Neuro 5 Flashcards
a sensory receptor either…
Either
• Specialized cells that send a chemical signal to the sensory neuron, or
• Specialized terminals of the sensory neuron
• Excitation or inhibition are typically the result of ion channels opening or closing
what are the 5 sensory receptor types
- mechanoreceptors - touch, vibration
- photoreceptors - light
- nociceptors - tissue damage
- chemoreceptors - chem.
- thermoreceptors -temp
sensory receptors play a…
homeostatic role
responding to food, light, chemicals, blood pressure etc.
Ear hair cell example
hair cells - line the cochlea
- vibration of the ear drum moves the cilia to open/close K+ channels - depolarizing nerve cells and sending a message
How to tell the dorsal and ventral side of a spinal cord
ventral side has long ventral medial fissure
dorsal side has a smaller dorsal medial sulcus and 2 dorsolateral sulci
3 parts of white matter in the spinal cord
dorsal, lateral, and ventral funiculus
how to tell the difference between cervical, thoracic, and lumbar spinal cord
C- more white matter than gray (small butterfly and deep ventral median fissure)
T- intermediolateral horn for sympathetic motor neurons (deep dorsolateral sulcus and overall rounded appearance)
L- more gray than white matter
Sensory pathways are mostly on the
dorsal side (and dorsal funiculus)
motor pathways are mostly on the…
ventral side and ventral funiculus
Dorsal somatosensory pathways is also called the…. and is a __#__ neuron pathway
dorsal column system (touch, position, vibration)
three!
Where are the three neurons in the dorsal somatosensory pathway?
First neuron
• Cell body in dorsal root ganglion
• Axon ascends in dorsal funiculus
• Synapses in brainstem (medulla)
Second neuron
• Cell body in medulla
• Axon crosses midline !!!!
• Synapses in thalamus
Third neuron
• Cell body in thalamus
• Synapses in sensory cortex
Lateral somatosensory pathway is also called the…. and is a __#__ neuron pathway
spinothalamic tract (pain and temperature)
Three!!
What is the neuron pathway of the lateral somatosensory pathway
First neuron
• Cell body in dorsal root ganglion
• Synapses in dorsal horn of spinal cord
Second neuron
• Cell body in dorsal horn of spinal cord
• Axon crosses midline !!!!!!
• Ascends in lateral funiculus
• Synapses in thalamus
Third neuron
• Cell body in thalamus
• Synapses in sensory cortex
what are the pyramids
external landmark on the ventral medulla
corresponds to tracts composed of axons from the motor cortex to the spinal cord
How many neurons are in the lateral corticospinal tracts and what is its purpose
two - voluntary control of skeletal muscle in distal limbs
What is the neuron pathway for the lateral corticospional tract
(goes from the brain down)
Upper motor neuron
• Cell body in primary motor cortex
• Axon crosses midline in the ventral medulla (pyramids) !!!!
• Axon descends in the lateral corticospinal tract
• Synapses in ventral horn
Lower motor neuron
• Cell body in ventral horn
• Innervates skeletal muscle
How many neurons are in the ventral corticospinal tracts and what is its purpose
two!
voluntary control of skeletal muscle in proximal limbs and trunk
Explain the neuron pathway for the corticospinal tract
(from the brain down)
Upper motor neuron
• Cell body in primary motor cortex
• Axon passes through the ventral medulla (pyramids) and descends in the ventral corticospinal tract
• Axon crosses midline at the level of the second neuron !!!!
• Synapses in ventral horn
Lower motor neuron
• Cell body in ventral horn
• Innervates skeletal muscle
What is the extrapyramidal tracts
Motor pathways other than the corticospinal tracts
• Axons do not travel in the pyramids of the medulla
what are the functions of the extrapyramidal tracts
• Alternative route of transmission from motor cortex to spinal cord
• Control of postural reflexes
• Control of eye movements
• Control of head movements in response to sound or light
• Regulate muscle tone
What is a neuromuscular junction
Synapse between a motor neuron and a muscle cell
How does the neuromuscular junction work in the somatic nervous system?
• Neurotransmitter = acetylcholine
• Receptors = nicotinic cholinergic
• Response to binding = channel opens and Na+ flows into cell
• Depolarization
• Calcium released from endoplasmic (sarcoplasmic) reticulum
• Calcium promotes muscle contraction
Processes involved in consciousness
Depends on multiple CNS structures
• Association cortex
• Ascending reticular activating system
• Thalamus
• Hypothalamus
• Midbrain
• Pons
• Medulla
processes involved in memory
• Hippocampus is important in memory formation
• Memory storage is distributed throughout the cerebral cortex
• Learning = strengthening of synapses between neurons
Intervertebral Disc Disease
nucleus of the disc bursts into the spinal cord space and damages nerve root
