Final Exam Flashcards
What are spinal nerves? How are spinal nerves connected to the spinal cord? What is located in each of these “connections”?
Spinal nerves originate in the spinal cord and are mixed nerves of sensory and motor neuron fibers that separate to spinal cord. They are connected to the spinal cord via dorsal and ventral roots.
Dorsal Root: afferent sensory axons of somatic and visceral sensory neurons extend here.
Ventral Root: somatic motor axons that extend from motor neuron cell bodies in ventral horn of grey matter in spinal cord.
How many cervical spinal nerves are there and where are they located?
There are 8 cervical spinal nerves. They are located cranial to each cervical vertebra (CSN 1 is cranial to C1). CSN 8 however is caudal to C7 and cranial to T1.
Cervical spinal nerves emerge through intervertebral foramina and branch into dorsal and ventral branches. What do each of these branches of nerves supply?
The dorsal branch of the cervical spinal nerves supplies the epaxial musculature. The ventral branch supplies the hypaxial musculature.
Where do thoracic and lumbar spinal nerves emerge in relation to their same numbered vertebra?
Caudal to their corresponding vertebra.
Where does the first pair of cervical spinal nerves emerge from?
The lateral vertebral foramina of the atlas.
Where do the 3 sacral spinal nerves emerge from?
The first 2 sacral spinal nerves emerge through the sacral foramina. The third sacral spinal nerve emerges between the intervertebral foramen between the sacrum and the first caudal vertebra.
Describe the ventral branches of cervical spinal nerve 2. Where does it emerge? What are the names of its ventral branches?
It emerges between the cleidomastoideus and the omotransversarius. It has 2 ventral branches: The Great Auricular Nerve and The Transverse Cervical Nerve.
What do the ventral branches of all cervical spinal nerves (except CSN 2) penetrate?
The omotransversarius.
What is another name for Cranial Nerve XI? Where does it pass? What muscle does it supply?
CN XI is also called the Accessory Nerve. Its dorsal branch crosses CSN1 to supply the trapezius muscle. It passes between the brachiocephalicus and the trapezius; dorsal to the omotransversarius.
What is the CNS composed of? What does the CNS do?
CNS relays and integrates information received from the periphery of the body. It is composed of the brain (Grey Matter: Nuclei, White Matter: Tracts) and spinal cord.
What is the PNS composed of? What does the PNS do?
PNS transmits sensory input to the CNS and relays motor output from the CNS to the periphery of the body. Composed of nerves and ganglia.
What are nuclei in the CNS? What do they make up?
Nuclei are collections of neuron cell bodies within the CNS. They make up the grey matter of the CNS
Pre-synaptic Autonomic (Sympathetic and Parasympathetic) cell bodies are located in nuclear regions of….?
PSNS = Brain SNS = Spinal Cord (Thoracolumbar) PSNS = Spinal Cord (Sacral)
What are tracts in regards to the CNS? What do they make up?
Tracts are formed by axonal processes of neurons that travel collectively together to common destination within the CNS. They make up the majority of white matter.
What are afferent sensory neurons? When are afferent sensory neurons bipolar and when are they unipolar?
Relay sensory input to the CNS.
Bipolar Neurons = special sensory systems (olfaction, vision, taste)
Unipolar Neurons = general sensory info from periphery to CNS
What are somatic afferent neurons vs. visceral afferent neurons?
Somatic Afferent Neurons = From skeletal muscle (voluntary) and proprioceptors.
Visceral Afferent Neurons = From involuntary tissue (cardia, smooth muscle, glands)
What are efferent motor neurons? What type of neurons are they? Where are their cell bodies located (be specific in regards to somatic, visceral (PSNS, SNS)?
Relay motor output from the CNS.
Multipolar neurons.
Cell bodies are located within the CNS in nuclei (grey matter):
Somatic: Cell bodies are in the ventral horn of spinal cord grey matter.
SNS pre-synaptic cell bodies: Lateral horn of spinal cord (thoracic and lumbar regions)
PSNS pre-synaptic cell bodies: Ventral horn/dorsal aspect of spinal cord (sacral region)
What are somatic efferent neurons vs. visceral efferent neurons? State whether or not each of these synapse before reaching their target tissue.
Somatic Efferent Neurons = to skeletal (voluntary) muscle. Do not synapse before reaching target tissue.
Visceral Efferent Neurons = to involuntary tissues (comprises ANS). Synapse onto a second neuron (pre-synaptic and post-synaptic)
What are interneurons? Where are they located? What do their axons travel via?
Interneurons integrate information between the CNS and PNS. They are located within the CNS (cell bodies are in nuclei in grey matter). Their axons travel via tracts.
What are ganglia in the PNS? What are nerves?
Ganglia are collections of neuronal cell bodies in the PNS.
Nerves are neuron processes of several neurons travelling together in the PNS
How many pairs of cranial nerves are there? Which 4 contain autonomic neurons & give their common names?
12 pairs. Pairs containing autonomic neurons: CN III: Oculomotor CN VII: Facial CN IX: Glossopharyngeal CN X: Vagus
Discuss the physiological and pharmacological differences between SNS vs. PSNS
SNS: Fight or Flight
Increase energy consumption to prepare for an action, adjust to stress
Adrenergic - release adrenaline
PSNS: Rest and Digest
Enhances activities that gain and conserve energy.
Cholinergic - release acetylcholine
Discuss the anatomical differences between SNS and PSNS.
SNS:
Thoracolumbar Division (Presynaptic Fibers exit T1-L5)
Presynaptic Fibers are SHORT and synapse with sympathetic chain of ganglia (paravertebral) located on either side of spinal cord.
PSNS:
Craniosacral Division (CN III, VII, IX, X) & S2-4
Pre-synaptic Fibers are LONG and synpase in ganglia located within organs they innervate.
Discuss the differences between the SNS and PSNS in regards to the synapse of pre-synaptic neurons onto post-synaptic neurons.
SNS:
Synapse of pre onto post neurons occurs at:
Paravertebral ganglia
Prevertebral ganglia (caudal to diaphragm: celiac, cranial and caudal mesenteric)
Cervicothoracic, middle cervical, cranial cervical ganglia Adrenal Medulla (not ganglion but pre-synaptic fibers can stimulate chromaffin cells resulting in hormonal release of adrenaline)
PSNS:
Synapse of pre onto post synaptic neurons at:
Cranial ganglia (visible in head)
Terminal ganglia (located within muscular walls of viscera (not visible)
Discuss the SNS innervation of sweat glands, cutaneous vessels and erector pili muscles.
Pre-ganglionic neuron cell body is in lateral horn of thoracolumbar spinal cord. Axon (pre-ganglionic fiber) passes back through a ramis communicans to a paravertebral ganglion.
Post-ganglionic neuron cell body is in a chain ganglion (paravertebral). Axon (post-ganglionic fiber) passes back through a ramus communicans to join a spinal nerve and is distributed to skin via cutaneous branch of a dorsal/ventral ramus branch of a spinal nerve.
Discuss the SNS innervation of cranial visceral structures.
Pre-ganglionic = lateral horn of upper thoracic spinal cord. Axon ascends via vagosympathetic trunk to cranial cervical region.
Post-ganglionic = cranial cervical ganglion.
Axon follows blood vessels to visceral structures of the head.
Discuss the SNS innervation of the thoracic viscera.
Pre-ganglionic = lateral horn of thoracic spinal cord.
Axon joins sympathetic chain/trunk via ramus communicans.
Post-ganglionic = cervicothoracic ganglion or middle cervical ganglion. Axon leaves in a cardiac nerve.
Discuss the SNS innervation of the abdominal viscera.
Pre-ganglionic = lateral horn of the lower thoracic or upper lumbar spinal cord. Axon joins the sympathetic chain via a ramus communicans and leaves in a sphanchnic nerve without synapsing onto a paravertebral ganglion. Post-ganglionic = pre-vertebral ganglion. Axon follows a blood vessel to an organ.
Discuss the SNS innervation of the adrenal medulla
Pre-ganglionic = lateral horn of the lower thoracic spinal cord. Axon joins the sympathetic chain via ramus communicans and leaves it in a thoracic (major or minor) splanchnic nerve, which passes over the lumbocostal arch of the diaphragm parallel to the sympathetic trunk to reach the adrenal gland.
Discuss the SNS innervation of the pelvic viscera.
Pre-ganglionic = lumbar spinal cord. Axon joins the lumbar sympathetic trunk via a communicating ramus from a lumbar spinal nerves and leaves the sympathetic trunk via a lumbar splanchnic nerve. Post-ganglionic = caudal mesenteric ganglion. Axon either follows a branch of the caudal mesenteric artery or runs in a R or L hypogastric nerve to the pelvic plexus and then to a pelvic viscus.
Discuss in general the PSNS innervation for cervical, thoracic and abdominal viscera.
Pre-ganglionic = Medulla. Axon leaves the brain in CN X (Vagus Nerve). Post-ganglionic = Terminal ganglion
Which Cranial Nerve is the Vagus Nerve? Which types of fibers does it contain?
CN X (Vagus Nerve) Contains both somatic and autonomic fibers.
When do somatic fibers leave the vagus nerve? When do parasympathetic fibers leave the vagus nerve?
They leave the vagus nerve just past the thoracic inlet (at the level of the middle cervical ganglion). The R and L vagus nerves leave the vagosympathetic trunk and release the R and L recurrent laryngeal nerves (containing the somatic fibers).
Parasympathetic fibers don’t leave! They continue on as the dorsal and ventral vagus nerve trunks to supply the abdominal viscera
Discuss the path travelled by the L recurrent laryngeal nerve and the R recurrent laryngeal nerve.
L recurrent laryngeal nerve leaves the L vagus nerve at the level of the middle cervical ganglion. It wraps around the ligamentum arteriosium and aortic arch and then continues back cranially.
R recurrent laryngeal nerve leaves the R vagus nerve at the level of the middle cervical ganglion and wraps around the R subclavian artery and then continues back cranially.
Describe the path of the vagus nerve.
R and L vagus nerves continue past the base of the heart and then each divides into dorsal and ventral branches. Ventral branches unite cranial to diaphragm to form the ventral vagal trunk (ventral to esophagus, caudal to heart). Dorsal branches unite cranial to diaphragm to form dorsal vagal trunk. Both dorsal and ventral vagal trunks travel with esophagus through the esophageal hiatus to abdominal cavity.
Also gives off celiac branch to celiacomesenteric plexus.
Discuss the PSNS innervation of pelvic viscera.
Pre-ganglionic = lateral region of sacral spinal cord. Axon courses in the ventral root of a sacral spinal nerve and joins the pelvic nerve. Post-ganglionic = terminal ganglion of pelvic viscera.
List the skeletal boundaries of the thorax.
Dorsal: Thoracic Vertebrae Lateral: Ribs and Costal Arches Ventral: Sternebrae and Costal Cartilages Cranial: Thoracic Inlet Caudal: Diaphragm
Discuss the muscular and tendinous parts of the diaphragm.
Muscular Parts: R and L costal parts, Sternal part, Lumbar part with L and R crura.
Tendinous Parts: Central tendon, L and R crural tendons (attach muscular crura to lumbar vertebral bodies)
What is the diaphragmatic line of pleural reflection?
Junction between the costal pleura and the diaphragmatic pleura. Cranial to this line is the costodiaphragmatic recess. Caudal to this line the diaphragm is directly attached to the thoracic wall.
What is the plica venae cavae?
Pleural covering from diaphragm. Envelopes caudal vena cava and right phrenic nerve.
What are the 4 openings through the diaphragm? What goes through each?
Lumbocostal Arch - area between the crura and the vertebrae (not a true opening), potential for herniation. Passage of splanchnic nerve.
Aortic Hiatus - passage of aorta, azygous vein, thoracic duct
Esophageal Hiatus - passage of esophagus, dorsal/ventral vagal trunks
Caval Foramen - passage of caudal vena cava
What is the costodiaphragmatic recess? Where is it located?
Junction where costal pleura reflects onto the surface of the diaphragm. Located between the basal border of the lung and the diaphragmatic line of reflection.
What is the lumbodiaphragmatic recess? Where is it located?
Region where the pleura extends ventrally from the caudal and dorsal thoracic wall to the crura of the diaphragm. Susceptible to herniation.
Which arteries supply the diaphragm? Which nerves supply the diaphragm?
Blood Supply: Musculophrenic artery (branch of internal thoracic artery) & Caudal phrenic artery.
Innervation: R and L phrenic nerves (originate from ventral branches of spinal nerves C5-C7; somatic)
What are serous membranes (aka tunica serosa)? What are they composed of?
Protective layers that secrete serous fluid to reduce friction of organs.
Composed of secretory epithelial layer (mesothelium) and a CT layer that provides blood vessels and nerves.
What are the 3 serous cavities within the thoracic cavity?
- Left pleural cavity
- Right pleural cavity
- Pericardial cavity
What is parietal pleura? What is visceral pleura?
Parietal pleura is pleura that lines the walls of the thoracic cavity and the mediastinum.
Visceral (pulmonary) pleura is pleura that is adhered to the surface of the lung.
What is the mediastinum?
Space between the 2 pleural sacs - where they meet medially. It is continuous with the cervical visceral space.
What are the 4 recesses of the pleura in the thoracic cavity? Describe where they are.
Pleural Cupula: located at the thoracic inlet where pleura reflects from the costal wall to the cranial mediastinum (dog L pleural cupula extends further cranially than R)
Costomediastinal Recess: at junction where the costal pleura reflects from the ventral thoracic wall and extends dorsally bilaterally
Costodiaphragmatic Recess: at junction where the costal pleura reflects onto the surface of the diaphragm, bilateral.
Mediastinal Recess: located between the R mediastinal pleura and the plica venae cavae (accessory lobe of R lung is in this recess)
What are the 3 components of the pericardium (pericardial cavity/sac)? Where does it develop?
Develops within the mediastinum.
3 components:
1. Parietal Pericardium: innermost layer of pericardial sac
2. Fibrous Pericardium: middle layer of pericardial sac (continues as the phrenicopericardial ligament in dog/cat or the sternopericardial ligament in LA)
3. Pericardial Mediastinal Pleura: outermost layer - formed by mediastinal pleura.
What is located within the mediastinum?
Trachea
Esophagus
Aorta (ascending, aortic arch, descending thoracic)
Lymphatic Structures (thoracic duct, sternal/mediastinal/tracheobronchial lymph nodes)
Thymus
Right azygous vein (R only in dog/horse, R and L in ox)
Paravertebral/sympathetic chain of ganglia (R and L)
R and L vagus nerves (dorsal/ventral branches/trunks)
Right recurrent laryngeal nerve
Left recurrent laryngeal nerve
R and L phrenic nerve
Pericardium and Heart
What are the components of the conducting portion of the respiratory system and the exhange portion?
Conducting Portion: Trachea (incomplete cartilaginous rings connected by tracheal annular ligaments, trachealis m. completes ring dorsally) Bronchial Tree: Principal bronchi (originate where trachea bifurcates - CARINA = partition between L and R principal bronchi at their origin from trachea), Lobar bronchi (branch from principal bronchi and supply lobes of lungs), Segmental bronchi (branch from lobar bronchi and supply bronchopulmonary segments), Bronchioles (branches of segmental bronchi that terminate as respiratory bronchioles) Exchange Portion: Respiratory Bronchioles Alveolar Ducts Alveolar Sacs Alveolus
Describe the differences in the lobes of the lungs between carnivores, ruminants and the horse.
Carnivores:
L lung: Divided cranial lobe, caudal lobe
R lung: Cranial lobe, middle lobe, caudal lobe, accessory lobe
Ruminants:
L lung: Divided cranial lobe, caudal lobe
R lung: Divided cranial lobe, middle lobe, caudal lobe, accessory lobe
Horse:
L lung: Cranial lobe, caudal lobe
R lung: Canial lobe, caudal lobe, accessory lobe
Horse has NO middle lobe
Where do you listen to the Left Lung and Right Lung in Canine, Ruminant and Horse?
Left Lung:
Canine: Between cranial and caudal parts of cranial lobe. Between 3 and 4 intercostal spaces.
Ruminant: Between 3 and 4 intercostal spaces.
Horse: Between 3 and 6 intercostal spaces
Right Lung:
Canine: Between ventral aspect of the cranial lobe and middle lobe. Within the 4 intercostal space, extends to 5
Ruminant: Spans 3 and 4 intercostal space.
Horse: Spans 3 and 4 intercostal space.
What is the hilus of the lung?
Region of lung that is perforated by vessels, nerves and bronchi
What is the functional blood supply of the lungs? What is the nutritional blood supply of the lungs?
Functional: Pulmonary arteries/veins
Nutritional: Bronchoesophageal artery, azygous vein
All species have deep fissures separating the lobes (external lobations) EXCEPT…?
The horse.
List the branches off of the L and R subclavian arteries and describe what they supply.
- Vertebral Artery - extends through transverse vertebral foramina to supply the brain
- Costocervical Trunk - supplies cranial intercostal spaces and muscles of the neck.
- Superficial Cervical Artery - supplies superficial structures of the neck
- Internal Thoracic Artery - Ventral intercostal arteries (intercostal spaces), musculophrenic artery (diaphragm), then continues as cranial epigastric artery
Describe the ductus arteriosus and the ligamentum arteriosum.
Ductus arteriosus - fetal structure that serves to shunt blood from the pulmonary trunk to the aorta bypassing pulmonary circulation to nonfunctional lungs.
Ligamentum arteriosum - fibrous remnant of ductus arteriosus in adult.
What happens if there is a vascular ring anomaly in the ligamentum arteriosum?
May constrict the esophagus. PRAA - Persistent Right Aortic Arch: R aortic arch forms, L regresses, esophagus gets trapped leading to megaesophagus.
What is epicardium, myocardium and endocardium?
Epicardium: Visceral pericardium
Myocardium: Muscle of the heart
Endocardium: Endothelial lining of the heart chamber
Describe the orientation of the heart within the thoracic cavity?
Positioned obliquely.
Base = craniodorsal
Apex = caudoventral
Lies at 45 degree angle in dog
What are the 4 main surfaces of the heart and where are they located?
Sternal Surface - cranioventral (RV, conus arteriosus)
Diaphragmatic Surface - caudodorsal (LV0)
Auricular Surface - both auricles in view, L side of animal
Atrial Surface - both atria in view
Where is the paraconal interventricular groove located on the heart? What is within it?
It is adjacent to the conus arteriosus of the RV. On the auricular surface of what would be the border between the 2 ventricles.
Great cardiac vein and the Left Coronary Artery are within the groove.
Where is the coronary groove of the heart located? What is within it?
Encircles the base of the heart. Located between atria and ventricles.
Coronary vessels are within the groove.
Where is the subsinuosal interventricular groove located? What is within it?
On caudodorsal surface.
Circumflex branch of left coronary artery is within groove (dog/ox)
Describe the nutritional blood supply to the heart itself.
R coronary artery: encircles R side of heart in coronary groove and extends to the caudodorsal surface. Continues to the subsinuosal interventricular groove as the subsinuosal interventricular branch (in horse/pig)
L coronary artery: branches into the paraconal interventricular branch and circumflex branch. In dog/ox, gives off the subsinuosal interventricular branch.
Great cardiac vein: begins in paraconal interventricular sulcus and returns blood supplied to heart by the left coronary artery. Expands as coronary sinus where it empties into right atrium.
Describe the anatomy of the auricle of the RA?
Crista Terminalis - boundary between auricle and sinus
Contains pectinate muscles
List the openings into/out of the RA and describe them.
Cranial vena cava - delivers blood from upper body
Caudal vena cava - delivers blood from lower body
Coronary sinus - delivers blood from heart muscle
Foramen ovale - between L and R atria that allows blood to bypass pulmonary cirulation (Closed after birth = Fossa Ovalis)
Right Atrioventricular Orifice - closed by AV valve during ventricular systole. (Parietal Cusp: originates from outer/marginal ventricular wall, Septal Cusp: originates from the interventricular septal wall)
Azygous vein - may empty directly into RA or into cranial vena cava
List the openings into/out of the LA and describe them.
Numerous pulmonary veins open into LA.
Left Atrioventricular Orifice - closed by AV valve during ventricular systole (Parietal Cusp, Septal Cusp)
List the important anatomical features of the RV and describe them.
Papillary muscles (Chordae tendineae - extend from cusps of AV valve to the papillary muscles) Trabeculae septomarginalis - from interventricular septal wall to the parietal wall of ventricle (part of conducting system) Conus arteriosus - cone shaped portion of RC that extends craniodorsally toward the pulmonary trunk Pulmonary Semilunar Valve - guards opening between RV and pulmonary trunk (Cusps: L, intermediate, R; Pulmonary Sinuses: within cup formed by each cusp)
List the important anatomical features of the LV and describe them.
Papillary muscles (Chordae tendineae) Trabeculae Septomarginalis Aortic Semilunar Valve (guards opening between teh LV and the aorta; cusps & nodules; Aortic sinuses: L aortic sinus (origin of L coronary artery), R aortic sinus (origin of R coronary artery) Interatrial Septum Interventricular Septum
For maximum intensity where would you listen for the Pulmonary Valve, Aortic Valve, L AV Valve and R AV Valve in the dog?
Left Side:
Pulmonary Valve: 3 IC space
Aortic Valve: 4 IC space
L AV Valve: 5 IC space
Right Side:
R AV Valve: 4 IC space
For maximum intensity where would you listen for the Pulmonary Valve, Aortic Valve, L AV Valve and R AV Valve in the horse?
Left Side:
Pulmonary Valve: 3 IC space below shoulder
Aortic Valve: 4 IC space
L AV Valve: 5 IC space
Right Side:
R AV Valve: 3/4 IC space
For maximum intensity where would you listen for the Pulmonary Valve, Aortic Valve, L AV Valve and R AV Valve in the ox?
Left Side:
Pulmonary Valve: 3 IC space below shoulder
Aortic Valve: upper 4 IC space
L AV Valve: lower 4 IC space
Right Side:
R AV Valve: 3/4 IC space
What happens in patent ductus arteriosus?
Blood is shunted from left to right (foramen ovale/fossa ovalis)
Causes congestive heart failure
Treatment: thoracotomy/occlusion catheter
What is pericardial effusion?
Accumulation of fluid in the pericardial sac. Many causes.
What is dilated cardiomyopathy?
Abnormality in myocardium that leads to decreases contractility.
Common in Dobermans.
Increase in L ventricular volume and diameter which leads to congestive heart failure.
What is hypertrophic cardiomyopathy?
Disease causing LV thickening. Most common cardiac disease for cats.
What is mitral valve deficiency?
Degenerative, progresses over time.
Common in King Charles Cavalier Spaniels.
Congenital.
What are the 9 regions of the abdomen?
Cranial Abdominal Region: Middle = Xiphoid, L and R Hypochondriac
Middle Abdominal Region: Middle = Umbilical, L and R Lateral Abdominal
Caudal Abdominal Region: Middle = Pubic, L and R inguinal
What are the Specific Names for Lumbar Spinal Nerves 1-4?
L1: Cranial Iliohypogastric
L2: Caudal Iliohypogastric
L3: Ilioinguinal
L4: Lateral Cutaneous Femoral
Which nerves innervate the abdominal wall?
Ventral Branches of Spinal Nerves T13-L5
Lateral cutaneous branches - located between skin and external abdominal oblique muscles
Medial branches - located between internal abdominal oblique and transversus abdominus msucles.
What is the blood supply for the 4 mains quadrants of the abdominal wall (Craniodorsal, Caudodorsal, Cranioventral, Caudoventral)?
Craniodorsal: Phrenicoabdominal Artery
Caudodorsal: Deep Circumflex Iliac Artery
Cranioventral: Cranial Epigastric Artery, Cranial Superficial Epigastric Artery
Caudoventral: Caudal Epigastric Artery, Caudal Superficial Epigastric Artery
What is the blood supply for the mammae?
Provided by cranial and caudal superficial epigastric arteries.
Internal Thoracic Artery –> cranial epigastric –> cranial superficial epigastric
External Pudendal –> Caudal superficial epigastric
What is located within the superficial inguinal ring?
vaginal process/tunic, genitofemoral nerve, external pudendal artery and vein, cremaster muscle
What is the rectus sheath?
The aponeuroses of the abdominal oblique muscles (internal and external) and the transversus absominis that form a sheath around the rectus abdominis
What is the inguinal canal?
A flattened canal between the deep and superficial inguinal rings
What is the superficial inguinal ring?
Opening in aponeurosis of external abdominal oblique. Located between the pelvis and abdominal tendons.
What is the deep inguinal ring?
Anatomical area defined by boundaries:
Cranial: Caudal border of internal abdominal oblique muscle
Medial: Rectus abdominis
Lateral and Caudal: Inguinal ligament.
What are the boundaries of the abdominal cavity?
Cranial: Diaphragm
Caudal: Pelvic Inlet
Dorsal: Lumbar Vertebrae and transverse processes, crura of diaphragm, sublumbar muscles
Lateral: Intrathoracic - ribs and costal arch, intercostal muscles. Extrathoracic - muscles of abdominal wall.
What are mesenteries? What are dorsal mesenteries vs. ventral mesenteries?
Double layer of peritoneum that connect the viscera to the dorsal and ventral body walls.
Dorsal mesenteries are extensions from the dorsal body wall.
Ventral mesenteries are extensions from the ventral body wall.
List the dorsal mesenteries of the abdominal cavity.
Greater omentum (gastrosplenic ligament; has superficial and deep leaves that enclose the omental bursa)
Mesoduodenum (Duodenocolic fold)
Mesojejunum
Mesoileum
Mesocolon
Mesorectum
Lateral ligaments of urinary bladder: contain remnants of the umbilical arteries = round ligaments
List the ventral mesenteries of the abdominal cavity.
Falciform ligament: contains remnants of umbilical vein = round ligament of liver
Lesser omentum
Median ligament of bladder: supports urachus of fetus
What is the tunica flava?
Large Animal: Deep yellow fascia of the trunk consisting of elastic tissue. Supports the heavy weight of the abdominal viscera. Thickest ventrally where fibers exchange with aponeurosis of external abdominal oblique muscle.
What is the prepubic tendon?
Large Animal: Broad plate formed by aponeuroses of the abominal muscles with the rectus abdominis muscle. Inserts on the pectin of the pubis. Susceptible to rupture in pregnant mare.
What can you access through the paralumbar fossa for bothe the horse and the ox?
Left Paralumbar Fossa (OX): Access to dorsal sac of rumen
Left Paralumbar Fossa (HORSE): Access to descending colon
Right Paralumbar Fossa (HORSE): Access to base of cecum
What are the borders of the paralumbar fossa in the ox? Horse?
Ox: Base: Along tips of lumbar transverse processes
Cranioventral Border: Last Rib
Caudoventral Border: Ridge formed by the part of the internal abdominal oblique muscle that extends from the tuber coxae to the ventral end of the last rib.
Horse: Not as pronounced, accessed cranial to tuber coxae
Describe the innervation of the large animal abdominal wall?
Innervated by the ventral branches of the last thoracic (T13/T18) and first 4 lumbar spinal nerves.
What are the names of T13/T18, L1-L4 spinal nerves in the large animal?
T13/T18 - costoabdominal
L1 - iliohypogastric (NO caudal and cranial)
L2 - ilioinguinal
L3/L4 - lateral cutaneous and genitofemoral
Where should you make a surgical incision on the stomach?
On the parietal surface (facing cranioventrally toward the liver). Can be made most easily without cutting into the omentum and blood supply.
List and describe the different internal regions of the stomach.
Cardia - surrounds esophageal entrance (cardiac sphincter)
Cardiac Notch - sharp angle formed at the junction of the cardia with the fundus
Fundus - blind region that extends to the L and dorsally to the cardia (first portion of stomach to fill with gas/ingesta)
Body - largest region of stomach. Communicates directly with the cardia and fundus. Lies to the L of midline with terminal portions extending across midline to blend with the pyloric region.
Pyloric Region - funnel shaped terminal portion of stomach; extends between body wall and duodenum. Last to fill with gas/ingesta (undergoes little distention).
Pyloric Antrum - continuous with the gastric body and is the first 2/3 of the pyloric region, funnels ingesta to pyloric canal
Pyloric Sphincter - between pyloric canal and duodenum
Describe the external features of the stomach.
Greater Curvature - faces caudoventrally and to the left. Attachment of greater omentum
Lesser Curvature - faces craniodorsally and to the right. Wraps around the papillary process of the liver. Attachment of lesser omentum.
Describe the blood supply of the stomach.
L and R Gastric Arteries - Supply Lesser Curvature
L and R Gastroepiploic Arteries - Supply Greater Curvature
Some branches of splenic artery supply portions of the fundus (less important)
Describe the innervation of the stomach.
Vagal Trunk (parasympathetic fibers) - Ventral Vagal Trunk: pylorus, liver Dorsal Vagal Trunk (MORE IMPORTANT): lesser curvature, ventral wall Celiomesenteric Plexus (Celiac Plexus - sympathetic fibers) reach stomach in nerves that travel alongside the celiac and cranial mesenteric arteries
Describe what Gastric Dilation-Volvulus is and what breeds it is common in.
Excessive dilation of the stomach (bloating) followed by twisting of the stomach around its longitudinal axis. Seen in large, deep-chested dogs.
Corrected by untwisting and a gastropexy
What are the 4 stomachs of a ruminant called? Which are the “forestomachs” and which is the “true stomach”?
Forestomachs: Reticulum, Rumen, Omasum
True Stomach: Abomasum
What is the reticular groove? What binds the reticular groove?
Reticular groove is the gutter that descends from the cardia over the right face of the reticulum towards to omasum and abomasum.
Located between L and R spiral fleshy lips.
Of the left and right reticular lips that form the reticular groove - describe their location as you move aborally.
The right lip becomes caudal and the left lip becomes cranial. Both descend to the reticulo-omasal orifice where the right lip overlaps the left.
Where is the cardia located in large animals?
At the junction of the rumen and the reticulum. Discharges into both chambers provided that the reticular lips are NOT closed.
What stimulates the closure of the reticular lips in the ruminant?
Suckling in the calf, ADH in the adult (dehydrated adult).
In adults, drugs like copper sulfate can help create this tube as well (to bypass the forestomachs) - only in large ruminants (will kill small ruminants).
What is unique about an unweaned ruminants reticular groove?
It will be converted into a closed tube and will form the gastric groove along with the omasal groove and abomasal groove. This will convey milk directly from the esophagus to the abomasum.
List the sequence of flow when the reticular groove is closed.
cardia–> reticular groove –> reticulo-omasal orifice –> omasal groove –> omasoabomasal orifice –> abomasal groove
List the sequence of flow when the reticular groove is open.
cardia –> reticular groove –> reticulum –> ruminoreticular orifice –> rumen –> ruminoreticular orifice –> reticulum –> regurgitation
What makes up the gastric groove?
Reticular groove, omasal groove and abomasal groove
Describe an important disease of the reticulum.
“Hardware Disease” - traumatic reticulitis occurs as the result of metal objects becoming lodged within the reticulum. Can pierce through the cranial aspect of the reticulum and diaphragm and may puncture the pericardium and/or heart. Place magnets to collect metal scraps.
What is the position of the reticulum?
Cranial position close to the liver, caudal to the diaphragm.
What is the appearance of the interior of the reticulum? What is the histology of this material?
Honeycomb like cells, subdivided by lower secondary crests all studded with conical papillae.
Histology: Keratinized stratified squamous epithelium.
What is the function of the reticulum?
Mechanical digestion, filtration of particulate matter.
Absorption of Volatile Fatty Acids, Electrolytes, Water.
From the reticulum: what materials pass into the omasum? what happens to the rest?
Fine materials will pass into the omasum while coarser material is lifted over the ruminoreticular fold and into the cranial sac of the rumen during ruminoreticular contraction. The coarse material can also be held in the reticulum.
Describe the blood supply and the innervation for the reticulum in the ruminant.
Blood Supply: Reticular Artery –> Left Ruminal Artery
Innervation: Dorsal Vagal Trunk
Where is the rumen located in the ruminant?
Projects to the left abdominal wall and fills the left half of the abdominal cavity. Extends from the diaphragm to the pelvic inlet. At times, the caudoventral part extends well over the median plane into the right half of the abdominal cavity.
Where is the parietal surface of the rumen? Where is the visceral surface?
Parietal surface: Left abdominal wall, diaphragm and ventral abdominal wall (floor of abdomen)
Visceral Surface: Faces to the right and is related chiefly to the intestines, the liver, the omasum, and the abomasum.
Where is the dorsal curvature of the rumen? Where is the ventral curvature of the rumen?
Dorsal Curvature: lies against the diaphragm and roof of the abdominal cavity
Ventral Curvature: follows the contour of the abdominal floor
Where does the spleen, superficial leaf and deep leaf of the greater omentum attach?
Spleen: attached to the craniodorsal aspect of the atrium of the rumen - located in the left hypochondriac region.
Superficial Leaf: attached to left longitudinal groove
Deep Leaf: attached to the right longitudinal groove
Which pillars (internal) or grooves (external) divide the rumen into dorsal and ventral sacs?
L and R longitudinal grooves connected by cranial and caudal groovers/pillars divide the rumen
What are the boundaries of the intraluminal orifice? What is it?
The R and L Longitudinal Pillars
Cranial and Caudal Pillars
It is the boundary between the dorsal and ventral ruminal sacs
What divides the caudal aspect of the rumen into caudodorsal and caudoventral blind sacs?
The Right Accessory Groove/Pillar
What is the Insula Ruminis?
An “island” located between the R longitudinal pillar and the R accessory pillar and found on the R side
Is there an insula ruminis on the left side?
No. The left accessory groove/pillar extends dorsally from the cranial groove/pillar. Does not extend to the caudal groove/pillar so it doesn’t form an insula.
What are the 4 sacs of the rumen and describe them.
Dorsal Sac: Atrium Ruminis - Cranial Ruminal Sac; cranial most compartment of the dorsal ruminal sac; located cranial and dorsal to the cranial pillar.
Caudodorsal Blind Sac: Caudal most compartment of the dorsal ruminal sac, not as prominent in small ruminants.
Ventral Sac: Ruminal Recess; cranial most compartment of the ventral ruminal sac; located caudal and ventral to the cranial pillar within omental bursa.
Caudoventral Blind Sac: Caudal most compartment of teh ventral ruminal sac.
What is the ruminoreticular fold?
It separates the reticulum from the atrium ruminis.
What is the function of the papillae in the rumen? What type of epithelium is this histologically?
Function of the papillae: increase surface area, protection, not for absorption (except volatile fatty acids, water, lactic acid, electrolytes)
Keratinized stratified squamous epithelium
What is the function of the rumen?
Digestion of complex carbohydrates. VFAs are produced as a result of ruminal fermentation and are absorbed across the ruminal epithelium.
What is the blood supply to the rumen? What is the innervation of the rumen?
Major blood supply: Right ruminal artery –> Right splenic artery
Minor blood supply: Left ruminal artery –> Left splenic artery
Innervation: Dorsal Vagal Trunk
Where does the right ruminal artery and right splenic artery run?
Courses in the R accessory groove through the caudal groove and gives off R and L, dorsal and ventral coronary arteries within the correspondent coronary grooves.
Where does the left ruminal artery and left splenic artery run?
Passes through the cranial groove from R to L and extends into the left accessory groove.
Where is the omasum located in the ruminant?
Located in the xiphoid and right hypochondriac regions, cranial to the pyloric part of the abomasum and covered by the lesser omentum.
Is the omasum larger or smaller than the reticulum in the ox/sheep/goat?
Ox: Larger than the reticulum
Sheep/Goat: Smaller than the reticulum
What does the omasum communicate with? What are the areas where these communications occur called?
Reticulum via reculo-omasal opening
Abomasum via omasoabomasal opening
What is the function of the omasum?
Mechanical digestion and absorption
The omasum has biphasic contractions - what does this mean and describe them?
2 phases:
Phase 1: Contractions and relaxations of the omasal canal bring ingesta from the reticulum and presses the content into the interlaminar recesses to expel fluids
Phase 2: Mass contraction of the omasum discharges solids into the abomasum
What is the blood supply and innervation of the omasum?
Blood supply: Left gastric artery –> Celiac Artery
Innervation: Dorsal Vagal Trunk
What is the internal appearance of the omasum?
Has many parallel folds of varying sizes (omasal laminae) with interlaminar recesses between them.
The laminae are studded with papillae.
Where is the abomasum located in the ruminant?
Fundus is located in the xiphoid region and protrudes into the left hypochondriac region. The body extends across the midline from the left to the right hypochondriac region.
Do the spiral folds on the internal aspect of the abomasum in the ruminant go away when the stomach is distended?
No.
What is the function of the abomasum?
Chemical digestion via release of enzymes from gastric glands.
The abomasum is lined with glandular mucosa - what are the 2 regions that it is divided into?
- Proper gastric glands
2. Pyloric gland region
What is the blood supply and innervation to the abomasum?
Blood supply: Lesser curvature: L and R gastric arteries
Greater curvature: L and R gastroepiploic arteries
Innervation: Ventral Vagal Trunk
In the ruminant where does the greater omentum (deep and superficial leaves) and the lesser omentum attach?
Greater Omentum: Attaches to abomasum (greater curvature) and reticulum. The superficial leaf: Attaches to L longitudinal groove of the rumen. The deep leaf: Attaches to the R longitudinal groove of the rumen.
Lesser Omentum: Attaches to abomasum (lesser curvature) and omasum. Connects the lesser curvature of the abomasum to the hilus of the liver.
What type of fermenters are horses?
Gut fermenters - fermentation occurs in the large colon.
Where is the stomach located in the horse?
Mainly in the left hypochondriac region.
What is special about the fundus in the horse’s stomach?
It is expanded as a blind sac, the saccus cecus and it extends dorsally from the cardia.
What are the 2 internal regions of the horse’s stomach and what are they divided by?
Glandular (columnar epithelium) and non-glandular (squamous epithelium) regions. They are separated by the Margo Plicatus (prominent line between the regions).
Where is it common to find bot fly larvae in the horse?
At the margo plicatus. Potentially also within the fundic and pyloric regions.
Where does the duodenum sit? What holds it in place?
Lies to right of midline, begins caudal to pyloric sphincter and ends at duodenojejunal flexure.
Held in place by short mesoduodenum.
List and describe the different parts of the duodenum from oral to aboral.
Cranial Portion - short and passes through the tight..
Cranial Duodenal Flexure where it is directed caudally.
Descending Duodenum - courses caudally adjacent to the right abdominal wall to the level of the pelvic inlet.
Caudal Duodenal Flexure - at level of tuber coxae where the duodenum makes a sharp bend and continues cranially (located caudal to the root of the mesentery).
Aschending Duodenum - continues cranially almost to the level of the greater curvature of the stomach
Duodenojejunal Flexure - where duodenum joins the jejunum
What is special about the duodenojejunal flexure in regards to blood supply and mesentery?
Mesentery becomes longer in jejunum and the blood supply changes from short straight vessels to arcades.
What are duodenal papillae?
Small elevations present in the initial part of the descending duodenum where ducts of the liver and pancreas open into the duodenum.
What are the 2 duodenal papillae and what does each provide openings for?
Major Duodenal Papilla: More cranial, provides openings for the Bile Duct and the Pancreatic Duct
Minor Duodenal Papilla: Slightly caudal to the major duodenal papilla, provides opening for the Accessory Pancreatic Duct
What is the blood supply for the duodenum?
Cranial pancreaticoduodenal –> gastroduodenal –> hepatic –> celiac
Caudal pancreaticoduodenal –> cranial mesenteric
What are the lymph nodes associated with the duodenum?
Hepatic ln.
Duodenal ln. (when present)
What is the root of the mesentery?
The cranial mesenteric artery along with the mesojejunum that surrounds the vessel.
Includes the cranial mesentery artery, intestinal lymphatics, mesenteric plexus
What is the blood supply and innervation for the jejunum? What lymph nodes are associated with the jejunum.
Jejunal arteries –> cranial mesenteric
Innervation: ventral vagal trunk
Lymph nodes: R and L mesenteric ln.
How do you determine the length of the ileum in the dog?
The antimesenteric ileal artery.
What is the orifice called in the dog where the ileum meets the large intestine?
The ileocolic orifice which is located near the cecocolic junction.
Ileocolic orifice is guarded by the ileocolic sphincter.
What is the blood supply and innervation for the ileum? What lymph nodes are associated with the ileum?
Blood Supply: Ileal artery; Antimesenteric ileal artery
Innervation: Mesenteric portion –> vagus n. and splanchnic n. by way of celiac and cranila mesenteric plexuses
Lymph Nodes: R and L mesenteric ln.; Colic ln.
Where does the jejunum lie in the ruminant?
Within the supraomental recess ventral to the spiral colon.
How does the blood supply compare in the ruminant for the duodenum, jejunum and ileum?
Duodenum - same as dog
Jejunum - same as dog, but with collateral branch of cranial mesenteric artery.
Ileum - same as dog, but with collateral branch.
Collateral branch of cranial mesenteric runs in jejunal mesentery along the last centrifugal gyrus and gives branches and rejoins the cranial mesenteric to supply distal jejunal a. and ileal a.
Which species have a gall bladder?
All but horse.
How the horse compensate without having a gall bladder?
Has a common bile duct that delivers bile to the duodenum directly from the liver. Opens through the major duodenal papilla along with the pancreatic duct.
What additional fold does the horse have that connects to the duodenum? Where does it go?
The duodenocolic fold. Extends from ascending duodenum and descending colon on the left side. Terminates at duodenojejunal junction.
What can be used to determine the length of the ileum in an equine and ruminant?
The ileocecal fold.
How does the blood supply of the equine duodenum, jejunum and ileum compare to the dog?
Duodenum: same as dog
Jejunum: Sam as dog
Ilum: same as dog except no antimesenteric ileal branch of cecal branch
What is the cecum? Where is it located?
Blind ended pouch at the junction of the small and large intestines. The most proximal part of the colon. Located to the right of the midline in the cranial abdomen close to dorsal body wall, dorsal to jejunal loops.
In the dog, which lacks a true ileocecal fold, what is the attachment of the cecum to the ileum called?
The peritoneal visceral ligament.
What is the blood supply to the cecum?
Cecal artery –> ileocolic common trunk –> cranial mesenteric artery.
Where is the colon located?
Positioned along the dorsal body wall. Begins in the right dorsal cranial abdominal region where is crosses from right to left cranial to the root of the mesentery and then it passes caudally in the left dorsal abdominal region to the rectum.
What are the different parts of the canine colon (from oral to aboral) and describe them?
Ascending Colon: initial shortest part of colon that extends from the ileocecal junction to the right colic flexure.
Right Colic Flexure: angle where the ascending colon becomes continuous with the transverse colon.
Transverse Colon: extends from the right colic flexure to the left colic flexure; cranial to the root of the mesentery, just caudal to the greater curvature of the stomach.
Left Colic Flexure: angle where the transverse colon becomes continuous with the descending colon.
Descending colon: longest portion of colon; continues in a straight course parallel to the left abdominal wall to the pelvic inlet where it continues as the rectum
What is the blood supply for the ascending colon?
Colic branch of the ileocolic artery –> ileocolic common trunk
What is the blood supply for the right colic flexure?
R colic artery –> ileocolic common trunk
What is the blood supply for the transverse colon?
R colic artery –> ileocolic common trunk
Middle Colic artery -> ileocolic common trunk
What sit eh blood supply for the descending colon?
Middle colic artery –> ileocolic common trunk
L colic artery –> caudal mesenteric artery
Which lymph node drains the cecum? Which lymph node drains the ascending and transverse colon?
Cecal ln. drains cecum
Colic ln. drains ascending and transverse colon
Describe the ascending colon in the ruminant.
Proximal Loop
Spiral Colon: Centripetal gyri, Central flexure, Centrifugal gyri
Distal Loop
What is the difference between the small ruminant and the large ruminant in regards to their centrifugal gyrus and jejunal lymph nodes?
Small Ruminant: Last centrifugal gyrus lies adjacent to the jejunum - lymph nodes better seen from other side
Large Ruminant: Jejunal ln. lies adjacent to jejunum.
What is the blood supply for the ascending colon in the ruminant?
Proximal part (proximal loop, centripetal gyri) = colic br. --> ileocolic artery Distal part (centrifugal gyri, distal loop) --> right colic artery
List the parts of the equine large intestine from oral to aboral and state the number of Taeniae Coli or “Bands”.
Cecum: 4 Right Ventral Colon: 4 Ventral Diaphragmatic Flexure: 4 Left Ventral Colon: 4 Pelvic Flexure: 1 Left Dorsal Colon: 1 Dorsal Diaphragmatic Flexure: 3 Right Dorsal Colon: 3 Transverse Colon: 2 Descending Colon: 2
What are taeniae coli?
“Bands” or longitudinal thickenings of the tunica muscularis
Which aspects of the cecum are mobile, which are not mobile? For those parts that are not mobile, what holds them in place?
Base: not mobile, attached to body wall
Body: projects onto R abdominal wall, held in place by cecocolic fold.
Apex: Most mobile - extends cranially along the floor of the abdomen and lies between the R and L ventral colon.
What is the blood supply for the cecum in the equine?
Lateral and medial cecal arteries –> ileocolic artery
What are the 2 parts of the equine large intestine where there is constriction and common impaction?
At Left Dorsal Colon (significantly smaller than ventral colon), Where Right Dorsal Colon transitions into Transverse Colon
What is the nephrosplenic ligament? What is a common ailment of the horse in regards to this ligament?
Ligament that extends between the L kidney and spleen. Common site of entrapment.
What is the function of the liver?
Has exocrine and endocrine functions. Plays a role in metabolism of food and detoxifies numerous substances.
What are the 6 lobes of the liver.
Right Lateral Lobe - has small renal impression for cranial pole of right kidney
Right Medial Lobe
Quadrate Lobe
Left Medial Lobe
Left Lateral Lobe
Caudate Lobe: Papillary process (nestled in lesser curvature of stomach, enveloped by lesser omentum); Caudate Process (Larger part of caudate lobe, projects caudally)
Where is the gall bladder located in regards to the lobes of the liver?
Located between the quadrate lobe and the right medial lobe.
Where is the round ligament of the liver located?
Located in the free edge of the falciform ligament lying between the quadrate lobe and the left medial lobe. It is the former umbilical vein.
What is the porta of the liver? Where is it located?
Located between the caudate and papillary processes of the caudate lobe. Similar to the hilus of the lung, transmits hepatic vessels, nerves, lymphatics and the bile duct to/from the liver.
What is the coronary ligament of the liver?
On the diaphragmatic surface where the peritoneum reflects onto the surface of the diaphragm –> crown on top of the liver
What are the triangular ligaments of the liver?
Right and Left. They are thin, transparent folds of peritoneum that extend from the left and right crura of the diaphragm to the left and right lateral lobes of the liver.
What is the falciform ligament of the liver?
The remnant of the ventral mesentery that extends between the liver and the umbilicus in the ventral body wall. In its free edge may be the round ligament of the liver (former umbilical vein)
The attachment of the lesser omentum (from the lesser curvature of the stomach) to the porta of the liver is called the….?
Hepatoduodenal ligament.
What is the hepatorenal ligament?
A delicate, double layer of peritoneum that extends between the liver and the right kidney.
What is the blood supply, innervation and lymph nodes for the liver?
Blood supply: Hepatic artery –> branch of celiac a.
Innervation: Sympathetic nerve fibers from the periarterial plexuses, Parasympathetic nerve fibers from vagal trunk
Lymph Nodes: Efferent vessels pass to hepatic nodes around hepatic porta, lymph drains into visceral cysterna chyli, some lymph travels to the accessory hepatic and caudal mediastinal lymph nodes on the caudal vena cava
How does the equine liver and ruminant liver differ from the canine?
Equine: On R side of midline, less lobulated, no gallbladder, no papillary process.
Ruminant: On R side of midline, fused lobes
What is the function of the gallbladder?
Stores bile produced by the hepatic cells in the liver. Biliary passages transport the bile either from the liver to the gallbladder or from the gallbladder to the duodenum.
Describe the cystic duct, hepatic ducts and common bile duct of the gallbladder?
Cystic duct: arises at neck of gall bladder, carries bile to duodenum, receives hepatic ducts from liver.
Hepatic Ducts: receive bile from liver - take it to cystic duct
Common bile duct: continuation of the cystic duct following the entrance of the last hepatic duct, opens into major duodenal papilla
What is the function of the pancreas?
Both an exocrine and an endocrine gland.
Describe the lobes of the pancreas and their locations.
Body: located at pylorus
R lobe: thinner, embedded in mesoduodenum of the descending duodenum
L lobe: in deep layer of greater omentum and caudal to stomach and liver but cranial to transverse colon.
What are the 2 ducts of the pancreas?
Pancreatic Duct - more cranial, smaller, opens into cranial part of the descending duodenum on the major duodenal papilla
Accessory Pancreatic Duct - located more caudally, major conduit of pancreas, opens onto minor duodenal papilla
What is the blood supply of the pancreas?
Pancreatic branches of the cranial and caudal pancreaticoduodenal arteries
Pancreatic branch of Splenic artery
What is the innervation and lymph nodes of the pancreas?
Innervation: Most sympathetic fibers come from the celiac plexus and reach organ by pancreatic branches of the cranial pancreaticoduodenal and celiac aa.
Vagus n.
Lymph nodes: drain in duodenal ln. (if not present into hepatic, splenic and mesenteric ln.)
What is the gastrosplenic ligament?
The specific portion of the greater omentum that extends between the stomach and the spleen.
Where is the visceral surface, parietal surface and hilus of the spleen?
Visceral Surface: faces the greater curvature of the stomach
Parietal Surface: faces the diaphragm and the left lateral abdominal wall.
Hilus - where the vessels enter/leave the organ
What is the blood supply and innervation for the spleen?
Blood supply: left gastroepiploic artery and vein –> splenic artery and vein –> celiac artery
Innervation: Sympathetic
What are the species differences in the splenic artery for ruminants, horses/pigs, cats/dogs?
Ruminants: passes through spleen without dividing
Horses/Pigs: Branches regularly as it passes through the spleen
Cats/Dogs: Branches before it reaches the spleen
What are the species differences (Carnivores, Ruminants, Horse, Pig) in regards to the shape of the spleen?
Carnivores: elongated, dumb-bell shaped
Ruminants: Flat and oblong
Horse: Lies under the last 3 ribs, dorsally it is broad, but narrows as it extends cranially and ventrally. Can feel on rectal palpation the smooth sharp border along body wall
Pig: Elongated and strap-like under last few ribs.
Where is the spleen located?
Largely on L side of midline.
Where are the kidneys located?
Lie against the dorsal body wall in the upper lumbar region.
L kidney: positioned slightly lower in relation to the R kidney. It is in contact with the dorsal pole of the spleen.
R kidney: Cranial pole nestles within a renal fossa of the caudate process of the caudate lobe of the liver and the right lateral lobe of the liver. Caudal vena cava is located at its medial border.
What structures enter/leave each kidney hilus?
Renal artery and vein
Ureter
Kidneys are retroperitoneal which means what?
Covered only on one surface by the peritoneum
What is unique about the feline’s kidneys?
They have a pendulous/floating R kidney
How do you locate the bladder?
Follow the median ligament tot its ventral surface.
What do the lateral ligaments of the bladder contain?
The remnants of the umbilical arteries (round ligaments of the bladder) in their free edges. The ducus deferens in the male wrap around the lateral ligaments.
What are the 3 broad ligaments of the uterus?
Mesometrium
Mesovarium
Mesoalpinx
Where does the mesoductus deferens go?
Mesentery that attaches the ductus deferens to the body wall, proximally and to the mesorchium of the vaginal tunic.
What is the vaginal ring?
Region where an extension of peritoneum protrudes through the deep inguinal ring.
What is the double layer of peritoneum called that exits the abdomen and extends through the inguinal canal in the male and female?
Male: Vaginal Tunic
Female: Vaginal Process
What lies on the left side of the ruminant abdomen?
Reticulum lies mainly on L side
Rumen
Spleen
Lesser Omentum
What lies on the right side of the ruminant abdomen?
Bulk of intestines are located within the supraomental recess bounded by greater omentum on the R
Liver - lies mostly on R side over reticulum, duodenum, and pancreas
Rumen
How do you access the rumen in the ruminant?
Access via left paralumbar fossa
What is located on the left side of the equine abdomen?
Stomach Liver Spleen Descending colon Jejunum Left Dorsal Colon Left Ventral Colon
What is located in the left ventral quadrant of the equine abdomen?
Left Ventral Colon
Left Dorsal Colon
What is located in the left dorsal quadrant of the equine abdomen?
Jejunum
Descending small colon
What is located on the right side of the equine abdomen?
Liver R Kidney Descending Duodenum Cecum - located between the tuber coxae and the 15th rib, lies between the ventral parts of the ascending colon Right Ventral Colon Right Dorsal Colon
