chapter 3: structure of the nervous system Flashcards
neuraxis
imaginary line drawn through the CNS from the bottom of the bottom of the spinal cord to the front of the brain
anterior/posterior
front/back
rostral/caudal
toward nose and mouth / toward tail
dorsal/ventral
top of the head and back / front of the head and front of the body
medial/lateral
toward center / toward sides
ipsilateral/contralateral
same side / opposite sides
coronal anatomical plane
divides brain into front and back
horizontal anatomical plane
divides brain into top and bottom
sagittal anatomical plane
divides brain into left and right
meninges
protective sheath surrounding the brain and spinal cord
dura mater
outer layer of the meninges that is thick and flexible but not stretchy
arachnoid
middle layer of the meninges that is soft, web-like, and spongy
pia mater
inner layer of the meninges that is thin and contains small blood vessels
subarachnoid space
space between the arachnoid and pia mater layers that contains cerebrospinal fluid
how many ventricles are in the brain?
4
lateral ventricles
two identical c-shaped ventricles located in each hemisphere of the forebrain that wrap around the third ventricle
third ventricle
ventricle in the forebrain that helps divide the brain into symmetrical halves
fourth ventricle
ventricle closer to the cerebellum in the hindbrain that connects to the third ventricle through the cerebral aqueduct which is located in the midbrain
choroid plexus
special tissue with a rich blood supply that extends into all four ventricles and produces cerebrospinal fluid
why are ventricles so important regarding cerebrospinal fluid?
the brain is fully immersed in CSF and the ventricles are where it is produced
how does CSF generally flow?
CSF is produced in all ventricles but starts in the lateral ventricle, then leaves the fourth ventricle through gaps in the subarachnoid space and is reabsorbed into the blood supply
what is the purpose of cerebrospinal fluid?
protects the brain from damage due to sudden head movements
obstructive hydrocephalus
blockage of normal CSF flow that increases pressure on the ventricles causing the ventricular walls to expand, can be fatal
what are the three major divisions of the brain?
forebrain, midbrain, and hindbrain
telencephalon
subdivision of the forebrain that contains most of the cerebral cortex, the basal ganglia, and the limbic system
cerebral cortex
the small (sulci) and large (fissures) grooves and bulges (gyri) on the brain that increase the surface area
what are the four lobes of the cerebral cortex?
frontal, parietal, temporal, and occipital lobes
what is the majority of the brain made up of?
gray matter which consists of myelinated axons
motor cortex
contains the premotor and motor association cortex
premotor cortex (motor association cortex)
directly controls movement
primary motor cortex
processes sensory information from the PNS
prefrontal cortex
critical to our executive function, planning, decision making
sensory cortex
located in the parietal lobe, contains the primary visual, auditory, and somatosensory cortexes
primary somatosensory cortex
receives sensory information from the body (except for smell and taste) and sends it to the contralateral primary sensory cortex
lateralization
the brain hemispheres both have their own prominent features
functions of the left hemisphere
analysis of information, logic, recognition of serial events, sequences of behavior, parts that make up a whole
functions of the right hemisphere
synthesis of information, creativity, putting events together to be perceived as a whole
corpus callosum
bundle of axons that connects the two hemispheres of the brain and facilitates communication between them
“split brain” procedure
in extreme medical cases such as sever epilepsy, the corpus callosum is removed and the only thing left connecting the two hemispheres is the optic chiasm
limbic system
medial edge of the cerebral hemispheres that contains the hippocampus and the amygdala and is responsible for emotional responses
fornix
a bundle of axons connecting the hippocampus and other areas of the brain including the hypothalamus
basal ganglia
collection of nuclei that includes the caudate nucleus, putamen, and globus pallidus, involved in the control of movement
diencephalon
subdivision of the forebrain between the telencephalon and the mesencephalon that surrounds the third ventricle and includes the thalamus and hypothalamus
thalamus
a sensory relay station that sends most of its neural input to the cerebral cortex
what are the nuclei of the thalamus and what kind of sensory input do they receive?
lateral geniculate nucleus receives visual input, medial geniculate nucleus receives auditory input, and ventrolateral nucleus doesn’t receive sensory input
how are the thalamus lobes connected?
a bridge of gray matter called the massa intermedia
hypothalamus
controls the autonomic nervous system and the endocrine system through the pituitary gland,
what are the two pituitary glands and what do they control?
anterior pituitary gland controls the endocrine glands and release of sex hormones, posterior pituitary gland controls the release of oxytocin and vasopressin
mesencephalon
subdivision of the forebrain that surrounds the cerebral aqueduct and contains the tectum and tegmentum
tectum
contains the superior colliculi which is important for auditory stimuli and the inferior colliculi which is important for visual stimuli and controls visual reflexes and reactions to moving stimuli
