

• Growth hormone

• Hormone that inhibits release of gastrin

Front 139

Regulation of gastric activity

Back 139

Production of acid and enzymes by the gastric mucosa can be

• Controlled by the CNS
• Regulated by short reflexes of ENS
• Regulated by hormones of digestive tract

Front 140

3 phases of gastric control

Back 140

1. Cephalic phase
2. Gastric phase
3. Intestinal phase

Front 141

Cephalic phase of gastric control

Back 141

• Takes place in brain (cephalic = head)
  
• Triggered by sight, smell, taste, or thought of food
  
• Perceived by CNS
• Vagus nerve stimulates mucous cells to produce mucous, chief cells to produce pepsinogen, parietal cells to produce HCl, and G cells to produce gastrin, and movement of the stomach
• Preparing for food

Front 142

Gastric phase of gastric control

Back 142

• Bolus enters stomach
• Stretches stomach
• Increase in pH
• Stretch receptors and chemoreceptors send signals to plexuses
• Secretes more mucus, pepsinogen, HCl, and gastrin
• Stomach moves more

Front 143

Intestinal phase of gastric control

Back 143

• Chyme leaves stomach and enters small intestine (duodenum)
• Stretches duodenum
• Chemoreceptors sense pH changes and presence of lipids and carbs
• Hormones secreted