Pathophysiology

Question 1

Gastrin (production site, action, and release stimulus)

Answer 1

Source: G cells

Action: Stimulates acid secretion and growth of stomach epithelium, increases SI and LI peristalsis

Stimulus: Food, partially digested proteins, increased pH of stomach

Question 2

Cholecystokinin (production site, action, and release stimulus)

Answer 2

Source: I cells

Action: Increases pancreatic enzyme release, inhibits HCl production in stomach, decreases gastric emptying, potentiates secretin

Stimulus: Fatty chyme, partially digested proteins

Question 3

Secretin (production site, action, and release stimulus)

Answer 3

Source: S cells in the SI

Action: Inhibits gastric secretions and motility, increases pancreatic enzyme release, increases bile output

Stimulus: acidic chyme, fatty acids, proteins

Question 4

Somatostatin (production site, action, and release stimulus)

Answer 4

Source: Duodenal and gastric mucosa

Action: Inhibits gastric and pancreatic secretions, inhibits contraction of gallbladder, inhibits intestinal absorption

Stimulus: Food in stomach, sympathetic stimulation

Question 5

Motilin (production site, action, and release stimulus)

Answer 5

Source: Duodenal mucosa

Action: Stimulates MMC

Stimulus: Fasting

Question 6

Acid secretion in the stomach is stimulated by….

Answer 6

Acetylcholine, gastrin, histamine

Question 7

UPPER GI STUDIES (DOGS, LIQUID BARIUM):

• Time for contrast to reach duodenum
• Gastric emptying time
• SI transit time (when it reaches cecum or colon)
• SI emptying time

Answer 7

• Time for contrast to reach duodenum: 15-25 minutes
• Gastric emptying time: 30-120 minutes
• SI transit time (when it reaches cecum or colon): 30-120 minutes
• SI emptying time: 3-5 hours

(approximately similar between Wallack, 2003 and O’Brien, 1973)

Question 8

UPPER GI STUDIES (CATS, LIQUID BARIUM):

• Time for contrast to reach duodenum
• Gastric emptying time
• SI transit time (when it reaches cecum or colon)

Answer 8

• Time for contrast to reach duodenum: 10 min
• Gastric emptying time: 15-60 min
• SI transit time (when it reaches cecum or colon): 30-60 min
• SI emptying time:

Source: Morgan, 1981

Question 9

UPPER GI STUDIES (FOALS, LIQUID BARIUM)

• Gastric emptying time
• Barium filling cecum
• Transit time to transvers colon

Answer 9

• Gastric emptying time: Variable, but almost all gone within 2 hours
• Barium filling cecum: 2 hours
• Transit time to transvers colon: 3-8 hours (slower with increasing age)

Source: Campbell, 1984

Question 10

Name the numbered structures in this image

Answer 10

1. Nasopharynx
2. Soft palate
3. Base of tongue
4. Epiglottis
5. Trachea
6. Cranial esophageal sphincter
7. Cranial esophagus with barium in the lumen

Question 11

What is cricopharyngeal achalasia?

Answer 11

Failure of the UES to open fully or open at the appropriate time

Question 12

What is the progression of distension of the components of the biliary system in EHBDO?

Answer 12

Day 1: GB and cystic duct dilated

Day 1-2: CBD dilated

Day 5-7: distension of intra-hepatic ducts

Question 13

What is GFR (definition)?

What is normal in dogs?

What is normal in cats?

Answer 13

GFR = the quantity of filtrate formed in the kidney/minute

Dogs: >3 ml/min/kg

Cats: > 2.5 ml/min/kg

Question 14

What range of GFR likely indicates subclinial renal insufficiency?

Answer 14

1.2 - 2.5 ml/min./kg

Question 15

What is the resistive index measuring in the kidney?

What is considered the cutoff for an abnormal kidney in a dog?

Answer 15

RI = (systolic velocity - diastolic velocity) / systolic velocity

Measure of vascular resistance within the kidney

RI > 0.7 is abnormal

Question 16

What is the effect of each of the following hormones on the Ca:P ratio?

1) Calcitonin
2) PTH
3) Calcitriol

Answer 16

1. Calcitonin: decrease Ca, minimal effect on P
2. PTH: increase Ca, decrease P
3. Calctriol: increase both

Question 17

Explain the renin-angiotensin-aldosterone system (RAAS). What stimulates RAAS?

Answer 17

1. Decreased BP in the afferent arteriole
2. Increased sympathetic tone
3. Decreased Na & Cl concentration at the macula densa (low GFR leads to over re-absorption in the ascending LOH)

Question 18

What is the effect of atrial natriuretic peptide (ANP)? What stimulates secretion of ANP?

Answer 18

Dilation of afferent arteriole –> increased GFR

Decreases renin production –> natriuresis & diuresis

Stimulated by atrial distension

Question 19

RADIOGRAPHIC FETAL OSSIFICATION INTERVALS

(Days Post-LH Peak)

• Mineralization of bones
• Radius/Ulna/Tibia
• Pelvis
• Distal extremities and teeth
• Also, what is gestation time in a dog?

Answer 19

(Days Post-LH Peak)

• Mineralization of bones: 45 days
• Radius/Ulna/Tibia: 52 days
• Pelvis and ribs: 54 days
• Distal extremities and teeth: 61 days
• Also, what is gestation time in a dog? About 64 days

Question 20

Fetal mineralization in cats on radiographs

Answer 20

Same sequence of mineralization as dogs, but everything except mineralization of the teeth happens a few days earlier.

Question 21

What are the radiographic signs of fetal death? (6 things)

Answer 21

1. Gas within the uterus
2. Lack of mineralization of the fetus at an appropriate time
3. Demineralization of fetal skeleton
4. Abnormal fetal position (rolling into a ball)
5. Overlap of the skull bones (Spalding sign)
6. Increased opacity of fetus with decreased visualization of the extremities

Question 22

Timing of pyometra: what part of estrus cycle

Answer 22

1-3 months post-estrus in the diestrus phase

Question 23

What are considered normal measurements of the prostate on radiographs?

Answer 23

Lateral view: < 70% of the height of the pubic-sacral promontory

VD view: <50% of the pelvic inlet width

Question 24

Differential diagnoses for diffusely decreased bone density (osteopenia)

Answer 24

1. Osteogenesis imperfecta
2. Hyperparathyroidism (nutritional, renal, primary)
3. Vitamin D deficiency
4. Mucopolysaccharidosis
5. Glucocorticoid excess
6. Osteoporosis

HOG MOV(e)

Question 25

Differential diagnoses for diffusely increased bone density

Answer 25

1. Osteopetrosis (inherited dz with abnormal osteoclastic function) 2. FeLV 3. Paraneoplastic (secondary hypertrophic osteopathy)

Question 26

How do you differentiate a viable non-union from a non-viable non-union fracture?

Answer 26

Viable -- fuzzy appearance to fracture margins, elephant or horse hoof callus Non-viable -- sclerosis, rounding of the fracture margins, visible fracture gap

Question 27

What is multiple epiphyseal dysplasia? How does it look on radiographs?

Answer 27

Failure of epiphyseal ossification; they will eventually mineralize but appear deformed. Metaphyses and diaphyses are _normal_. Radiographic apperance: small, distorted epiphyses

Question 28

What are the differentials for abnormal epiphyseal development?

Answer 28

1. Multiple epiphsyeal dysplasia 2. Pituitary dwarfism (proportionate dwarfism) 3. Congenital hypothyroidism (disproportionate dwarfism) 4. MPS

Question 29

# Define: 1. Amelia 2. Hemimelia 3. Polydactyly 4. Ectrodactyly 5. Syndactyly

Answer 29

1. Amelia: absence of a limb 2. Hemimelia: one bone of a pair (usually radius or ulna) is absent or hypoplastic 3. Polydactyly: excess numbers of digits 4. Ectrodactyly: distal forelimb is split, with phalanges, metacarpals and carpal bones divided to become associated with either the distal radius or ulna (lobster claw) 5. Syndactyly -- lack of differentiation between 2 or more digits

Question 30

This is a characteristic appearance of what disease/disorder?

Answer 30

Rickets: reduced dietary intake or inborn error of vit D metabolism Rads: characteristic widening of physes due to hypertrophied cartilage Widening and concavity of the metaphyseal edge with extreme, 'beaked' cupping of the adjacent metaphyses due to continued periosteal growth - “mushroom” or flared

Question 31

What are the radiographic changes associated with hypervitaminosis A?

Answer 31

Ankylosing spondylopathy of the cervical and thoracic spine Exuberent exostosis, enthesophytes, and OA of the shoulder

Question 32

Patella alta vs. patella baja

Answer 32

Alta: proximally displaced (high altitude) Baja: distally displaced (down in the Bahamas)

Question 33

Formation of osteochondroma/multiple cartilaginous exostoses

Answer 33

Chondrocytes are pushed into the metaphysis and do not differentiate into osteoblasts Cartilage islands continue to proliferate as cartilagenous masses that eventually ossify Wide base, narrower tip

Question 34

What are the radiographic characteristics of physitis/epiphysitis?

Answer 34

Widened physis, flared metaphysis, periosteal lipping

Question 35

What are the radiographic features of an aneurysmal bone cyst?

Answer 35

LYSIS! Locally invasive, expansile, osteolytic lesion. Generally eccentric and in a metaphyseal location.

Question 36

What is spinal dysraphism? What breed is predisposed?

Answer 36

Congenital defect that results from failure of normal closure of the neural tube. Weimeranar

Question 37

What is spina bifida?

Answer 37

Incomplete or failure of fusion of the dorsal vertebral arches with or without spinal cord/meningeal involvement (spina bifida occulta)