Week 20 Flashcards
(26 cards)
What is the pathway that nerve impulses follow from a neuron to another in different parts of the body?
Reflex Arc
A reflex arc is the simplest type of pathway.
What are the 5 components of a reflex arc?
- Receptor
- Sensory neuron
- Integrating center
- Motor neuron
- Effector
Where does the spinal cord serve as an integrating center for spinal reflexes?
In the gray matter.
What is a reflex?
A fast, predictable, automatic response to changes in the environment that helps to maintain homeostasis.
What are the two types of reflexes based on their integration location?
- Spinal reflexes
- Cranial reflexes
What is a nerve plexus?
Networks formed by joining spinal nerve branches with axons from adjacent nerves.
Name the major plexuses.
- Cervical plexus
- Brachial plexus
- Lumbar plexus
- Sacral plexus
What are dermatomes?
Unique segments of the skin primarily supplied by a single afferent (sensory) spinal nerve fibre.
What happens when spinal cord damage occurs?
Produces numbness patterns according to specific dermatomes affected.
What do spinal nerves branch into?
- Dorsal rami
- Ventral rami
- Meningeal branches
What do dorsal rami supply?
Skin and muscles of the back.
What do ventral rami form?
Plexus that supply the anterior trunk and limbs.
What is the typical length of the adult spinal cord?
Approximately 42-45 cm long.
At what level does the spinal cord begin?
At the level of the foramen magnum.
Where does the adult spinal cord end?
Between the first and second lumbar vertebrae.
What are the two principal functions of the spinal cord?
- Conducts impulses to and from the brain
- Serves as a center for spinal reflexes
What do ascending tracts carry?
Sensory information to the brain.
What do descending tracts carry?
Motor instructions from the brain to muscles and glands.
What is the structure of the spinal cord?
A slender column of nervous tissue that passes downward from the brain.
What does gray matter consist of?
- Neuron cell bodies
- Dendrites
- Neuroglia
- Blood vessels
What does white matter consist of?
- Nerve fibres (axons with myelinated fibres)
- Neuroglia
- Blood vessels
What is the function of spinal nerves?
Connect the CNS to sensory receptors, muscles, and glands.
What are the three coverings of a spinal nerve?
- Endoneurium
- Perineurium
- Epineurium
What is the cauda equina?
Roots of the lower lumbar, sacral, and coccygeal nerves that are not in line with their corresponding vertebrae.
