Chapter 2 ( Neurology ) Flashcards
Agonists and antagonists of alpha1 receptor ?
Agonists :
Norepinephrine
Phenylephrine
Antagonists :
Phenoxybenzamine
Phentolamine
Prazosine
Agonists and antagonists of alpha2 receptors ?
Agonists : Clonidine
Antagonists : Yohimbine
Agonists and antagonists of beta1 receptors ?
Agonists :
Norepinephrine
Isoproterenol
Dobutamine
Antagonists :
Propranolol
Metoprolol
Agonists and antagonists of beta2 receptors ?
Agonists :
Isoproterenol
Albuterol
Antagonists :
propranolol
Butoxamine
Agonists and antagonists of nicotinic receptors ?
Agonists :
ACh
Nicotine
Carbachol
Antagonists :
Curare —> N1 in neuromuscular junction
Hexamethonium —> N2 in ganglionic receptors
Agonists and antagonists of muscarinic receptors ?
Agonists :
ACh
Muscarine
Carbachol
Antagonists :
Atropine
Autonomic centers in the brain stem and hypothalamus ?
Medulla :
Vasomotor
Respiratory
Swallowing , coughing , vomiting
Pons : Pneumotaxic center
Midbrain : Micturation center
Hypothalamus :
Temperature regulation center
Thirst and food intake regulatory center
Slowly adapting ( tonic ) receptors ?
Muscle spindle
Pressure
Slow pain
Rapidly adapting ( Phasic ) receptors ?
Pacinian corpuscle
Light touch
4th order neuron of the sensory pathway site ? Function ?
In the appropriate sensory area of the cerebral cortex
The information received results in conscious perception of the stimulus
Type of fibers carrying deep sensation and fine touch ?
Group ll fibers
Type of fibers carrying superficial sensation ( except fine touch ) ?
Group lll and lV fibers
Fast pain is carried by ?
Group lll fibers
Slow pain ( aching , burning , throbbing ) is carried by ?
C fibers
Description , sensation encoded and adaptation of Pacinian corpuscle ?
Onion like structure in the subcutaneous skin
Vibration/tapping
Rapidly adapting
Description , sensation encoded and adaptation of Meissner corpuscle ?
Present in nonhairy skin
Velocity
Rapidly adapting
Description , sensation encoded and adaptation of Ruffini corpuscle ?
Encapsulated
Pressure
Slowly adapting
Description , sensation encoded and adaptation of Merkel disk ?
Transducer is on epithelial cells
Location
Slowly adapting
Hypertropia is corrected by ?
Convex lens
Myopia is corrected by ?
Biconcave lens
Astigmatism is corrected by ?
Cylindrical lens
Presbyopia is corrected by ?
Convex lens
Function of pigment epithelial cells of the retina ?
Absorb stray light , prevent scatter of light
Convert 11-cis retinal to all-trans retinal
Function of horizontal and amacrine cells in the retina ?
Form local circuits with the bipolar cells
Where is ration of cones to bipolar cells is 1:1 ?
The fovea
The photosensitive element is ? Composed of ?
Rhodopsin
Composed of :
Opsin ( G protein coupled-receptor )
Retinal ( and aldehyde of vitamin A )
Light converts 11-cis retinal to all trans retinal process ?
Photoisomerization
Vitamin necessary for the regeneration of 11-cis rhodopsin ?
Vitamin A
Deficiency of which causes Night Blindness
Activator of Gt ( transducin ) ?
Metarhodopsin ll
Active Gt function ?
Activates phosphodiesterase
Types of glutamate receptors on bipolar and horizontal cells ?
1- Ionotropic glutamate receptors : Excitatory
2- Metabotropic glutamate receptors : Inhibitory
Visual cortex cell types ?
Simple cells
Complex cells
Hypercomplex cells
Simple cells of the visual cortex responds best to ?
Bars of light that have the correct position and orientation
Complex cells of the visual cortex responds best to ?
Moving bars or edges of light with the correct orientation
Hypercomplex cells of the visual cortex responds best to ?
Lines with particular length
Curves
Angles
How the sound is amplified in the middle ear ?
1- the lever action of the ossicles
2- the concentration of sound waves from the large tympanic membrane onto the smaller oval window
Perilymph site and character ?
In scala vestibuli and scala tympani
Has a high Na+
Endolymph site and character ?
In scala media
Has high K+
Scala media is bordered by ? Which is the site of ?
The basilar membrane
Organ of corti
Why sound waves causes vibration of organ of Corti ?
Because the basilar membrane is more elastic than the tectorial membrane , vibration of the basilar membrane causes the hair cells to bend by a shearing force as they push against the tectorial membrane
Consequence of bending of the cilia of hair cells ?
Changes in K conductance in the hair cells
Bending in one direction causing depolarization , bending in the other direction causes repolarization
The oscillating potential that results is the cochlear microphonic potential
The hair cells in the base of basilar membrane responds best to which sound ?
High frequencies sounds
The apex of the basilar membrane responds best to which sound ?
Low frequencies sounds
Structures of the vestibular organ ?
Three perpendicular semicircular canals
Utricle
Saccule
Receptors of the semicircular canals ? Located in ?
Cilia on the hair cells
Embedded in a gelatinous structure called the Cupula
The only neurons in the adult human male that replace themselves ?
The olfactory receptor cells
Nerve fiber type of olfactory neves ?
C fibers
Mitral cells in the olfactory bulb ?
Second order neurons
Output of the mitral cells forms the olfactory tract which projects to the prepiriform cortex
Type of taste papillae in the anterior 2/3 of the tongue ? Detects what ? Innervated by ?
Fungiform papillae
Salty , sweet , umami sensation
CN Vll ( chorda tympani )
Type of papillae in the posterior 1/3 of the tongue ? Detects ? Innervated by ?
Circumvallate and folliate papillae
Sour and bitter sensation
CN lX
Taste pathway ?
Fibers from CN Vll, lX, X enter the medulla and ascends in the solitary tract —> solitary nucleus —> ventral posteromedial nucleus of the thalamus —> the taste cortex
Group of motoneurons that innervates fibers within the same muscle ?
The motoneuron pool
Types of muscle sensors ? Type of their afferent fibers ? Detects what ?
1- Muscle spindle
Group la, ll afferents
Detects static and dynamic changes in muscle length
2- Golgi tendon organs
Group lb afferents
Detect muscle tension
3- Pacinian corpuscles
Group ll afferents
Detect vibration
4- Free nerve endings
Group lll, lV afferents
Detects noxious stimuli
Extrafusal fibers are innervated by ?
Alpha-motoneurons
Intrafusal fibers are innervated by ?
Gamma-motoneurons
Types of intrafusal fibers in muscle spindles ? Innervated by which type of afferent fibers ? Detects what ?
1- Nuclear bag fibers
Group la afferents
Detects dynamic changes in muscle length
2- Nuclear chain fibers
Group ll afferents
Detects static changes in muscle length
Functions of gamma motoneurons ?
Adjust the sensitivity of muscle spindle so that it will respond appropriately during muscle contraction
Stretch reflex number of synapses ? Stimulus ? Afferent fibers type ? Response ?
Monosynaptic
Stretch of muscle
Group la fibers
Contraction of the muscle
Golgi tendon reflex number of synapses ? Stimulus ? Afferent fibers type ? Response ?
Disynaptic
Contraction of muscle
Group Ib fibers
Relaxation of the muscle
Flexor withdrawal reflex number of synapses ? Stimulus ? Afferent fibers type ? Response ?
Polysynaptic
Pain
Groups ll, lll, lV fibers
Ipsilateral flexion and contralateral extension
Renshaw cells site and function ?
Inhibitory cells in the ventral horn of the spinal cord
Receives input from collateral axons from motoneurons and when stimulated negatively feedback on the motoneurons
Rubrospinal tract originates in ? Projects to ? Stimulation of its origin produces ?
The red nucleus
Interneurons in the lateral spinal cord
Stimulation of flexors and inhibition of extensors
Pontine reticulospinal tract originates in ? Projects to ? Stimulation of it produces ?
The nuclei in the pons
The ventromedial spinal cord
General stimulatory effect on both extensors and flexors , with the predominant effect on extensors
Medullary reticulospinal tract originates in ? Projects to ? Stimulation of it produces ?
Medullary reticular formation
Spinal cord interneurons in the intermediate grey area
A general inhibitory effect on both extensors and flexors , with the predominant effect on extensors
Lateral vestibular tract originates in ? Projects to ? Stimulation of it produces ?
Deiters nucleus
Projects to ipsilateral motoneurons and interneurons
Powerful stimulation of extensors and inhibition of flexors
Tectospinal tract originates in ? Projects to ? Involved in ?
The superior colliculus
The cervical spinal cord
The control of neck muscles
Transection of the spinal cord at C7 produces ?
Loss of sympathetic tone on the heart ( ⬇️ HR and BP )
Transection of the spinal cord at C3 produces ?
Breathing will stop ( because respiratory muscles have been disconnected from centers in the brain stem )
Transection of the spinal cord at C1 produces ?
Death ( Hanging )
Effect of transection above lateral vestibular nucleus ?
Decerebrate rigidity
Effect of transection above the pontine reticular formation but below the midbrain ?
Decerebrate rigidity
Effect of transection above the red nucleus ?
Decorticate posturing and intact tonic neck reflexes
Functions of the cerebellum ?
Vestibulocerebellum : control of balance and eye movement
Pontocerebellum : planning and initiation of movement
Spinocerebellum : synergy
Layers of the cerebellar cortex ? Types of cells in it ?
1- Granular layer :
Granule cells , Golgi type ll cells , Glomeruli
( in the glomeruli axons of mossy fibers forms synaptic connections on dendrites of granular and golgi type ll cells )
2- Purkinje cell layer :
Purkinje cells
( output is always inhibitory )
3- Molecular layer :
Stellate cells , Basket cells , Dendrites of purkinje and golgi type ll cells , Parallel fibers ( axone of granule cells )
( the parallel fibers synapse on dendrites of purkinje cells , basket cells , stellate cells and golgi type ll cells
Input to the cerebellar cortex through which fibers ?
Climbing fibers
Mossy fibers
Climbing fibers origin ? Type of its spikes ? Function ?
From a single region of the medulla ( olive nucleus )
Complex spikes ( high frequency bursts )
Play a role in cerebellar motor learning
Mossy fibers origin ? Type of its spikes ?
From many centers in the brain stem and spinal cord
Include vestibulocerebellar , pontocerebellar and spinocerebellar afferents
Simple spikes
The only output of the cerebellar cortex ? Inhibitory or excitatory ? Neurotransmitters involved ? Projects to ? Function ?
Purkinje cells
Inhibitory
GABA
Projects to Deep cerebellar nuclei and to the Vestibular nucleus
Synergy
The basal ganglia consists of ?
Striatum
Globus pallidus
Subthalamic nuclei
Substantia nigra
Function of the basal ganglia ?
Modulates thalamic outflow to the motor cortex to plan and excute smooth movements
The striatum consists of ?
Caudate
Putamen
Nucleus accumbens
The striatum communicates with the thalamus and the cerebral cortex by ?
Indirect pathway : inhibitory
Direct pathway : excitatory
Connections between the striatum and substantia nigra use which neurotransmitter ?
Dopamine
The overall action of dopamine is ?
Excitatory
Dopamine on the indirect pathway ?
Inhibitory through D2 receptors
Dopamine on the direct pathway ?
Excitatory through D1 receptors
Lesions of the globus pallidus results in ?
Inability to maintain postural support
Lesions of the striatum result in ? Occurs in patients with ?
Quick continuous uncontrollable movements
Huntington disease
Lesions of the subthalamic nucleus results in ?
Wild flinging movements ( hemiballismus )
Lesions of the substantia nigra caused by ? Occurs in patients with ? Symptoms ?
Destruction of dopaminergic neurons
Parkinson disease
Lead pipe rigidity , tremors , reduced voluntary movements
Function of premotor cortex and supplementary cortex ( area 6 ) ?
Generating a plan for movements which is transferred to primary motor cortex ( area 4 ) for execution
The supplementary motor cortex programs complex motor sequences and is active during mental rehearsal for a movement
EEG waves consists of ?
Alternating excitatory and inhibitory synaptic potentials in the pyramidal cells of the cerebral cortex
Cortical evoked potential ?
EEG change which reflects synaptic potential evoked in large numbers of neurons
Type of EEG waves in awake adults with eye open ?
Beta waves predominates
Type of EEG waves in awake adults with eyes closed ?
Alpha waves predominates
Type of EEG waves during sleep ?
Slow waves predominates
The circadian periodicity of sleep-wake cycles is driven by ?
Suprachiasmatic nucleus of the hypothalamus
REM sleep is characterized by ?
Eye movements
Loss of muscle tone
Pupillary constriction
Penile erection
Factors decreasing REM sleep duration ?
Benzodiazepines
Increasing age
The right hemisphere is dominant in ?
Facial expression
Intonation
Body language
Spatial tasks
Short term memory involves ?
Synaptic changes
Long term memory involves ?
Structural changes in the nervous system
What type of lesions block the abolity to form new long term memories ?
Bilateral lesions of the Hippocampus
BBB consists of ?
Endothelial cells of the cerebral capillaries
Choroid plexus epithelium
Substances that are excluded from the CSF ?
Protein
Cholesterol
Substances which concentration is equal in CSF and blood ?
Na
Cl
HCO3
Osmolarity
Substances which concentration in CSF is less than that in blood ?
K Ca Glucose Protein Cholesterol
Substances which concentration is more in CSF than in Blood ?
Mg
Creatinine
The most potent mechanism for increasing heat production ? Mechanism ?
Shivering
Cold temperature activate the shivering response which is orchestrated by the posterior hypothalamus
Heat loss mechanism ( response to heat ) is orchestrated by ?
Anterior hypothalamus
How steroids reduce fever ?
By blocking the release of arachidonic acid from brain phospholipids , thereby preventing the production of prostaglandins
How the pyrogens causes fever ?
Increase production of IL-1 by phagocytic cells which acts on the anterior hypothalamus to increase the production of prostaglandins which increase the set point temperature
Heat exhaustion is caused by ?
Excessive sweating which decreases blood volume and arterial BP leading to syncope
Cause of malignant hyperthermia ?
Inhalation anesthetics in susceptible individuals
