22 - Brain Flashcards
What makes up the CNS?
Brain
Spinal cord
What makes up the PNS?
Cranial nerves
Spinal nerves
What makes up the ANS?
Sympathetic
Parasympathetic
Formation of nervous system occurs during the embryonic stage from the end of _______ week to the end of ________ week.
Second
Eighth
Superior (anterior or cranial) neuropore closes by day ______.
27
Inferior (posterior or caudal) neuropore closes by day ______.
30
The tripartite brain consists of what?
Prosencephalon
Mesencephalon
Rhombencephalon
The tripartite brain then divides into the pentapartite brain. The prosencephalon becomes _________ and _________; mesencephalon; and rhombencephalon becomes _________ and _________.
Telencephalon (most anterior)
Diencephalon
Metencephalon
Myelencephalon
The prosencephalon is not divided into ______ and ______ plates like rest of neural tube.
Alar
Basal
There are two pairs of evaginations from the prosencephalon which are…
Telencephalic vesicles
Optic vesicles
Telencephalic vesicles become what?
Cerebral hemispheres
Optic vesicles become what?
Retinas of the eye
Associate with diencephalon
Subphylum craniata (newer term for subphylum vertebrata) has two subgroups, which are…
Hagfishes (craniates without vertebrae)
Vertebrates (craniates with vertebrae)
The cranial end of the neural tube of all craniates is characterized by three primary brain vesicles, which are…
Prosencephalon
Mesencephalon
Rhombencephalon
The prosencephalon is the future…
Forebrain
The mesencephalon is the future…
Midbrain
The rhombencephalon is the future…
Hindbrain
The cranial end of the neural tube of all craniates is characterized by three primary brain vesicles. The differentiation of these vesicles occurs through localized thickenings of lateral walls and floor, and _________.
Evaginations
What is the major derivative of the myelencephalon that becomes continuous with the spinal cord?
Medulla oblongata
In this fish, the myelencephalon ism ore developed than other areas of the brain. Large neurons run the length of the tail, thought to be involved in swimming. (Myelencephalon is well developed in all the rest of the vertebrates).
Agnathans
Gray matter in the mesencephalon is organized into discrete _______ interspersed among myelinated (white) fiber tracts.
Nuclei
Gray matter in the spinal cord is continuous and is located more centrally and surrounded by myelinated fiber _______.
Tracts
This type of fish have vagal lobes associated with myelencephalon. The site of sensory nucleus (nucleus solitarius) in alar plate which may cause an enormous bulge on either side of the brainstem. May be associated with sense of taste.
Teleosts
In these, vagal lobes disappear from myelencephalon.
Amphibians
In these, the myelencephalon is well-developed.
Mammals
What are the components of the brainstem?
Medulla
Pons
Midbrain
In general, the ________ is made up of a mixture of long fiber pathways, 10 of 12 cranial nerves that enter and leave, well-organized nuclei, and a network of cells which forms the ________ reticular formation.
Brainstem
Brainstem
In the brainstem, most of the nuclei are related directly to…
Cranial nerve functions
Motor control pathways
List the descending tracts in the medulla.
Corticospinal Spinal tract V Medial longitudinal fasciculus Tectospinal Rubrospinal
List the ascending tracts of the medulla.
Medial lemniscus Spinothalamic tract Spinoreticular tract Spinocerebellar tract Cuneocerebellar tract
There are two additional components of the medulla that are not ascending or descending tracts. What are they?
Cranial nerve nuclei VIII-XII
Inferior cerebellar peduncles
The medullary pyramids (anterior) are the location of what?
Lateral corticospinal tracts
85 percent of corticospinal fibers decussate in the inferior border of the ________.
Medulla
After corticospinal fibers decussate at the inferior border of the medulla, the fibers then enter the…
Lateral columns of spinal cord
The lateral corticospinal tracts help with initiating and modulating _________.
Movement
In the medullary olives (anterior), the inferior olivary nuclei receive input from most motor areas of the brain and spinal cord. What are the functions of this?
Balance
Coordination
Sound impulse modulation
Axons of the medullary olives project to the contralateral cerebellar hemisphere via the ________ ________. These axons signal the cerebellum when a movement deviates form the planned movement.
Olivocerebellar tract
The medulla sends many fibers to the cerebellum via the inferior cerebellar peduncles via which tracts?
Spinocerebellar
Olivocerebellar
Vestibulocerebellar
Reticulocerebellar
This tract sends information from the cerebellum to the medulla.
Cerebellovestibular
The medullary nuclei consists of vestibular nuclear complex and which cranial nerve nuclei?
VIII - XII
This part of the dorsal medullary nuclei is the point of synapse for ascending fibers of the fasciculus cuneatus.
Nucleus cuneatus
This part of the dorsal medullary nuclei is the point of synapse for ascending fibers of the fasciculus gracilis.
Nucleus gracilis
The medulla contains portions of the reticular formation, which are associated with ________ and ________.
Consciousness
Arousal
List the vital reflex centers located in the medulla.
- Cardiac center
- Medullary rhythmicity center
- Vasomotor center
- Centers for coordination of head movement and swallowing
The cardiac center in the medulla is inhibitory via _______ and excitatory via _______.
CN X
T1-T5
List the non-vital reflex centers located in the medulla.
Swallowing Vomiting Coughing Sneezing Hiccuping
The cranial portion of the roof of the medulla is called the…
Superior medullary velum
The caudal portion of the roof of the medulla is called the…
Inferior medullary velum
The caudal portion of the roof of the medulla is called the inferior medullary velum and is very then and contains what foramen?
Foramen (aperture) of Magendie
What are the components of the roof of the medulla?
Superior medullary velum (cranial portion)
Inferior medullary velum (caudal portion)
Posterior choroid plexus
In this syndrome the following things are affected:
– Spinothalamic tract
– Spinal trigeminal tract and nucleus
– Fibers and nuclei of the glossopharyngeal nerve, vagus nerve, and part of the reticular formation
– Portions of the vestibular nuclei and/or portions of the inferior cerebellar peduncle
Wallenberg’s syndrome
Results of the Wallenberg’s syndrome includes –
– Loss of pain and temperature on the contralateral side (_________ tract)
– Loss of pain and temperature on the same side of the face and nasal and oral cavities (uncrossed ______ _______ tract)
– Difficulty swallowing and a hoarse, weak voice due to damage to _______ _______
– Loss of gag reflex on the same side and absence of sensation of the same side due to damage to __________ nerve
Spinothalamic
Spinal trigeminal
Nucleus ambiguous
Glossopharyngeal
In the pons, this fiber tract travels through the middle cerebellar peduncles and connects the pons to the cerebellum.
Transverse
In the pons, this fiber tract is both sensory and motor. It connects the spinal cord to the upper brain stem and most pass through the pons without synapsing.
Longitudinal
Two longitudinal tracts synapse in the pons. _________ tracts synapse on pontine nuclei and some _________ tracts synapse with neurons in the trigeminal motor nucleus and neurons in the facial nucleus.
Corticopontine
Corticobulbar
The pons has what cranial nerve nuclei?
V, VI, VII, VIII (part)
The pontine is responsible for relaying information from the ________ to ________.
Cerebrum
Cerebellum
The pons has other centers, which include…
Sleep
Respiratory (Pneumotaxic; Apneustic)
A lesion in the lateral half of the pons affects what?
Trigeminal nerve
Medial lemniscus
Pontocerebellar fibers
A lesion to the lateral half of the pons affects the trigeminal nerve, resulting in:
– Loss of general sensation to the face on the same side
– Paralysis to the muscles of _________, with the chin deviating to the side of the lesion
Mastication
A lesion to the lateral half of the pons affects the medial lemniscus, resulting in a loss of position, muscle, and joint sense on the (SAME/OPPOSITE) side.
Opposite
A lesion to the lateral half of the pons affects the pontocerebellar fibers, resulting in ________, coarse intention tremor, and tendency to fall to the same side as the lesion.
Hypotonia
A lesion to what location on the pons is caused by occlusion to the basilar artery that spares the reticular formation and interrupts the corticospinal and some corticobulbar tracts.
Bilateral lesions to the ventral pons
A bilateral lesion to the ventral pons results in a patient who is _________ and unable to speak or have tongue or facial movements. The patients are conscious and can communicate with eye movements if the _________ fibers to the oculomotor nuclei are intact.
Quadriplegic
Corticobulbar
Extensive bilateral lesions involving the pons and the midbrain reticular formation are associated with…
Coma
What are the nuclei in the midbrain?
CN nuclei III and IV Red nucleus (nucleus ruber)
This nuclei of the midbrain is involved in unconscious regulation and coordination of motor activities.
Red nucleus (nucleus ruber)
In the midbrain, the _______ consists of the superior and inferior colliculi.
Tectum
The (SUPERIOR/INFERIOR) colliculi is responsible for visual reflexes. It is involved in visual tracking of moving objects.
Superior
The (SUPERIOR/INFERIOR) colliculi is responsible for auditory and olfactory reflexes.
Inferior
This is gray matter surrounding the cerebral aquaduct involved in pain suppression. It coordinates somatic and autonomic reactions to pain, threats, and emotions. Activity results in fight-or-flight reactions and in vocalization during laughing and crying.
Periaquaductal gray
In ______ ______, transection of the midbrain at the midcollicular level causes decerebration (disconnection) of cerebral control. The patient is comatose.
Decerebrate rigidity
In decerebrate rigidity, the _______ system drives the rigidity which is released from control by higher centers.
Vestibular
This type of fish has cell bodies of the cerebellum on the surface, and the cerebellum does not bulge out as it does in other craniates.
Agnathans
This type of fish has a well-developed cerebellum and restiform bodies.
Chondrichthyes
In this type of fish, the cerebellum is more developed. It is larger in the fishes than amphibians because swimming involves schooling, vertical movements, adjusting to water currents and keeping the dorsal part of the body from tipping over.
Teleosts
In these the cerebellum is poorly developed. Aquatic urodeles rely more on spinal cord reflexes and primitive hindbrain nuclei for muscle swimming coordination.
Amphibians
In these, there is a poorly developed metencephalon. The cerebellum is more developed in swimmers, and there are floccular lobes which may correspond to restiform bodies.
Reptiles
In these there is a very large cerebellum, which is associated with flight. There are also well-developed floccular lobes.
Birds
In these there is a well-developed cerebellum. It is controlled by motor cortex in the cerebral hemispheres and is connected to the brainstem by three pairs of large fiber tracts called peduncles.
Mammals
The three large peduncles (cerebral tracts) that connect the cerebellum to the brainstem are superior to the ________, middle to the ________, and inferior to the ________.
Midbrain
Cerebellum
Medulla
The roof of the mesencephalon is the _______ which displays a prominent pair of optic lobes in all craniates.
Tectum
The _______ lobes in craniates contain gray matter masses, serve as reflex and relay centers for impulses from the retina, and are especially large in birds.
Optic
Chondrichthyes and amphibians have (WELL/POOR) developed optic lobes and tracts.
Well
In amniotes there are two pairs of dorsal lobes, called…
Optic lobes (superior colliculi) Auditory lobes (inferior colliculi)
In amniotes there are two pairs of dorsal lobes called the optic lobes and the auditory lobes. Collectively, these are called…
Corpora quadrigemina
The floor (basal plate) of the mesencephalon is the _________ and it carries large fiber tracts and red nuclei in mammals.
Tegmentum
This lies along the midline of the medulla and midbrain. It’s important in maintaining wakefulness and damage may result in permanent coma.
Reticular formation
All sensory input that enters the brain via the medulla is also sent to neurons of the _______ _______.
Reticular formation
The reticular formation receives input from ______ ______ and may use this input as a basis for its decisions.
Cerebral cortex
The reticular formation functions in:
- Modulates sensation of ______
- Modulates certain postural reflexes and muscle tone
- Helps control ________ and ________
- Regulates level of brain arousal and consciousness
Pain
Breathing
Heartbeat
The RAS (reticular activating system) is made up of diffuse aggregations of cells. It has a __________ zone that consists of large cells restricted to the medial 2/3 of the reticular formation, and the __________ zone has small cell found in lateral regions.
Magnocellular
Parvocellular
The magnocellular zone is characterized by a specific type of neuron with long radiating ________. They spread out in a plane perpendicular to long axis of brain stem and are suited to pick up information from a variety of sources.
Dendrites
