Week 2 Flashcards

Question

Why would you want to image the oesophagus and what are some radiographic considerations

Answer 1

Can be hard to see if problem is in trachea of oesophagus when looking at cranial aspect black (gas) high up in abdomen is probably stomach (not lungs

Answer 2

Can be congenital (puppy wont gain weight & is always regurgitating clumps of food with no liquid) Also in older dogs because NS is damaged/changed & oesophagus doesn't contract anymore (spinal tumour, nervous system disorder etc.) Dogs cant rely on gravity because their chest is so flat so food sits in oesophagus

Answer 3

dorsoventral

Answer 4

ventrodorsal

Answer 5

right lateral

Answer 6

left lateral

Answer 7

GDV gastric dilation and volvulus gas and gastric contents cant leave so stomach continues to stretch

Answer 8

ring of muscle surrounding opening

Answer 9

involuntary constriction & relaxation of muscles creating wave-like movements that push contents forwards

Answer 10

process of swallowing

Answer 11

primary: classic coordinated motor pattern of oesophagus initiated by swallowing secondary: if food gets stuck, oesophagus will distend. local reflexes at these distention sites trigger forceful secondary waves

Answer 12

in medulla oblongata & activated by pressure-sensitive sensors in pharynx

Answer 13

swallowing difficulties

Answer 14

regurgitation: action of bringing swallowed food up again into mouth vomiting: eject matter from stomach through mouth

Answer 15

gas in stomach, contrast media in oesophagus, displaced abdominal organs

Answer 16

catalysis of a reaction by one of its products

Answer 17

Pepsin (breaks fown proteins) would digest chief cells so chief cells produce/store pepsin as inactive proenzyme (pepsinogen) HCl would dissolve parietal cells so they produce H+ & Cl- ions instead which they release into lumen where HCl forms Mucosal mucous cells secrete mucus containing HCO3- to create protective layer protecting against pepsin & HCl in stomach Negative feedback loops prevent constant release of gastric juiuces

Answer 18

ECL = enterochromaffin like cells (release histamine) endocrine cells include G cells & D cells

Answer 19

Ghrelin stimulates appetite Leptin supresses appetite appetite affected by nutrient balance, sensory stimuli, feeding schedule, health/illness, exercise

Answer 20

- electrical coupling refers to smooth muscle cells being in communication with each other & responding together (being a synctium) to electrical stimulus (action potential) - achieved by gap junctions between smooth muscle cells which allow ions to pass between smooth muscle cells, thus allowing adjacent cells to contract as one - spread of action potential down muscle also allows for relaxation of muscle that just contracted to get ready for another wave of contraction

Answer 21

- interstitial cells of Cajal (ICC) are coupled with another type of interstitial cell & smooth muscle to form syncytium - ICC have intrinsic pacemaker activity that is responsible for waves of contraction/relaxation that run down GI tract - waves of depolarisation are propagated along ICC network to create segmented contractions

Answer 22

Contractions are peristaltic and start in the fundus They appear at intervals of 15 seconds lasting 2-3 seconds Contractions lead to circular narrowing of lumen of stomach, moving from fundus towards duodenum Muscles in upper part of stomach are poorly developed so contractions are weak & content is not well mixed Contractions become stronger moving towards pylorus Large part of pylorus wall contracts simultaneously --> increases luminal presses --> forces chyme through pyloric sphincter into intestine Most pyloric content remains in stomach for further mixing & dividing

Answer 23

Nausea Chemoreceptors in GI tract CNS (medulla oblongata) Pharynx contracts to close respiratory passages Deep inspiration Closure of glottis Contraction of abdominal muscles to increase intra-abdominal pressure Lower sphincter relaxes

Answer 24

produced by G cells in lower part of stomach stimulate gastric acid secretion & enhance motility stimulated by vagal nerve fibres & activation of stretch receptors

Answer 25

produced by S cells in duodenum & upper jejunum stimulates pancreas to secrete bicarbonate-rich pancreatic juice to neutralise acidic chyme in SI & inhibits gasric acid secretion stimulated by chyme entering duodenum

Answer 26

produced by I cells in duodenum & jejunum stimulates release of digestive enzymes from pancreas Induces contraction of gallbladder to release bile into duodenum & inhibits gastric emptying stimulated by presence of peptides, amino acids, fatty acids & monoglycerides in SI

Answer 27

produced by M cells in duodenum & jejunum stimulates migrating motor complex (MMC) in stomach & SI during fasting Enhances gastric & SI motility stimulated by absence of food in digestive tract & acid in duodenum

Answer 28

produced by D1 cells in stomach stimulates hunger & promotes gastric emptying stimulated by empty stomach

Answer 29

produced by D cells in stomach & duodenum inhibits release of gastrin, insulin, glucagon & growth hormone suppresses gastric acid secretion stimulated by acidic chyme in stomach

Answer 30

Rumen = fermentation vat Reticulum = part of rumen Omasum = water absorption Abomasum = true stomach

Answer 31

Lined by stratified keratinised epithelium (constantly renewed because wall is always being eroded)

Answer 32

Lined by simple columnar epithelium with occasional goblet cells

Answer 33

surgery always done from LHS

Answer 34

Total capacity of stomach is approx. 100-250L in adult cow - Rumen ~ 80% - Reticulum ~ 5% - Omasum ~ 7% - Abomasum ~ 8% In sheep & goats reticulum is relatively larger whilst omasum is relatively smaller than in cattle

Answer 35

Large (diameter up to 6 cm) and distensible Striated muscle along its whole length Mucosa is insensitive Heavily keratinised - Helps protect it from abrasive plant material “Chock” (obstruction of oesophagus) most commonly occurs close to pharynx & at thoracic inlet (potatoes, sugar beet)

Answer 36

Large volume - ~ 200 L in the adult cow Warm (close to body temperature) Moist (~ 90% of contents is water) Anaerobic --> “Fermentation” pH ~ 6.5 - Important - Too much grain can cause acidosis which kills flora Environment suitable for range of microorganism that digest & degrade plant material - Particularly cellulose & hemicellulose Fermentation results in production of volatile fatty acids, carbon dioxide & methane Fibrous feedstuffs remain long enough for complex carbohydrate digestion Surface area increased by initial mastication & ruminating (long fibre particles are regurgitated & re-chewed) Rumen-reticulo contractions (~3 every 2 mins) - Stirs, redistributes and mechanically grinds - Partitions fibre for re-chewing.

Answer 37

Structure and function similar to monogastrics Divided into fundus, body and pylorus Approximately a dozen large longitudinal rugae (persist when distended) Glands producing mucus, pepsinogen & hydrochloric acid pH ~3-4 (diluted by large volumes of fluid from forestomach) Weak, rhythmical contractions No proper pyloric sphincter – wall thickening (torus) acts as valve

Answer 38

Abomasum proportionately larger in young ruminants Growth of Re/Ru/Om commences as calf/lamb eats more roughage Rumen not developed in lambs

Answer 39

After birth the forestomach starts to develop and grow Development is promoted by presence of forage in rumen as young animal starts to pick at solid food A rumen flora develops within a couple of weeks of birth Functional by 6-8 weeks By the time animals are weaned forestomach is capable of digesting adult diet

Answer 40

During process of digestion in preruminant calf, casein protein in cows' milk clots in abomasum due to action of enzymes pepsin & rennin (chymosin) & hydrochloric acid

Answer 41

Reticulum keratinised Ridges 1-2mm high & 1-2cm wide

Answer 42

Poor quality feed e.g., rough hay spends more time in the rumen - this is good for the rumen as ruminants are designed to be slow digesters Grains - spend less time in rumen but leads to acidity problems

Answer 43

Function still remains unclear: - Probably water absorption - Pumping of ingesta from reticulum into abomasum Contains approx. 100 laminae (like leaves in book) covered with conical papillae which hugely increase its surface area Laminae are in 3 distinct size groups i.e. not random sizes Regular biphasic contractions squeeze material into recesses & then general contraction progresses fluid forward Relatively smaller in sheep and goats Not present in tylopods (camelids) Bolus gets squashed in omasal leaves so water squeezed out & then drier bolus flows along bottom

Answer 44

Leaf-shaped Keratinised Poorly developed in roof of dorsal sac Increased surface area for flora and absorption

Answer 45

Vary in size & shape depending on age, diet & location in rumen Growth stimulated by: - High concentration of VFAs (esp. butyrate) - Long fibre Thus longest at top of fluid layer, where long fibre floats Shortest at top of rumen, where the gas cap sits Medium length in middle to bottom of rumen They take time to adapt to dietary changes

Answer 46

Milk is digested in the abomasum Fundic glands produce rennin which coagulates casein (milk protein) in acidic environments Clot retains milk to allow complete digestion by pepsin

Answer 47

In neonates, milk needs to go directly to abomasum, otherwise it ferments in rumen & causes scour Special structure, reticular groove, acts as diversion for milk Relaxed: oesophagus empties into reticulum/rumen Contracted: edges of groove curl up & create tunnel between oesophagus & reticulo-omasal orifice Groove persists but only works in calves

Answer 48

When stimulated by vagus, groove contracts to form closed tube The reflex is stimulated by: - Suckling milk / pharyngeal stimulation - Noises associated with the “feeding routine” The reflex is poorly reactive to: - Drinking – hence bucket-fed calves are prone to scour since milk enters rumen * Also drink too fast which floods groove - Stomach tubing Reflex still works in adults: - Dehydration via ADH - Drenches containing copper (sheep) or sodium salts (cattle) - Apart from this, reflex can be considered inactive in adult feeding & drinking

Answer 49

The rumen ‘microbial population’ is very dense - ca. 10^10 bacteria/ml - 10^6 protozoa/ml - 10^3 fungi/ml Rumen microbes specialized to survive & thrive within rumen Conditions are strictly anaerobic Oxygen is toxic to many rumen microbes If microbiota is disrupted, then nutrition of ruminant is disrupted

Answer 50

Food of ruminants consists mainly of β-linked polysaccharides e.g. cellulose These can't be broken down by mammalian digestive enzymes Ruminants have evolved to use microbial fermentation of food prior to normal digestion Bacteria produce products that can be directly used by animal Bacteria also multiply on poor food to provide accessible form of proteins, nucleic acids, sugars & lipids that can be digested by ruminant

Answer 51

High-Quality Protein from Poor quality feed Nitrogen Incorporation: Rumen microbes use nitrogen from non-protein sources like urea for protein synthesis Hard-to-Digest Carbon: Microbes convert difficult-to-digest carbon into microbial proteins and nucleic acids. Essential Amino Acids: Rumen microbes synthesize all essential amino acids that vertebrates cannot produce. B Vitamins Production: Rumen microbes produce all B vitamins, preventing deficiencies common in other mammals.

Answer 52

Catabolic reactions producing ATP in which organic compounds serve as both primary electron donor & ultimate electron acceptor - Don’t use oxygen as terminal electron acceptor in respiration Fermentation requires anaerobic conditions

Answer 53

Holotrichs and oliotrichs

Answer 54

Actively ferment cellulose & soluble sugars (but not all) resulting in generation of mixture of products Products include acetate, lactate, ethanol, formate, succinate, CO2 & H2

Answer 55

When a diet changes the microbiota will adjust This takes time Can take up to two weeks to re-establish a balance The balance of organisms may be different Sudden changes in diet composition can have undesired effects on rumen function

Answer 56

Bacteria of rumen (& hind gut) flora will vary in susceptibility to antibiotics - Oral antibiotics can affect bacteria in rumen & lower intestine * This can impact on both rumen and gut health Oral antibiotics are NOT given for adult ruminants as they can disrupt rumen function Some species are susceptible to oral antibiotics as they disturb balance of gut microbes & cause disease

Answer 57

A barrier to infection of the lower intestinal tract Minimal Microbiology (but there is a base microflora) One bacterial pathogen to consider (Helicobacter) Bacteria killed by acid pH Disruption of acid can lead to infection or breakdown of protection Age may impact on pH barrier function Neonatal stomachs may be infected by overgrowth Food type may effect the barrier function Pharmacology can effect the barrier function (i.e. antacids)

Answer 58

Helical / ‘s’ shaped Gram –ve Related to Campylobacter Range of species effected: - Ferrets, dogs, cats, lab rodents but found in many other species Chronic gastritis in ferrets Found in gastric mucosa of dogs and cats Considered limited pathogenic significance to animals but possibly zoonotic.

Answer 59

1. Drills into the mucus gel layer of the stomach 2. Binds to membrane-associated lipids of epithelial cells 3. Secretes large amounts of Urease 4. Urease metabolizes urea to produce ammonia 5. Ammonia will neutralize gastric acid Survival in the acidic stomach is dependant on urease The ammonia that is produced is toxic to the epithelial cells Also produces other products protease, catalase & phospholipases which can cause damage to those cells

Answer 60

Diagnosis of infection with Helicobacter is rare in practice as there is lot of asymptomatic carriage in range of species The following approaches can be used - Non invasive tests - blood antibody test - Stool antigen test - carbon urea breath test, uses radio labelled urea which urease metabolises to produce radiolabelled CO2 which can be monitored - Most reliable method is combination of biopsy check during endoscopy with rapid urease test, histological examination & microbial culture

Answer 61

The rumen is designed to digest cellulose, which is from the plant cell walls. This digestion results in the production of volatile fatty acids (VFAs), which are the primary energy source of the ruminant.

Answer 62

1. rumen fill (has cow been eating?) 2. palpate to feel consistency (should be doughy consistency & feel 3 contractions every 2 min) 3. auscultation to listen to rumen contractions 4. volume & consistency of faeces (score of 3 ideal)

Answer 63

The reticulum is adjacent to the diaphragm, lungs, abomasum, rumen and liver. It is in the cranial abdomen, situated on ventral abdominal wall, just to the left of the midline.

Answer 64

The omasum is located in the cranial abdomen, on the ventral abdominal wall, just to the right of the midline. It is covered by lesser omentum and is bilaterally flattened.

Answer 65

The abomasum sits on the ventral wall of the cranial abdomen, to the right hand side of the midline. It is divided into the fundus, body and pylorus.

Answer 66

digest protein from both feed (bypass protein) and ruminal microbes (ruminal protein).

Answer 67

There are approximately 12 large folds Surface is columnar epithelial cells There are also glands which produce mucus, pepsinogen and hydrochloric acid (resulting pH 3-4)

Answer 68

Contains approximately 100 laminae (leaf-like structures) which are grouped into different sizes; these leaf-like fronds drastically increase the surface area for absorption The interior surface is lined by stratified squamous epithelial cells.

Answer 69

Main Role: Collects smaller digesta particles, moving them to the omasum; larger particles stay in the rumen for further digestion. Fluid Role: Helps in particle separation. Biphasic Contractions: First Contraction: Sends large particles back to the rumen. Reticulo-omasal Orifice: Allows finer particles to pass to the omasum.

Answer 70

Acidifying affects of VFA buffered by bicarbonate & phosphate in large volumes of saliva

Answer 71

protein is digested into rumen undegradable protein (moved into abomasum and SI) and rumen degradable protein Rumen degradable protein is broken down into amino acids which is either converted to microbial protein (this uses energy) or ammonia (if no energy available)

Answer 72

Protein degraded into ammonia when no energy present to convert it to microbial proteins Ammonia transported to liver where it is converted to urea Some is excreted in urine Some is recycled back into saliva where it returns to the rumen to be converted back to ammonia this ammonia can be converted into microbial protein (uses energy) or be recycled again

Answer 73

Limited High fat diets depress microbial activity Long chain fatty acids not absorbed

Answer 74

If more protein is present than energy, amount of MCP produced is limited by energy Increase ammonia - elevated blood urea Can recycle but high urea causes issues with reproduction

Answer 75

If more energy is present than protein, amount of MCP produced is limited by protein Wasted energy to methane…

Answer 76

too much concentrate or not enough fibre can lead to increased levels of lactic acid

Answer 77

Balance of rumen microflora changes Decreased rate of digestion due to decreased number of viable microorganisms Changes proportion of different VFAs produced

Answer 78

High producing animals fed diets high in concentrate - sub-optimal rumen function - reduced food intake - pain - indigestion - loose faeces - low milk fat levels

Answer 79

grain engorgement

Answer 80

Methane & CO2

Answer 81

gases produced not removed by eructation

Answer 82

Gas bloat Frothy bloat

Answer 83

Something blocks or hinders normal eructation Physical obstruction - e.g. foreign bodies blocking the oesophagus * e.g. potatoes or neoplastic growths Cessation of normal rumination - e.g. ruminal acidosis, vagal indigestion Gas being unable to reach the oesophagus - e.g lateral recumbency

Answer 84

Pastures rich in clover - Soluble leaf proteins form a gassy foam with rumen gases - Gassy foam can't be removed by eructation & builds up in rumen - Lots of air trapped in liquid

Answer 85

Causes compression of other organs e.g., heart, lungs

Answer 86

Camelids only have 3 compartments (lack omasum) instead of 4 Rumen & reticulum are combined (c1 - most nutrient absorption here)

Answer 87

multicompartmental stomach Rumen microbial population Cud chewing Large surface area Reticulorumen contractions Large amount of saliva

Answer 88

hypersalivation

Answer 89

Spleen on greater curvature Liver on lesser curvature Pancreas SI Oesophagus

Answer 90

Fe/Se/Cu/Co deficiency hypocalcaemia (milk fever) bacterial imbalance LDA Rumen acidosis dehydration

Answer 91

LDA due to gas in abomasum ping between 9th and 13th rib

Answer 92

after birth there is lots of space for abomasum to move

Answer 93

Ingestion of high concentrate, low roughage diets reduced emptying of abomasum Sudden change in diet can stress the abomasum More volatile acids -> hypomotility of abomasum -> more gas -> blocks entrance and exit

Week 2 Flashcards

(177 cards)