Lecture 2: Structure and function of the nervous system Flashcards
anatomical terminology:
Dorsal
ventral
rostral
caudal
Dorsal: the back
ventral: the belly
rostral: the beak
caudal: the tail
Cross-sections of the brain:
coronal
sagittal
axial
coronal: front to back
sagittal: left to right
axial: top to bottom
The nervous system:
CNS
brain (cerebrum, cerebellum, brainstem)
spinal cord
cluster of neurons in CNS
Nuclues (nuclei)
The nervous system:
PNS
Nervous system that is not the brain and spine.
cluster of neurons in PNS
ganglion (ganglia)
Function of PNS
to connect the CNS to the limbs and organs
PNS consists of 2 systems
somatic motor system: voluntary muscles
autonomic motor system: involuntary muscles (reflexes) and organs. system is always active but can be in a sympathetic or parasympathetic state
sympathetic state
expending the energy (fight or flight)
Parasympathetic state
conserving energy (rest and digest)
CNS:
Grey matter
neurons can be found in the thin sheet of tissue on the outside of the brain, this is the grey matter
CNS:
White matter
neurons in distant brain areas are connected via axons with myelin sheets that form the white matter.
CNS:
menignes
The three protective layers of membranes that the CNS is covered in.
1. dura matter: thick membrane, closest to the scull
2. arachnoid matter: not attached to the dura matter does not line the brain down to the sulci.
3. pia matter: delicate membrane that firmly adheres to the surface of the brain. can get infected; mengingites)
CNS:
cerebrospinal fluid (CSF)
your brain floats in CNF; the area between the arachnoid membrane and the pia matter (subarchnoid space) is filled with CNF.
CNF is there to protect the brain. it reduces shock when hit on the head. and to clean it.
CNS:
4 large Ventricles
cavities in the brain filles with CSF
1. left and right lateral ventrical
2. third ventricle
3. fourth ventricle
interventricular foramen
a short passage extending from the lateral ventricle to the third ventricle
cerebral aquaduct
narrow 15mm conduit that allows for cerebrospinal fluid (CNF) to flow between third and fourth ventricle
Bloodsupply:
irruptions of the blood supply to the brain can be caused by?
obstruction of an artery
heamorrhage from the blood vessel
> causes damage to the brain (brain lesions)
Two main sources of blood supply
internal carotid arteries
vertebral arteries
basilar artery
left and right arteries merge at the level of the pons: basilar artery
basilar artery and internal cartotid meat at the circle of willis
Spinal cord
cervical, thoracic, lumbar, sacral and coccygeal
sensory signals enter the spinal cord via?
the dorsal horn (afferent signals)
Afferent signals
Towards the CNS
sensory signals leave the spinal cord via?
ventral horn (efferent signals)
Efferent signals
away from the CNS
Three parts of the brainstem:
medulla: oblongata
pons +cerebellum
midbrain
Medulla
responsible for automatic (involuntary) functions such as heart rate, sneezing, blood pressure.
corticospinal motor axons
axons coming from the cortex to the spinal cord. the motor neurons from left hemisphere cross here to contol muscles from the right side of the body
Pons
pons: bridge. contains nuclei that connect the forebrain to the cerebellum.
Nuclei that deal with sleep, swallowing, facial expressions and more (related to sleep paralysis)
Cerebellum
Cerebellum: Little brain. mostly known for involvement in motor control and maintaining balance.
also implicated in aspects of congitive processing (language, attention)
Reticular formation
located througout the brainstem
involved in arousal and attention.
damage affects the state of consciousness (coma)
home of the raphe nuclei (serotonin synthesis)
Midbrain (mesenchepahlon)
Dorsal part:
dorsal part: superior and inferior colliculi that are involved in reflections towards visual and auditory stimuli.
midbrain (mesenchepahlon)
Ventral part:
Ventral part: ventral tegment area and substantia nigra where dopamine is produced.
periaqueductal grey: modulation of pain signals.
Diencephalon consist of two areas
Thalamus and hypothalamus
Thalamus
left and right thalamus is connected via the massa intermedia
switch board of the brain; receives al input from sensory areas of the brain except for smell
4 types of Nuclei in the Thalamus
Lateral geniculate nucleus: visual information
medial geniculate nucleus: auditory information
ventral posterior nuclei: somatosensory information
pulvinar: attention and integrative functions.
Hypothalamus
controls the functions necessary for homeostatis (normal state of the body)
body temperature
metabolic rate
circadian rhythm
produces hormones but also regulates hormone production in other areas for example in the Pituitary gland
Thelecephalon (cerebrum)
Limbic system, basal ganglia, olfactory bulbs and cerebral cortex
Limbic system
hippocampus: critical for memory, spatial processing
amygdala: emotional processing
basal ganglia
striatum: putamen + caudate nucleus
globus pallidus
nuclues accumbend
regulating voluntary motor control, movement modulation, procedural learning, and various cognitive and emotional processes.
olfactory bulbs
processing of olfactory information (smell)
cerebral cortex
thin folded sheet of neurons and supporting cells.
gyri & sulci
folding of the cerebral cortex creates convolutions (gyri) and concavities between the gyri (sulci)
central suclus
dividing concavity between frontal and parietal lobe.
4 devisions in cerebral cortex
frontal lobe
parietal lobe
occipital lobe
temporal lobe
Frontal lobe
motor cortex: in front of central sulcus
primary motor cortex: generating movements
premotor cortex: controlling movements
supplemental motor cortex: planning movements.
frontal lobe
Prefrontal cortex
executive functions: planning, organizing, controlling and executing behavior.
last to develop: evolutionary the youngest
The parietal lobe
somatosensory cortex:
primary somatosensory cortex (S1); receives an input from the thalamus. info about pain, touch, temperature, limb position.
Secondary somatosensory cortex (S2); unimodal association area that further processes sensory information
The temporal lobe
Auditory cortex
The occipital lobe
Visual cortex
Structural connectivity relates to functional connectivity.
Wernicke’s area & Broca’s area
language processing, wernicke’s area (related to interpreting an auditory code) is strongly connected to distant Broca’s area (related to speech production) via a dense bundle of axons = Arcuate fasciculus.
The size of the brain quadruples from birth to adulthood, How?
the size of the brain quadruples from birth to adulthood.
because of synaptogenisis; the formation of synapses. and the growth of dendric trees, exention of axons and myelineation and proliferation of glial cells
