What does the CNS include?
Brain and spinal cord
What does the PNS include?
Spinal nerves, cranial nerves, and ganglia
what is the highest functional subdivision of the brain?
What are the functions of the cerebrum?
Consciousness and cognitive function.
Receive ALL sensory info and reaches conscious perception, makes decision and initiates/directs response
What are the regions of the cerebrum and their function?
Occipital = Visual
Temporal = Auditory
Pyriforn = Olfactory
Frontoparietal = Somatosensory
What are clinical signs of cerebral cortex disease?
Disturbances of consciousness
Paresis (weakness) of voluntary movement
Disturbances of sensory function
Disturbances of perception and seizures
What are the functions of the cerebellum?
1. Adjusts activity in the motor centers of the brain, insures rate, range, and force of voluntary movement.
2. Receives info from the cerebral cortex, vestibular system, spinal cord and reticular formation.
3. Influences posture and locomotion
What are clinical signs of disease within the cerebellum?
Ataxia (uncoordinated movements)
Spasticity (Increase in muscle tone)
Dysmetria ( Inability to regulate rate, range, and force of movements)
Fine Head tremor that worsens with initiation of voluntary head movements
What are the functions of the spinal cord?
1. Provide sensory input and output
2. Receive sensory info from peripheral nerves o dorsal roots
3. Reflex control patterns of movements and glandular activity
4. Interneurons receive and integrate afferent input to adjust local muscle
5. Transmit info to and from the brain
What are gyri?
What are sulci?
Depressions next to gyrus
What is the pia mater?
Thin layer of connective tissue covering the cortex
What is the function of the blood brain barrier?
Protect the brain
What is folia?
Narrow ridges of the cerebellum
What is the arbor vitae?
White matter core of the cerebellum
Where is the 4th ventricle located?
Space between choroid plexus and medulla
What are some metabolic differences within the CNS?
1. CNS is the most demanding tissue of the body
2. Always metabolic active
3. Maintains membrane potential
4. Does NOT store energy (No fat or glycogen stores)
5. Cannot work in anaerobic conditions
What is the blood pattern of the CNS?
Highly anastomotic pattern
How is the blood vasculature within the CNS maintained?
Maintained by intrinsic auto-regulatory mechanisms to ensure constant blood flow
What is the blood configuration of the CNS in most species?
Cerebral Arterial Circle aka Circle of Willis
What is the blood configuration of the CNS in Ruminant, Feline and Porcine?
What are the 3 main arteries that supply the brain?
1. Bilateral Internal Carotid Arteries
2. Basilar Arteries
3. Vertebral Artery
What arteries complete the cerebral arterial circle?
1. Rostral Cerebral arteries
2. Middle cerebral arteries
3. Caudal Communicating arteries
4. Caudal cerebral arteries
Where does most of venous blood empty?
What is the dural sinus?
Space created by dural reflections of the meninges
Is the pattern of venous drainage from the braincase species dependent?
Is venous blood supply a low pressure and valveless system?
What happens when opthalmic vein brings venous blood from head to dural sinus?
Brain Abscess = Very Bad!
What is the primary blood supply to the spinal cord?
Ventral Spinal Artery
What is the secondary supply to the spinal cord?
Paired dorsal spinal arteries
What is the internal vertebral venous plexus?
Venous system within the epidural space
Can you puncture the internal vertebral venous plexus during a CSF tap?
How many connective membranes surround the brain and spinal cord?
What are the functions of the meninges?
1. Production, Circulation and re-absorption of CSF
2. Convey arterial vessels into nervous tissue and return venous blood to dural sinus
3. Divide cranium into smaller compartments
What ligament supports the spinal cord?
Denticulate ligament which extends from laterally between the dorsal and ventral rootlets to connect overlying meninges
Where is the subarchnoid space?
Between arachnoid layer and pia mater
Does the subarchnoid space contain CSF?
Where is the epidural space?
Between the dura mater and periosteum of vertebrae
Is the Dura Mater will innervated?
What are the caudal Spinal Cord Meningeal Layers?
1. Dura Mater
2. Arachnoid Mater
3. Conus Medularis
4. Caudal Ligament
5. Filum terminate
6. Pia Mater with denticulate ligaments
What distinguishes the subarchnoid space?
Where is the cerebellomedullary cistern (cisterna magna)?
Located between the cerebellum and medulla
Can the cerebellomedullary cistern be used for CSF collection?
Do the 2 layers of the dura mater seperate?
No, they do not seperate, except @ dural sinuses
Does the Dura Mater have epidural spaces?
No b/c of close attachments of periosteal and meningeal layers
What 2 types of hematomas develop int he cranial meninges due to trauma or other pathogens?
1. Epidural Hematoma
2. Subdural Hematoma
What is an epidural hematoma?
When blood collects between the skull and dura mater
What is an subdural hematoma?
When blood collects between dura mater and arachnoid space
What can epidural and subdural hematomas cause?
Can cause neurological abnormalities and oxidative damage
What is the function of dural reflections?
Aid in the reduction of movement of the brain within the braincase during sudden rapid acceleration or deceleration
What is the falx cerebri?
Dural reflection between cerebrum and cerebellum
What is the ventricular system?
Series of fluid filled cavities within the cerebrum and brainstem which is lined with ependymal cells which helps to produce and circulate CSF within ventricles
How do the lateral ventricles communicate?
Communicate through a narrow passage (interventricular foramen)
How does the 3rd and 4th ventricle communicate?
Communicate through the Mesencephalic aqueduct aka cerebral aqueduct
Where is the 4th ventricle located?
Resides within the pons and medulla
Does the choroid plexus produce CSF?
What are the functions of CSF?
1. Protective jacket around the nervous tissue of the CNS
2. Maintain extracellular fluid composition
3. Lymphatic system of the CNS
4. Transports hypothalamic hormones of the CNS
T/F. CSF production is an active process.
T/F. CSF production is dependent of blood pressure.
False. Independent of blood pressure via hydrostatic system
Is the production of CSF easily affected by osmotic pressure of blood plasma?
How does CSF leave the subarachnoid space?
Leave through specialized 1 way valves associated with dural sinuses when CSF pressure exceeds venous pressure
When is caudal epidural anesthesia routinely used?
Used in cattle, sheep, and goats for surgery of the perineum
Where is the needle placement of the caudal epidural?
Sacrococcygeal (S5-Cd1) or the 1st caudal (Cd1-Cd2) interspace, identify by pumping the tail
When is lumbosacral epidural anesthesia routinely used?
Surgical procedure caudal to the umbilicus used in dogs
Where is the needle placement for lumbosacral epidural?
Inject into the L7-S1 space, caudal to L7, you will feel a "popping" sensation when the needle passes through the interarcuate ligament
What should you check your needle for before injecting epidural anesthesia?
Check for blood and CSF