Exam 4 Flashcards
Efferent neurons
Takes information from the CNS
Afferent neurons
Takes information to the CNS
Spinal nerves
On each side of the vertebrae; “mixed” nerves of sensory and motor neurons
Cauda equina
Where the spinal cord goes from being compact to fraying off
Nerve
Bundle of neurons
Ganglion
Bundle of cell bodies outside the CNS
Dorsal root ganglion
The cell bodies of sensory neurons outside the CNS
Dorsal root
The axons of the sensory (afferent) neurons
Ventral root
Axons of motor (efferent) neurons
White matter
The region outside the spine; consists of the axons
Why is white matter white
Because it is myelinated
How are axons in white matter organized
- Short tract
2. Long tract
Short tract
Axons that connect parts of the spine
Long tract
Axons that connect the spine to the brain
Types of long tracts
- Ascending
2. Descending
Ascending long tracts
Carry information to the brain from the spine (sensory)
Descending long tracts
Carry information from the spine to the brain (motor)
Gray matter
The inside region of the spine; the cell bodies; the nissl bodies (ER) make it gray; this is the integration center; very organized/each section does something different
How do the cell bodies in gray matter accumulate
Based on function; organize into nuclei
Nucleus
Cell bodies organize themselves into different nuclei based on their function
Where is the amount of gray matter the greatest
- Cervical enlargement
2. Lumbar enlargement
Cervical enlargement
Area in the cervical area where there is more gray matter; controls movement of shoulder and upper limbs
Lumbar enlargement
Area in lumbar area where there is more gray matter; controls movement of lower limbs
Meninges
Protects the spine from the vertebrae in case of injury; the “air bags”
Dura mater
Meninge; The outermost membrane; “tough mother”
Epidural space
Space between dura mater and vertebrae that is filled with adipose tissue
Arachnoid mater
Meninge; The middle membrane
Pia mater
Meninge; The deepest membrane; wraps directly around the spine
Subarachnoid space
Space between arachnoid mater and pia mater; filled with cerebrospinal fluid (CSF)
Main function of the brain stem
Controls unconscious thought; visceral function/autonomic function
Medulla oblongata
Directly connected to the spinal cord; all sensory information goes through the medulla before going to the brain
How is the medulla oblongata separated
It is separated into different nuclei
Nuclei of the medulla
- Cardiovascular centers
- Respiratory rhythimicity centers
- Solitary nucleus
Cardiovascular centers
Controls heart function; autonomic
Parts in the cardiovascular centers
- Cardioacceleratory center
2. Cardioinhibitory center
Cardioacceleratory center
Enhances heart function; uses sympathetic neurons (fight or flight)
Cardioinhibitory center
Inhibits heart function; uses parasynthetic neurons (rest and digest)
How does the cardiovascular center know which center to use
- Baroreceptors
2. Chemoreceptors
Baroreceptors
Measure blood pressure and sends that information to the CNS
Chemoreceptors
Monitors the chemical content of blood
What chemicals in blood do chemoreceptors monitor
Oxygen and carbon dioxide
What does the medulla decide to do if chemoreceptors detect that carbon deoxide levels are too high
It uses sympathetic neurons to pump blood faster to get carbon dioxide out of the blood faster
Respiratory rhythmicity center
Controls respiration rate; stimulates muscles that make us inhale and relaxes them to exhale
Why are the respiratory rhythmicity center and cardiovascular centers right next to each other
Because they work together
What cant the respiratory rhythmicity center do
Decide when to inhale/exhale
What tells the respiratory rhythmicity center when to inhale/exhale
The pons
Solitary nucleus
Is a relay station; takes in sensory information from different places and makes sure that that information gets sent to the right centers; takes in information from visceral functions then sends it to the correct nuclei centers
Decussation
Means “crossing over”; where motor commands from one side of the brain cross over and go to the opposite side of the body (contralaterally
Pons
Controls muscle movements of the face
Respiratory center (of the pons)
A nuclei in pons
Parts in the respiratory center of the pons
- Apneustic center
2. Pneumotaxic center
Apneustic center
Responsible for causing respiratory muscles to contract/inhale
What does the apneustic center not know how to do
When to relax respiratory muscles in order to exhale
Pneumotaxic center
Silences the apneustic center in order to exhale/relax
What controls the respiratory centers in the medulla
The respiratory centers in the pons
Midbrain
Mesencephalon; the most conserved region, meaning most species have this
Corpora quadrigemina
Collection of 4 nuclei in the midbrain that control reflexes of the head and neck in response to stimuli