Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/68

Click to flip

68 Cards in this Set

  • Front
  • Back
5 FUNCTIONS
THAT REQUIRE
CEREBRAL CORTEX
Voluntary Movements

Conscious Sensory Perceptions
- localization via somatopic map

Conscious Proprioception

Conscious Pain Perception

Conscious Visual Perception
BLIND SIGHT
Cortical Blindness

Functionally Blind

Retina and midbrain cortex are functional
- tf subconscious visual awareness
- tf visual processing below level of cortex
5 AFFECTS OF
LESIONS OF CEREBRAL CORTEX
UMN Signs

Sensory Deficits

Consciousness

Behavior

Learning
LESIONS OF CEREBRAL CORTEX
UMN SIGNS
Deficits in Voluntary Movement
- paresis
- paralysis

Normal to increased muscle tone

Deficits in Conscious Proprioception
- knuckling
- abnormal gait

UNILATERAL LESIONS PRODUCE DEFICITS ON CONTRALATERAL SIDE
LESIONS OF CEREBRAL CORTEX
SENSORY DEFICITS
Hypalgesia aka Hypoalgesic

- loss of conscious peception of feeling

Domestic Animals
- difficult to detect
- usually found in head because head represents major portion of somatosensory cortex - ie muzzle

Visual Cortex
- blindness

NOT LOCALIZING
- because many other lesions produce the same signs
LESIONS OF CEREBRAL CORTEX
CONSCIOUSNESS
Affects level of consciousness
- depression to coma

Consciousness involves
- all regions of cortex
- brain stem including
medulla
pons
midbrain
thalamus
ascending reticular activating system
- DOES NOT INVOLVE SPINAL CORD
SUBCORTICAL STRUCTURES

OF

CEREBRUM

FOUR
Olfactory System

Basal Nuclei

Hippocampus

Amygdala

All involved in behaviour
LIMBIC SYSTEM

5 COMPONENTS
Coordinates and controls behaviour Associated with STRONG EMOTIONS
- Fear
- Rage
- Pleasure
- Sexual Drive

Olfactory System

Hippocampus

Amygdala

Hypothalamus

Parts of Cerebral Cortex
LIMBIC SYSTEM

TARGETED BY WHICH DISEASE
Rabies
AMYGDALA
Recognition of Emotions
- ie recognizing and producing fear reaction
HIPPOCAMPUS
Creating NEW memory
- memories before lesion are intact
OLFACTORY SYSTEM
Odours Stimulate
- memories
- emotions
PSHYCOMOTOR SEIZURES
Abnormal Activity in Limbic System
- sudden unusual behavior
- sudden fear for no reason
- sudden aggesion
- snapping at phantom flies

Rare
LESIONS OF CEREBRUM

BEHAVIOR

FIVE
Pacing

Circling
- unilateral lesion
- circles to side of lesion
- larger circles

Head Pressing
- also lead poisoning

Tremors
- especially at rest
- tf NOT cerebellar intention tremors

Seizures
- neuronally based
- could also be thalamic
- Generalized Motor Seizure
- Opisthotinus
- Partial Motor Seizures
~~ affects heas or specific part of body
SEIZURE

3 STAGES
Preictal Stage

Period of Ictus

Post Ictal Stage
- animal may be
~~ depressed
~~ disoriented
~~ sleep
- lasts hours to days
GENERALIZED MOTOR SEIZURES
Involve whole body

Animal Unconscious

Lateral Recumbrancy

Limbs Tonically (ridgedly) extended

May have CLONIC CONTRACTIONS
- ridgid oscillations
- antagonistic muscles excite each others stretch recptors
- initiate oscillating myotatic reflex
OPISTHOTINUS
Activation of ALL EXTENSOR MUSCLES in body

Pupilary Dilation

Salivation

Chewing Motions

Usually last a few inuctes
- depends on cause

Behaviour Changes in PreIctal Period
- staring
- restlessness
- run and hide
SEIZURES

MECHANISMS
All seizures due to neurons which become SPONTANEOUSLY ACTIVE

Activity spreads to surrounding meurons

Mechanism is unknown

Involves large parts of CORTEX
- due to extensive connections

Spreads between left and right hemispheres via CORPUS CALLOSUM

Typically Common Source of Activation
- ie epillepsy
SEIZURES

CAUSES

3
Metabolic
- hyperglycemia
- hypoxia
- toxins

Neurologica
- tumors
- trauma
- inflammation
- infection

Epilepsy
- idiopathic
- describes pattern of discrete seizure in the same animal with no known cause
- tend to be classic Generalized Seizures
~~ pre and post ictal phases
MOTOR CONTROL
Involves many regions of Brain
- Cerebral Cortex
- Brainstem
- Spinal Cord
- Thalamus
- Basal Ganglia
- Cerebellum
MOTOR CONTROL

MOTOR CORTEX
Corticospinal Tract
- aka internal capsule
- fibre bound output of motor cortex through brain stem
- no synapses
~~ has collaterals
- travel directly to spinal cord
- Cerbral Peduncles
~~ passage through ventral surface of Midbrain
- Pyramids
~~ passage through hind brain
MOTOR CONTROL

BRAIN STEM
Indirect syanpse of UMN

Most important motor path of animals
- strong influence onf LMN

Red Nucleus
- Mid Brain

Vestibular Nucleus
- Medulla

Reticular Nucleus
- Pons and Meddula

Note
- Cerebral Cortex UMN affect LMN of Brain Stem
RED NUCLEUS
Flexors and Extensors

Net Exitatory effect on FLEXORS

Larger effect on DISTAL limbs

Effects are CONTRALATERAL
VESTIBULAR NUCLEI
Net excitatory effect on EXTENSOR MUSCLES

Larger effect on PROXIMAL limbs

Effects are IPSOLATERAL
RETICULAR NUCLEI
Diffusely Distributed

Effects both EXTENSOR AND FLEXORS

Net excitatory effect on EXTENSORS

Effects are BILATERAL
SPINAL REFLEX CIRCUITRY
Spinal Cord contains circuitry for reflexes
- withdrawal
- crossed extensor
- locomotion
- scratching

Cat transected T3-L3
- no motor neurons in this region
- initially hypertonic
- with training can walk without cerebrum
- hip extension important to generate flexion
THREE BEHAVIORS

THAT REQUIRE

INPUT FROM BRAIN STEM
Via
- Red nuclei
- Vestibular nuclei
- Reticular nuclei

Initiating Movement

Balance Control

Changing Direction

If cerebral cortex and cerebellum transected
- can walk
- can right self
FOUR BEHAVIORS

THAT REQUIRE

INPUT FROM CEREBRAL CORTEX
voluntary movement

volunatry direction changes

fine motor control of movement
- navigation
- rough terrain

reflexes associated with concious proprioception
- knucling
~~ UMN tell LNM to invert paw
- hopping
LATERAL OR VENTRAL

FUNNICULUS

WHITE MATTER DAMAGE
Note that will not see UMN signs if LMN damaged

Note that sensory neurons also run in Lateral Funiculus

C1-C5
- UMN for and hind limbs
- LMN in neck
~~ hard to detect

C6-T2
- UNM Hind Limb
- LMN Fore Limb

T3-L3
- UMN Hind Limb
- LMN Trunk
~~ Paniculus Reflex

L4-S2
- LMN Hind Limb
- Femoral Nerve
~~ L456
~~ Quads
~~-- patellar reflex
~~-- weight bearing
- Sciatic Nerve
~~ L67S12
~~ enervates everthing else in hind limb
- lesion in L45
~~ LMN Quad
~~ UNM in rest of hindlimb via sciatic
THREE STRUCTURES

INVOLVED IN MOTOR CONTROL

NOT UMN
Basal Nuclei
- Cerebral cortex

Subcortical Structures
- diencephalon
-
-
- thalamus
- midbrain

Cerebellum
BASAL NUCLEI
Involved in INITIATION of movement
- Huntingtons Disease
- Parkinsons Disease
- Terrets
- Dystonia
~~ repetitive movements characterized by abnormalities of coordination
~~ star thistle poisoning in horses
~~ Substantia Nigra
~~-- midbrain structure of one of the basal nuclei
~~ unable to initiate muscles of mastication
SUBCORTICAL STRUCTURES
Receive input from cerebral cortex

Feedback to cerebral cortex via thalamus
- subcortical feedback loop
- no direct influence over LMN

Planning and correct execution of complex movements

Important in initiation of movement

Important in switching between movements
CEREBELLUM
Not directly involved in control of LMN
- tf lesions do not produce paresis and other UMN signs

General Functions
- coordinates and refines ongoing movement
- involved in maintenance of equillibrium and body posture

Lesions
- Mild
~~ uncoordinated movements
~~ hypermetria
- Severe
~~ loss of equlllibrium
~~ abnormal body postures
~~ associated with vestibular system and pathways

Receives input from
- UMN
- Proprioceptive afferents and efferents
~~ compares reality with plan
~~ makes corrections via input to UMN

Vermis
- Medial and Dorsal
- wraps ventrally and longitudinally

Lateral Hemisphere

Connected to branstem via Cerebellar Peduncles
- Rostral
- Middle
- Caudal
- arranged medial lateral
CAUDAL CEREBELLAR PEDUNCLE
Proprioceptive Afferent Input
- unconscious proprioceptive input
~~ spinocerobellar tract
~~ Front limb
~~-- cuneocerobellar
~~ Hind limb
~~-- Dorsal and ventral lateral
MIDDLE CEREBELLAR PEDUNCLE
Continuation of Tranverse Fibres of Pons
- travel laterally then dorsally to form middle cerebellar peduncle

Input from UNM in Cerebral Cortex
- neurnons first synapse in pons
ROSTRAL CEREBELLAR PEDUNCLE
Mainly contains output from cerebellum to
- Brain Stem UMN
- Cerebral Cortex UMN
CEREBELLUM

3 FUNCTIONAL DIVISIONS
Highest Density in CNS
- repeating circuit patterns
- tf performs similar functions

Vestibulor Cerebellum
- flocculo nodylar node
- inputs from vestibular nuclei
- outputs to vestibular nuclei
- equillibrium and postural control
- primative part of vestibular system

Spinao Cerebellum
- vermis and parvermis
- inputs from brain stem UMN
- outputs to brain stem UMN
- posture and limb movement and control

Cerebro Cerebellum
- Lateral hemispheres
- inputs from cerebral cortex via synapes in pons
- outputs to cerebral cortex via thalamus
- planning movement
- motor learning
~~ initially cortex then cerebellum
CEREBELLAR DAMAGE

2 TYPES

5 SIGNS
Diffues Damage
- Bilateral signs
- abnormal development
- BVD, Toxins, genetic
- PRESSURE
~~ herniation through foramen magnum impacts cerebellum

Focused Damage

Ataxia
- most common sign
- incoordination
~~ not specific to cerebrum
- increased muscle tone but NO PARESIS
~~ especially extensor muscle
~~-- vestibular nucleus strongly inhibitory

DYSMETRIA
- inability to regulate movement
~~ rate
~~ range
~~ force
- Hypermetria most common
- produces INTENTION TREMOR
~~ not present at rest
~~ associated with start of movement
~~ undershoot/overshoot
~~ ofene associated with head
~~ SPECIFIC to cerebellum
- influences knucling response
~~ delayed then rapid motion

TRUNCAL ATAXIA
- more severe lesion
- vermis and paravermis
- broad base stance
- sway
~~ lateral or longitudinal
- staggering gate
- tendency to fall
- specific if no other signs

VESTIBULAR DISEASE
- loss of equillibrium
- very diffuse and sever
- involvement of Vestibular Cerebellum
- Nystagmus
- abnormal head tilt

OPISTHOTONUS
- extremely severe lesions
- recumbrancy with
~~ extended limbs
~~ arched spine
- usually herniation of cerebellum into foramen magnum
- specific if sole sign
~~ usually associated with seizures
CONTROL OF POSTURE
Trunk and Limbs
- head is via vestibular system

Posture requires maintenance at Rest and in Motion
- tf constant activity in postrual muscles
~~ axial muscles
~~ limbs
~~-- proximal extensors and flexors
~~-- distal extensors

Postural control is coordinated by
- Red Nuclei
~~ Inhibition of postural muscles
- Vestibular Nuclei
~~ Excitation of postural muscles
- Reticular Nuclei
~~ Excitation of postural muscles
- tf postural control is maintained by brain stem UMN
- tf postural control is acheived by balance between Excitation and Inhibition

Postural UMN are influenced by
- Cerebellum
~~ inhibits vestibular nucleus
- Cerebral Cortex
~~ net inhibitory inputs to vestibular and reticular nucleus
EXTENSOR RIGIDITY
Caused by Lesion that disrupts Inhibitory Pathway from Cerebral Cortex
- increased muscle tone
~~ pronounced in Extensor muscles
- Subsides after one week
DECEREBRATE RIGIDITY
Transection or Lesion
- experimental
- mid brain hemmorahge
- caudal to midbrain
~~ tf los of Red Nuclei inhibition
- severe extension
- can be relieved by activating cerebellum
~~ ie increase inhibition
CONTROL OF MICTURATON

DETRUSSOR REFLEX

WHAT IS INVOLVED
Detrussor Reflex
- detrussor muscle
~~ smooth muscle
~~ stretch receptors
~~ parsympathetic cholenergic receptors
~~ sympathetic catecholamine receptors
~~-- Beta Adrenergic body of bladder
~~-- Alpha Adrenergic neck of bladder
- S123
~~ Parasympathetic preganglionic motor ganglion to detrussor muscle
- pelvic nerve
~~ S123
~~ sensory stretch afferents to Pons
~~ conscious stretch afferents
- L1-L4
~~ detrussor stretch afferent inhibitory synapse
~~ Sympathetic trunk chain ganglia
- hypogastric nerve
~~ sympathetic
~~-- L1-L4
~~-- Sympathetic postganglionic motor fibres
~~ conscious stretch afferents
- Pons
~~ unknown integration
- Cerebellum
~~ inhibits detrussor reflex at level of Pons
- Thalamus
- Cortex
~~ Conscious active control
~~ must be learned
CONTROL OF MICTURATON

SPHINTER REFLEX

WHAT IS INVOLVED
Sphincter Reflex
- Urethralis (sphincter) muscle
~~ skeletal muscle
~~ stretch receptors
- S12
~~ stretch reflex
~~ detrussor stretch afferent inhibitory synapse
- voluntary UMN synapse
- Pudendal Nerve
~~ S12
~~ sensory afferent
~~ somatic motor efferent
- Cerebral Cortex
~~ voluntary control
MICTURATION

BLADDER FILLING
Sphincter
- Normal state is excitation and contraction via spinal stretch reflex
- stretch receptors on relaxed bladder do not inhibit spinal stretch reflex
- cerebral cortex conscious control maintains contraction

Bladder
- SNS excitation facillitates filling via
~~ relaxes wall of bladder via beta adrenergic receptors
~~ contracts neck of bladder via alpha adrenergic receptors
- cerebellum inhibits detrusser reflex at level of pons
- cerebral cortex inhibits detrusser reflex at level of pons
MICTURATION

URINATION
Sphincter
- cerebral cortex concious UMN releases inhibition to somatic motor efferent
- excitation of detrussor muscles stretch afferents inhibit somatic motor efferent

Bladder
- cerebral cortex releases inhibition of detrussor reflex at level of pons
- detrussor stretch afferents inhibit SNS enervation
~~ removes relaxation of bladder wall
~~ removes excitation of bladder neck
- detrussor reflex at level of pons contracts detrussor muscle
MICTURATION

COMPLETE LESION
Anywhere along detrusor reflex arc
- Inability to contract detrussor muscle

Anywhere along sphinter spinal reflex arc
- leakage
~~ relaxation of sphincter
MICTURATION

CEREBRAL CORTEX LESION
Voluntary Control
- Absent

Bladder
- sustained detrussor reflex
~~ Normal
- Tone
~~ Normal
- Volume
~~ variable
- Residual Urine
~~ none

Sphinter
- Voluntary Control
~~ Absent
- Pernial Reflex
~~ normal to increased
- Tone
~~ normal to increased
- Synergy with Detrussor
~~ normal
MICTURATION

CEREBELLAR LESIONS
Bladder
- Voluntary Control
~~ normal or increased frequency
- Sustained detrussor reflex
~~ Normal or hyperreflexic
- Tone
~~ Normal
- Volume
~~ decreased
- Residual Urine
~~ none

Sphincter
- Voluntary Control
~~ normal
- Pernial Reflex
~~ normal
- Tone
~~ normal
- Synergy with Detrussor
~~ normal
MICTURATION

PONS LESION
Bladder
- Voluntary Control
~~ absent
- Sustained detrussor reflex
~~ absent
- Tone
~~ variable
- Volume
~~ increased
- Residual Urine
~~ increased

Sphincter
- Voluntary Control
~~ absent
- Pernial Reflex
~~ normal to increased
- Tone
~~ increased
- Synergy with Detrussor
~~ absent
MICTURATION

PONS TO SACRAL CORD

COMPELTE LESION
Bladder
- Voluntary Control
~~ absent
- Sustained detrussor reflex
~~ absent ie areflexia
- Tone
~~ variable
- Volume
~~ increased
- Residual Urine
~~ increased

Sphincter
- Voluntary Control
~~ absent
- Pernial Reflex
~~ normal to increased
- Tone
~~ normal to increased
- Synergy with Detrussor
~~ absent
MICTURATION

PONS TO SACRAL CORD

PARTIAL LESION
Bladder
- Voluntary Control
~~ absent
- Sustained detrussor reflex
~~ absent ie areflexia or increased ie hypereflexia
- Tone
~~ variable
- Volume
~~ decreased according to Muir
- Residual Urine
~~ variable

Sphincter
- Voluntary Control
~~ may be present
- Pernial Reflex
~~ normal to increased
- Tone
~~ normal to increased
- Synergy with Detrussor
~~ absent
MICTURATION

SACRAL SPINAL CORD S123 LESION
Bladder
- Voluntary Control
~~ absent
- Sustained detrussor reflex
~~ absent ie areflexia
- Tone
~~ decreased
- Volume
~~ increase
- Residual Urine
~~ increased

Sphincter
- Voluntary Control
~~ absent
- Pernial Reflex
~~ absent
- Tone
~~ decreased
- Synergy with Detrussor
~~ absent
MICTURATION

PERIPERAL PUDENDAL LESION
Bladder
- Voluntary Control
~~ normal
- Sustained detrussor reflex
~~ normal
- Tone
~~ normal
- Volume
~~ normal
- Residual Urine
~~ none

Sphincter
- Voluntary Control
~~ absent
- Pernial Reflex
~~ absent
- Tone
~~ decreased
- Synergy with Detrussor
~~ absent
MICTURATION

LACK OF SEX HORMONES
Hormone Sensitive Incontinence

Bladder
- Voluntary Control
~~ normal
- Sustained detrussor reflex
~~ normal
- Tone
~~ normal
- Volume
~~ normal
- Residual Urine
~~ none

Sphincter
- Voluntary Control
~~ absent
- Pernial Reflex
~~ absent
- Tone
~~ decreased
- Synergy with Detrussor
~~ absent
CEREBROSPINAL FLUID

FACTOIDS
No connective tissue in CNS
- originates form Neuroectoderm
- no lymphatics
- tf no typical system to deal with extracellular fluid
- limited space tf SUSCEPTABLE TO PRESSURE
VENTRICULAR SYSTEM
Two Lateral Ventricles
- one in each cerebrum
- telencephalon

Third Ventricle
- diencephalon

Mesencephalic Aquaduct
- mid brain

Fourth Ventricle
- pons and medulla

Entire ventrical System
- lined with Ependymal cells
- filled with CSF
CHOROID PLEXUS
Produce CSF

Two in Lateral Ventricles
- one in each

One in Third Ventricle

One in Fourth Ventricle
CSF

PRODUCTION
Produced through Blood-CSF Barrier
- blood vessels in close opposition to emendymal cells
- flow of nutrients is ONE WAY into CSF
- Ependymal cells have tight junctions in region of Coroid Plexus
~~ tf nutrients are transported via active transport
~~-- high number of glucose transporters
~~ oxygen and CO2 diffuse
~~ tf NOT filtrate of blood

Normally continuously produced
- turned over 4 to 5 times daily
- 150 ml human

Rate of Production
- regulated by osmolarity of blood
- hypertonic blood decreases production
~~ tf Mannitol used to treat increased CSF pressure
~~-- one time treatment
- hypotonic blood increases production
CSF

COMPOSITION
Compared to Blood

99% H2O
- hypotonic to blood

Acellular

Very Low Protein

Lower Glucose

Lower pH

Same Osmolarity
FLOW OF CSF
Cranial to Caudal
- through ventricles to LATERAL APERTURES
- connect to SUBARACHNOID SPACE
~~ holds most of CSF volume
- fluid absorbed from Subarachnoid space through ARACHNOID VILLI
- passes into Venus System
~~ one way flow via pressure differential

Brain-CSF Interface
- two way flow in majority of ventricular system
~~--leaky junctions of ependymal cells
- one way flow in regions of Choroid Plexi
~~-- tight juctions of Ependymal cells

Blood CSF Barrier
- production of CSF
- blood closely apposed to Ependymal cells
~~-- tight juctions
~~-- one way flow into CSF
~~-- diffusion and active transport

Blood Brain Barrier
- vessels travel along pia and enter brain tissue
- Unique Tight Juntions between Endothelial Cells
~~-- main component of BBB
~~-- diffusion or active transport
~~-- very few endocytotic vesicles
- material passes BBB into Extra Cellular Matrix
~~-- passes into CSF
~~-- passes into Intra Cellular Space
CSF

THREE FUNCTIONS
Act as lymphatic system to releive brain pressure

Nutrition

Cushion Brain
BBB

2 REGIONS WITHOUT
Area Postrema
- Medulla near Chemorceptor Trigger Zone
~~-- vomition

Neurohypothesis
- transport of substances (hormones) into blood
- portal system
~~-- stimulation of Anterior Pituitary

Tanycytes
- isolate regions without BBB from rest of brain
- ie protect from non discriminant movement of material

No Tight Junctions in Edothelium
EDEMA

DEFINITION

3 TYPES
Accumulation of fluid in Extra Cellular Space
- significant in CNS because enclosed space

Vasegenic

Interstitial

Cytogenic
EDEMA

VASOGENIC
Breakdown of BBB

Increased capillary permeability
- increased flow into extra cellular space

Tumors

Infection
EDEMA

INTERSTITIAL
Increase water flow into CSF

Flow of CSF into sub aracnoid space blocked
- blockage of ventricular system
- blockage of Lateral Aperatures

Tumors
EDEMA

CYTOGENIC
Hypoxia
- general or ischemic
- disrupts cellular metabolism
- lowered ATP production
- increased intracellular Na
~~-- Na/KATPase
- water follows Na
~~-- cells swell

Salt Poisoning
- deprive of water then drink ad libum
- hypoosmotic plasma
~~-- fluid flows into cells

Swelling of cells not techically edema but same effect on CNS
EDEMA

TREATMENT
Mannitol
- not excreted
- increases plasma osmolarity
- pulls water from CSF
- one time treatment

Steroids
- stabilize cell membranes
HYDROCEPHALUS
Increased Volume of Ventricles

Congenital in dogs
- domed headed breeds

Any blockage of CSF
- tumor
- inflammation
- may or may not be associated with Edema
~~-- ie if gradual flow pressue will adjust
- occurance during development ablates cortex