Nervous system Part 2 Flashcards
(179 cards)
What are the four main divisions of the brain?
the cerebrum, cerebellum, brainstem, diencephalon
What are the protective structures of the brain and why is it important to have those protections?
Meneges, cerebrospinal fluid, the skull, and blood brain barrier.
Nervous tissue is damaged by even the slightest pressure, and can not regenerate once damaged.
Ventricles
The brain has 4 ventricles
These are cavities in the brain that are filled with cerebrospinal fluid.
Two lateral ventricles, third and fourth ventricle
Where does the 4th ventricle drain?
into the central canal of the spinal cord, which also has cerebrospinal fluid.
meninges
Three layers of connective tissue membranes that cover and protect the CNS organs and enclose the cerebrospinal fluid.
Three layers of the meninges
Dura mater (outer menix)
arachnoid (middle menix)
pia mater (inner menix)
Dura mater
leathery double-layer outer menix
arachnoid menix
a loose layer seperated from the dura mater by the subdural space (middle menix)
**beneath the arachnoid menix is the subarachnoid space.
subarachnoid space
beneath the arachnid menix
contains blood vessels and is filled with cerebrospinal fluid
Pia mater
inner menix - thin connective tissue tissue tightly attached to the brain.
Cerebrospinal Fluid
a special fluid formed in the walls of ventricles from blood plasma by permeating the choroid plexus
choroid plexus
formed by a network of blood vessels and within the ventricles
CSF that is made in the walls of the ventricals by blood plasma permeates the choroid plexus
CSF circulates through the ventricles and into the mengines.
Cerebrospinal fluid
circulates through the ventricles into the meninges
cushions the brain and spinal cord by providing buoyancy allowing the brain to float
Blood brain barrier
a diffusion barrier that prevents most particles from entering the system tissue
this keeps the brain and spinal cord separate from general blood circulation
formed by glial cells- astrocytes
astrocytes
glial cell
blood brain barrier is formed by relatively impermeable brain capillaries, due to astrocytes
this barrier provides a stable chemical environment for the neurons
why is a stable chemical environment important in the brain?
to protect neurons from chemical variations that could cause uncontrollable firing of neurons
cerebrum
foremost part of brain
largest part of brain -83% of brain mass
contains 2 large masses - left and right cerebral hemispheres
median longitudinal fissure
separates the right and left cerebral hemispheres
The right cerebral hemisphere controls the left side of the body and the right cerebral hemisphere control the left side of the body
gyri
the cerebral cortex has raised ridges of tissue called gyri (like mountains)
sulci separate the gyri -these are shallow grooves (valley in between the mountain)
transverse fissure
separates the cerebrum from the cerebellum
corpus callosum
a bridge of white nerve fibers called corpus callosum that connects the cerebral hemispheres
cerebral cortex
outer portion of cerebral hemispheres that is highly convoluted and gray in color
Frontal lobe
controls higher levels of executive functions such as reasoning and decision making
controls motor function
permits control over voluntary muscle actions
parietal lobe
receives sensory information from receptors in the mouth for taste and located in the skin, such as those for touch, pressure, pain