Exam 1 - Structure of NS Flashcards
What is in the Central Nervous System?
brain and spinal cord
What is in the Peripheral Nervous System?
all the nerves that relay info btwn CNS and rest of the body
Anatomical Directions (Dorsal, Ventral, Medial, Ipsilateral, Contralateral)
Dorsal - towards back or top of head
Ventral - towards the belly
Medial - towards neuraxis/midline
Ipsilateral - located on same side of body
Contralateral - located on opposite side of body
Blood Brain Barrier
semi-permeable barrier between the blood and the brain, made by the cells in the walls of the brain’s capillaries, helps regulate balance of extracellular fluid and neural transmission, prevents potentially harmful chemicals from reaching the brain
Meninges
(3 layers) protective sheaths around the brain and spinal cord, 3 layers from outside to inside: Dura mater, Arachnoid membrane, Pia mater
Dura mater
durable, thick, touch outer layer (one of the meninges)
Arachnoid membrane
soft, spongy, middle layer (one of the meninges)
Pia mater
delicate, thin, inner layer, clings to the surface of the brain (one of the meninges)
Subarachnoid space (not a meninge)
area in-between arachnoid membrane and pia mater, filled with cerebrospinal fluid CSF, allows brain to float in CSF, reduces shock due to sudden movement
Cerebrospinal fluid CSF
clear fluid that fills ventricles and space surrounding brain and spinal cord, what the brain floats in, protects brain and nourishes it, removing waste and toxins. coats the CNS.
Ventricular system
produces, transports, and excretes CSF. Consists of 4 ventricles
What are ventricles in the ventricular system?
hollow spaces “little bellies” filled with CSF. This is where CSF is produced and contained. 2 lateral ventricles, 3rd ventricle, 4th ventricle
Lateral ventricles
There are 2. They are the located bilaterally in the cerebrum, connected to 3rd ventricle, They are largest in the ventricular system
3rd ventricle
located at the midline, cerebral aqueduct connects the 3rd and 4th ventricle
4th ventricle
located on the ventral side of the brain, diamond shaped, below the 3rd ventricle. connected to the 3rd ventricle by cerebral aqueduct
CSF order of flow
Continually produced within the choroid plexus by ependymal cells. Produced in lateral ventricles and flows to 3rd and 4th ventricle, then flows to subarachnoid space of both brain and spinal via the Foramen of Magendie. Then it’s reabsorbed into blood stream by arachnoid granulations which are at the top of the meninges
Problems with CSF flow
Obstructive hydrocephalus - something impedes flow of CSF (ex. Choroid plexus may produce too much CSF), which results in increased pressure to ventricles and ventricles expand. Shunt tubes can be surgically inserted to drain excess CSF
Cerebral Cortex
(Forebrain, Tel…). Has sulci, fissures, and gyri. The convolutions (folds) allow for greater surface area. 2/3rds of the cortex are in these folds. Cortex consists of mostly glia and cell bodies, dendrites, and interconnecting axons and neurons. Has gray matter. There are hemispheres and 4 lobes and many cortices
sulci, fissures, and gyri
sulci - small grooves in brain. fissures = large grooves. gyri - bulges between sulci and fissures
gray matter vs white matter
gray matter - cell bodies. white matter - myelin that covers the axons underneath the cortex
Hemispheres of the cerebral cortex
bilateral/both hemispheres. Left and right hemisphere connected by corpus callosum. Some functions are lateralized (meaning they are located on 1 side of the brain). Each hemisphere responds to sensory info from contralateral side of the body. Left - analysis, Right - broad view of things
4 lobe names (of the cortex)
frontal, parietal, occipital, temporal
corpus callosum
large band of axons that connect L and R hemispheres
frontal lobe
movement, higher order cognitions like planning, decision making