08 25 2014 organization of the Nervous System Flashcards
What is the basic division of the CNS?
- Prosencephalon (forebrain)
- Mesencephalon (midbrain)
- Rhombencephalon (hindbrain)
What composes the prosencephalon?
= forebrain
1. Telencephalon
cerebral hemispheres
cerebral cortex
subcortical white matter
Basal ganglion
Basal forebrain
- Dicephalon
Thalamus
hypothalamus
Epithalamus
Mesencephalon?
= midbrain
Cerebral peduncles
midbrain tectum
midbrain tegmentum
Rhombencephalon
= hind brain
Metencephalon: pons and cerebellum
Myelencephalon: Medulla
What segments compose the brainstem?
Midbrain, Pons, and Medulla
Medulla
Transition between spinal cord and brainstem
Cranial nerves: 9, 10, 11, 12
-recieves info from taste, scalp, heart and lungs, major blood vessels and digestive system.
- cardiovascular reflex, respiration, and
digestive function.
Regulates body homeostasis:
-HR, Respiration, Swallowing, vasomotor tone, gastric secretions
Related reflexes:
- vomiting, coughing, sneezing, swallowing, gagging.
Pons
bridge to cerebellum
Cranial nerves: 5, 6, 7, 8
Balance, localizing sound, coordinating eye movements, and facial expression
reflexes: eye movements and jaw jerk
Midbrain
top of brainstem (aka mesencephalon)
Cranial nerves: 3, 4
Control orienting to sound, visual reflexes, motor control.
Projections to cortex: (Dopamine projections)
- Substntia Nigra – control movements
- defect = Parkinson’s Disease - Ventral segmental area – reward system
- addiction pathway - orientation reflexes
Frontal Lobe of cortex
- function? - Location?
Planning, organizing, control, controlling behavior
Located from front of brain –> central sulcus
Separated from temporal via Sylvian fissure
Parietal Lobe of cortex
- function? - Location?
Sensory perception of self and world (know where you are and where you are in your environment)
From central sulcus –> Parieto-occipital sulcus (found in the medial aspect of brain)
Occipital Lobe of cortex
-function?
Visual processing
Temporal Lobe of cortex
-function?
Auditory processing (superior) Visual processing (middle) Memory processing (medial)
Limbic Lobe of cortex
-Function?
Emotional processing and memory consolidation
Layer 1 of cortex
Molecular layer
Dendrites and axons from deeper layers
Layer 2 of cortex
Small pyramidal layer
Cortical-cortical connections
Layer 3 of cortex
Medium pyramidal layer
Cortical-cortical connections
Layer 4 of cortex
Granular layer
Receives inputs from thalamus
Layer 5 of cortex
Large pyramidal layer
Sends outputs to subcortical structures (other than thalamus)
-brain stem, spinal cord, basal ganglion
Layer 6 of cortex
Polymorphic layer
Sends outputs to thalamus.
Thalamus
major relay station for all inputs heading into cortex.
A cluster of nuclei that have specific functions. Reticular and intralaminar nuclei receive from the reticular activating system
-projections into cortex are called thalamocortical radiations
Also regulates states of sleep and wakefulness
Reticular formation
mass of interwoven cells and synapses that go through the entire brainstem
-project into cortical ascending and several descending projections to the spinal cord
Reticular Activating system
Rostral projections from pons and midbrain
- Norepinephrine = role in wake/sleep states
- If this formation is affected, people will go into a coma and you can’t wake them up from it.
- modulates forebrain activity
Caudal Reticular formation
Medulla
- respiratory rhythms
- blood pressure
- digestions
Reflexes: facial expression, gag, yawn, swallowing, vomit.
-premotor coordination of lower somatic and visceral motor neuron pools
