Digestive System Part 2 - Gastrointestinal Tract

Question 1

when we are done mechanically chewing our food, where does it go?

Answer 1

the oropharynx then into the laryngopharynx

Question 2

at what point in food ingestion does the epiglottis drop?

Answer 2

at the laryngopharynx

Question 3

what does the epiglottis do?

Answer 3

block the larynx to force food into the epiglottis

Question 4

what is the esophagus?

Answer 4

a smooth muscle tube that has muscles that go into two different directions

Question 5

what are the two types of muscles in the esophagus?

Answer 5

1. circular smooth muscles
2. longitudinal smooth muscles that run down the wall of the tube

Question 6

where does the circular smooth muscles in the esophagus contract?

Answer 6

behind the bolus of food

Question 7

what happens when a circular smooth muscle contracts in the esophagus?

Answer 7

they are going to squeeze and make the lumen of the esophagus smaller to push the bolus down
- longitudinal muscles work simultaneously

Question 8

how does the longitudinal smooth muscles of the esophagus contract?

Answer 8

• in a wave-like motion to push the bolus down (sort of works with the circular muscles because the ‘pinch’ is in the same area)

Question 9

how long does the circular and longitudinal smooth muscles of the esophagus contract and relax for?

Answer 9

all the way until we reach the opening of the stomach

Question 10

what is a sphincter?

Answer 10

circular smooth muscle that when it contracts, it squeezes the tube shut

Question 11

where is the lower esophageal spincter?

Answer 11

between the bottom of esophagus and the opening of the stomach
- sometimes called the cardiac sphincter because its not too far below the heart

Question 12

what is the job of the low esophageal spincter?

Answer 12

• open when there is a bolus and let it into the stomach
• close behind the food (real job) because we don’t want the contents of the stomach going back up in the wrong direction

Question 13

what is the top area of the stomach called?

Answer 13

the fundus

Question 14

what is the entryway to the stomach called?

Answer 14

the cardia

Question 15

what is the largest part of the stomach?

Answer 15

the body of the stomach

Question 16

what are the two smaller, distal areas of the stomach?

Answer 16

• pyloric antrum
• pyloric canal

Question 17

what happens when a bolus of food enters the stomach?

Answer 17

it spends quite some time in there going through mechanical and chemical breakdown

Question 18

what are the two curvatures of the stomach?

Answer 18

• lesser curvature (superior side)
• greater curvature (inferior side)

Question 19

how is mechanical breakdown of food done in the stomach?

Answer 19

squeezing and crushing and sloshing the bolus of food around

Question 20

what is the difference between each of the 3 muscular layers of the stomach?

Answer 20

the fibres all go in different directions

Question 20

what happens when all of the walls of smooth muscle in the stomach contract?

Answer 20

you get a lot of crushing of the food that is in the stomach and some sloshing

Question 21

what does the inner wall of the stomach look like?

Answer 21

sort of lumpy like the brain
- called rugae

Question 22

where do we find pits in the stomach called gastric glands?

Answer 22

in the rugae of the stomach
- all over inside the stomach

Question 23

in the gastric glands, there is many types of cells in there. what are they all going to contribute to?

Answer 23

the digestive stuff in our stomach
- digestive enzymes
- mucous

Question 24

what are the types of cells we can find in our gastric glands?

Answer 24

- surface mucous cell - mucous neck cell - parietal cell - chief cell - g cell

Question 25

which gastric gland cells are the most superficial?

Answer 25

- surface mucous cell - mucous neck cell

Question 26

what do the superficial gastric gland cells produce?

Answer 26

mucous

Question 27

why is fluid/mucous so important in the breakdown of food?

Answer 27

it allows us to chemically separate all the food and helps with the mechanical breakdown (makes it mushier)

Question 28

what does the gastric gland parietal cell secrete?

Answer 28

- hydrochloric acid - intrinsic factor

Question 29

why is hydrochloric acid important in gastric glands?

Answer 29

because it is highly acidic (low pH), which will help us break down protein - we cannot breakdown protein unless we have a very acidic environment

Question 30

why is the only place in our body we see hydrochloric acid, is the stomach?

Answer 30

- other areas of the gastrointestinal tract, don't have the lining in their walls to withstand that level of acid

Question 31

when would we personally experience how acidic our stomach is?

Answer 31

- when we have vommitted - if our lower esophageal sphincter for some reason as let stomach contents up into the esophagus and we get that burning sensation (heart burn)

Question 32

what is gastroesophageal reflux?

Answer 32

an issue in some people when the lower esophageal sphincter does not close properly on a frequent basis - can cause pain frequently in the esophagus (epithelial cells can be replenished, but still hurts)

Question 33

what is intrinsic factor, secreted by parietal cells, important for?

Answer 33

the absorption of vitamin B12 - we cannot absorb vitamin B12 without it

Question 34

what is vitamin B12 very important for?

Answer 34

for red blood cell function

Question 35

what does chief cells and G cells produce?

Answer 35

digestive enzymes - helps break down other nutrients and aspects of your food

Question 36

when all the food is broken down by the stomach, what nervous system brings it where?

Answer 36

the enteric nervous system will send a message to the the pyloric sphincter to tell it that it is ready to be moved along and the food will move into the first section of the small intestine, called the duodenum

Question 37

where is the pyloric sphincter?

Answer 37

at the bottom/end of the stomach

Question 38

where is the duodenum in relation to the large intestine and the stomach?

Answer 38

below stomach, behind large intestine

Question 39

what are the sections of the small intestine in order and how long are they?

Answer 39

1. duodenum (10inch) 2. jejunum (3ft) 3. ileum (6ft)

Question 40

what is the function of the small intestine?

Answer 40

absorption

Question 41

where do we absorb all of our nutrients?

Answer 41

the small intestine

Question 42

because we are absorbing all of our nutrients in the small intestine, what do we need in the small intestine?

Answer 42

- a lot of surface area - a lot of blood

Question 43

what is the form of food once it reaches the small intestine?

Answer 43

its molecular component so it can be absorbed

Question 44

where are we trying to move our nutrients to in the small intestine?

Answer 44

from the interior of the intestine, to into the blood so that it can be distributed to the cells of our body

Question 45

in order to get our nutrients from the intestine to the blood, what do we need?

Answer 45

- we need to be able to get access to all of the stuff inside our intestine to an area of the wall of the intestine

Question 46

what gives us the big surface area of our small intestine?

Answer 46

all the bumps

Question 47

on the inside of the small intestine, there are little bumps what are they?

Answer 47

villi - then we have microvilli on the villi - this gives us a big surface area in a fairly compact structure

Question 48

what do we have inside our villi?

Answer 48

blood vessels

Question 49

what cells are the walls of our small intestine?

Answer 49

single layer epithelial cells - makes it very thin

Question 50

what is allowing easy diffusion of nutrients across from the small intestine to the blood?

Answer 50

the single layer epithelial cells in the wall of the small intestine (makes it very thin)

Question 51

after the small intestine, where does the blood go?

Answer 51

to the liver to be checked for toxins before it joins the bloodstream

Question 52

once all of our food has gone through the small intestine, where does it go?

Answer 52

the large intestine

Question 53

what is the large intestine important for?

Answer 53

- water absorption - vitamin absorption (which doesn't really happen in small intestine because it focuses on carbs, lipids and proteins)

Question 54

where does the ileum of the small intestine end at?

Answer 54

a sphincter called the 'ileocecal sphincter' because its between the ileum and the first part of the large intestine called the cecum

Question 55

what is the job of the ileocecal sphincter?

Answer 55

to keep things from going back into the small intestine

Question 56

what is the first part of the large intestine called?

Answer 56

the cecum

Question 57

where is the appendix?

Answer 57

a pouch that is attached to the medial, posterior portion of the cecum and hangs off - also called the vermiform appendix

Question 58

what is the function of the appendix?

Answer 58

apart of the immune system - immune function - can recognize bacteria and will send a signal to the immune system to come and get it and to be on the lookout for more

Question 59

do we need the appendix?

Answer 59

no - the immune system has many backups

Question 60

from the cecum, where does the food go?

Answer 60

up the ascending colon

Question 61

where is the ascending colon located?

Answer 61

the right side of the abdomen

Question 62

after the ascending colon, where does food go?

Answer 62

the transverse colon

Question 63

there is a sharp turn to get from the ascending colon to the transverse colon. what is it called?

Answer 63

the right colic flexure (also known as hepatic flexure which means liver and that's because the liver in located right above it)

Question 64

what aspect of the large intestine is hanging in front of the duodenum of the small intestine?

Answer 64

the transverse colon

Question 65

from the transverse colon, where does the food go?

Answer 65

down the descending colon

Question 66

there is a sharp turn to get from the transverse colon to the descending colon. what is it called?

Answer 66

left colic flexure (sometimes called the splenic flexure because spleen is located right behind it)

Question 67

is the spleen apart of the digestive system?

Answer 67

no - located close but it is not involved

Question 68

from the descending colon, where does the food go?

Answer 68

through the sigmoid colon

Question 69

from the sigmoid colon, where does the food go?

Answer 69

through the rectum, into the anal canal, to the anus

Question 70

by the time we get through the large intestine, what is left?

Answer 70

all the aspects of your diet that the body did not want

Question 71

what is dumped into the large intestine by metabolism and other things?

Answer 71

waste products that would be excreted by the anus

Question 72

what is the rectum?

Answer 72

the area between the sigmoid colon and the anal canal

Question 73

what does the anal canal make up in the gastrointestinal tract?

Answer 73

the 1-1.5 inch of the gastrointestinal tract

Question 74

if we hold onto the excretions in the rectum, anal canal and the anus, what happens?

Answer 74

pain

Question 75

do we have conscious control of when our waste products are excreted?

Answer 75

yes

Question 76

how do we control when our waste products are excreted?

Answer 76

we have smooth muscle in the wall of our anal canal

Question 77

what are the muscles in the walls of the anal canal called?

Answer 77

1. internal anal sphincter (smooth muscle / involuntary) 2. external anal sphincter (skeletal muscle / voluntary)

Question 78

what does our internal anal sphincter do since it is involuntary?

Answer 78

it just opens

Question 79

what is the external anal sphincter connected to?

Answer 79

the levator ani muscle

Question 80

what is the levator ani muscle apart of? what type of muscle is it?

Answer 80

- apart of the pelvic floor - it is skeletal muscle (makes it voluntary)

Question 81

which muscle in the wall of the anal canal can we choose to contract and relax?

Answer 81

external anal sphincter