Lecture 20

Question 1

The small intestine is anchored in the body by the __________ (a fold of peritoneum, a membrane lining the abdominal cavity)

3 main regions of the small intestine in order
1.
2.
3.

Answer 1

mesentery
1. Duodenum
2. Jejunum
3. Ileum

Question 2

• Region of the small intestine that receives the chyme= __________
• Region of the small intestine that receives the pancreatic juice and bile= ________
• what function does the ileum serve? absorption of __________ and reabsorption of _________

Answer 2

• duodenum
• duodenum
• vitamin B12; bile salts

Question 3

• The duodenum neutralizes acidic chyme through the _____________ which secrete ________- rich mucus
• neutralizing acidic chyme serves to safeguard the _______ of the small intestine from potential damage induced by acid content, while also promoting ________ enzyme activity

Answer 3

• duodenal glands; bicarbonate
• lining; optimal

Question 4

• Majority of nutrient digestion and absorption takes place in the _________ of the small intestine

Answer 4

jejunum

Question 5

Advantages that circular folds, vili, and microvilli provide to the digestive process
- collectively enhance the _________ and __________ of the small intestine, optimizing the __________ of nutrients during the digestive process

Answer 5

• surface area; functionality; absorption

Question 6

___________: lymphoid follicles, mainly B-cells
- found in the lining of the small intestine particularly in the _______

Answer 6

Peyer’s patches
- ileum

Question 7

_____________: sphincter controlling flow from the ileum into the cecum of the large intestine (_____ way valve)
______ of the small intestine

Answer 7

ileocecal valve; ONE
END

Question 8

___________: at the lower end of the stomach; it regulates the passage of chyme from the stomach into the duodenum
______ of the small intestine

Answer 8

pyloric sphincter
START

Question 9

Two types of motility in the small intestine
1. ________: promotes mechanical breakdown and mixing of chyme with digestive juices and bile
2. __________: short-distance; slow propulsion

Answer 9

1. Segmentation
2. Perstalsis

Question 10

3 structures that enhance the absorptive surface area of the small intestine going large to small
1.
2.
3.

Answer 10

1. circular folds
2. villi
3. microvilli

Question 11

Two types of epithelial cells that make up the covering of a villus
1.
2.

A villus contains ________ and _______ which aid in the absorption of nutrients form the small intestine into the bloodstream

Answer 11

1. enterocytes (absorptive cells)
2. goblet cells

blood vessels; lacteal

Question 12

________ corresponds to a finger-like projection (will increase absorptive surface area) , while a ______ corresponds to a pit of invagination (houses the intestinal glands)

Answer 12

villus; crypt

Question 13

• another name for absorptive cells=
• another name for intestinal glands=

Answer 13

• enterocytes
• crypts

Question 14

What constitutes the brush border on the surface of each enterocyte? ________ (tiny fingerlike projections) which contain brush border ________ (role in digestion)

Answer 14

microvilli; enzymes

Question 15

Five major types of cells found in the mucosal epithelium of the intestinal crypts
1.
2.
3.
4.
5.

Answer 15

1. Goblet cells
2. Enterocytes
3. Enteroendocrine cells
4. Paneth cells
5. Stem cells

Question 16

• Role of enterocytes covering the villi in the small intestine= ________ and _______ absorption
• Role of enterocytes covering the crypts in the small intestine= secretion of __________ (water and mucus)

Answer 16

• nutrient; electrolytes
• intestinal juce

Question 17

Paneth cells are found in the intestinal ______ at the BASE and they secrete _________ _______ (including _______)

Answer 17

crypts; antimicrobial peptides (lysozyme)

Question 18

Where are the hormones Secretin and CCK produced in the small intestine?
- produced by ___________ cells in the mucosal lining of the small intestine (crypt), specifically in the _________ and _________ regions
- specifically by _______ cells and _____ cells

Answer 18

• enteroendocrine; duodenum; jejunum
• S (secretin cells); I (enteroendocrine cells producing cholecystokinin-CCK)

Question 19

Three juices in the small intestine
1.
2.
3. _________: produces by specialized glands in the lining of the small intestine, specifically in the ________ of the __________ region

Answer 19

1. Bile
2. Pancreatic juice
3. Intestinal juice; mucosa; duodenum

Question 20

4 factors that stimulate the release of intestinal juice
1.
2.
3.
4.

Answer 20

1. Presence of chyme
2. Acidic pH of chyme
3. hormonal regulation (secretin and CCK)
4. mechanical distention of the intestinal wall

Question 21

Sequence of regions in the large intestine
1.
2.
3.
4.
5.
6.

Answer 21

1. Cecum
2. Ascending colon
3. Transverse colon
4. Descending colon
5. Sigmoid colon
6. Rectum

Question 22

Two main functions of the large intestine
1. absorption of _______ (_____, ____, ____)generated by ________ action
2. absorption of ______/_______ and _______ intestinal contents into feces

Answer 22

1. vitamins (K, B5, B7); bacterial
2. water/electrolytes; compact

Question 23

The intestinal crypts of the large intestine contain _______ goblet cells because they produce _______ which eases the passage of ______ and protects the intestinal walls from irritating _____ and gases released by resident _______

Answer 23

INCREASED; mucus; feces; acids; bacteria

Question 24

• Does the large intestine have circular folds or intestinal villi? _______ because most of the food is absorbed _______ reaching the large intestine
• Does the large intestine have intestinal crypts? _____

Answer 24

• NO; before
• YES

Question 25

- The vermiform appendix is a finger-like projection attached to the ______ of the large intestine - plays a role in the ______ system (it contains lymphoid tissue)

Answer 25

- cecum - immune

Question 26

____________: 3 distinct longitudinal bands of smooth longitudinal muscle from the musclaris externa that run along the outer surface of the _________ - these bands contribute to the formation of the _______, the pouches seen in the wall of the colon

Answer 26

Taenia coli; large intestine haustra

Question 27

Haustra are sacculations or pouches that characterize the wall of the colon; they are formed by the contraction of ___________ and contribute to the ________ and movement of fecal material through the digestive tract

Answer 27

teniae coli; segmentation

Question 28

_____________: sacs of fat in the _______ ; found along the external surface of the large intestine - function: _________, but normal anatomical structures

Answer 28

omental appendages; serosa - UNKNOWN

Question 29

- ___________: rhythmic contractions of the colon, particularly in the areas known as _______ (every ___ min) - function is to facilitate the ______ and ________ of contents within the ______, aiding in the absorption of ________ and ________ - stimulus that promotes this is _________ of a ________ with ________

Answer 29

- Haustral contractions; haustra (30 min) - mixing; segmentation; haustra; water; electrolytes - distension; haustrum; feces

Question 30

______________: happens ___-____ times a day and they are slow, powerful contractions that move undigested waste over _______ areas of the colon to the ________ for defecation

Answer 30

Mass peristalsis (movements); 3-4; LARGE; rectum

Question 31

Two sphincters located in the anal canal 1. ___________: composed of _______ muscle so ________ 2. ____________: composed of _______ muscle so _______

Answer 31

1. internal anal sphincter; smooth; NOT voluntary 2. external anal sphincter; skeletal; voluntary

Question 32

Designation for the opening at the end of the anal canal= _______

Answer 32

anus

Question 33

Defecation reflex is a involuntary response (______ reflex) that leads to the elimination of _______ from the _____ - it is initiated by the ________ of the rectal walls due to the accumulation of fecal material, which is detected by ____________

Answer 33

spinal; feces; rectum - distention; stretch receptors

Question 34

Division of the ANS that regulates the defecation reflex= ___________ - __________ of the internal anal sphincter - ________ of the rectum

Answer 34

parasympathetic - relaxation - contraction

Question 35

- The gut microbiome refers to all the _______________ living in your digestive system - its a _________ ________, ________ to each person, population by __________ (bacteria, fungi, etc.) - particularly in the ______, ________, and _________

Answer 35

- microorganisms - microscopic ecosystem; unique; trillions - stomach; small intestine; large intestine

Question 36

The gut microbiome... - prevent the _________ of __________ __________ by competing for nutrients and adhesion sites - breakdown complex _________ and dietary _______ - ferment dietary _______, creating anti-inflammatory ______-______ __________ ________ (such as butyrate) that nourish the gut lining - synthesize vitamins _____ and ____ - stimulate the ________ system

Answer 36

- overgrowth; harmful bacteria - carbohydrates; fibers - fibers; short-chain fatty acids - B and K - immune

Question 37

- ________ bacteria refers to a group of bacteria that primarily inhabit the gastrointestinal tract - the ____________ contains the highest concentration of these (about ______ species) mostly in the colon

Answer 37

- enteric - large intestine; 800