Lecture 1- Introduction to GI system of Horses

Question 1

What prevents horses from vomiting

Answer 1

Sharp angle of esophagus into stomach and strong esophageal muscles

Question 2

What organ secretes digestive enzymes into the small intestines to breakdown food into starch, fiber, proteins and fats

Answer 2

Pancreas

Question 3

Where is the primary site of enzymatic digestion

Answer 3

Stomach

Question 4

How long is the small intestine

Answer 4

70 ft

Question 5

What is broken down in the small intestine

Answer 5

Starch, proteins and fats

Question 6

What enzyme is secreted from pancreas , enters the small intestines and breaks down starch into disaccharide

Answer 6

Alpha-amylase

Question 7

Enzymes break disaccharides down to simple sugars which a re then

Answer 7

Absorbed through intestinal wall into capillary network and sent to body tissues for immediate use for energy or stored as glycogen

Question 8

What is released from the pancreas in response to increased glucose levels and drives absorption of glucose

Answer 8

Insulin

Question 9

Horses have no ____ so bile is continually secreted

Answer 9

Gall bladder

Question 10

What is responsible for emulsifying fats and making it available for enzymatic degradation via lipases secreted from pancreas

Answer 10

Bile salts

Question 11

Enzymatic degradation of fats via bile salts combine with vila acid to form my- cells which then….

Answer 11

Diffuse into intestinal lining, packaged with cholesterol and then expelled and taken up by lymphatic system via thoracic duct where lipids can be used as fuel or stored as fat

Question 12

What breaks proteins to peptides in upper gut

Answer 12

Pepsin

Question 13

Once pepsin converts proteins to peptides what happens

Answer 13

Amino acids are absorbed into blood capillaries and carried to tissues where they are used to build proteins

Question 14

What portion of the gut is responsible for digestion of fiber

Answer 14

Hind gut- cecum and large intestines

Question 15

What is the end product of microbial break down and fermentation

Answer 15

Volatile fatty acids (VFA’s)

Question 16

What is the mechanism of converting glucose in hindgut

Answer 16

VFA—> propionate—>glucose production in liver

Question 17

What happens to the proteins that aren’t absorbed in foregut and make it to hindgut

Answer 17

Don’t absorb amino acids—> will produce nitrogen and carbon that is excreted as ammonia

Question 18

What is involved in the completion of digestion

Answer 18

Muscular contractions move ingesta and reabsorption of water to result in dry fecal balls

Question 19

Horses are ____fermenters

Answer 19

Hindgut

Question 20

What is the pathway from mouth to rectum

Answer 20

1. Mouth
2. Esophagus
3. Stomach
4. Duodenum (R)
5. Jejunum
6. Ileum
7. Cecum (R)
8. Right ventral colon
9. Sternal flexors
10. Left ventral colon
11. Pelvic flexors
12. Left dorsal colon flexors
13. Diaphragmatic flexors
14. Right dorsal colon
15. Transverse colon
16. Descending/small colon
17. Rectum/anus

Question 21

Where are the bands of Taenia

Answer 21

Large intestine

Question 22

What band is located in ileum

Answer 22

Antimesenteric band- can’t reach on palpation

Question 23

How many bands does the cecum have

Answer 23

4
Dorsal to ileum
Lateral to right ventral colon
Ventral/medial

Question 24

How many bands does the ventral colon have

Answer 24

4

Question 25

How many bands does the pelvic flexure have

Answer 25

1

Question 26

How many bands does the dorsal colon have

Answer 26

3

Question 27

How many bands does the small colon have

Answer 27

2

Question 28

What are rugae

Answer 28

Series of ridges produced by folding of the wall of an organ, most commonly refers to gastric rugae of the internal surface of the stomach

Question 29

What are haustra

Answer 29

Refer to the small segmented pouches of bowel separated by haustral folds

Question 30

How are haustra formed

Answer 30

Circumferential contraction of the inner muscular layer of the colon

Question 31

The outer longitudinal muscular layer of the colon is organized into 3 bands which run from the cecum to the rectum. What are the 3 bands called

Answer 31

Taeniae coli

Question 32

What takes up a majority of the right side of GI tract in horse

Answer 32

Cecum

Question 33

What takes up majority of left abdominal region of horse

Answer 33

Spleen

Question 34

What side is the duodenum on

Answer 34

Right

Question 35

What is the function of the stomach

Answer 35

Enzymatic breakdown

Question 36

What is the function of the small intestines

Answer 36

Digests simple carbs and readily accessible proteins

Question 37

What is the function of the cecum

Answer 37

Some carbs and proteins escape small intestine and move onto hindgut for fermentation Where CELLULOSE (fiber) is broken down Creates and absorbs VFA’s

Question 38

What is the function of the colon

Answer 38

Reabsorption of water, some further fermentation

Question 39

What is the function of the descending or small colon

Answer 39

Forms fecal balls

Question 40

Where does microbial fermentation occur

Answer 40

Cecum and colon Allows horses to break down cellulose (fiber)

Question 41

What does fermentation in the hindgut produce

Answer 41

CO2, methane, VFA’s

Question 42

What is propionate used for

Answer 42

Glucose production

Question 43

What is acetate converted to and what is it used for

Answer 43

Converted to acetyl CoA and used for immediate energy or fat synthesis

Question 44

What is butyrate converted to

Answer 44

Acetyl CoA

Question 45

Hindgut= _____ and foregut = _____ (types of digestion)

Answer 45

Hindgut=Microbial fermentation Foregut=enzymatic digestion

Question 46

What are some disadvantages in horses hindgut fermentation compared to ruminants foregut fermentation

Answer 46

Less efficient, less nutrients entering hindgut so promotes less microbial growth, passage through hindgut is more rapid so fermentation less efficient than in rumen, protein present in microbes is not digestible thus lost

Question 47

What does the microbiota consist of

Answer 47

Bacteria, fungi and Protozoa

Question 48

what bacteria are present in microbiota

Answer 48

Phylum, fermicutes, bacteriodetes, proteobacteria, verrucomicrobia, actinobacteria and spirochaetes

Question 49

What is the primary bacteria in the microbiota

Answer 49

Phylum fermicutes (46-70%)

Question 50

How does the microbiota differ in a diarrheic horse vs healthy horse

Answer 50

Diarrheic horses have more fusobacteria and less clostridiales

Question 51

Lactobaccillus is often used in ____ for horses

Answer 51

Probiotics

Question 52

What is colic

Answer 52

Any abdominal pain

Question 53

What are some clinical signs of colic

Answer 53

Sweating, pawing, tachycardia, tachypnea, up and down, rolling, stretching out, shifting, biting or looking at sides, kicking at abdomen

Question 54

What divides the stomach into upper squamous and lower glandular

Answer 54

Margo Plicatus

Question 55

what equine gastric ulcer syndrome is associated with management in horses with otherwise normal GI tracts

Answer 55

Primary equine squamous gastric disease

Question 56

What equine gastric ulcer syndrome occurs secondary to delayed gastric emptying because of other disease states

Answer 56

Secondary squamous gastric disease

Question 57

What is Grade=0 for ESGD

Answer 57

Normal

Question 58

What is Grade=1 in ESGD

Answer 58

Hyperkeratosis

Question 59

What is Grade=2 in ESGD

Answer 59

Small, single, or multifocal lesions

Question 60

What is grade 3 ESGD

Answer 60

Large single or extensive superficial lesions

Question 61

What is grade 4 ESGD

Answer 61

Extensive lesions with areas of apparent deep ulceration

Question 62

What is the grading system for EGGD

Answer 62

No grading system, describe anatomical location, distribution and appearance

Question 63

What is enteritis

Answer 63

Inflammatory disease of small intestine Thickened >3mm

Question 64

What are symptoms of acute:proximal enteritis

Answer 64

Fever, reflux, leukocytosis, colic that resolves with decompression

Question 65

What are some symptoms of chronic/insidious enteritis

Answer 65

Inflammatory bowel syndromes, neoplasia, weight loss, panhypoproteinemia

Question 66

What are some simple obstructive lesions of small intestines

Answer 66

Ileal impactions, adhesions and ascardiasis

Question 67

What can cause ileal impactions

Answer 67

Feeding costal Bermuda hay (hydrophobic) and tapeworm infestation (anoplocephala)

Question 68

What age group is ascardiasisa common in

Answer 68

4-24 months

Question 69

What are some clinical signs of small intestinal strangulations

Answer 69

Severe pain, serosanguinous belly tap

Question 70

What are some causes of small intestinal strangulations

Answer 70

Strangulating lipoma, epiploic foramen entrapment, intussusception, inguinal hernia

Question 71

Where do strangulating lipomas form in small intestine

Answer 71

Stalks in mesentery

Question 72

What is an epiploic foramen entrapment

Answer 72

Potential space: liver, caudal vena cava and portal vein Nothing else is supposed to be there but small intestine can end up there

Question 73

What is the most common intussusception

Answer 73

Ileocecal

Question 74

What is a commonly implicated cause of intussusception

Answer 74

Tapeworms

Question 75

What are some examples of large colon impactions

Answer 75

Pelvic flexure, sand impactions enteroliths, and Cecal impactions

Question 76

Where is the most common large colon impaction

Answer 76

Pelvic flexure

Question 77

Where do sand impactions accumulate

Answer 77

Ventral colon, rightdorsal colon, pelvic flexure

Question 78

California alfalfa is associated with what large colon impaction

Answer 78

Enteroliths

Question 79

Where are enteroliths most commonly found

Answer 79

Right dorsal colon/transverse colon

Question 80

What large colon impaction is commonly associated with orthopedic surgical disease

Answer 80

Cecal impaction from stall rest and laying down a lot

Question 81

What is a nephrosplenic entrapment

Answer 81

Left dorsal displacement NSE of the colon hangs between the kidney and spleen

Question 82

What is colitis

Answer 82

Inflammatory disease of large colon

Question 83

What are some common etiologies of colitis

Answer 83

Infectious (salmonella, clostridium, coronavirus, Potomac horse fever Verminous- encysted small strongyles Caustic- sand colitis

Question 84

What are some symptoms of colon volvulus

Answer 84

Severe, unrelenting abdominal pain, gross distention of abdomen

Question 85

Where are colon volvulus normally located

Answer 85

Mesenteric attachment of the colon to the dorsal body wall involving the cecum and entire large colon Twist at sternal/diaphragmatic flexure

Question 86

What is a common impaction of the descending small colon

Answer 86

Fecoliths (salmonellosis) Foals with meconioum impactions

Question 87

What is peritonitis

Answer 87

Inflammation of peritoneum

Question 88

What are some causes of peritonitis

Answer 88

Recent abdominal surgery, cyathostomiasis (small strongyles), IBD, internal abscess

Question 89

What is the result of peritonitis

Answer 89

Ileus- intestines not moving can’t get gas out can result in bloat and death

Question 90

Tapeworms and colic

Answer 90

Ileocecal intussusception, cecocolic intussusception, typhilitis

Question 91

Ascarids and colic

Answer 91

Small intestinal impaction

Question 92

Large strongyles and colic

Answer 92

Thromoembolic colic, cranial mesenteric aneurysm

Question 93

Small strongyles and colic

Answer 93

Encysted cytathostomes

Question 94

What does lawsonia intracellularis cause

Answer 94

Proliferative enteropathy