Q&A - Cases 9-13 Flashcards
What effect does pericardial effusion have on the filling of the heart?
The increase in pericardial pressure will decrease the volume of ventricular fill- the function of the right side of the heart loses function
Assuming the foreign body coursed from the reticlum and penetrated the myocardium, how many serous layers did it pass through and what were they?
6 - visceral peritoneum, diaphragmatic peritoneum, diaphragmatic pleura, parietal pericardium, visceral pericardium
What is the course of food through the adult ruminant stomach?
rumen to reticulum to omasum to abomasum
What happens in the rumen and reticulum?
they act as a combined fermentation vat where VFAs are absorbed across the rumen wall
What occurs in the omasum?
absorption of VFAs, electrolytes and water occurs, and additional fermentation can occur there
What is the function of the abomasum?
it functions like the stomach of monogastrics
What does the parasympathetic innervation to the cranial portion fo the GI tract come from?
dorsal and ventral vagus
What does the sympathetic innervation for the cranial GI tract come from?
the greater splanchnic nerve
______ is pro-motility, _______ is inhibitory.
parasympathetic, sympathetic
What are the three most important volatile fatty acids in ruminant metabolism?
acetic acid, butyric acid, and propionic acid
What is the function of propionic acid in ruminant metabolism?
it is the only VFA that can be used for glucose production
What is the function of acetate in ruminant metabolism?
it is oxidized by the TCA cycle by muscle and synthesis for fat
What is the function of butyric acid in ruminant metabolism?
it is converted to ketone bodies
What two organs are responsible for gluconeogenesis in ruminants and what are their percentages?
85% in the liver and 15% in the renal cortex
A cow with hardware disease has elevated ketones in the urine, why?
the cow was nearing peak lactation and trigliceride mobilization is increased - FFA are oxidized into acetyl-CoA which condenses to form ketone bodies, the liver cannot convert them back into acetyl-Coa so they are released in the body
What are the three routes of excretion for ketone bodies?
urine, milk, and the breath
What consequences would rumen atony have on digestion?
free gas bloat - atonic fermentation will continue at a reduced rate but the gasses formed will not escape by eructation
What consequences would rumen hypermotility have on digestion?
stratification of the material within the rumen does not occur, the rumen contents are only churned into a frothy uniform fluid
How would you perform a pericardiocentesis in a ruminant?
the needle should be inserted cranial to the 6th rib on the left side - this place (the 5th intercostal space) is chosen because it is the most accessible spot to gain access the pericardial cavity because the cardiac notch is greater on this side and there is more contact with the thoracic cavity
What is the fluid and base defecit of a calf that weighs 85 pounds is 8% dehydrated, and has HCO3 of 15.8?
(BW)(normal bicarb -measured bicarb)(0.5)
38kg (30-15.8)(0.5) = 270 mmol
If we use isotonic solution of 1.3% bicarb then there is 156 mmol/L so 270/156 = 1.7 liters of 1.3% solution
How does milk pass from the esophagous to the duodenum in the calf?
cardia to reticular groove to omasal groove to abomasal groove to abomasum to pulorus to duodenum
True or False: The ruminoreticulum produces digestive enzymes
FALSE
How is milk digested?
Curd proteins and butter fat clot when exposed to renin and HCl of the abomasum. Other proteins and lactise remain in the fluid part which is called whey. The whey portion is transported into the duodenum and the curd remains in the abomasum. Over 12-18 hours the curd is broken down and moves into the duodenum
In what region of the gastrointestinal tract of the ruminant does water absorption occur?
the jejunum then ileum then large intestine
How is water absorbed?
water moves into the lumen via paracellular and transcellular transport, Na/K ATPase pumps sodium into the lateral intracellular spaces and this along with sugar, amino acids, and other osmotic element accumulation creating an osmotic gradient to increase water absorption
What is the normal histology of the tunica mucosa of the bovine small intestine?
lining epithelium, lamina propria, and lamina muscularis with projecting villi as part of the lamina propria
What is the epithelial lining oc the small intestine made up of?
simple columnar, goblet cells, and APUD cells
Where are the intestinal glands found and what are they composed of?
lamina propria - undifferentiated columnar cells, goblet cells, and paneth cells
What is the tela mucosa made up of and what does it contain?
dense connective tissuem submucosal glands
What is the tela muscularis made up of?
inner circular and outer longitudinal muscle layers
What is the tela serosa made up of?
loose connective tissue covered by mesothelial cells
What endocrine responses will compensate for dehydration?
increases of both the rening-angiotensin and anti-diurteic hormones
Why do animals with diarrhea develop metabolic acidosis and what electrolytes are commonly lost?
lose bicarbonate and tend to be in a negative energy balance promoting increased hydrogen ion production. Na and K are the other major electrolytes lost in large amounts
What are the three main mechanisms of intestinal mucosal repair?
villous contraction, epithelial restitution, and epithelial proliferation
What is the repair process of intestinal mucosal repair initiated by?
migration of epithelium from the crypts toward the tip of the villus across the denuded basement membrane
What is intestinal mucosal repair signaled by?
components of the extracellular matrix cia integral membrane proteins (integrins)
What is the role of villous contraction and epithelial restitution in mucosal repair?
it is to reduce the surface area of a denuded basement membrane to recover the epithelial barrier
Once the epithelial barrier is recovered in mucosal repair, what happens?
new enterocytes proliferate in the crypt epithelium and migrate onto the villus - the villous architechture is reestablished and the GI tract returns to normal function
Why is passive transfer of immunity by the ingestion of colostrum necessary to protect the calf from disease?
because they are born without antibodies and the only way they get it is from colostrum in the first 24 hours of life
What is colostrum?
the first milk of a lactating cow
What does colostum contain?
casein, fat, lactose, vitamin A, and E, growth factors, laxatives, and IgG
What are the major structural componenets of articular cartilage?
water (70%), collagen (50%), proteoglycans (35%), and glycoproteins (10%)
How do chondrocytes obtain nutrients and eliminate waste products?
by diffusion from the synovial fluid
What is the predominant type of collagen in the joint capsule, ligaments and menisci?
type I collagen
What is the predominant type of collagen in articular cartilage?
type II collagen
What is the function of type II collagen?
tensile strength of the articular cartilage
What is the function of synoviocytes?
they are phagocytic functions (type A) and synovial lining cells that synthesize hyaluronan and probably lubricin
What is the composition of synovial fluid?
ultrafiltrate of plasma plus hyaluronan
What is the function of hyaluronan?
it absorbs to the synovial lining and forms a steric barrier to small molecular exchange and decreases the resistance to movement of the soft tissues of the joint
What is the cellular composition of synovial fluid?
predominantly mononuclear cells, monocytes, and lymphocytes and a few polymorphonuclear cells
Where does synovial fluid get its viscosity?
due to hyaluronan content
What does the viscous nature of synovial fluid allow for?
to support transient shear stresses and to absorb some of the energy generated by movement
What are the two systems that require lubrication?
a soft tissue system that involves sliding of synovial membrane on itself or other tissues and a cartilage on cartilage system
What is the primary component of lubrication of the synovial membrane?
hyaluron
What are the 2 systems of cartilage on cartilage lubrication?
boundary lubrication and hydrostatic lubrication
When does boundary lubrication operate?
at minimal or low loads - primary component is lubricin
At higher loads, what is the joint lubricated by?
hydrostatic or squeeze film lubrication
What is the difference between nociception and pain?
nociception is the reaction of the nervous system to noxious stimuli while pain is the sensory and emotional experiencce associated with a noxious stimulus
What are the types of nerve receptors in joints?
type I, II, III, and IV
What are type I nerve receptors and where are they located?
low-threshold mechanoreceptors that are uniformly distributed in the joint capsule and monitor mechanical events in and around the joint
Where are type II nerve receptors located?
more deeply in the joint capsule than type I receptors
What is the function of type II receptors in joint capsules?
low-threshold, rapidly adapting mechanoreceptors that are activated when the joint undergoes movement and experiences tension; they help modulate arthrokinetic reflexes
Where are type III nerve receptors located?
neary bondy insertions of ligaments
What is the function of type III nerve receptors?
high-threshold, slowly adapting mechanoreceptors also capable of nociception - activation is expressed as inhibition of muscular activity, presumably as a protective mechanism to joint injury
Where are type IV nerve receptors located?
in the fibrous joint capsule, synovial membrane, fat pads, adventitia of capsular and subsynocial vasculature, bone, periostem, and intrinsic and extrinsic ligaments
What is the function of type IV nerve receptors?
high-threshold slowly adapting nociceptors that respond to thermal, chemical, and mechanical stimuli
What is the role of histamine?
it contracts airway smooth muscle, facilitates neurotransmission at airway autonomic ganglia, and sensitizes smooth muscle to the effects of acetylcholine released from the parasympathetic nerve fibers
What are the roles of leukotrienes?
contract peripheral airway smooth muscle, sensitize peripheral airways to acetylcholine release from the parasympathetic nervous system, and they can cause respiratory distress when administered to horses
What role do leukotrienes have on neutrophils?
they can be chemotactic to neutrophils and activate them
Describe the sequence of events and physiologic response of the lower respiratory system to the inhalation of irritating material such as dust.
when irritating materials such as dust are inhaled, tracheobronchial irritant receptors are stimulated, which in turn activates the parasympathetic nervous system supplying the airway smooth muscle via the vagus nerve; this causes the release of acetyl choline which binds to muscurinic receptors on airway smooth muscle, leading to muscle contraction and bronchoconstriction
Why do animals cough?
to clear foreign material from lower airways
What initiates coughing?
stimulation of irritant receptors located within and just below epithelium
What is the sequence of events that occurs when the cough reflex is initiated?
After inhalation, the glottis closes and the expiratory muscles contract, raising the pressure within the thorax and compressing the air within the lung. The glottis then opens and the compressed air is expelled with a high
Why does airway disease and exercise result in coughing?
Airway disease results in impaired mucociliary clearance with the accumulation of mucus. The inflammation also increases the sensitivity of the irritant receptors and epithelial damage exposes irritant receptors to the airway lumen, increasing their stimulation.
How does the mucociliary transport mechanism of the respiratory system work?
the conduction portion of the respiratory system is lined with ciliated pseudostratified columnar epithelium rich in mucus producing goblet cells - the mucus traps particulate matter and the cilia move the matter up the respiratory tract to the mouth where it is either swallowed or expectorated
Identify A.
macrophage
Identify B.
neutrophil
Identify C.
lymphocyte
What is the predominant resident effector cell of the pulmonary innate immune response?
alveolar macrophage
What receptors on the alveolar macrophage most likely mediate its response that initiates inflammation?
toll-like receptors
What cytokines do the alveolar macrophages release in the pulmonary innate immune response?
IL1, TNF, IL6, IL8
Why are wheezes originating in the bronchioles best heard on expiration?
turbulance occurs when the bronchioles are narrowest which is during expiration
What is the ventilation perfusion ratio?
the amount of alveolar ventilation in relation to pulmonary capillary blood flow
What is the effect of inflammatory airway disease on the ventilation perfusion ration and what is the result on PAO2?
it reduces alveolar ventilation in relation to perfusion, lowers the V/Q ratio resulting in hypoxemia and a low PAO2
What is the effect of low PAO2 on ventilation?
PaO2 must be really low before there is a significant response from the peripheral chemoreceptors
Which receptors are involved in detecting low PaO2 and where are they located?
peripheral chemoreceptors in the carotid and aortic bodies
How do you explain the prolonged expiration and heaves in horses with RAO?
diffuse airway obstruction results in increased pulmonary resistance and decreased dynamic compliance so the horse must use greater effort to maintain its tidal volume
What is the heave line caused by?
hypertrophy of the external abdominal oblique muscle
What is the affect of atropine on bronchioles and the gastrointestinal system?
dilation of the bronchioles and gastrointestinal ileus
How does clenbuterol help in relieving clinical signs of RAO?
it is a bronchodilator and anti-inflammatory drug
Predict what the ostrich’s acid/base balance would be immediately following surgery, but prior to anesthetic recovery. Why?
respiratory acidosis due to hypoventilation and build-up of CO2 as well as some metabolic acidosis
During which phase of respiration does a bird extract oxygen?
all phases, the bird has primarily unidirectional airflow - the countercurrent exchange of gases takes place continually
How many breathing cycles does it take for air to go through the avian respiratory system?
2- the bird must inhale and exhale twice
Can a bird vocalize when it is properly intubated?
yes - the syrinx is located near the carnia
What musculoskeletal/neurological problems can arise from egg binding?
limb paralysis/paresis related to the ischiatic nerve, abdominal tumors can also cause similar lameness
What urogenital problems can arise from egg binding?
renal disease related to pressure necrosis and ischemia as well as post renal obstruction
What gastrointestinal problems can arise from egg binding?
constipation
What veins can be used for blood draws on a bird?
external jugular, wing (cutaneous ulnar), and caudal tibial vein
Why would you pluck feathers instead of just cutting them?
to stimulate new feather growth
