Lecture 33: Abdomen VI Midgut And Hindgut

Question 1

Where does the vagus nerve stop

Answer 1

End of midgut

Question 2

Topography of midgut/hindgut

Answer 2

-right side: duodenum and ascending colon
-mediolateral: transverse colon
-left side: descending colon

Question 3

What travels within the mesentery to sustain jejunum and ileum

Answer 3

Mesenteric vessels and innervation

Question 4

What are arcades

Answer 4

Loops of artery

Question 5

Vasa recta

Answer 5

Straight arteries out to organ

Question 6

Mesenteric vs anti Mesenteric sides/edges

Answer 6

Antimesenteri = opposite to side attached to Mesentery

Question 7

What arteries supply distal duodenum and jejunum

Answer 7

Jejunal arteries

Question 8

What artery supplies right pancreatic lobe and middle of duodenum

Answer 8

Caudal pancreaticoduodenal

Question 9

Blood supply to ascending colon and terminal end of ileum

Answer 9

Ileocolic artery

Question 10

2 branches of ileocolic artery

Answer 10

Cecal
Right colic

Question 11

Cecal artery supplies

Answer 11

Cecum

Question 12

Right colic artery supplies

Answer 12

Right colic flexure (between ascending and transverse colons)

Question 13

Blood supply to first 2/3 of transverse colon

Answer 13

Middle colic

Question 14

What structures are absent in colon

Answer 14

-villi
-digestive glands

Question 15

Function of goblet cells in colon

Answer 15

Secrete mucous to lubricate feces for passage

Question 16

Where are goblet cells located (specific colon)

Answer 16

Transverse colon

Question 17

Alimentary canal definition

Answer 17

Continuous tube
Esophagus —> colon

Question 18

What tissue layer differs the most along alimentary canal

Answer 18

Mucosa

Question 19

Which tissue layer contracts mucosa for mobility

Answer 19

Muscularis mucosa

Question 20

Plica circulares: features and function

Answer 20

-circular folds
-non distensible
-covered with villi to increase surface area of proximal small intestine

Question 21

What happens to size and number of plica circulares along small intestine (jejunum to ileum)

Answer 21

Decrease

Question 22

specializations for absorptive function along small intestine (duodenum, jejunum, ileum)

Answer 22

-intestinal villi
-goblet cells and microvilli within simple columnar epithelial cells
-lacteal

Question 23

what are lacteals

Answer 23

specialization lymphatic structure within each villus of small intestine (lymphatic capillaries)
carry absorbed fats away from small intestine

Question 24

what structure covers surface of each plica circularis

Answer 24

intestinal villi

Question 25

what is each intestinal villus covered with

Answer 25

goblet cells and simple columnar epithelial cells with microvilli

Question 26

predominant function of small intestine

Answer 26

absorption

Question 27

2 hallmarks of small intestine mucosal epithelium

Answer 27

-villi -intestinal crypts

Question 28

enterocytes definition

Answer 28

cell of intestinal lining

Question 29

2 functions of enterocytes

Answer 29

-absorption -digestion

Question 30

what 3 features allow for enterocytes absorptive function

Answer 30

-tall microvilli -tight junctions to contain luminal contents -lateral enfoldings

Question 31

what 2 features allow for enterocytes digestive function

Answer 31

-glycocalyx enzymes -glycoproteins mixed with mucous creates coating that traps molecule near apical membrane

Question 32

what structure is present specifically in the proximal portion of the duodenum (closest to pylorus)

Answer 32

brunner's glands

Question 33

brunner's glands: definition and function

Answer 33

-specialized mucous secreting glands -protect duodenal lining from acidic chyme delivered from stomach -secrete peptide hormone urogastrone that inhibits HCl secretion

Question 34

what kind of epithelium is found in brunners glands

Answer 34

tall cuboidal

Question 35

2 structures/features within lamina propria: small intestine

Answer 35

-fenestrated capillaries for transport of proteins and carbs -lacteals for transport of dietary fats

Question 36

what tissue layer of small intestine provides critical host defense

Answer 36

lamina propria

Question 37

what is GALT

Answer 37

gut associated lymphoid tissue aggregated nodules of lymphoid tissue

Question 38

peyer's patches

Answer 38

aggregates of GALT

Question 39

where is GALT concentrated

Answer 39

lamina propria of ileum

Question 40

Paneth cells: location and function

Answer 40

base of crypts of lierbukuhn in small intestine (ileum) in GALT innate immunity

Question 41

what 2 cells/structures are in lamina propria of ileum that provides host defense

Answer 41

-GALT -paneth cells

Question 42

what kind of muscle is muscularis mucosa

Answer 42

smooth

Question 43

how is muscularis mucosa organized

Answer 43

inner circular layer outer longitudinal layer

Question 44

function of muscularis mucosa in small intestine

Answer 44

-move mucosa and lymph

Question 45

where are brunner's glands only found

Answer 45

duodenum

Question 46

where is plicae circularis found (2)

Answer 46

jejunum and ileum

Question 47

plicae circularis vs rugae

Answer 47

plicae circulares can't flatten

Question 48

where does material pass through from small intestine to ascending colon (2 structures)

Answer 48

ileal orifice and annular fold

Question 49

does the cecum have any specialized functions in carnivorans

Answer 49

no

Question 50

shape of cecum

Answer 50

spiral

Question 51

where does ileum/small intestine end

Answer 51

ileocolic junction

Question 52

rectum and cranial 1/4 of anal canal at end of hindgut: blood supply and innervation

Answer 52

hindgut cranial rectal and left colic

Question 53

what supplies distal descending colon and cranial half of rectum

Answer 53

cranial rectal

Question 54

what supplies descending colon and part of transverse colon

Answer 54

left colic

Question 55

anastamoses at splenic flexure occurs between

Answer 55

middle colic and left colic

Question 56

hallmark of large intestine/colon cross section

Answer 56

intestinal glands are straight and regular

Question 57

5 features of mucosal epithelium: colon

Answer 57

-simple columnar epithelium -short microvilli -invagination into long straight intestinal glands/crypts -enterocytes -goblet cells

Question 58

function of enterocytes: colon

Answer 58

absorb water dehydrate feces

Question 59

surface area is __________ in large intestine

Answer 59

reduced

Question 60

is absorption important in colon

Answer 60

not really

Question 61

specialized cecum in horses

Answer 61

-microfauna for microbial fermentation of cellulose -very large cecum

Question 62

equine cecum similar to

Answer 62

forestomach in ruminants

Question 63

functions of lamina propria: colon

Answer 63

-host defense -GALT -no lymphatic capillaries

Question 64

functions of muscularis mucosa: colon

Answer 64

contract intestinal glands shake loose lodged feces smooth muscle

Question 65

features of submucosa" colon

Answer 65

blood and lymphatic vessels dense irregular CT

Question 66

lamina propria vs submucosa in colon: spread of cancer

Answer 66

-rapidly in submucosa due to lymphatic vessels/capillaries -no lymphatic vessels in lamina propria

Question 67

2 key features of equine large intestine/colon

Answer 67

-haustra -tenia coli

Question 68

haustra: definition and formed by

Answer 68

sacs/segments of colon in equines formed by specialized muscularis externa created because tenia coli is shorter than large intestine = bunches up

Question 69

tenia coli

Answer 69

outer longitudinal layer reduced to 3 strips (smooth muscle)

Question 70

function of muscularis externa in colon

Answer 70

compaction of feces

Question 71

what structure is formed by specialized muscularis externa in colon

Answer 71

haustrae

Question 72

how does fecal mass pass through colon (4 processes)

Answer 72

-peristalsis -antiperistalsis -rhythmic segmentation -mass movement

Question 73

composition of feces (6)

Answer 73

-water and fiber -mucus -dead and living bacteria -contents of anal sacs -sloughed intestinal cells -stercobilin pigment

Question 74

what type of epithelium lines rectum and anal canal (and why)

Answer 74

stratified squamous epithelium protection

Question 75

3 features of rectum and anal canal

Answer 75

-stratified squamous epithelium -mucous glands -skeletal and smooth muscle

Question 76

what kind of muscle are internal and external anal sphincters

Answer 76

skeletal muscle

Question 77

where do foregut lymph nodes drain to

Answer 77

cisterna chyli

Question 78

what is the largest lymphatic vessel of lymphatic system

Answer 78

thoracic duct

Question 79

where does thoracic duct drain to

Answer 79

-left brachiocephalic vein

Question 80

what 3 veins drain into gastroduodenal vein

Answer 80

-right gastric -cranial pancreaticoduodenal -right gastroepiploic

Question 81

what vein drains into splenic vein

Answer 81

left gastroepiploic

Question 82

what 3 veins drain into caudal mesenteric vein (hindgut)

Answer 82

-middle colic -left colic -cranial rectal

Question 83

what 4 veins drain into cranial mesenteric vein (midgut)

Answer 83

-jejunal -caudal pancreaticoduodenal -ileocolic -right colic