Digestion Flashcards

Question

Passage time in: Sheep

Answer 1

14-19 hours

Answer 2

11-13 hours ## Footnote *Peaking at 12-24 hours*

Answer 3

12-15 hours

Answer 4

Ablactation

Answer 5

Fundus (Next to the cardia)

Answer 6

The terminal part of the fundus

Answer 7

* Ruminoreticulum doesn't function * Animal lives on mother's milk * Carbohydrate metabolism is similar to a monogastric animal

Answer 8

* Early ruminous stadium * From 3-8 weeks since birth * Increased volume of rumen + reticulum * Animal interested in rougher fodder * Decreased blood glucose * Volatile fatty acids increase

Answer 9

* Forestomachs completely developed * Rumen at largest volume * Food enters rumen via the cardia * Growth and thyroid gland hormones may play a role

Answer 10

* Reflex mechanism * Stimulation of pharyngeal receptors: * From milk * From suckling mechanism

Answer 11

Copper-salt CuSO₄ solution orally

Answer 12

1. Antrum becomes slightly stretched 2. Fundus region becomes relaxed (Vagovagal reflex) 3. Antrum becomes relaxed by an adrenergic effect 4. Inhibits motility of the abomasum

Answer 13

* Accessory glands related to the alimentary canal * Epithelial cells

Answer 14

* Its secretion is low * Increasing with age and then decreasing after 2-3 weeks

Answer 15

So as to not degrade the immunoglobulin content of the colostrum

Answer 16

* Increased enzyme secretion from the pancreas * Change in feedstuff components

Answer 17

Young require milk less and less in the transition from milk → solid food

Answer 18

Via: * Colostrum * Fetal circulation

Answer 19

When the species has a multi-layered placenta

Answer 20

* Group I * Group II * Group III

Answer 21

* Primates + Rabbits * Immunoglobulins (IgG) from the placenta reach the fetus * Mothers milk: * Low IgG * High IgA

Answer 22

* Rodents, dog, cat * Immunoglobulins from the _placenta and colostrum_

Answer 23

* Most domestic farm animals * IgG immunoglobulins from the colostrum * Immunoglobulins absorbed into the small intestine _only_ within the first 2 hours of life * Important that colostrum is supplied quickly after birth

Answer 24

* Specific cell structures * Transport through enterocytes to the lymphatic pathways

Answer 25

Lymph node

Answer 26

1. Mucosa 2. Submucosa 3. Stratum ciliare 4. Stratum longitudinale 5. Serosa 6. Smooth muscle layer

Answer 27

Submucosa (interstitial tissue)

Answer 28

Immune responses * Local cellular * Humoral

Answer 29

In the centre

Answer 30

Electric activity of gastrointestinal smooth muscle cells

Answer 31

Slow waves

Answer 32

Spike potential

Answer 33

Slow waves

Answer 34

Depolarisation

Answer 35

Resting potential

Answer 36

Hyperpolarisation

Answer 37

Tonus contraction of the GI smooth muscle cells

Answer 38

Basic electrical rhythm

Answer 39

Action potentials

Answer 40

3-12 waves per minute

Answer 41

Action potential of the gastrointestinal smooth muscle cells.

Answer 42

1. Resting potential becomes positive (due to slow waves) 2. Hyperpolarisation reaches threshold level (40mV) 3. Spike potential stimulation

Answer 43

...the higher the frequency of the "onbuilt" spikes

Answer 44

1-10 per second

Answer 45

Slow Ca²⁺ influx

Answer 46

Fast Na⁺ influx

Answer 47

Slow waves → Na⁺migration Spike potentials → Ca²⁺ migration

Answer 48

* Stretching of muscle cell * Acetylcholine * Parasympathomimetics * GI hormones

Answer 49

* Adrenaline * Noradrenaline * GI hormones

Answer 50

* GI Hormones * The permanent influx of Ca²⁺ with no change in membrane potential

Answer 51

* Motor function * Digestive function * Absorptive function

Answer 52

Local regulation ## Footnote *Influenced by the CNS*

Answer 53

Amygdala + Prefrontal cortex

Answer 54

Hypothalamus

Answer 55

Lateral nucleus

Answer 56

Ventromedial nucleus

Answer 57

Brain stem

Answer 58

The mechanics of food intake

Answer 59

* Stimulation → Aphagia * Lesion → Hyperphagia

Answer 60

Hunger complex directing food selection

Answer 61

* Nutritional regulatory signals (Slow regulation) * Effects arising from the gastrointestinal canal (Fast regulation)

Answer 62

* Glucostatic effect * Aminostatic effect * Volatile fatty acid effect

Answer 63

* Gastric and intestinal filling * Hormonal factors

Answer 64

* Temperature * Estrogens * Volemia * Density of population * Hierarchy * Night-day cycle

Answer 65

A large amount of indigestible polypropylene fibres

Answer 66

By changing the glucose uptake of the hypothalamic cells

Answer 67

* Serotonin * Cholecystokinin * Glucagon * Somatostatin * VIP * Neurotensin

Answer 68

* Hypothalamic neuropeptide Y * Opioid peptides * GABA * Dopamine

Answer 69

Stimulation/blocking of satiety centres

Answer 70

Decrease of food intake

Answer 71

Hunger decrease

Answer 72

Decreased food uptake

Answer 73

Adipocytes

Answer 74

Reduces food intake when enough reserves have already been formed

Answer 75

* Feed intake increases insulin secretion * Increasing LPL

Answer 76

Decreasing HSL

Answer 77

Activity of adipose cells * Triglyceride uptake increase * Fat synthesis increase * Adipocytes grow

Answer 78

Adipocyte growth

Answer 79

Adipocyte division

Answer 80

More leptin produced

Answer 81

* Leptin enters hypothalamus *(via blood)* * Increases local GLP-1 production

Answer 82

* Depression of the effect of feed uptake * NPY stimulation

Answer 83

* An increasing amount of adipose tissue signals back * Decreased feed intake

Answer 84

Insensitivity of the hypothalamus towards leptin

Answer 85

* Sympathetic nervous system * Parasympathetic nervous system ## Footnote *Extrinsic regulation*

Answer 86

Inhibition of the intestinal tract

Answer 87

* Hyperpolarises the smooth muscle * Decreases RMP of enteral plexus _Inhibits_ the passing of intestinal content

Answer 88

Enteral plexus

Answer 89

1. Hyperpolarisation of almost all enteral nerve cells 2. Increasing GI activities 3. Increasing motility and secretion

Answer 90

1. Excitation of the mucous membrane 2. Vigorous dilation of the intestines 3. Presence of specific substances

Answer 91

The enteral nervous system

Answer 92

Longitudinal muscle tract

Answer 93

Circular muscle tract

Answer 94

Plexus myentericus

Answer 95

Plexus submucosus

Answer 96

Intrinsic regulation

Answer 97

Acetylcholine

Answer 98

* Vasoactive intestinal peptide (VIP) * Opoid peptides

Answer 99

Plexus myentericus

Answer 100

* Increase in tone contraction * Raise the intensity and frequency of rhythmic contractions * Increase the spreading speed of the stimulus * Increase speed of peristaltic waves

Answer 101

Receptors and afferent fibres of the local reflex arcs

Answer 102

Regulation of peristaltic movements

Answer 103

* Local circulation * Secretion of GI juices * Absorption * Submucosa muscles defining the haustrum

Answer 104

* Gastric-colon reflex * Colon-gastric reflex * Colon-ileum reflex

Answer 105

* Reflexes influencing gastric functions * Nociceptive reflexes * Defecation reflex

Answer 106

* Autonomous (intrinsic) * Prevertebral sympathetic ganglia reflexes * Spinal cord and brain stem reflexes

Answer 107

Colon empties by the effect of the fullness of the stomach

Answer 108

Termination of: * Colon dilation * Gastric motor activity * Secretion

Answer 109

Fullness of the colon inhibits the emptying of the ileum towards the colon

Answer 110

Paresis of the GI tract

Answer 111

Vigorous contractions of the colon, rectum and abdominal muscles

Answer 112

The GI canal

Answer 113

Amine precursor uptake and decarboxylation (APUD) cells

Answer 114

Synthesis of peptides and amines that are transmitted by adequate stimulus

Answer 115

* Hormonal effect (mainly) * Local effects

Answer 116

* Substance-P * Somatostatin * Vasoactive intestinal peptide (VIP) * Endorphins

Answer 117

* Sympathetic nervous system * Parasympathetic nervous system * Enteral nervous system * APUD cells

Answer 118

* Paracrine * Endocrine * Gastrin * Secretin * CCK * Pancreatic polypeptide * GIP * Motilin * Enteroglucagon

Answer 119

* Gastrin (+CCK) * Stimulate (Gastrin) * Inhibit (CCK) * Secretin, VIP, GIP, Enteroglucagon * Inhibit * Stimulate

Answer 120

* Motility * Intestinal mucosa growth * Secrete: * Gastric Juices * Enzyme * Pancreatic juice

Answer 121

* Gastric emptying * Gastric motility

Answer 122

* Secretin * VIP * GIP * Enteroglucagon * Gastrin

Answer 123

* Passing movement * Mixing movement

Answer 124

1. Dilation of the intestines 2. Peristaltic contraction 3. Receptive relaxation

Answer 125

The content of the intestines

Answer 126

1. Bolus influences stretch receptors 2. Intestinal wall narrows orally 3. Intestinal wall dilates aborally

Answer 127

1. Serotoninergic interneurons excite 2. Cholinergic motor neurons excite 3. Circular muscle layer contracts before the bolus

Answer 128

* Circular muscles released from inhibition * Become inhibited towards progression * Dilation formed, pressing intestinal content aborally

Answer 129

* Segmentation of bolus * Causes mingling * Detaches the content

Answer 130

* Carried out by the muscle layer of their mucosa * Secures direct contact between epithelium and intestinal content

Answer 131

* Intestinal canal lets food in proper timing to each of the digesting sections * Mixing it properly with enzymes

Answer 132

* Quick ingestion * Great amounts

Answer 133

* Regular eating * Smaller portions

Answer 134

* Encircle rough food with their sensitive lips * Food is then bitten off with their corner teeth

Answer 135

* Pull rough food into their mouth with their tongue twisted round it * Press food between their lower incisor teeth and their upper edentate edge and tear

Answer 136

* Nuzzle up to the ground with their nose ring * Using their extended lower lip, place food inside mouth

Answer 137

Mechanical sensation

Answer 138

Brain Stem: Reflex inhibition

Answer 139

Relaxation of the chewing muscles

Answer 140

Mouth opens

Answer 141

Stretching of the stretch receptors

Answer 142

Brain stem: Stretch reflex

Answer 143

Contraction

Answer 144

Mechanical sensation

Answer 145

Reflex inhibition

Answer 146

Relaxation of the chewing muscles

Answer 147

Stretching of the stretch receptors

Answer 148

Stretch reflex

Answer 149

Contraction

Answer 150

* Initiated consensually by the cortex * Controls reflex motions

Answer 151

Afferent stimuli arising from the mechanoreceptors

Answer 152

* Radioscopy * Pressure conditions are examined with the balloon technique

Answer 153

1. Bolus: Oral cavity → Pharynx 2. Bolus: Pharynx → Oesophagus 3. Bolus is passed in the oesophagus

Answer 154

1. Tongue forms boluses 2. Placed between the tongue and hard palate

Answer 155

1. Soft palate rises 2. Dorsal opening of the nasopharynx closes 3. Breathing inhibited 4. Larynx rises, glottis closes

Answer 156

1. Pressure from tongue movements presses bolus into the pharynx 2. Bolus presses epiglottis backwards 3. Entrance to pharynx closes

Answer 157

1. The pressure in the pharynx increases 2. Pharyngoesophageal sphincter relaxes 3. Pharyngoesophageal sphincter contracts tightly 4. Bolus can no longer re-enter the pharynx

Answer 158

1. The pressure in the pharynx increases 2. Pharyngoesophageal sphincter relaxes 3. Pharyngoesophageal sphincter contracts tightly 4. The bolus can no longer re-enter the pharynx 5. Contraction of muscles in the oesophagus

Answer 159

1. Peristaltic wave pushes bolus toward the stomach 2. Pressure is larger in the sub-diaphragmatic region of the oesophagus than the stomach 3. Bolus arrives at the cardia 4. The tone of cardia decreases 5. Peristaltic wave passes 6. Cardia pressure doubles (Preventing regurgitation)

Answer 160

* Store ingested food until it's passed to the duodenum * Mixing food with gastric secretions to form the pulpy chyme * Chyme passed to ileum in a proper rhythm to secure digestion + absorption

Answer 161

Proximal stomach

Answer 162

Distal stomach

Answer 163

* Weakest = Fundus + Pylorus * Strongest = Antrum

Answer 164

* Doesn't increase * This is known as adaptive relaxation * Independent from gastric innervation * Accounted for by the law of laplace

Answer 165

* The increase of stomach content causes: * The proportional increase in the stretching of the wall

Answer 166

30 minutes

Answer 167

Vagus nerve

Answer 168

1. Repeated inhalation with a closed glottis 2. Thoracic section of oesophagus fills with stomach content 3. Up and down movements of stomach content 4. Due to abd. pressure, stomach content moves orally 5. Intrathoracic pressure repeatedly increases suddenly 6. Stomach content pushed to the oral cavity

Answer 169

1. Circular retraction (rolling mixing tonic contraction) 2. Moving food toward the antrum

Answer 170

Circular contraction in the middle of the corpus

Answer 171

1. Peristalsis starts from the corpus 2. Increases with the process of digestion 3. Contraction rings become tighter

Answer 172

* Chyme whirls through the contraction ring * Then back towards the oral part of the stomach * Mixing * Increase in tone of proximal part presses chyme aborally

Answer 173

* The more diluted the gastric content, the more is pressed through into the intestines * Dependent on pressure conditions * Strengthened by the pre-pyloric activity of antrum

Answer 174

* Plexus myentericus * Plexus submucosus

Answer 175

* Gastrin facilitates gastric motility * Facilitates: * Physiological gastrooesophageal tone * Amplitude and velocity of BER

Answer 176

* Decreases the motions of the stomach * Decreases tone of the pylorus * Increasing physicochemical effects in the duodenum

Answer 177

* The inhibitory effect on gastric motility * Caused by hormones * Caused by low pH/High lipid content of the duodenum

Answer 178

* Inhibitory effect of gastric motility * Produced in small intestines * Due to low pH in the small intestines * Opposite effect of gastrin

Answer 179

High lipid content

Answer 180

* Mingling movements * Processing movements

Answer 181

* Mingling action - degrading protein, lipid and carbohydrate * Absorption of nutritive materials * Forwarding content to the colon

Answer 182

* Increase the emulsification of content * Achieve increased degree of contact with nutritive material

Answer 183

* Segmental movements * Movements of the villi

Answer 184

* Muscle fibres pull the villi toward their basal part * The content of lymphatic and blood vessels are pumped in their drainage vessels * Responsible by the hormone villiquinine

Answer 185

* Slow peristalsis * Accession peristalsis

Answer 186

0.5-2 cm/sec

Answer 187

Prevention of regurgitation of colon contents

Answer 188

By gently contracting the ileocaecal sphincter

Answer 189

1. Chyme remains longer in the ileum 2. Greater absorption in the ileum

Answer 190

The filling of the stomach | (Gastroilial reflex)

Answer 191

Makes possible the quick passing of the piled up ilial conten towrd the colon * Secured by: * Enteral reflex * Effect of gastrin

Answer 192

* BER * Nervous control * Reflexes

Answer 193

Influenced by * Sympathetic splanchnic nerve (Inhibition) * Parasympathetic vagus nerve (Excitation)

Answer 194

17-18/minute

Answer 195

14-15/minute

Answer 196

Lowers gastric motility

Answer 197

* Stomach activity ↑ → Ileum activity ↑ * Therefore chyme passes through the ileocaecal sphincter speeds up

Answer 198

* Microbial digestion * Water + electrolyte reabsorption

Answer 199

1. Small intestine 2. Colon 3. Retrograde flow 4. Colon

Answer 200

* Some content of the colon returns to the caecum for microbial digestion * This slows down the flow intestinal content

Answer 201

1. Basal part of caecum 2. Cupola of caecum 3. Caecum presses part of the content to colon

Answer 202

1. Small intestine content pressed into the basal part and cupola of the caecum 2. Cupola becomes segregated, part of it's content is pressed into the colon

Answer 203

* Gas removal * Contraction of the basal caecum presses gasses into the cupola, dilating it * The liquid content of the cupola sinks * Gases enter the colon

Answer 204

* Constant contraction appearing in haustra * Creates continuous mixing which contracts during peristalsis * Inhibits the passing of intestinal content * Backward whirling is formed

Answer 205

Carnivores * Caused by aboral mass-peristalsis

Answer 206

Regulation of the storage and evacuation of the faeces

Answer 207

Hypothalmic and cortical control

Answer 208

* Thickening of the circular muscles in the rectum * Smooth muscle

Answer 209

* Striped-striated muscle * Circularly thickened part of the perineum

Answer 210

* Relaxation of the muscle wall of the rectum * Raise the tone of the inner sphincter * Relaxation of the inner sphincter * Increased peristalsis in the colon

Answer 211

Sacral segments

Answer 212

Motor fibres from the brain cortex

Answer 213

* The rectum is empty * Faeces are stored in the colon

Answer 214

15-20 Hgmm pressure is exerted on the wall of the rectum

Answer 215

* Faeces evacuation reflex * Receptors sensitive to rectal wall stretching * Afferent nerves travel to S₁-S₄

Answer 216

1. Increases contraction of the rectum + peristalsis 2. Relaxes tone of the inner sphincter 3. Longitudinal muscles contract 4. Rectum shortens 5. Faecal evacuation

Answer 217

1. Slow waves 2. Transmitters in the autonomic nervous system 3. Stimulation from pacemaker areas

Answer 218

* Arise from the circular muscle layer * Spread to the longitudinal fibres * (Stomach - ileum)

Answer 219

The slow waves of the colon

Answer 220

Both directions * Peristalsis * Antiperistalsis = Mixing

Answer 221

Dog and cat

Answer 222

* Secondary signal sequence produced by pacemaker cells * AP is retained for a long time * Generates an elongated and strong contraction of the circular muscle layer * Causes evacuation of the majority of colic content

Answer 223

* Digestive enzyme secretion * Mucin-rich fluid for chemical protection of mucosa * Secretions contribute to the optimal pH for digestive enzymes

Answer 224

3 pairs * Parotid * Mandibular * Sublingual

Answer 225

* Digestion - initiation and maintenance of chewing * Buffer capacity * Protection * Taste sensation * Mouth hygiene * Thermoregulation in carnivores

Answer 226

Serous and mucinous salivary glands

Answer 227

* Serous secretion * Mucinous secretion

Answer 228

Mucinous secretion only

Answer 229

Ptyalin (a-amylase)

Answer 230

1, 4 glycosidic bond of carbohydrates

Answer 231

Mucin * Protects the mouth * Forms the bolus

Answer 232

Saliva of the calf

Answer 233

Hydrolysis of triglycerides

Answer 234

Urea (For microbial homeostasis in the forestomachs)

Answer 235

In ruminants * Inhibits formation of gas bubbles * These wouldn't be emptied from the forestomachs by eructation

Answer 236

* Moisten * Mashing off bacteria * Antibodies * Bacteriolytic enzymes: Lysozyme

Answer 237

* Filtration * Secretion * Reabsorption * Double capillarisation

Answer 238

* Na⁺, Cl^-, Phosphate, bicarbonate transported to primary saliva by active secretion * Produced by diffusion + secretion * Isotonic with the plasma * Acini cells produce ptyalin mucin

Answer 239

1. Capillarisation occurs first around the tubules 2. Then around the acini Primary saliva flows through the tubules where secretory reabsorptive processes influence it's composition

Answer 240

* Electrolyte composition change of primary saliva * Na⁺ and Cl^- are partly absorbed * K⁺ and HCO₃^- is secreted * Partial water reabsorption * Hypotonic in monogastric animals

Answer 241

pH of saliva = pH of the blood (pH 7.4)

Answer 242

* Always isotonic * Slightly alkaline (8.2) * High in: HCO₃^- and HPO₄^2- * Buffer capacity caused by their secretion

Answer 243

A large amount of saliva is released

Answer 244

* Neural reflexes * (Hormonal effects)

Answer 245

* Chemical stimuli: * Taste buds * Mechanoreceptors of the olfactory epithelium

Answer 246

Activation of the salivary centre in the mesencephalon

Answer 247

* Parasympathetic (cholinergic) efferentation * Sympathetic (adrenergic) efferentation

Answer 248

Running inside the: * Collateral of the glossopharyngeal nerve (parotid) * Facial nerve (mandibular/ sublingual)

Answer 249

* Arising from the upper thoracic segments of the spinal cord * Then to the cranial cervical ganglion * Then to the glands through different plexuses

Answer 250

Regulation of salivary excretion

Answer 251

Acinar cell

Answer 252

Kallikrein

Answer 253

Bradykinin

Answer 254

Vasodilation

Answer 255

The IP3 activating system of the acini cells

Answer 256

Vasodilators * VIP * Bradykinin

Answer 257

Aldosterone conc. of blood

Answer 258

* Parasympathetic + sympathetic nervous systems

Answer 259

1. Parasympathetic fibres release acetylcholine 2. This binds to muscarine type Acetyl choline-receptors via IP3 system 3. This increases Ca²⁺ in the cells 4. Increases Na⁺ +Cl^- secretion toward the lumen 5. Higher enzyme secretion due to DAG + protein kinase C mechanism activation

Answer 260

* Sympathetic innervation initiates cAMP system * Small volume of saliva * Rich in mucin (high viscosity)

Answer 261

Aldosterone conc. in the blood

Answer 262

_Chief cells_ * Producing pepsinogen _Parietal cells_ * Producing HCl → gastric juice

Answer 263

Cobalamin (Vitamin B₁₂) absorption

Answer 264

* Aglandular region * Cardia * Fundus * Pylorus

Answer 265

Microbial digestion (ruminants)

Answer 266

Mucin production * Protection of the gastric mucosa

Answer 267

HCl + pepsinogen synthesis

Answer 268

* Mucin * Pepsinogen * Gastrin

Answer 269

Parietal cells

Answer 270

The blind sac

Answer 271

The diverticulum

Answer 272

Chief cells

Answer 273

HCl + Pepsinogen

Answer 274

HCO₃^- ions are transported to the interstitium during HCl secretion

Answer 275

The canaliculi

Answer 276

* H⁺/K⁺ pump moves H⁺ into the lumen and K⁺ into the cell * K⁺ flows out of the cell via K⁺ channel * Cl^- channel into the lumen

Answer 277

* Water dissociation * H₂O → OH^- + H⁺

Answer 278

OH^- + CO₂ → HCO₃ _Carbonic anhydrase_ enzyme

Answer 279

Anion-exchange pump ## Footnote *in the basal membrane*

Answer 280

In the granules of the chief cells

Answer 281

* Autocatalytically activates other pepsinogens * If pH= 1.8-3.8 hydrolysis of peptide bonds in: * Phe * Tyr * His

Answer 282

The proteins are denatured by HCl/heat

Answer 283

* Vagus nerve stimulation * Low blood sugar level (induced by insulin) * Histamine → HCl secretion → Pepsinogen release

Answer 284

* Epithelial cells of the gastric mucosa * Release mucin + bicarbonate on the luminal surface * pH of mucosa is therefore neutral

Answer 285

1. Cephalic phase 2. Gastric phase 3. Intestinal phase

Answer 286

* Indirect HCl production by parietal cells * Higher [HCl] in the stomach → Higher pepsinogen release

Answer 287

Neuronal + endocrine regulation 1. Acetylcholine (released from paras. vagus nerve) 2. Gastrin (released from G-cells 3. Histamine (produced by H-cells)

Answer 288

Proceeded through the nervous system 1. Food stimulates taste buds 2. Stimulus → CNS 3. Efferentation (via vagus) stimulating chief and parietal cells\* 4. Indirect stimulation of gastrin-producing cells\* 5. 3+ 4 cause gastric secretion ^{_{*These steps occur in parallel}}

Answer 289

1. Gastric stretch + chemoreceptors stimulated by bolus 2. Chief + parietal cells stimulated

Answer 290

1. G-cell activation → Gastrin secretion 2. Gastric secretion until pH=3

Answer 291

1. Gastrin stimulated H-cells → Histamine production 2. Parietal cells have an H-receptor → Increased HCl

Answer 292

Gastrin secretion of G-cells is blocked

Answer 293

Multiplied

Answer 294

H₂ receptors ## Footnote *Most antihistamines block H₁-receptors only*

Answer 295

H₂-receptor family ## Footnote *and not the widespread H₁ receptor family*

Answer 296

1. Acetylcholine released (acts as a mediator) 2. Acetylcholine binds to muscarine-type receptors on: 1. G-cells 2. H-cells 3. Parietal cells 3. The effect is mediated by the increase of IC Ca²⁺

Answer 297

1. Gastrin-synthesising G-cells are found in the pylorus 2. Gastrin is secreted into the blood upon: 1. Vagal effect 2. Chemical stimulus

Answer 298

* m-ACh receptor (Acetylcholine) * Gastrin receptor * H₂ type receptor

Answer 299

Substances entering the duodenum which induce gastrin secretion cause gastric juice secretion Same effect if jejunum is mechanically expanded

Answer 300

Motor and secretory activity is inhibited

Answer 301

1. Chemical + mechanical effects of the chyme induce secretion of: 1. Secretin 2. CCK 3. GIP 4. V|P 2. These effects inhibit HCl production + gastric motility

Answer 302

* Stomach mucosa produces intrinsic factor * This absorbs Vitamin B₁₂ into the ileum

Answer 303

* Anaemia develops * Caused by lack of absorption * Caused by absence of _transcorrin_

Answer 304

Synthesised by microorganisms

Answer 305

* Bound to a complex * Released in the stomach, binding to R-protein (salivary origin)

Answer 306

R-protein *Releasing vitamin B₁₂*

Answer 307

* Selectively bind B₁₂-IF complex taking them to the cell if: * pH \> 5.6 * Ca²⁺ are present

Answer 308

* Transcobalamin 1 (TC1) * Transcobalamin 2 (TC2) * Transcobalamin 3 (TC3)

Answer 309

Stores cobalamin in the plasma

Answer 310

Transfers cobalamin to the liver ## Footnote *where it is stored and excreted*

Answer 311

Passes cobalamin to almost all mitotically dividing cells

Answer 312

Pancreatic juice

Answer 313

* Neutralise contents of the duodenum and colon (Buffer) * Enzyme activity - digesting: * Proteins * Fats * Carbohydrates

Answer 314

Composition and amount chyme in the initial segment of the ileum

Answer 315

* Exocrine cells organised into acinar cells * Containing zymogen granules * Drainage tubules * Produce bicarbonate

Answer 316

* Produced by acinar cells * Isotonic * Contains pancreatic enzymes + proenzymes * Highly concentrated

Answer 317

1. Primary secretion 2. Ions secreted into the intralobular duct 3. HCO₃^- is secreted *influenced by secretin* 4. Ion pump secretes bicarbonate and takes up Cl^-

Answer 318

* Anion conc. independent of flow rate * Low enzyme conc. * High water + electrolyte production * Can be increased by stimulus

Answer 319

0.0015-0.02

Answer 320

Tubular cells

Answer 321

1. Na⁺/H⁺ pumps H⁺ toward interstitium 2. H⁺released from water decomposition 3. OH^- + CO₂ → HCO₃^- *with carbonic anhydrase* 4. HCO₃^-→ Lumen *via bicarbonate channel* 5. Na⁺+ K⁺ + H₂O enter lumen

Answer 322

* Activated in the lumen of the ileum * Activated by enzymatic cleavage in the duodenum * Initiated by enteropeptidase (brush border enzyme) * Produces trypsin from trypsinogen

Answer 323

* Hormones * Neurotransmitters

Answer 324

* Increased enzyme secretion * An increase of electrolytes + water

Answer 325

* Pancreatic juice decreased * Secretin + CCK release * Water-electrolyte + enzyme content altered

Answer 326

* Small volume of pancreatic juice released * High protein content

Answer 327

* Parasympathetic predominance * Gastrin appears in blood, secreted in the stomach * Increased enzyme secretion

Answer 328

* Stimulated by secretin * Presence of peptides/amino acids leads to enzyme rich secretion * Presence of fatty acids/monoglycerides leads to CCK secretion * Secretin + CCK amplify each others effect

Answer 329

* Bilirubin secretion * Carb, lipid and protein metabolism * Glycogen storage * Bile production (emulsifies lipids) * Parenchyma cells * Bile salts * Cholesterol * Phospholipids * Epithelial cells * Electrolytes

Answer 330

Oddi-sphincter ## Footnote *expressed well in carnivores*

Answer 331

Juice flows into the bile duct

Answer 332

Perisinusoid gap

Answer 333

Pericellular space

Answer 334

Junctional complex

Answer 335

Bile canaliculi

Answer 336

Fenestrated endothelial cells

Answer 337

Between endothelial cells and liver cells

Answer 338

Bile canaliculi

Answer 339

Cats + Dogs

Answer 340

Reabsorbing: * NaCl * Water * NaHCO₃

Answer 341

No gall bladder: * Continuous evacuation to the duodenum in high amounts

Answer 342

* Bile salts * Cholesterol * Lecithin * Bile pigment * Electrolytes

Answer 343

Formation of micelles containing bile salts

Answer 344

Detected in the border of micelles

Answer 345

Cholesterol

Answer 346

* Lecithin solubilises the solution * Extra solution may form crystals *(Pathological significance)*

Answer 347

Bile acids ## Footnote *these are synthesised from cholesterol*

Answer 348

* Cholic acid * Chenodeoxycholic acid

Answer 349

* Taurine * Glycine ## Footnote *in liver cells*

Answer 350

* Increases water solubility * Increasing emulsification efficiency

Answer 351

Bacteria in the intestines * *Forming secondary bile acids*

Answer 352

Cholic acid

Answer 353

Chenodeoxycholic acid

Answer 354

Bile salts *Made mainly Na⁺cations*

Answer 355

* Aggregated bile salts * Hydrophobic parts turn inward * Hydrophilic parts turn outward

Answer 356

Emulsify nutritional lipid in mixed micelles

Answer 357

Terminal ileum

Answer 358

Bacteria in the terminal ileum * *increasing lipid solubility* * *and increasing absorption with passive diffusion*

Answer 359

Portal vein *then taken up by hepatocytes*

Answer 360

Enterohepatic circle of bile acids

Answer 361

Cholesterol

Answer 362

**Liver** * Primary bile acids

Answer 363

Cholic acid

Answer 364

Chenodeoxycholic acid

Answer 365

7a-dehydroxylation

Answer 366

Deoxycholic acid

Answer 367

**Intestines** * Secondary bile acids

Answer 368

Lithocholic acid

Answer 369

Conjugation of bile acids

Answer 370

Because they dissociate at a slightly alkaline pH

Answer 371

Primary bile acid

Answer 372

Conjugation

Answer 373

Primary bile acid

Answer 374

Secondary bile acid

Answer 375

Bacterial dehydroxylation

Answer 376

**Passive** * From jejunum

Answer 377

**Active** * From the ileum

Answer 378

Repression mechanism ## Footnote *Bile salts transported to liver by the enterohepatic circle cause inhibition*

Answer 379

* Bile salt anions and accompanying Na+ attract water into the lumen * Osmotic activity therefore depends on bile acid conc.

Answer 380

Vagus nerve activity (Paras.)

Answer 381

Cholagogues

Answer 382

* Sympathetic nervous stimuli * VIP

Answer 383

1. Lipid metabolites → CCK release 2. CCK → Gall bladder contraction

Answer 384

When absorption of bile acids is temporarily ceased

Answer 385

During significant Na⁺, Cl^- and bicarbonate ion absorption

Answer 386

Diluted with a high level of bicarbonate

Answer 387

Buffering the intestinal fluid ## Footnote *similarly to pancreatic juice*

Answer 388

Cholecystokinin release from the mucosa * Results in gall bladder contraction + Oddi sphincter relaxation

Answer 389

* Inhibit synthesis of bile salts * Increase bile production (choleretic effect)

Answer 390

* Bile salts * Cholecystokinin * Secretin * Vagus nerve

Answer 391

1. Local mechanic effects 2. Parasympathetic stimulus (Vagus) 3. Hormones of the ileum (Secretin primarily)

Answer 392

Lieberkuhn crypts

Answer 393

Plasma filtrate * However bicarbonate conc. increases in contradiction to chloride with increasing distance from pylorus

Answer 394

Secretory Later becoming absorptive

Answer 395

* Cl^- * H₂O * Primary function - Dilute intestinal content * Secondary function - Buffer intestinal content

Answer 396

* Na⁺/K⁺/2Cl^- co-transporter in basolateral membrane * Na⁺→ cell→ lumen * K⁺ → Interstitium (*via K⁺ channel)* * Cl^-→ Lumen (via channel protein) * This is regulated by VIP receptor by increasing cAMP level

Answer 397

1. Cholera toxin maintains high cAMP conc. by stimulating adenylate-cyclase 2. Cl^- channel remains open 3. Cl^- and water get into the intestinal lumen

Answer 398

* Mechanical protection * Faeces formation

Answer 399

Buffering the volatile fatty acids

Answer 400

* Mucin * Bicarbonate ions

Answer 401

Hydrolysis

Answer 402

Villikinin

Answer 403

1. Length of the intestine 2. Folds 3. Villi 4. Brush border

Answer 404

* Passing on nutritive material to be transported to the capillaries + lymphatic vessels * Influenced by villikinin

Answer 405

1. Absorptive cylindrical epithelium 2. Mucinous cells 3. Enteroendocrine cells 4. Paneth's cells 5. Non-differentiated cylindrical epithelium

Answer 406

At the base of the crypt

Answer 407

Absorptive epithelial cell

Answer 408

Base of the crypts

Answer 409

The apex of the villus

Answer 410

Microbial fermentation

Answer 411

Ptyalin in the saliva cleaves the molecules

Answer 412

Two phases: 1. Alpha-amylase from the pancreatic juice reduces molecule size 2. Molecules are cleaved to its basic units in the brush border

Answer 413

* Duodenum * Upper jejunum

Answer 414

Co-transporter *Exchange of Na⁺ + glucose + galactose*

Answer 415

* Only the _straight chain_ of starch (1, 4 glycosidic bond) * This forms: * Maltose * Maltotriose * Dextran

Answer 416

* Swallowed boluses form layers * They are mixed with the gastric juice * Gastric juices denature salivary amylase

Answer 417

A biphasic process

Answer 418

Alpha-amylase hydrolyses starch to di- and oligosaccharides

Answer 419

* 'Brush-border digestion' * Small molecules bind to specific receptors → Enzymatic effects * Localised on the enterocyte surface * Generation of monosaccharides * Transport to blood

Answer 420

* GLUT-5 transporter needed * Found in both the: * Luminal membrane * Basolateral membrane

Answer 421

1. Luminal receptor takes up glucose/galactose *(Only after binding Na⁺)* 2. Conformational change 3. The two molecules are released intracellularly 4. Glucose/galactose binds to GLUT-2 5. Glucose/galactose enters intestinal space

Answer 422

* Fibrous carbohydrates can only be digested by microbial enzymes * Microbial fermentation produces volatile fatty acids (VFA) * 75% of energy is provided by VFAs

Answer 423

* An amount of soluble carbohydrate isn't digested and absorbed from the small intestines * This would be lost without microbial digestion (Caecum/colon) * Unabsorbed carbohydrates affect the osmotic pressure * Cause a loss of water if they weren't digested to VFAs

Answer 424

* Neutralisation of acidic products * Ensuring 'retention time' * Dilution of fermentation products * Acidic end-product absorption

Answer 425

* Neutralisation of acidic end products *(of digestion)* * Long retention time *(to allow fermentation)* * Proper volume of fluid in the large intestine * So that microbial processes aren't inhibited * Continuous absorption of the end products

Answer 426

* Bicarbonate buffer * Phosphate buffer

Answer 427

Bicarbonate buffer * From pancreatic juice and intestinal juice

Answer 428

Phosphate buffer

Answer 429

Mucosa of the large intestine is able to secrete HCO₃^-

Answer 430

Absorption of phosphate is weak

Answer 431

Luminal digestion * With proteolytic enzymes produced by stomach and pancreas

Answer 432

Small intestines

Answer 433

Brush border digestion

Answer 434

* Bound peptides to tri- and dipeptides * Free amino acids

Answer 435

Secondary active transport

Answer 436

1. Pepsinogen cleaved by HCl → Pepsin 2. Pepsin activates other pepsinogens 3. Pepsin hydrolyses peptide bonds of: 1. Phe 2. Tyr 3. His

Answer 437

1. Peptidase is produced in the duodenum and jejunum 2. Peptidases catabolise peptides → amino acids + oligopeptides 3. These enter the enterocyte cytoplasm *via brush border membrane* 4. Amino acids + dipeptides → portal circulation 5. Some amino acids enter the enterocytes via facilitated diffusion 6. The other amino acids enter the enterocytes via active transport

Answer 438

Trypsin + enteropeptidase

Answer 439

Become active enzymes in the intestines

Answer 440

Carbonyl bonds containing arginine or lysine

Answer 441

Cleaves carbonyl bonds formed by tyrosine or phenylalanine

Answer 442

* Amino peptidases * Dipeptidases * Dipeptidil-aminopeptidases

Answer 443

Cleaves amino acid from the n-terminal of the peptide

Answer 444

Cleaves dipeptidases to amino acids

Answer 445

Cleave dipeptides from the n-terminal of the peptides

Answer 446

Di- and tripeptides

Answer 447

* Facilitated diffusion (F) * Active transport (symport-S)

Answer 448

Secondary active transport (Na⁺ symport)

Answer 449

1. Neutral amino-acids 2. Phenylalanine, methionine 3. Proline, hydroxyproline

Answer 450

* Hydrophobic, neutral amino acids * Alkaline amino acids

Answer 451

1. Small hydrophilic amino-acids 2. Structure-dependent uptake of neutral amino acids ## Footnote *Facilitated transport plays a role in transport of neutral, hydrophobic amino acids*

Answer 452

* Protein → Amino acids *in the small intestine* * Enzymatic catabolism of protein + amino acid absorption isn't in monogastric herbivores

Answer 453

* Most lipids are triglycerides * Lipids digested by pancreatic lipase * Bile acids emulsify lipids with lecithin * Fatty acids and 2-monoglycerides form micelles * Digested products get to the brush border

Answer 454

1. Product enters enterocyte → Smooth ER 2. Fatty acids are re-esterified (resynthesis) 3. Triglycerides are synthesised, these absorb cholesterol and phospholipid 4. Apolipoproteins emerge onto the chylomicron surface 5. Further transport and metabolism 6. Chylomicrons exit the cell through exocytosis 7. These enter the lymphatic capillaries → to blood

Answer 455

* Lipids emptied later than other gastric content * Fat droplets appear * Inhibition of emulsion formation by high acidity * Duodenal lipid content inhibits gastric motility

Answer 456

1. Bile acids + lecithin emulsify lipids 2. The large surface area of lipids allow digestion *(due to pancreatic lipase)* 3. Lipase digestion 4. Triglycerides + phospholipids + cholesterol ester enter the intestinal canal

Answer 457

* Cleaves ester bonds in the 1st and 3rd position of the triglycerides * Forms: * 2 x fatty acids * 1x 2-monoglyceride molecule

Answer 458

Cleaves phospholipids in the presence of co-lipase

Answer 459

* Hydrolyses cholesterol ester * 2nd ester bond of triglycerides * Ester bonds of the other lipids *(nonspecifically)*

Answer 460

* Made from * Lipid catabolism products * Bile salts * Cholesterol * Phospholipids * Hydrophilic inside; Hydrophobic outside

Answer 461

Superficial microclimate is slightly acidic

Answer 462

They can dissolve through the lipid membrane → cytoplasm

Answer 463

At the end of the jejunum

Answer 464

* Re-synthesised lipids appearing in the cell * These lipids contain apolipoproteins * These allow the blood to transport hydrophobic substances * Enter the interstitial space * Leave by lymph

Answer 465

1. Chylomicrons modified by lipoprotein lipase in the capillaries 2. Free fatty acids released from the capillaries 3. Remainder chylomicrons are taken up by the liver

Answer 466

1. VLDL synthesis of liver 2. VLDL → Blood

Answer 467

Triglycerides + cholesterol

Answer 468

1. Binds to specific receptors 2. Digestion in the capillaries 3. Triglycerides lost to form 'VLDL remains' 4. These are reformed in the liver to generate LDL

Answer 469

Decreasing cholesterol content of non-hepatic cells

Answer 470

1. Triglycerides, cholesterol and lecithin → Smooth ER 2. Form small drops where: 1. Polar elements - Placed interphase 2. Apolar elements - Placed centrally 3. Apolipoproteins embedded onto small lipid drops 4. This forms the chylomicron

Answer 471

* C-type * B-48 type * E-type

Answer 472

* Activator of lipoprotein lipase in the capillary wall * Binds to the endothelial receptor of the capillary * Facilitates its activity

Answer 473

Involved in the structure and secretion of chylomicrons

Answer 474

Takes part in binding of chylomicron remains to liver-like receptors

Answer 475

* Rapid transport in the capillary * Bound with the help of C-type apolipoprotein * Free fatty acids are released * These are transported by albumin to target organs

Answer 476

* Fewer triglycerides * Increased cholesterol conc. * Size decreases

Answer 477

* Enters liver cells through E-type ligands * VLDL synthesis processed in hepatocytes * (Exogenous metabolism)

Answer 478

* Synthesised in hepatocytes * Contains a high amount of triglycerides * VLDL appearance → endogenous metabolism * Contains B-100-type apolipoproteins * Needed for VLDL secretion + structure

Answer 479

* VLDL binds to C-type receptors of capillaries * Goes through lipoprotein lipase catabolism * VLDL remnant binds to B-100 receptors of liver * Then retransformed to LDL complex

Answer 480

* Binds to B-100 receptors of the liver * LDL generated from it in the liver

Answer 481

* Most important cholesterol source of extrahepatic tissues * High concentration * Binds to cells through B-100 ligand * Special receptor needed

Answer 482

* Non-esterified cholesterol released from LDL enters the cells * Results in: * Decreased cholesterol synthesis of cells * Cholesterol stored as cholesterol-ester * LDL receptor expression decrease * Inhibiting further cholesterol uptake

Answer 483

* HDL fraction * Prevents over-accumulation of cholesterol * Nascen HDL (No cholesterol) is secreted by hepatocytes and enterocytes

Answer 484

* A-1 apolipoprotein * Activates LCAT enzyme * Cholesterol from extrahepatic cells + other lipoproteins

Answer 485

Reabsorption of digestive secretions

Answer 486

* Food = Hyperosmotic * Chyme entering the duodenum = Isosmotic

Answer 487

* Glucocorticoids * Aldosterone

Answer 488

* Influence: * Reabsorption from the small + large intestines

Answer 489

The colon only

Answer 490

* Small intestine water transport: Osmosis * Chyme becomes hyperosmotic due to digestion * Water enters into the lumen to dilute

Answer 491

Hyposmotic ## Footnote *Water is therefore reabsorbed*

Answer 492

* Enters lumen by secretions * It is entirely absorbed * Low IC Na⁺ level maintained by Na⁺/K⁺ exchange

Answer 493

1. Na⁺/Cl^- co-transport 2. Co-transport of Na⁺ with organic substances 3. Na⁺ absorbed it's own All of these are facilitated by aldosterone

Answer 494

* K⁺moves in/out of mucosa cells * Towards blood/intestinal lumen All of this is based on electrochemical difference

Answer 495

* In the upper region of small intestines * Influenced by proteins + amino acids * Lysine, arginine, citrate * Large amounts of fatty acid form complexes with Ca²⁺ * Inhibits its absorption

Answer 496

* Low Mg²⁺reabsorption in the small intestine * MgSO₄ causes hyperosmosis → Diarrhea * Absorption of Mg²⁺ facilitated by proteins * High Mg²⁺ obstructs water reabsorption

Answer 497

* Rapid passive diffusion in small intestine * Follows the movements of sodium ions

Answer 498

* Main source of bicarbonate = Pancreatic juice * Role: Buffer intestinal fluid * Absorption of bicarbonate: * Mucosa cells exchange H⁺ with Na⁺ absorption * H⁺ binds to bicarbonate in the lumen → Carbonic acid * Carbonic acid → H₂O + CO₂ (Enters the blood)

Answer 499

* Iron absorption differs depending on the animal's requirements * Iron is generally in water-insoluble complexes (blocking absorption) * These dissociate at low pH * This is why gastric HCl is important for iron absorption

Answer 500

1. Enterocytes secrete transferrin (Tf) (Transports iron) 2. Tf binds 2 Fe³⁺ ions 3. Brush border presents receptors to bind Tf-Fe complex 4. Cell takes the complex up by endocytosis 5. Receptor is released and re-expressed on cell surface 6. Iron is released on the basolateral side 7. Free transferrin molecules are secreted back to lumen

Answer 501

* Produced by enterocytes * Irreversibly binds iron transported into the cell * If iron can't exit the cell, it enters the faeces (Ferritin-trap) * This is determined by the amount of apoferritin (without iron) * Synthesis of apoferritin is stimulated by iron

Answer 502

Ruminal papillae

Answer 503

Reticulum foliae

Answer 504

Muscle bundles

Answer 505

Omasal foliae

Answer 506

Muscularis mucosae

Answer 507

Tunica muscularis

Answer 508

Keratinised epithelium ## Footnote *also containing transport channels*

Answer 509

1. Local vasodilation → Lower BP 2. Negative effective filtration pressure 3. Absorption or 1. Local vasoconstriction → Higher BP 2. Positive effective filtration pressure 3. Filtration

Answer 510

* Rumen: Ø * Reticulum: Partly * Omasum: Entirely

Answer 511

* Motility dependent on the vagus nerve * Parasympathetic drugs also have a similar effect * Large doses: Tonic spasm → relaxation *(inhibitory effect)*

Answer 512

* Decrease motility * From solar plexus * Small significance

Answer 513

* Termination of cyclic contractions in the: * Reticulum * Rumen * Omasum * Termination of: * Rumination * Eructation * Reticular groove mechanism

Answer 514

* Reticulum * Omasum * Abomasum

Answer 515

* Rumen * *Collateral nerves to the reticulum*

Answer 516

It's composition and density

Answer 517

* Hay/Straw 1. Enter dorsal sac 2. Bolus is broken down → Soaked for several days 3. Bolus density increases → Sinks to the ventral sac 4. Cranial sac → Omasum

Answer 518

1. Enter ventral sac → mixing 2. Reticulum → Omasum * Food enters reticulum in short time

Answer 519

In the first three compartments of the stomach

Answer 520

* Resting * Rumination * Eructation ## Footnote *These separate fermentation products based on density*

Answer 521

Contractile activity when the animal isn't eating nor ruminating

Answer 522

A belch * Caused by repeated contraction of the dorsal sac

Answer 523

Increased fermentation efficiency

Answer 524

6-8 times in 5 minutes

Answer 525

* Reticular-rumen cycle * Omasal contractions

Answer 526

Between rumination and eructation

Answer 527

* Starts with a double reticular (R2) contraction * Followed by contractions of ruminal parts

Answer 528

Introduced by a triple reticular contraction (R3)

Answer 529

* Starts in the reticulum * Spreads to the rest of the rumen

Answer 530

* Starting in the reticulum (2 contractions) * First is weak, second is strong * The second wave evacuates the reticulum

Answer 531

* Forms liquid flow * Less dense material returns to dorsal sac * Regulates flow from the reticulum → omasum * Allows regurgitation

Answer 532

1. Contraction of the cranial ruminal sac 2. Content enters the relaxed reticulum * Inhibits flow of ruminal content between: * Cranial sac * Caudal sac

Answer 533

1. Contraction of the caudodorsal sac 2. Content pushed ventrally (mixing) Gas bubble pushed cranially by contracting pillars

Answer 534

* Dorsal blind sac relaxes * Ventral + Caudoventral blind sac contract (mixing)

Answer 535

1. Contraction of ventral sac 2. Caudo-cranial contraction follows (mixing)

Answer 536

1. Caudal regions of the lumen (still contracted) 2. Dorsal sac contracts (Pushing gas bubble cranially) 3. Gas bubble leaves rumen through the cardia 4. Contraction of ventral sac

Answer 537

Rumination 1. Regurgitation contraction 2. Regurgitation 3. Reticulum content pushed to relaxed cardia 4. Two reticulum contractions (cycle I)

Answer 538

Cortical and hypothalamic effects

Answer 539

1. Bolus enters cardia-oesophagus 2. Oesophageal phase

Answer 540

1. Saliva swallowing 2. Inspiration with a closed glottis 3. Cardia opens reflexively 4. Regurgitation contraction

Answer 541

1. Bolus squeezed 2. Bolus separated and passed further by antiperistalsis 3. Bolus enters oral cavity

Answer 542

1. Remastication 2. Mixing with saliva 3. Swallowing saliva (2-3 times)

Answer 543

1. Swallowing the remasticated bolus 2. Bolus mixed in the rumen

Answer 544

Presence of gas in the dorsal sac

Answer 545

Pushes gas in the oesophagus to the pharynx

Answer 546

1. Nasopharyngeal sphincter closes 2. This forces part of the gas to the trachea 3. Some eructated gas enters the lung This may be secreted into the milk, giving an unusual taste

Answer 547

1. Small gas bubbles can't merge to form a big one 2. Therefore no foam is formed 3. Receptors in the cardia connect with liquid foam, and not gas 4. Eructation isn't initiated

Answer 548

1. Gas production in ruminoreticulum 2. Gas bubble in dorsal sac 3. The gas bubble moves to the cardia 4. Antiperistaltic gas transport in the oesophagus 5. Gas leaves rumen

Answer 549

* CO₂: 50% * CH₄: 25% * N₂: 10% * O₂: 5%

Answer 550

* Fermentation of carbohydrates * Deamination of amino acids

Answer 551

Reduction of CO₂

Answer 552

1. Stretch receptors of the dorsal sac stimulated by distension 2. Contraction of: Dorsal sac and ruminal pillars 3. Gas pressed cranially 4. Reticulum dilates

Answer 553

1. Oesophagus filled with gas 2. This is passed toward the pharynx by antiperistalsis

Answer 554

* The further breakdown of bolus * Absorb water and electrolytes

Answer 555

* Sorting gate * Blocks long, undigested fibred from entering the omasum

Answer 556

1. Dilation of omasal canal, sucking effect on bolus 2. Omasal canal contracts, pressing content between lamellae (omasal body relaxes) 3. Omasal body contracts, content pushed between lamellae toward the abomasum

Answer 557

10⁴-10⁶

Answer 558

10⁴-10⁵

Answer 559

The stability of the ruminoreticulum * By inhibiting the extended reproduction of certain ruminal bacteria

Answer 560

* Isotrichiadae

Answer 561

Ophryscolecidae

Answer 562

* *Bacteriodes succinigones* * *Ruminacola* * *Rumniatium* * *Lachnispira multiparus* * *Corinebactericeae*

Answer 563

Volatile fatty acids (VFA) * Acetic acid * Propionic acid * Butyric acid

Answer 564

* Branched fatty acids

Answer 565

Hydrolyses carbamide * Releasing ammonia

Answer 566

* Substrates produced absorbed into rumino-intestinal system * Produced ammonia is used in gastro-intestinal sections * Toxic substances are usually detoxicated

Answer 567

1. Enter abomasum → Small intestine 2. Bacterial proteins, amyloid and lipids broken down B-vitamin broken down and recycled

Answer 568

* Locally * The rest is absorbed in further sections in the GI tract

Answer 569

VFA absorption is increased

Answer 570

* Rapid release of lactic acid damages the mucosa layer * Acidosis is also induced * Absorption speed is faster at a low pH * Absorption is 10-20 times slower than VFA absorption

Answer 571

1. Absorbed in the rumen 2. Rumen → Liver 3. Synthesis of urea 4. Urea returns to rumen via blood Low pH decreases ammonia diffusion

Answer 572

* Only site of enzyme production * Fundus contains: * HCl * Pepsinogen * Renin

Answer 573

Converts casein of the milk to insoluble paracasein *in the presence of Ca²⁺*

Answer 574

1. Renin is inactivated 2. The milk can't curdle 3. Milk flows to the small intestine 4. Digestive disorders

Answer 575

* Volume and acidity of HCl is also decreased

Answer 576

The peristaltic wave forwarding the ingesta aborally gets closer to the opened pylorus in ruminants rather than monogastric

Answer 577

1. Peristaltic wave approaches pylorus, content reaches the duodenum 2. Pylorus contracts, a small amount of abomasal content reaches duodenum 3. Relaxation and closure of pylorus

Answer 578

* No teeth * No soft palate * No parotis * Unified oral-pharyngeal cavity * Gallinaceae - ptyalin

Answer 579

* High temp: Decreased intake * High energy/protein food content: Decreased intake

Answer 580

* Crop: * Secretes mucin and ptyalin * Stores/softens/crop milk production

Answer 581

* Feeds nestling birds * Rich in fat and protein (no carb)

Answer 582

* Secretion of gastric enzymes * Sometimes storage Gland types: * Mucosal → Mucin * Complex → HCl, pepsinogen, mucin

Answer 583

1. Muscular stomach → duodenum 2. Muscular stomach → aboral/oral passage 3. Glandular stomach → Aboral passage ## Footnote *Each lasting 30 seconds*

Answer 584

Carnivorous birds

Answer 585

* Long and thin villi * Longer in omnivorous birds * Duodenum contractions related to: * glandular/muscular stomach contractions

Answer 586

* Double lobed * Double bile duct * Left lobe opens: Into duodenum * Right lobe opens: Into gall bladder

Answer 587

* Chicken * Goose * Duck

Answer 588

* Double-lobed * 3 tubes enter the duodenum * Liver possesses 2 * Left → Duodenum * Right → Gall bladder

Answer 589

* Doubled * Microbial fermentation * Only volatile fatty acid absorption * Water absorption

Answer 590

* Mixing contraction * Less powerful but more frequent contractions * Propulsive contraction * More powerful less frequent

Answer 591

* Microbial digestion * Volatile fatty acid absorption only * Real faeces absorption (coprophagia) * Permanent antiperistalsis: * Water absorption from urea + Faeces

Digestion Flashcards

(675 cards)