1.1 Brain Anatomy
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1.1 Brain Anatomy
3 things that consist of PNS
-autonomic NS components
2 parts to the CNS
Integrates and controls the entire nervous system
What is the input that the CNS receives called?
Sensory or afferent
Information that CNS gives out
-motor or efferent
Positional terminology for the brain) towards the nose
Positional terminology for the brain) towards the back
Positional terminology for the brain) towards the tail
Positional terminology for the brain) towards the belly
4 parts of the brain
Cerebrum) total brain mass it makes up?
80% total brain mass
Cerebrum) do both sides of the cerebrum function the same?
No, they look the same but differ in function slightly
4 functions of the cerebrum
-voluntary motor function
-somatic and visceral sensory perception
-special sensory functions
-language and learning
What are the gyri ?
Hills on the cerebrum
What are the sulci
Valleys on the cerebrum
What are the gyri and sulci called collectively?
According to L Mahadevan, patterns of folding on the brain are a function of...
-cortical thickness relative to brain size
*as cortex expands, if it stays attached to the white matter below, it will physically buckle
Where can grey matter be found?
External covering of the cerebrum
Brief description of cerebral cortex (2)
-covers the gyri
-composed of unmyelinated structures
2 examples of un-myelinated structures
-neuronal cell bodies
What is the cerebral cortex like?
Bark on a tree.
What is white matter?
Internal brain nerve fibers
White matter) where can commissural fibers be found?
White matter) where are association fibers found?
Between lobes and gyri
White matter) where are projection fibers found? (3)
-lower brain areas
Where are pyramidal cell bodies located?
In cerebral cortex
Histology slide) what do projection fibers eventually turn into?
*send somatic motor signals down this tract
What are the 4 cerebral lobes?
Which the thought to be the fifth lobe?
What is a fissure?
Sulci and 4 lobes
Sulci divides each hemisphere into 4 lobes
What does the central sulcus divide?
Frontal & parental lobe
What does the Pareto-occipital sulcus divides?
Parietal and occipital lobes
Where can Parieto-occipital sulcus be seen?
What does the longitudinal fissure?
Separates left and right hemispheres
What is the precentral gyrus? (2)
-sits rostral to the central sulcus
-primary motor cortex
What is postcentral gyrus ? (2)
-Primary somato sensory cortex
-sits caudal to the central sulcus
Sensation example ) Where does sensation originate?
Sensation example ) where is it realized?
Motor example) where does volitional movement originate ?
Motor example) where is the signal realized?>
What is the paracentral lobule?
Continuation of pre and post central gyri on medial side of brain
*both coupled onto the medial side view
What does the diencephalon form?
Forms the central core of the cerebrum
What are the 4 parts of the diencephalon?
Diencephalon) how is the pituitary gland connected to the hypothalamus?
What is pineal body/gland a part of?
What does the brainstem connect?
Cerebrum to the spinal cord
What are the 3 parts of the brainstem?
Where is the cerebellum located?
Located causal and inferior to the cerebrum
What are the 3 layers of the cerebellum?
*top most layer, most pink, most bulky
*thin layer has circles
*most bottom, little granules
Meninges ) into which 2 layers does the dura mater split into?
What are the 3 meninges?
What is septa? And which are they ? (1+3)
Meningeal layer of dura forms 3 separations
What's the falx cerebri?
Between cerebral hemispheres
*in longitudinal fissures
dural septa) what is tentorium cerebelli?
Separates cerebrum from cerebellum
*covers the cerebellum like a tent
dural septa) what is falx cerebelli?
Separates left/right cerebellum hemispheres
How do dural sinuses made?
2 layers of dura split to form large veins in regions of brain such as superior sagittal sinus
What does the subarachnoid space contain?
CSF cerebrospinal fluid
Between which 2 structures does is the subarachnoid space located?
Arachnoid and pia mater
What are the 2 meningeal spaces?
How many ventricles do we have?
*2 lateral, 3rd, 4th
Lateral ventricles leak their CSF to the 3rd ventricle using
3rd ventricle leaks CSF to 4th ventricle using
Where is the septum pellucidum located?
Between lateral ventricles
What is choroid plexus?
Single layer ependymal cells lining a blood capillary
*forms a blood brain barrier
By what is the CSF produced by? And within where?
Choroid plexus within all ventricles
CSF flow (3)
-Flows from lateral to 3rd by inter-ventricular foremen then 3rd to 4th by cerebral aqueduct
-It exits 4th ventricle to subarachnoid space. It then travels all over this space surrounding and cushioning the brain and spinal cord
-exits subarachnoid space into dural sinuses (superior sagittal sinus) via arachnoid villi
How often is CSF replaced?
3-4 times per day
What is hydrocephalus?
Excessive accumulation of CSF in the brain