Lecture 1 NS - Introduction to Neuro Flashcards
What is the central nervous system comprised of?
Brain and spinal cord
What is the PNS comprised of?
Nerves and ganglia outside brain and spinal cord
What are the divisions of the PNS?
Autonomic and somatic
What does the somatic PNS do?
Controls motor and sensory function for the body wall - skin and skeletal muscle
What does the autonomic NS do?
Regulates viscera: internal organs, smooth muscle, pupils, sweating, blood vessels, bladder, intestine, glands and controls heart contraction rate
What are the 2 subtypes of autonomic NS?
Sympathetic and parasympathetic
In which direction does the information flow in the NS?
Axons enter and leave the CNS through pairs of spinal nerves and cranial nerves
What are afferent axons?
They propagate AP TOWARDS CNS from PNS SENSORY
What are efferent axons?
Propagate AP FROM CNS to PNS MOTOR
What are interneurons?
CNS neurons that synapse with other CNS neurons within the brain/spinal cord
What are the ways that information flows through the NS?
AP generation/propagation Synaptic transmission Nerve conduction
What does the cerebral cortex do and what does it look like?
2 hemispheres, each receives sensory info from and controls movement of opposite side of body
What does the cerebellum do?
Controls coordination of movement
What does the brain stem do?
Most primitive part w/densely packed fibres Regulates vital functions and damage here can be fatal
What is the anatomy of the spinal cord? Fill in the blanks
Where does the CNS end?
At the margins of the spinal cord
What emerges from the spinal cord?
Dorsal and ventral roots - part of PNS
How are axons packed into nerves?
Spinal nerves contain both afferent and efferent axons, bundled into fascicles surrounded by perineurium, with a tough epineurium capsule Individual axons are also wrapped w/myelin and endoneurium, though some are unmyelinated
What is the anatomy of a nerve (with axons inside)? Fill in the blanks
What is the function of a neuron?
Transmit and receive AP, or stimulate target tissue
What is the anatomy of a nerve cell? Fill in the blanks
How does regeneration differ between PNS and CNS?
PNS: axons can regenerate after injury, CNS axons are unable to regenerate over long enough distances to be useful
What is a compromise that can occur during PNS regeneration?
Aberrant axon sprouting and non-specific target reinnervation - can lead to neuropathic pain
Why can’t CNS neurons regenerate?
There are inhibitory molecules in CNS (myelin differences), absence of guidance cues that stimulate axon growth during development and some loss of intrinsic axon growth capacity by neurons
What is the grey matter comprised of?
Neuronal cell bodies
What is the white matter comprised of?
Ascending and descending axon tracts to and from the brain
Which type of neuron is each one?
What types of inputs and outputs are required for a reflex response?
Somatic sensory inputs to interneurons then motor outputs from spinal cord
What does a reflex response require?
Sensory and motor neurons to be intact between periphery and spinal cord
What type of input/output is needed for conscious registering of sensory stimulus?
Sensory input activates sensory neurons in spinal cord grey matter that transmit AP upwards to sensory cortex of brain - then neurons in motor cortex of brain extend axons downward to synapse with the spinal motor neurons and transmit AP for voluntary movement
What do A, B, C, D form and what are they?
Neurons A-D form the motor pathways controlling voluntary movement, C/D are motor neurons in spinal cord which innervate skeletal muscle to stimulate contraction directly A/B are cortical neurons in motor cortex which activate spinal cord motor neurons C/D respectively
What do somatic sensory neurons do?
Convey sensory information from the body to the spinal cord and from there to the sensory cortex where sensation is perceived - stimulate reflex activity via spinal cord motor neurons and activate spinal cord sensory neurons which relay signals to the brain
What are E and F?
Single neurons which represent the sensory pathways for the limbs in the dorsal root ganglia - depicted as synapsing with a motor neurone in both spinal cord and motor cortex
