Midterm 13,14,15 Flashcards
What are the two main divisions of the nervous system?
The central nervous system (CNS) and the peripheral nervous system (PNS).
What are the primary functions of neurons?
Neurons are responsible for transmitting electrical impulses throughout the nervous system.
What is the role of neuroglia in the nervous system?
Neuroglia support, protect, and nourish neurons.
Describe the structure of a typical neuron.
A neuron consists of a cell body (soma), dendrites, and an axon.
What is the function of myelin sheaths?
Myelin sheaths insulate axons and increase the speed of nerve impulse conduction.
Differentiate between afferent and efferent neurons.
Afferent neurons carry sensory information to the CNS, while efferent neurons transmit motor commands from the CNS to effectors.
What is a synapse?
A synapse is a junction between two neurons or between a neuron and an effector cell, facilitating signal transmission.
Name the four types of neuroglia in the CNS.
Astrocytes, oligodendrocytes, microglia, and ependymal cells.
What is the blood-brain barrier, and which cells contribute to its formation?
The blood-brain barrier protects the brain from harmful substances in the blood; astrocytes play a key role in its formation.
Explain the difference between white matter and gray matter.
White matter consists of myelinated axons, while gray matter contains neuron cell bodies, dendrites, and unmyelinated axons.
What are the main functions of the spinal cord?
The spinal cord conducts sensory and motor information between the brain and the body and mediates reflexes.
How many pairs of spinal nerves are there, and how are they categorized?
There are 31 pairs of spinal nerves, categorized as cervical (8), thoracic (12), lumbar (5), sacral (5), and coccygeal (1).
What is the cauda equina?
The cauda equina is a bundle of spinal nerve roots located at the lower end of the spinal cord.
Describe the structure and function of the meninges.
The meninges are three protective membranes (dura mater, arachnoid mater, and pia mater) that surround the brain and spinal cord.
What is a reflex arc?
A reflex arc is the neural pathway that mediates a reflex action, typically involving a sensory neuron, interneuron, and motor neuron.
Differentiate between ascending and descending tracts in the spinal cord.
Ascending tracts carry sensory information to the brain, while descending tracts transmit motor commands from the brain to the body.
What is the function of the dorsal root ganglion?
The dorsal root ganglion contains the cell bodies of sensory neurons entering the spinal cord.
Explain the significance of the cervical and lumbar enlargements of the spinal cord.
These enlargements correspond to the increased number of neurons needed to innervate the limbs.
What is the role of the ventral horn in the spinal cord?
The ventral horn contains motor neurons that send axons to skeletal muscles.
How are spinal nerves connected to the spinal cord?
Spinal nerves are connected to the spinal cord via dorsal (sensory) and ventral (motor) roots.
What are the primary functions of sensory and motor tracts in the spinal cord?
Sensory tracts carry information to the brain, while motor tracts transmit signals from the brain to the body for movement.
What is the difference between ascending and descending tracts?
Ascending tracts carry sensory information to the brain, and descending tracts carry motor commands from the brain to the spinal cord.
What are the three major sensory pathways in the spinal cord?
The posterior column pathway, spinothalamic pathway, and spinocerebellar pathway.
What type of information does the posterior column pathway carry?
It transmits sensations of fine touch, pressure, vibration, and proprioception.
Which two tracts make up the posterior column pathway?
The fasciculus gracilis and fasciculus cuneatus.
What sensory information does the spinothalamic pathway convey?
It carries pain, temperature, crude touch, and pressure sensations.
What are the two components of the spinothalamic pathway?
The anterior spinothalamic tract (crude touch and pressure) and the lateral spinothalamic tract (pain and temperature).
What is the role of the spinocerebellar pathway?
It transmits proprioceptive information to the cerebellum for motor coordination.
How are the sensory tracts organized within the spinal cord?
Sensory tracts are somatotopically organized, meaning specific regions correspond to particular body parts.
What are motor tracts, and what do they control?
Motor tracts transmit signals from the brain to skeletal muscles, controlling voluntary and involuntary movements.
What are the two main types of descending motor pathways?
The corticospinal pathway (voluntary movement) and the subconscious motor pathways (involuntary movement).
What is the corticospinal pathway responsible for?
It controls voluntary movements of the skeletal muscles.
What are the three tracts within the corticospinal pathway?
The corticobulbar tracts, lateral corticospinal tracts, and anterior corticospinal tracts.
What is the role of the corticobulbar tracts?
They control voluntary movements of the face, head, and neck muscles.
How does the lateral corticospinal tract differ from the anterior corticospinal tract?
The lateral corticospinal tract controls precise movements of the limbs, while the anterior corticospinal tract controls axial muscles.
What are the subconscious motor pathways?
They regulate involuntary movements such as posture, balance, and muscle tone.
Name the four tracts of the subconscious motor pathways.
Vestibulospinal, tectospinal, reticulospinal, and rubrospinal tracts.
What is the function of the vestibulospinal tract?
It helps maintain balance and posture by controlling muscle tone in response to vestibular (balance) input.
What is the tectospinal tract responsible for?
It directs reflexive head, neck, and upper body movements in response to visual and auditory stimuli.
What is the role of the reticulospinal tract?
It controls involuntary reflexes and autonomic functions, such as posture adjustment.
