Intro Flashcards
The brain is the body’s most complex organ
Billions of neurons. Malfunction can lead to multitude of clinical signs.
___ circuits bring info to the nervous system to make animal aware of environment
sensory
___ circuits send information from the brain and spinal cord to muscle and glands to produce a response
motor
Principles of neurological exam are based on
knowledge of anatomy and physiology of the CNS and PNS
Nervous system includes
brain, spinal cord and all nerces that communicate between tissues and brain and spinal cord
Neurons are
specialized cells of nervous tissue that can conduct electrical signals and transmit information from one part of the nervous system to another or to peripheral targets
glia are
the supporting cells of the nervous system; broad range of function
Neurons communicate using both
electrical and chemical signals
Action potentials are
electical signals carried along the axons of neurons.
synapses are
chemical or electrical junctions that allow electrical signals to pass from one neuron to the next or to a target cell
largest part of the brain;
cerebrum/telencephalon
cerebrum/telencephalon controls _____; is inbolbed with
learning and behavior (personality); interpreting sensation
cerebrum/telencephalon is divided into
frontal parietal, temporal, and occipital lobes
Cerebrum clinical signs
dementia, compulsive pacing, circle towards damage, seizures
Brainstem includes
diencephalon (thalamus, hypothalamus); midbrain; pons; medulla
Brainstem is responsible for
basic functions of life including HR, R, swallowing
Diencephalon location and function
most rostral. coordinates and regulates all functional activity of the cerebral cortex; integration center of the ANS; vision, hearing
Clinical signs for diencephalon
altered levels of consciousness; endocrinopathies, behavioral abnormalities, disorders of thirst, appetites and temperature regulation.
Midbrain function
(cranial nerves 3&4) visual reflexes; hearing reflexes; eye movement; body movement;
Clinical signs for midbrain
decreased state of consiousness, loss of papillary light reflex, pupils dilated, extensor rigidity in all 4 limbs; contralteral paralysis or weakness with unilateral lesions.
Pons function
gives rise to trigeminal nerve (jaw opening and receives sensation from head and face). parts important for level of consciousness and sleep
Clinical signs for pons
hopping and placing deficits, muscle atrophy of the head, loss of facial sensation, vital sign changes
medulla function
responsible for maintaining vital body functions (breathing and HR), pain modulation
Clinical signs for medulla
head tilt, facial paralysis, difficulty swallowing, atrophy of the tongue, regurgitation, vital sign changes, vestibular signs, nystagmus
Structure located dorsal to the pons and meulla and connected to these strucures by the cerebellar peduncles
cerebellum
Cerebellum function
processes input from other areas of the brain, spinal cord and sensory receptors to provide precise timing for coordinated, smooth movements of the skeletal-musculo system
Clinical signs for cerebellum
ataxia of all four limbs and head. intention tremors, vestibular signs
spinal cord function
connects much of the PNS to the brain. sensory info reaching spinal cord primary afferent neurons is transmitted to higher brain regions. signals arising in the motor areas of the brain travel back down to the cord to affect motor neurons and influence muscle contraction
clinical signs of spinal cord
cercical/upper thoracic: ataxia, tetraparesis; ipsilateral hemiplegia; hopping, placing and proprioceptive deficits; hyperactive spinal reflexes; neck pain. Lumbosacral: atasia rear limbs; paraparesis; paraplegia; hopping, placing and proprioceptive deficits; depressed or absent rear limb spinal reflexes; deep peain alterations
Each part of the CNS is anatomically distince and associated with different functions. Thus:
damage to different brain regions will result in differnt functional deficits and clinical signs.
White matter consists of
bundles of axons (myelin)
Gray matter is comprised of
neuronal cell bodies, dendrites and glial cells
