Quiz 3: Lecture: Medulla-Limbic System Flashcards
What does the medulla oblongata connect?
The brain to the spinal cord through the foramen magnum
What does the medulla oblongata do?
Relays information, Regulates autonomic functions
What autonomic functions do the medulla oblongata regulate?
heart rate, blood, pressure, respiration, digestion
Do we have control over autonomic functions?
No (can modify but don’t have much say)
Most of the functions in the brainstem are _____ functions.
visceral (more voluntary as we go higher)
Autonomic centers (4) in the brainstem (medulla oblongata):
Reticular formation, Cardiovascular centers, Respiratory rhythmicity center, Solitary nucleus
Relay stations in the brainstem (medulla oblongata):
Olivary nucleus, Nucleus cuneatus, Nucleus gracilis
Where is the fourth ventricle located?
Posterior region of pons and medulla, Anterior to the cerebellum, Extends from cerebral aqueduct superiorly, Extends inferiorly into central canal of brainstem and spinal cord
The medulla oblongata does these 3 things:
Allows brain and spinal cord to communicate, Coordinates complex autonomic reflexes, Controls visceral functions
Types of nuclei in the medulla and what they do
Autonomic nuclei: control visceral activities
Sensory and motor nuclei: of cranial nerves
Relay stations: along sensory and motor pathways
Autonomic nuclei of the Medulla Oblongata consist of these two parts:
Reticular formation; Reflex centers
What is the reticular formation and what is its function?
Gray matter with embedded nuclei; Regulates autonomic functions
What do reflex centers do and what do they consist of?
Control peripheral systems
Cardiovascular centers; Respiratory rhythmicity centers
What are cardiovascular centers and what are their function?
Cardiac center
Control blood flow through peripheral tissues
What is the function of respiratory rhythmicity centers?
Sets pace for respiratory movements (can be modified)
What is the Pre-Botzinger complex?
“Originate signals that control normal breathing”
Neurons that will fire action potentials on their own regularly to help set pace for respiratory movement (don’t need stimuli coming in to generate action potential)
Where do the neurons of the Pre-Botzinger complex exit the brain?
They exit through the phrenic nerve (which is the sole innervation for the diaphragm)
The breathing rhythm is relayed to the _____ _____ from the pre-Botzinger complexes.
hypoglossal nuclei
What are the 3 Relay Stations of the Medulla Oblongata?
Nucleus gracilis and nucleus cuneatus, Solitary nucleus, Olivary nuclei (olives)
How many Nucleus gracilis and Nucleus cuneatus do we have?
Two, one in each hemisphere (Nucleus gracilis inward and Nucleus cuneatus outward)
What is the function of the Nucleus gracilis and Nucleus cuneatus? Which structure does it go to next?
Pass somatic sensory information to thalamus
Primary somatosensory cortex located in postcentral gyrus
What is the function of the Solitary nucleus?
Receives visceral sensory information
What is the function of the Olivary nuclei (olives)?
Relay information about somatic motor commands (Have control over these)
Ascending pathway of relay stations of the Medulla Oblongata
fasciculus gracilis, fasciculus cuneatus (S-2, L-3, T-4, C-3), receptors, primary afferent neuron, (decussation), medial cuneate nucleus, nucleus gracilis
Descending pathway of relay stations of the Medulla Oblongata
Medulla oblongata, Pyramid, pyramidal decusation, lateral corticospinal tract, ventral corticospinal tract, motor end plates, spinal cord, ventral root
The medulla oblongata regulates:
blood pressure; respiration
What do the pons connect? What does this link to?
Cerebellum to brainstem (bridge)
Links to mesencephalon, diencephalon, cerebrum and spinal cord
What is the pons involved in?
Somatic and visceral motor control
Damage to the _____ or _____ may result in _____ _____ of _____ _____
cerebellum; pons; poor coordination; limb movement
The job of the cerebellum is to:
Prepare motor movements with the plan of a motor movement with the actual execution of the motor movement
The pons have these 2 nuclei:
Nuclei involved with respiration, Nuclei and tracts
What are the nuclei involved with respiration and what are their function?
Apneustic and pneumotaxic center
Modify respiratory rhythmicity center activity
What is the function of nuclei and tracts and what are they?
Process and relay information to and from cerebellum
Ascending, descending, and transverse tracts
What are ascending, descending, and transverse tracts and what is their function?
Transverse fibers (axons)
Link nuclei of pons with opposite cerebellar hemisphere
The Pons contains:
sensory and motor nuclei for four cranial nerves
nuclei concerned with the control of respiration
tracts that link the cerebellum with the brain stem
Cranial Nerve #1, function, and direction
Olfactory nerve (sense of smell)
olfactory bulb > olfactory tract > olfactory cortex
What is the only sensory sensation that doesn’t have to go to the thalamus before being processed?
Cranial nerve 1- olfactory nerve (sense of smell)
Goes directly to its primary center- olfactory cortex
Cranial nerve #2, function, direction
Optic nerve
Processing visual information from the eye
Axons lead to ganglion cells that forms optic nerve > optic chiasm > thalamus > occipital lobe
Cranial nerve #3, function, direction
Oculomotor nerve, Respond to light
Sympathetic: Fight or flight (eyes dilate, slow digestion, saliva production stops, urinary stops)
Blood supply to muscle increase (increased heart rate), increased respiration, tense up
Parasympathetic after: eyes constrict, let everything go
Mnemonic to remember cranial nerves 1-12
Some= (S) Olfactory
Say= (S) Optic
Marry= (M) Oculomotor
Money= (M) Trochlear
But= (B) Trigeminal
My= (M) Abducens
Brother= (B) Facial
Says= (S) Vestibulocochlear
Big= (B) Glossopharyngeal
Brains= (B) Vagus
Matter= (M) Accessory
Most= (M) Hypoglossal
Structures in brain on slide 45
Medulla, pons, midbrain, third ventricle, cerebral aqueduct (in midbrain- mesencephalon), fourth ventricle, then behind septum pellucidum is lateral ventricle.
Corpus callosum looks like upside down Nike check
Colliculi (bumps) called corpora quadrigemina (4)
Two bumps on top: Superior colliculi
Two bumps on bottom: Inferior colliculi
The inferior colliculi are involved in:
Auditory reflexes
The superior colliculi are involved in:
Visual reflexes (at most basic level)
Not developing a conscious perception
Red nucleus function
Involved in subconscious positioning of upper limbs
What are the two parts of the substantia nigra? What are their functions?
Pars compacta; Pars reticulara
Pars compacta: dopaminergic neurons
Pars reticula: GABAminergic neurons
Pars compacta function
Dopaminergic neurons
In the synthesis of dopamine, these cells create neuromelanin which creates the pigmentation we see in the brain
In Parkinson’s disease, area is pale due to:
Pars compacta (dopaminergic neurons lead to neuromelanin)
They selectively die off then develop Parkinson’s (initially motor disorder- no cognitive disorder, just can’t initiate movement)
Substantia nigra function
Structure that is part of the basal nuclei (also known as basal ganglia)
What is the part that selectively degenerates in Parkinson’s disease?
Substantia nigra (basal ganglia)
What is the mesencephalon and what is its functions?
Midbrain
Processes sight, sound, and associated reflexes, Maintains consciousness
A superior view of a transverse section at the level of the midbrain (Slide 45) includes which structures?
Cerebral peduncle, Substantia nigra, Red nucleus, Cerebral aqueduct, Superior colliculus, Tectumn; Tegmentum; Cerebellum
What are the 3 structures of the Mesencephalon?
Tectum; Tegmentum; Cerebral peduncle
What is the tectum made up of?
Two pairs of sensory nuclei (corpora quadrigemina)
- Superior colliculus (visual)
- Inferior colliculus (auditory)
What is the Tegmentum made up of?
Red nucleus (many blood tests), Substantia nigra (pigmented gray matter)
What does the pineal gland do?
Secretes melatonin involved in sleep
What is a Sagittal section made/ what’s it separating?
Separating right and left so looking at midbrain
What are cerebral peduncles and what do they contain?
Nerve fiber bundles on ventrolateral surfaces
Contain descending fibers to cerebellum, motor command fibers
What is the function of reticular formation? What is the direction?
Involved in general sense of arousal. When stimulated, increases awareness
Runs good length of brainstem so ignore boundaries between midbrain, pons, medulla