Book 2 Flashcards
What are the classifications of burn wounds?
1st degree: only epidermis
2nd degree: full thickness epidermal necrosis
3rd degree: full thickness through dermis
4th degree: involves muscle/fascia
5th degree: bone
What are the 3 ways in which heat is transferred to the patient during burns?
Conduction = direct contact
Convection = hot air
Radiation = electromagnetic energy converted to heat
What is the time/duration of a burn that results in:
Failure of the Na pump
Epidermal necrosis
Full thickness burn
Failure of the Na pump: 40-44 C
Epidermal necrosis: 60 C for 1 sec
Full thickness burn: >70 C for < 1 sec
What are the zones of tissue in a burn?
- ZONE OF COAGULATION = zone of destruction, no viable tissues
- ZONE OF STASIS = ↓ in deformability of RBCs + ↓ vascular luminal diameter –> ↑ interstitial pressure + ↑ capillary permeability
- ZONE OF HYPEREMIA = primary zone of inflammatory response to burn (viable tissues). Local inflammation –> vasodilation + ↑ vascular permeability, edema, influx of inflammatory cells
Why do burns heal slower than normal wounds?
<5% of FGF-2, fewer wound healing cytokines, and no capillary endothelial chemotactic/proliferative activity
How does scald temperature impact the zone of stasis in burns?
Local lymph flow and protein content increase proportionately with scald temp
Arterial supply and venous drainage of the spleen?
Arterial = Celiac A –> Splenic (+ L Gastric + Hepatic)
Venous = Splenic v –> Gastrosplenic v –> Portal v
What is the difference between dog and cat spleens?
Dog = sinusoidal
Cat = nonsinusoidal (nodular hyperplasia is uncommon)
How much of the body’s RBC mass does the spleen hold? Platelet mass?
RBC: 10-20%
Platelet: 30%
What are the 3 pools of blood in the spleen?
Rapid: 90%, takes 30 sec to rejoin circulation
Intermediate: 9%, takes 8 min to rejoin
Slow: 1%
What are the muscle origins of the external abdominal oblique, the internal abdominal oblique, and the transversus abdominus?
ext abd oblique: 4/5th thru 12th rib
int abd oblique: TL fascia caudal to last rib to tuber coxae
transversus abdominis: lumbar portion from transverse processes of lumbar vertebrae/TL fascia + costal portion from 12-13th ribs + 8-11 costal cartilages
Which diaphragmatic crura is larger?
Right
What are the 1 minor and 3 major openings in the diaphragm?
AORTIC HIATUS = most dorsal: aorta, azygous + hemiazygos v + lumbar cistern of TD
ESOPHAGEAL HIATUS = more dorsal: esophagus + blood supply + dorsal/ventral vagal trunks
CAVAL FORAMEN = dorsal portion of central tendon to R of midline: caudal vena cava (adventitia fuses with tendon)
Minor Foramina of Morgagni = sternocostal triangles: cranial epigastric a (termination of internal thoracic a)
What is the innervation of the diaphragm?
Phrenic n - C5-7
(C5-C7 all dogs go to heaven)
What runs through the inguinal canal? Through the vascular lacunae?
Inguinal Canal = vaginal process + spermatic cord [male]/round lig [female] + ext pudendal vessels + genital n
R/L Vascular Lacunae = femoral a/v + lymphatics + saphenous n
What is the TP and cell count for the following types of fluid:
Normal peritoneal fluid
Transudate
Modified transudate
Exudate
Normal peritoneal fluid: <2 ; <300
Transudate: <2.5 ; <1500
Modified transudate: 2.5 - 5 (or 7.5) ; 1500 - 7000
Exudate: >3 ; >7000 (or >5000)
How much fluid can the peritoneum absorb per hour?
3-8% body weight/hr
What is the normal intraperitoneal pressure? What pressure is seen with acute abdominal compartment syndrome?
Normal 2-7.5 cmH2O
Comp Syndr: >20-25 cmH2O
What organs are retroperitoneal?
Kidneys, ureters, adrenals, aorta, CVC, lumbar LN
Splanchnic circulation receives what % of cardiac output and blood vol?
25% CO, 20% blood vol
Innervation of the lips/cheeks?
Blood supply to upper lip? Lower lip?
Motor = CN 7, sensory = CN 5
Upper: infraorbital A
Lower: facial A
What are the gustatory and non-gustatory taste buds?
Gustatory: Fungiform, vallate, and foliate
Non-Gustatory: Filiform, conical
[restaurants have fungi (mushrooms), foliage (lettuce), and valet parking; we don’t eat filamentous stuff (mold) or traffic cones]
What is the innervation of the tongue?
Motor: CN 12
Sensory: CN 5, 7, 9
What are the phases of swallowing?
- Oropharyngeal
1a. Oral (only voluntary), CN 5, 7, 12
1b. Pharyngeal, CN 9, 10
1c. Pharyngoesophageal, CN 9, 10 - Esophageal
- Gastroesophageal
Where do the following salivary gland ducts drain to:
Parotid
Zygomatic
Mandibular
Sublingual
Parotid = at level of upper PM4
Zygomatic = caudolateral to last molar
Mandibular = sublingual caruncle near frenulum
Sublingual = combined with mandibular and polystomatic directly into oral cavity
What organ is within the veil portion of the greater omentum?
Left limb of pancreas
What is the flow of saliva?
Acinus produces saliva –> intercalated ducts –> intralobular ducts –> interlobular ducts –> lobular ducts –> lobar ducts –> major excretory ducts
What are the layers of the esophagus? What is different between cats and dogs?
Adventitia (NO serosa!)
Muscularis - skeletal (caudal 1/3 is smooth in CATS)
Submucosa
Mucosa
What muscles make up the upper and lower esophageal sphincters?
UES: No thickening pr true sphincter, made of thyropharyngeus and cricopharyngeus
LES: Thickening of circumferential striated muscle (dogs) + diaphragmatic crural muscles + angle at which esophagus and stomach meet + folds of gastroesophageal mucosa
What is the segmental blood supply to the esophagus?
Proximal 1/3 = cranial and caudal thyroid arteries
Thoracic cranial 2/3 = bronchoesophageal
Thoracic caudal 1/3 = esophageal branches of aorta/intercostals
Termination: L gastric A
Segmental venous drainage of the esophagus?
Cervical: External jugular
Thoracic/caudal 1/3: Azygous v
Termination: portal system
What factors (4) contribute to a higher complication rate with esophageal surgery compared to other GI surgery?
- No serosa
- No omentum
- Constant motion/tension from swallowing: use feeding tube for 24 hrs to 7 d
- Segmental blood supply
What are the 3 categories of swallowing disorders?
Mechanical/anatomic
Functional/neuromuscular
Inflammatory/esophagitis
What is the blood supply to the stomach?
Celiac A
1. Splenic A –> L gastroepiploic A
2. Hepatic A –> R gastric + gastroduodenal –> cranial pancreaticoduodenal + R gastroepiploic
3. L gastric
What are the glands of the stomach? Where are they located and what do they secrete?
Parietal cells: body; intrinsic factor + acid
Chief cells: body; pepsinogen
Endocrine cells: body; serotonin + gastrin + histamine
Epithelial cells: Everywhere; bicarb + mucus
Mucous neck cells: body/antrum; mucus
Short gastric arteries supply the fundus of the stomach. Where do they originate from?
Originate from splenic branches of splenic A, anastomose with L gastric A
How do superficial gastric erosions heal? How about injuries extending into the submucosa?
Superficial heal rapidly by epithelial migration without proliferation
Deep heal with fibrotic repair and scar formation
What is special about collagen production in the GIT?
It is produced by both fibroblasts and smooth muscle cells
What is the functional unit of digestion/absorption? Where does secretion happen vs absorption?
Villi + crypt
Secretion in crypts, absorption in villi
What are the primary sources of intrinsic factor? Where is vit B12 (cobalamin) absorbed?
Pancreas (dogs and cats) and stomach (dogs only) produce IF
B12 abs in ileum
What are the two primary types of intestinal motility? What occurs when each type is impaired?
Segmental contractions for mixing and absorption, if impaired –> diarrhea
Peristaltic contractions for moving food aborad, if impaired –> ileus
What is the blood supply to each portion of the colon?
Cr mes –> common colic –>
Ascending colon: ileocolic A prox and R colic dist
Transverse colon: R colic prox and middle colic dist
Descending colon: middle colic prox and L colic (from cd mesenteric A) distal
Terminal colon: cranial rectal A (from cd mesenteric)
What prostaglandin is most important for maintaining gastric mucosa?
PGE2
What factors negatively affect healing in the colon? (Local and systemic)
Local: hypoperfusion, poor apposition, tension, infection, distal obstruction
Systemic: hypovolemia, transfusions, icterus, chemo, diabetes, zinc/iron deficiency
T/F: Anemia does NOT affect colonic healing until HCT is <15%
TRUE
T/F: Hypothyroidism and Cushing’s disease have NOT been demonstrated to negatively affect colonic healing
TRUE
What is colonic wound strength at 48 hrs and 4 mos after injury?
48 hrs: 30% of normal
4 mos: 75% of normal (slower than small intestine)
What blood vessel marks the colorectal junction? What blood vessel is the primary blood supply to the rectum?
The cranial rectal A
What makes up the pelvic diaphragm? What is the primary blood supply?
Pelvic fascia + coccygeus m + levator ani m
Internal pudendal A and caudal gluteal A
What amount of bacteria is found in feces? What percent of that is anaerobes?
10^9 bacteria/g
90% anaerobes
What provides voluntary motor to the external anal sphincter? Sensory?
Motor = caudal rectal branch of pudendal n
Sensory = perineal branch of pudendal n
What are the different glands of the anus and perineum?
Circumanal glands - in SQ up to 4 cm out from anus, regress in females
Anal glands - tubuloalveolar glands, produce fatty secretions
Paranal sinus glands - in wall of anal sac and duct, produce smelly liquid
What is the innervation of the internal anal sphincter?
Pelvic plexus:
Parasympathetic fibers from S1-3 –> contract rectum and relax internal anal sphincter
Sympathetic fibers from hypogastric n –> relax rectum, contract internal anal sphincter
What % of hepatic blood flow and O2 supply comes from the hepatic A? What are its branches/what do they supply?
20% of blood flow, 50% of O2 supply
R lateral branch –> R lat and caudate lobes
R middle branch –> R med lobe
L branch –> L lat, L med, quadrate lobes
Cystic A branches from L branch –> GB
What % of hepatic blood flow and O2 supply come from the portal v? What are the branches of the portal v and what do they supply?
80% blood flow, 50% O2 supply
R branch –> R lat, caudate process
L branch –> L lat, L med, quadrate lobes
Central branch from L branch –> R med, papillary process
How many branches of the CVC drain the liver?
6-8 branches
What is the flow of bile from the liver to the duodenum?
Canaliculi –> interlobar ducts –> lobar ducts –> hepatic ducts –> CBD –> duodenum at major duodenal papilla
What % of functional liver mass must be lost to see hypoalbuminemia and hypoglycemia? How much must be lost to see hepatic encaphalopathy?
70-80%
70%
What are the differences between cats and dogs in terms of the CBD and pancreatic ducts?
DOGS = CBD enters duodenum at major duodenal papilla adjacent to pancreatic duct (Sphincter of Oddi). The majority of canine pancreatic secretions are through the accessory pancreatic duct which enters at the minor duodenal papilla
CATS = CBD + pancreatic duct join + enter at major duodenal papilla –> concurrent hepatic/pancreatic dz (only 20% cats have accessory pancreatic duct + minor papilla)
How much of the liver can be acutely removed? What leads to morbidity if more is removed?
70%
portal hypertension is the cause of morbidity
What % of total liver volume is made up by the:
L Lat + L Med lobes
R Med + Quad lobes
R Lat + Caud lobes
L Lat + L Med lobes: 44%
R Med + Quad lobes: 28%
R Lat + Caud lobes: 28%
Which coag factors are NOT synthesized in the liver? What must coag factors be depleted to in order to see a clinical coagulopathy?
Factor 8 and vWF
<15%
When does functional closure of the ductus venosus occur? Structural closure? What 2 factors stimulate closure? What does patency typically result in?
2-6 days after birth for functional closure
3 weeks after birth for structural closure
Cytochrome p450 and TXA2 stimulate closure
Patency leads to L sided intrahepatic shunt
What is the prevalence of congenital PSS in dogs? What percent of PSS are extrahepatic?
0.18%
65-75% EHPSS
How does ammonia cause signs of hepatic encephalopathy?
Ammonia prod by GI flora –> urea/glutamate via urea cycle
Glutamate is excitotoxic –> overactivation of NMDA R –> seizures
What percent of the pancreas has endocrine function? What are the 4 primary cells of the endocrine pancreas and what do they secrete?
2% endocrine, 98% exocrine
Alpha - glucagon, increase BG
Beta - insulin, decrease BG
Delta - somatostatin
F/PP - pancreatic polypeptide
What percent of dogs have a single duct from each limb of the pancreas that form a Y? What percent of cats LACK an accessory pancreatic duct?
68% of dogs have single duct from each limb that form a Y with the tail being the larger ACCESSORY pancreatic duct
80% of cats lack an accessory pancreatic duct
What are the exocrine secretions of the pancreas?
Inorganic components = bicarbonate, water, K, Na, Cl
Intrinsic factor
Zymogens (activated by enterokinase from duodenum which activates trypsin) = trypsinogen, chymotrypsinogen, proelastases, procarboxypeptidase, amylases, lipase, prophospholipase A2, carboxylesterase
How are pancreatic exocrine secretions regulated?
Duodenum secretes secretin and cholecystokinin and enterokinase
Cholecystokinin –> stimulates release of digestive enzymes
Secretin –> stimulates pancreas to release bicarb to neutralize gastric HCl
Enterokinase –> cleaves trypsinogen to trypsin which activates other zymogens
What are gastrinomas?
Pancreatic islet cell tumors where somatostatin secreting delta cells undergo malignant transformation to cells that excrete excessive gastrin
Results in gastric acid hypersecretion –> GI ulcers and erosions
Enzymatic maldigestion d/t loss of alkaline environment in proximal duodenum
Delayed gastric emptying (antral hypertrophy)
What is the maximum gastric capacity?
22-30 mL/kg
When using a feeding tube, how much fluid is required for hydration?
50-100 mL/kg/day, more if sick
What is refeeding syndrome?
IC cations depleted, plasma levels can still appear normal
With feeding, cations rush into cells –> low K/Phos/Mg –> fluid retention, ECG changes, dyspnea, V/D, ileus, renal dysfunction, tetany
Where does the nasal alar fold extend from?
extension of the ventral nasal conchae, fuses with the wing of the nostril
What are the 4 paired processes of the arytenoid cartilages? What type of joints are the articulations?
Cuneiform, corniculate, vocal, muscular
Articulations are synovial joints
What are the extrinsic muscles of the larynx and their innervation?
Thyropharyngeus m and cricopharyngeus m
CN 9 and 10
What are the intrinsic muscles of the larynx and their innervation?
Cricoarytenoideus dorsalis, cricoarytenoideus lateralis, thyroarytenoideus, arytenoideus transversus, hyoepiglotticus –> recurrent laryngeal n from CAUDAL laryngeal n (from CN X)
Cricothyroideus –> external branch of CRANIAL laryngeal n (from CN X)
Internal branch of cranial laryngeal n = sensory
What is the vascular supply of the larynx?
Cranial and caudal thyroid arteries
What is unique about the arytenoid cartilage in cats?
It lacks cuneiform and corniculate processes, has no aryepiglottic folds, and no ventricles/saccules
What are the functions of the cricoarytenoid dorsalis and lateralis?
Dorsalis - abducts arytenoid cartilages to open rima glotis
Lateralis - closes rima glottidis
What is the main innervation to the trachealis muscle and tracheal mucosa?
RIGHT vagus n and recurrent laryngeal n
The pulmonary arteries travel along what surface of each bronchus?
Craniodorsal aspect
What are elastance and compliance in the lungs?
Elastance = degree of recoil after inspiration, = change in P / change in V
Compliance = measure of lung distensibility, = change in V / change in P
What is surfactant produced by and how does it affect compliance?
Alveolar type II cells
surfactant –> decrease surface tension –> increase compliance (easier to inflate lungs)