A&P - Chapter 20 (Part 3) Flashcards
What are interneurons?
Central neruons
Were are interneruons sometimes located?
Between sensory and motor neurons
Where can you only find internerons?
In the spinal cords gray matter
What is gray matter made predominantly up of? (2)
- Unmyelinated cell bodies of interneurons
2. Motor neurons
What forms when dorsal and ventral roots join?
Spinal nerves
What does white matter surround?
Gray matter
What is white matter subdivided into?
Half of the spinal cord into three areas called funiculi
What are the 3 parts of the funiculi?
- Anterior white column
- Posterior white column
- Lateral white column
What does each white column consist of?
Large bundles of axons divided into spinal tracts
What is the spinal cord a centre for thousands of?
Spinal cord reflexes
Which way are sensory tracts?
Ascending tracts
What do sensory tracts conduct?
Impulses from sensory neurons/receptors up to the brain
Which way are motor tracts?
Descending tracts
What do motor tracts conduct?
Impulses from the brain down to motor neurons/effectors
What are 2 examples of spinal cord injuries?
- Anethesia
2. Paralysis
What do the tracts of the spinal cord provide?
Conduction routes to ascending tracts and from descending tracts of the brain
What are 2 types of organizations for tracts?
- Structural
2. Functional
Structural organization
All axons of any one tract originate in the same structure and terminate in the same structure
Functional organization
All axons that compose one tract serve one general function
What is ONE of the largest organs in the body?
The brain
How many neurons are contained in the brain?
Almost 100 billion neurons
When are most neurons produced?
Before and shortly after birth
What happens to synapses throughout our life?
They are made and broken
What is the last neuron to develop?
The neuron that controls your bladder
Why do your synapses form and break?
In order to create better fine motor development skills
-eg. improve hand writing
What are the 4 main divisions of the brain?
- Brainstem
- Cerebellum
- Diencephalon
- Cerebrum
What are 3 parts that make up the brainstem?
- Medulla oblongata
- Pons
- Midbrain
What are 2 parts that make up the diencephalon?
- Hypothalamus
2. Thalamus
Where is the medulla oblongata?
It is the lowest part of the brain stem
- enlarged upward extension of the spinal cord
What do the pons connect?
The medulla oblongata with the surface of the cerebrum
What do the pons act as?
A bridge
What does the midbrain contain?
Cerebral peduncles
What do cerebral peduncles conduct?
Impulses between the midbrain and the cerebrum
Reticular formation
Scattered bits of gray and white matter that are closely mixed together
