Neuroscience Week 3: Lab 2 Study Guide Flashcards
Identify
Houses the caudate head in its lateral wall
Frontal horn of the lateral ventricles
extends deep into the occipital lobe
Occipital horn
houses the hippocampus in its anterior medial wall
Temporal horn of lateral ventricles
(aka trigone) is the convergence of the body, and temporal and occipital horns
Atrium
Choroid plexus is found in?
s the temporal horn, body and atrium produces cerebrospinal fluid (CSF) CSF flows from the lateral ventricles through the paired foramina of Monro into the 3 rd Ventricle
within the midbrain connects the 3rd and 4th ventricles.
Narrow cerebral aqueduct (of Sylvius)
CSF from the 4 th ventricle flows into the subarachnoid space through the
foramen of Magendie (in midline) and the bilateral foramina of Luschka (laterally)
Dural venous channels are mostly filled with ________ because the rate of ________ and ____________ is far slower than the rate of ___________ and ____________ into and out of the cranial vault
Dural venous channels are mostly filled with blood because the rate of CSF production and reabsorption is far slower than the rate of blood entry and reabsorption into and out of the cranial vault
(about 20ml per hour).
Arachnoid granulations comprise
e arachnoid villi, which drain from the subarachnoid space into the venous sinuses.
Neoplastic arachnoid villi cells form
meningiomas; thus meningiomas are typically found where there are the greatest concentration of arachnoid villi: at the cerebral convexity (falx cerebri) and base of the skull
Basal ganglia Description
The basal ganglia are deep brain nuclei that are involved in motor function and addiction/reward behaviors.
Parts of the Basal ganglia
Caudate nucleus
Putamen
Globus pallidus
Identify
Caudate nucleus
has a c-shaped structure with a rostral/superior Head, a Body extending caudally Tail projecting inferiorly into the temporal lobe
Putamen
Collectively, the caudate and Putatmen are known as The Striatum due to the striations that connect them.
Globus pallidus
which incorporates an External (lateral) and Internal (medial) segment, sometimes referred to as Palladium
Collectively the Putamen and the Globus Pallidus are known as
Lentiform nucleus due to their lens shape.
Lentiform nucleus is composed of?
Collectively the Putamen and the Globus Pallidus
Thalamus
The thalamus is a deep brain structure that relays information between cortex and brainstem and between cortical structures.
Thalamic nuclei
the thalamus consists of a large number of nuclei that form eight nuclear masses according to their anatomic locations. It can be divided into three major subdivisions: Anterior, Medial and Lateral.
Identify
Identify
Corticospinal Motor Pathway
- Originates from upper motor neurons located within the Primary Motor Cortex of the precentral gyrus.
- Descends through the white matter of the cerebral hemisphere (corona radiate) and then the Posterior Limb of the Internal Capsule.
- Exits the cerebrum via the crus cerebri (Cerebral Peduncles) of the Midbrain.
- Continues descending internally through the base (ventral surface) of the Pons.
- Forms the prominent Pyramids of the Medulla.
- At the junction of the Medulla and Cervical Spinal cord, the fibers decussate (crossover) and enter the column of white matter in the spinal cord on the side opposite of where they originated.
- Synapse on Lower Motor Neurons (Second Order Neurons) in the anterior horn which exit at the appropriate level.
Dorsal Column Medial Lemniscal Pathway
Anterolateral Pathway / Lateral Spinothalamic tract
Identify
Decerebrate posturing
- occurs when brainstem impairment occurs between the levels of the rostral poles of the red nucleus and vestibular nuclei.
- Both upper and lower limbs extend when a comatose patient receives an appropriate stimuli (startling painful or auditory).
- Extensor posturing is likely because of impaired extensor inhibition.
Decorticate posturing
- occurs when the brainstem lesion occurs more rostrally above the red nucleus (shown in dark blue).
- The lower limbs extend and the upper limbs flex following appropriate stimulus in a comatose patient.
Control of Facial Motor Function
- Corticobulbar input is bilateral to the portion of the facial nucleus innervating the frontalis and orbicularis oculi muscles (upper face).
- The fibers innervating the muscles of facial expression in the lower half of the face arise in the portion of the nucleus that receives only contralateral corticobulbar projections.
UPPER MOTOR VS LOWER MOTOR NEURON FACIAL WEAKNESS
- With an upper motor lesion (Lesion A), the upper face is spared because both hemispheres can compensate.
- With a lower motor neuron lesion (Lesion B), the entire face is affected on one side.
Control of Ocular Motor Function
- Brainstem motor nuclei that innervate extraocular muscles (CNIII, IV and VI) do not receive direct corticobulbar innervation.
- Coordinated eye movements are carried out by cortical input to centers in the reticular formation either in the midbrain or pons, that project to the various brainstem nuclei on both sides of the midline (R and L, CNIII, IV or VI).
- Voluntary horizontal movement of the eyes is controlled by neurons in the frontal eye fields of the cerebral cortex, and each hemisphere evokes conjugate eye movement towards the opposite side.
Upper motor neuron type facial weakness vs Lower motor neuron type
Identify
Identify & Cord Segment
Identify & Cord Segment
Identify & Cord Segment
Identify & Cord Segment
Identify & Cord Segment
