Final Exam Flashcards
What are spinal nerves? How are spinal nerves connected to the spinal cord? What is located in each of these “connections”?
Spinal nerves originate in the spinal cord and are mixed nerves of sensory and motor neuron fibers that separate to spinal cord. They are connected to the spinal cord via dorsal and ventral roots.
Dorsal Root: afferent sensory axons of somatic and visceral sensory neurons extend here.
Ventral Root: somatic motor axons that extend from motor neuron cell bodies in ventral horn of grey matter in spinal cord.
How many cervical spinal nerves are there and where are they located?
There are 8 cervical spinal nerves. They are located cranial to each cervical vertebra (CSN 1 is cranial to C1). CSN 8 however is caudal to C7 and cranial to T1.
Cervical spinal nerves emerge through intervertebral foramina and branch into dorsal and ventral branches. What do each of these branches of nerves supply?
The dorsal branch of the cervical spinal nerves supplies the epaxial musculature. The ventral branch supplies the hypaxial musculature.
Where do thoracic and lumbar spinal nerves emerge in relation to their same numbered vertebra?
Caudal to their corresponding vertebra.
Where does the first pair of cervical spinal nerves emerge from?
The lateral vertebral foramina of the atlas.
Where do the 3 sacral spinal nerves emerge from?
The first 2 sacral spinal nerves emerge through the sacral foramina. The third sacral spinal nerve emerges between the intervertebral foramen between the sacrum and the first caudal vertebra.
Describe the ventral branches of cervical spinal nerve 2. Where does it emerge? What are the names of its ventral branches?
It emerges between the cleidomastoideus and the omotransversarius. It has 2 ventral branches: The Great Auricular Nerve and The Transverse Cervical Nerve.
What do the ventral branches of all cervical spinal nerves (except CSN 2) penetrate?
The omotransversarius.
What is another name for Cranial Nerve XI? Where does it pass? What muscle does it supply?
CN XI is also called the Accessory Nerve. Its dorsal branch crosses CSN1 to supply the trapezius muscle. It passes between the brachiocephalicus and the trapezius; dorsal to the omotransversarius.
What is the CNS composed of? What does the CNS do?
CNS relays and integrates information received from the periphery of the body. It is composed of the brain (Grey Matter: Nuclei, White Matter: Tracts) and spinal cord.
What is the PNS composed of? What does the PNS do?
PNS transmits sensory input to the CNS and relays motor output from the CNS to the periphery of the body. Composed of nerves and ganglia.
What are nuclei in the CNS? What do they make up?
Nuclei are collections of neuron cell bodies within the CNS. They make up the grey matter of the CNS
Pre-synaptic Autonomic (Sympathetic and Parasympathetic) cell bodies are located in nuclear regions of….?
PSNS = Brain SNS = Spinal Cord (Thoracolumbar) PSNS = Spinal Cord (Sacral)
What are tracts in regards to the CNS? What do they make up?
Tracts are formed by axonal processes of neurons that travel collectively together to common destination within the CNS. They make up the majority of white matter.
What are afferent sensory neurons? When are afferent sensory neurons bipolar and when are they unipolar?
Relay sensory input to the CNS.
Bipolar Neurons = special sensory systems (olfaction, vision, taste)
Unipolar Neurons = general sensory info from periphery to CNS
What are somatic afferent neurons vs. visceral afferent neurons?
Somatic Afferent Neurons = From skeletal muscle (voluntary) and proprioceptors.
Visceral Afferent Neurons = From involuntary tissue (cardia, smooth muscle, glands)
What are efferent motor neurons? What type of neurons are they? Where are their cell bodies located (be specific in regards to somatic, visceral (PSNS, SNS)?
Relay motor output from the CNS.
Multipolar neurons.
Cell bodies are located within the CNS in nuclei (grey matter):
Somatic: Cell bodies are in the ventral horn of spinal cord grey matter.
SNS pre-synaptic cell bodies: Lateral horn of spinal cord (thoracic and lumbar regions)
PSNS pre-synaptic cell bodies: Ventral horn/dorsal aspect of spinal cord (sacral region)
What are somatic efferent neurons vs. visceral efferent neurons? State whether or not each of these synapse before reaching their target tissue.
Somatic Efferent Neurons = to skeletal (voluntary) muscle. Do not synapse before reaching target tissue.
Visceral Efferent Neurons = to involuntary tissues (comprises ANS). Synapse onto a second neuron (pre-synaptic and post-synaptic)
What are interneurons? Where are they located? What do their axons travel via?
Interneurons integrate information between the CNS and PNS. They are located within the CNS (cell bodies are in nuclei in grey matter). Their axons travel via tracts.
What are ganglia in the PNS? What are nerves?
Ganglia are collections of neuronal cell bodies in the PNS.
Nerves are neuron processes of several neurons travelling together in the PNS
How many pairs of cranial nerves are there? Which 4 contain autonomic neurons & give their common names?
12 pairs. Pairs containing autonomic neurons: CN III: Oculomotor CN VII: Facial CN IX: Glossopharyngeal CN X: Vagus
Discuss the physiological and pharmacological differences between SNS vs. PSNS
SNS: Fight or Flight
Increase energy consumption to prepare for an action, adjust to stress
Adrenergic - release adrenaline
PSNS: Rest and Digest
Enhances activities that gain and conserve energy.
Cholinergic - release acetylcholine
Discuss the anatomical differences between SNS and PSNS.
SNS:
Thoracolumbar Division (Presynaptic Fibers exit T1-L5)
Presynaptic Fibers are SHORT and synapse with sympathetic chain of ganglia (paravertebral) located on either side of spinal cord.
PSNS:
Craniosacral Division (CN III, VII, IX, X) & S2-4
Pre-synaptic Fibers are LONG and synpase in ganglia located within organs they innervate.
Discuss the differences between the SNS and PSNS in regards to the synapse of pre-synaptic neurons onto post-synaptic neurons.
SNS:
Synapse of pre onto post neurons occurs at:
Paravertebral ganglia
Prevertebral ganglia (caudal to diaphragm: celiac, cranial and caudal mesenteric)
Cervicothoracic, middle cervical, cranial cervical ganglia Adrenal Medulla (not ganglion but pre-synaptic fibers can stimulate chromaffin cells resulting in hormonal release of adrenaline)
PSNS:
Synapse of pre onto post synaptic neurons at:
Cranial ganglia (visible in head)
Terminal ganglia (located within muscular walls of viscera (not visible)