test 3: Digestive pt 1

Question 1

what are the structures that make up the digestive tract?

Answer 1

• oral cavity
• pharynx
• esophagus
• stomach
• small intestine
• large intestine

Question 2

what are the accessory organs to the digestive system?

Answer 2

• teeth, tongue, salivary glands
• liver
• gallbladder
• pancreas

Question 3

what are the 7 main functions of the digestive tract?

Answer 3

1) ingestion
2) mechanical processing
3) absorption
4) secretion
5) excretion
6) compaction
7) digestion

Question 4

what are the 4 general layers of the digestive tract from superficial to deep?

Answer 4

1) mucosa
2) submucosa
3) muscular layer
4) serosa (or adventitia)

Question 5

what are the 3 layers of the mucosa?

Answer 5

1) epithelium
2) lamina propria
3) muscular mucosa

Question 6

mucosal epithelium

Answer 6

• most superficial layer of mucosa
• stratified
• moves to simple in stomach and small and large intestine

Question 7

lamina propria

Answer 7

• middle layer of mucosa

- CT where BV, nerve endings, lymphatic vessels reside

Question 8

muscular mucosa

Answer 8

• deepest layer of mucosa
• 2 thin concentric layers of muscle (internal circular and external longitudinal); alter diameter of lumen, move epithelial plates and folds around (folds are transverse or longitudinal in digestive tract - allows extension of area; increases surface are for more secretion and absorption)

Question 9

what are the components of the submucosa

Answer 9

1) large blood and lymphatic vessels
2) exocrine glands
3) neural plexuses
- sensation to digestive tract

Question 10

what are the components of the muscular layer?

Answer 10

1) inner circular layer (contains myenteric plexus; parasympathetic and sympathetic stimulation occurs here to dilate or constrict)
2) outer longitudinal layer
3) sphincters

Question 11

where is the 4th layer of the digestive tract an adventitia rather than a serosa?

Answer 11

• pharynx
• esophagus
• rectum

Question 12

mesentery - def

Answer 12

fused double layer of the peritoneal membrane

Question 13

which structures make up the mesentery?

Answer 13

1) falciform ligament
- runs between liver and diaphragm
2) lesser omentum
- between liver and stomach (lesser curvature)
3) greater omentum
- greater curvature of stomach to transverse colon

Question 14

which parts of the small intestine are supported by the mesentery proper?

Answer 14

-jejunum and ilium (these are inter peritoneal)

Question 15

peritoneum - def

Answer 15

bilayer of serous membrane

Question 16

which organs are retroperitoneal?

Answer 16

• pancreas
• duodenum
• ascending and descending colon
• middle third of rectum
• kidneys
• adrenal glands
• proximal ureters
• renal vessels

Question 17

the uvula is an extension of the _____ palate

Answer 17

soft

Question 18

what is the function of the uvula?

Answer 18

prevents food from entering pharynx too soon

Question 19

what is the function of the tongue?

Answer 19

• mechanical processing: helps teeth chew
• helps in swallowing
• provides sensory analysis of foods (touch, temp, taste)
• chemical processing (secretion of mucins and lingual lipase)

Question 20

salivary glands are located in the oral cavity

true or false?

Answer 20

false

Question 21

what are the 3 salivary glands and their location?

Answer 21

1) parotid gland (largest)
- deep to mandible, inferior to zygomatic arch
2) sublingual gland
- floor of mouth
3) submandibular gland
- floor of mouth (medial mandible)

Question 22

where do the parotid glands release their contents?

Answer 22

-duct empties into oral vestibule around second upper molar

Question 23

where do the submandibular glands release their contents?

Answer 23

• ducts empty on either side of the frenulum (base of tongue)
• posterior to teeth

Question 24

what percentage does each salivary gland contribute to the formation of saliva?

Answer 24

• 70% from submandibular glands
• 25% parotid salivary glands
• 5% from sublingual salivary glands

Question 25

where do the sublingual glands empty?

Answer 25

numerous ducts open along either side of frenulum

Question 26

what is the location of the esophagus?

Answer 26

runs in the mediastinum posterior to the trachea | -starts at C6 (cricoid cartilage) and goes to T7

Question 27

esophageal hiatus - def

Answer 27

hole in the diaphragm where the esophagus passes

Question 28

describe the mucosal layer of the esophagus

Answer 28

- folds; run the length of the esophagus | - muscular mucosa: thin or absent in pharynx; single layer of longitudinal smooth muscle in esophagus

Question 29

describe the submucosa of the esophagus

Answer 29

- esophageal glands - lubricate bolus, protect mucosal layers as food passes - only other place we find mucus is large intestine

Question 30

describe the muscular layer of the esophagus

Answer 30

- inner circular and outer longitudinal layer - changes as you run down tract (superior = skeletal, middle = mix, inferior = smooth) - even though there is skeletal muscle, there is no voluntary movement in the esophagus at all

Question 31

describe the adventitia of the esophagus

Answer 31

-connects esophagus to posterior aspect of the body wall so it stays in place

Question 32

what are the three functions of the stomach

Answer 32

1) temporary food storage 2) mechanical digestion 3) chemical digestion (acid, enzymes)

Question 33

what is the location of the stomach

Answer 33

- sits around T7/L3 region - occupies 4 regions (left hypochondriac, left lumbar, umbilical, epigastric) - this varies

Question 34

what is the fundus of the stomach

Answer 34

superior (above esophagus) | -contacts diaphragm

Question 35

what is the cardia of the stomach?

Answer 35

where the esophagus ends and the stomach begins

Question 36

what is the pylorus of the stomach?

Answer 36

lower portion

Question 37

describe the histology of the stomach: gastric folds

Answer 37

- the surface epithelium of the gastric mucosa is a simple columnar epithelium - gastric pits open to gastric surface (these are temporary, not present when stomach is full)

Question 38

describe the histology of the stomach: muscular layer and mucosal layer

Answer 38

- creates esophageal and pyloric sphincters - contains extra layers of smooth muscle in addition to circular and longitudinal (extra oblique layer) - strengthen the stomach wall and assist in mixing and churning

Question 39

what are the 4 secretory cells found in the stomach?

Answer 39

1) mucous neck cells 2) parietal cells 3) enteroendocrine cells 4) chief cells

Question 40

function of mucous neck cells

Answer 40

water soluble stomach lubricant - found in all regions of the stomach - in gastric pits (shallow depression)

Question 41

function of parietal cells

Answer 41

- intrinsic factor (vitamin B12 absorption) - HCl (lowers pH, kills microorganisms, breaks down CT and protein) -found in proximal portion of gland (base of pit, beginning of gland)

Question 42

function of enteroendocrine cells

Answer 42

-gastrin (hormone) that stimulates parietal and chief cells and promotes muscle contraction (activates smooth muscle)

Question 43

what is the function of chief cells

Answer 43

- pepsinogen (converted to pepsin; activated by acid of stomach) - breaks down proteins - found primarily in fundus of stomach

Question 44

where does 90% of the absorption of material occur

Answer 44

small intestine

Question 45

what are the 3 portions of the small intestine?

Answer 45

- duodenum - jejunum - ileum

Question 46

duodenum

Answer 46

- closely associated with pancreas (sits in curvature) and liver (bile secretion) - shortest and widest section - majority is retroperitoneal - receives chyme from stomach

Question 47

jejunum

Answer 47

- interperitoneal - supported by mesentery proper - bulk of absorption - thicker wall than ileum - umbilical region

Question 48

ileum

Answer 48

- longest section - interperitoneal - hypogastric region - mesentery thicker, more fatty tissue than jejunum

Question 49

what structures are found in the small intestine to increase surface area?

Answer 49

1) circular folds - permanent folds 2) villi - simple columnar epithelium - project into lumen diameter 3) microvilli

Question 50

What is the name of the lymphatic vessel found within the intestinal villi

Answer 50

lacteals (found in lamina propria) | -material that can't be absorbed by capillaries will be picked up here to enter venous circulation by thoracic duct

Question 51

which cells in the small intestine are responsible for creating our good gut bacteria?

Answer 51

paneth cells

Question 52

what are the regional differences between the 3 regions of the small intestine?

Answer 52

Duodenum: - contains mucus producing glands to protect from acidic chyme - contains duodenal ampulla (receives bile from pancreas) Jejunum: - circular folds and villi prominent in proximal half - most nutrient absorption ileum - distal portion lacks circular folds - lamina propria contains aggregated lymphoid nodules (Peters patch)