Digestive System lab10

Question 1

which two parts of the digestive system can participate in the mechanical breakdown of food?

Answer 1

mouth and stomach

Question 2

what is the stomachs role in mechanical breakdown?

Answer 2

churning and mixing action of the smooth muscle in the organ wall pummel the food and physically breaks it down into smaller pieces.

Question 3

does chemical breakdown happen in the mouth and stomach if so, how?

Answer 3

yes.
mouth: salivary glands
stomach: pepsin, HCl, and acid

Question 4

the pharynx contributes to the process of digestion by….

Answer 4

swallowing

Question 5

the esophagus’ role in digestion is

Answer 5

delivering the food to the stomach

Question 6

the small intestine is responsible for

Answer 6

chemical digestion, some mechanical digestion (segmentation) and absorption of nutrients

Question 7

the large intestine is primarily involved in

Answer 7

the absorption of water and elimination of feces

Question 8

what is the process by which food is propelled from the pharynx to the stomach?

Answer 8

peristalsis in esophagus

Question 9

esophagus:

Answer 9

long muscular tube that delivers food from the pharynx to the stomach by the process of peristalsis.

Question 10

peristalsis:

Answer 10

alternating waves of contraction and relaxation of muscles in the organ walls.
main effect: squeeze food along the tract

Question 11

where does the majority of digestion and absorption occur in the gi tract?

Answer 11

the small intestines

Question 12

secretions from the liver, gall bladder, and pancreas are delivered to which organ?

Answer 12

small intestines.
the duodenum (first part of small intestine)

Question 13

food is tasted by the ______ in the tastebuds of the tongue

Answer 13

chemoreceptors

Question 14

what are the three sets of tonsils that are a part of the lymphatic system

Answer 14

pharyngeal, palatine, and lingual

Question 15

the pharynx is what kind of muscle

Answer 15

skeletal muscle

Question 16

the pharynx is commonly called the throat and is divided into 3 regions

Answer 16

nasopharynx (posterior to nasal cavity)
oropharynx (posterior to oral cavity)
laryngopharynx (posterior to the larynx)

Question 17

what are the four layers that make up the wall of the digestive tract? list in order starting with the layer closes to the food in the lumen of the GI tract

Answer 17

mucosa, submucosa, muscularis externa, serousa (adventitia)

Question 18

the mucosa can be further divided into three layers….

Answer 18

epithelium, lamina propria, and muscularis mucosae

Question 19

what is another name for serosa?

Answer 19

visceral peritoneum

Question 20

which structures are part of the enteric nervous system?

Answer 20

submucosal plexus and myenteric plexus

Question 21

what do the submucosal plexus and myenteric plexus contribute to the digestive process?

Answer 21

nerve fibers are located in the wall of the GI that communicate widely with one another to regulate and coordinate digestive system activity.

Question 22

the enteric nervous system

Answer 22

over 100 million neurons that communicate widely throughout the digestive system to regulate digestions
‘gut brain’

Question 23

the submucosal nerve plexus is located in the

Answer 23

submucosa

Question 24

the myenteric nerve plexus is located

Answer 24

between the circular and longitudinal muscle layers of the muscularis externa.

Question 25

which nervous plexus is located between the layers of the muscularis externa?

Answer 25

myenteric plexus located between the muscle layers

Question 26

the muscularis mucosae is part of which layer?

Answer 26

mucosa

Question 27

segmentation:

Answer 27

contractions that lead to mixing- no forward mixing

Question 28

peristalsis:

Answer 28

contractions that propel food forward in the tube

Question 29

where does peristalsis happen?

Answer 29

muscularis externa

Question 30

the outer tunic is called

Answer 30

serousa or adventita depending on whether the organ is wrapped by the peritonium

Question 31

serosa is the term used for organs that...

Answer 31

are suspended in the mesentery (peritoneum)

Question 32

serosa:

Answer 32

a connective tissue layer with an outer simple squamous epithelium called the mesothelium

Question 33

adventitia belongs to organs that....

Answer 33

are not suspended in mesentery and instead are embedded in the body wall

Question 34

adventitia:

Answer 34

a connective tissue layer that blends in with the rest of the connective tissue of the body wall

Question 35

which layer of the alimentary canal or gastrointestinal tract can include either a stratified squamous or simple columnar epithelium?

Answer 35

mucosa

Question 36

the mucosa contains two types of epethilium. what are they and why?

Answer 36

the inner lining of the mucosa is composed of columnar epithelium for most of the GI tract, but areas that experience more abrasive forces the epithelium is stratified squamous

Question 37

which part of the digestive tract have stratified squamous in the mucosa

Answer 37

esophagus, oral cavity, anus

Question 38

which layer of the alimentary canal is responsible for segmentation and peristalsis

Answer 38

muscularis externa

Question 39

what is the job of the esophagus?

Answer 39

to transmit food from the pharynx to the stomach

Question 40

how does the esophagus transmit food bolus to the stomach?

Answer 40

peristalsis

Question 41

which type of epithelium lines the esophagus?

Answer 41

stratified squamous (the protective epithelium) because of undigested food that must pass through the lumen.

Question 42

is the stratified squamous epithelium of the esophagus keratinized?

Answer 42

NO

Question 43

what is true about the muscularis externa in the esophagus?

Answer 43

the muscularis externa has skeletal muscle in the upper regions of the esophagus, and smooth muscle in the lower regions.

Question 44

an empty stomach has a volume of...

Answer 44

50ml

Question 45

the stomach can hold about ______ of food when it is distended.

Answer 45

4L

Question 46

when empty, the stomach collapses inward, throwing its mucosa and submucosa into large longitudinal folds called

Answer 46

rugae

Question 47

what is the name of the large periotoneal fold that contains fat and hangs off the greater curvature of the stomach?

Answer 47

greater omentum

Question 48

what is the name of the fold in the wall of the stomach that allow the stomach to expand more than 10 times its size in order to accommodate large meals?

Answer 48

rugae

Question 49

what do parietal cells in the gastric glands secrete?

Answer 49

hydochloric acid and intrinsic factor

Question 50

what do chief cells secrete?

Answer 50

pepsinogen: an inactive form of the enzyme pepsin

Question 51

pepsinogen is converted to the active enzyme pepsin how?

Answer 51

the acidic environment of the stomach

Question 52

what is produced by enteroendocrine cells?

Answer 52

hormones

Question 53

where do enteroendocrine cells secrete hormones?

Answer 53

into the blood capillaries in the lamina propria of the mucosa. the hormones travel through the bloodstream and influence the digestive process indirectly.

Question 54

what layer of the stomach contains gastric pits that secret mucus, acid, and digestive enzymes?

Answer 54

mucosa

Question 55

which of these structures is found in the stomach but nowhere else in the alimentary canal?

Answer 55

an oblique muscle layer

Question 56

which area of the stomach empties into the small intestines?

Answer 56

pylorus. via pyloric sphincter

Question 57

what is the primary purpose of the small intestine?

Answer 57

chemical digestion and absorption of nutrients

Question 58

which part of the small intestine receives secretions from the liver, gall bladder, and pancreas?

Answer 58

duodenum

Question 59

secretions from the liver, gall bladder, and pancreas enter the small intestine (duodenum) through a duct controlled by

Answer 59

hepatopancreatic sphincter sphincter of Oddi

Question 60

which part of the small intestine delivers chyme to the large intestine?

Answer 60

ileum.

Question 61

what is the name of the structure that anchors the small intestine to the posterior abdominal wall?

Answer 61

mesentery

Question 62

what is the name of the permanent folds seen in the wall of the small intestine?

Answer 62

plicae circulares (circular folds)

Question 63

what is the function of the plicae circulares

Answer 63

slow down the flow of chyme through the small intestine and increase the surface area in order to increase the efficiency of absorption in the small intestine.

Question 64

what are the finger-like projections of mucosa in the small intestine that help increase the surface area for absorption?

Answer 64

villi

Question 65

villi:

Answer 65

finger-like projections of mucosa that are covering the surface of the plicae circularis in the small intestine

Question 66

the wall of the small intestine has 3 features that help to increase surface area for absorption. what are they? list from largest to smallest.

Answer 66

pilicae ciruclaris, villi, microvilli

Question 67

what structural modification of the small intestine slows the movement of chyme through the lumen?

Answer 67

circular folds (plicae circularis)

Question 68

which cells in the small intestine's mucosa secrete mucus?

Answer 68

goblet cells

Question 69

which of these bests describes a lacteal?

Answer 69

a lymphatic vessel designed to help introduce fats to the blood.

Question 70

list the main sections of the large intestine in order

Answer 70

cecum, ascending colon, transverse colon, descending colon, sigmond colon, rectum, anal canal

Question 71

what is the epithelium in most of the large intestine?

Answer 71

simple columnar (with goblet cells)

Question 72

notable true characteristic features of the wall of the large intestine:

Answer 72

the outer layer of longitudinal smooth muscle is incomplete in the muscularis externa (results in the formation to tenia coli)

Question 73

teniae coli:

Answer 73

longitudinal strips of smooth muscle that are seen on the outer surface of the large intestine a result of incomplete outer layer of the muscularis externa

Question 74

what are the 3 longitudinal bands of smooth muscle that can be seen from the external surface of the large intestine?

Answer 74

teniae coli

Question 75

what is the primary physiological function of the large intestine?

Answer 75

water absorption and feces elimination

Question 76

which sphincter prevents backwards flow (reflux) from the large intestine into the small intestine?

Answer 76

ileocecal sphincter

Question 77

which sphincter controls the flow of chyme from the stomach to the small intestines?

Answer 77

pyloric sphincter

Question 78

which sphincter prevents reflux of gastric contents into the esophagus?

Answer 78

lower esophageal sphincter (LES)

Question 79

defecation requires

Answer 79

relaxation of both anal sphincters

Question 80

what is the largest lobe of the liver?

Answer 80

the right lobe