Chapters 1 and 2 Flashcards
anterior/rostral
front
posterior/caudal
back
inferior
below (toward ventral)
superior
above (toward dorsal)
medial
middle
lateral
side/away from middle
three principal planes of reference
coronal, sagittal, horizontal
coronal
cut in half by hemispheres
sagittal
cut in half by front and back
horizontal
cut in half horizontally
gyrus (gyri)
a small protrusion of bump formed by the folding of the cerebral cortex
sulcus (sulci)
a groove in brain matter, often found in the neocortex or cerebellum
fissure
a very deep sulcus
neuropsychology
the study of the relationship between behavior, mental processes, and biological factors
- nervous system
- biochemistry
- hormones
- genetics
neuroscience
the overarching discipline that covers many areas dealing with the nervous system
ancient civilization and the brain
craniotonomy-skulls were opened and brains were exposed since the Paleolithic and Neolithic times
- usually undertaken to treat head injuries
- how much evidence about brain functions was brought from that era is lost because of the absence of written language among these early people
Edwin Smith surgical papyrus
- dated to 1700 BCE
- first recorded writing about the brain
- Egyptians thought the brain was less important than other organs –> during mummification they would remove the brain and throw it away
- Greeks started seeing the importance of the brain
The Canon of Medicine by Persian physician-philosopher Avicenna c. 1025
- Persians compiled first medical textbook
- used as standard medical textbook through the 18th century in Europe and the Islamic world
- divided into 5 books
- style of this textbook is still used in Western medical education today
trepanation
- first attempt at brain surgery
- boring holes in the head
- relieve pressure, drain puss, or let out evil spirits
- blacksmiths performed this
Renaissance
- artists like Leonardo da Vinci and Michelangelo began depicting the brain and nervous system in art
monism
the mind is what the brain does; they are one
lesion studies (19th century)
the birth of modern neuropsychology
19th and 20th century
- time of great advancements in research methods, theories, and staining techniques
- Charles Darwin
- Wilhelm Wundt (first to study the mind as separate from other fields)
- Camillo Golgi
- Santiago Ramón y Cajal
- phrenology
phrenology
pseudoscience about reading the bumps on the skull
- Franz Josef Gall
- named the bones of the skull first, then named brain lobes after them
Broca’s aphasia
inability to produce words (vocally)
Broca and the localization of speech
exhibited the brain of his patient “Tan” who had died only the day before and who had not been able to speak normally, with the only that he was able to utter was “Tan”
- lesion lay in the posterior part of the left frontal lobe
dorsal
top
ventral
bottom
ipsilateral
same side
- same side of the body as the hemisphere
contralateral
opposite side
- opposite side of the body as the hemisphere
meninges
the protective sheath around brain and spinal cord
dura mater
tough, flexible outermost meninx; thick outer meninges layer against the skull
arachnoid membrane
middle layer of the meninges; web-like membrane between the dura and pia mater; contains CSF and blood vessels
pia mater
last layer of the meninges, which adheres to the surface of the brain; thin membrane following the contours of the cerebral cortex
layers outside of the brain
skull –> dura mater –> arachnoid membrane –> pia mater –> subarachnoid space (filled with CSF)
gray matter
cell bodies
- outer part of the brain
- inner layer of the spinal cord
white matter
nerve tracts; myelin sheaths of the neuron
- inner part of the brain
- outer layer of the spinal cord
ventricles
set of holes within brain filled with CSF
epidural hematoma
a collection of blood that pools in the space between the skull and dura mater
subdural hematoma
a collection of blood that pools in the space between dura and arachnoid space
treatment of hematoma when there is inflammation
remove a portion of the skull to relieve pressure on inflammation
ventricular system and production of CSF
- production of CSF begins in the lateral ventricles (one in each hemisphere)
- CSF goes into third ventricles then cerebral aqueduct then fourth ventricle
- CSF goes outside to buffer the cerebral cortex
- as CSF flows, it picks up cell waste
- drains CSF in the arachnoid granulations into the veins so that the CSF is carried to other parts of the body and, ultimately, the heart
ependymal cells
make up the walls of the lateral ventricles and produces CSF that is released into the lateral ventricles
the brain receives blood supply from four arteries
- two internal carotid arteries
- two vertebral arteries
arch of the aorta
- right common carotid artery
- left common carotid artery
- right vertebral artery (off the right subclavian artery)
- left vertebral artery (off the left subclavian artery)
right common carotid artery
- right external carotid artery
- right internal carotid artery
left common carotid artery
- left external carotid artery
- left internal carotid artery
blood supply of the central nervous system
- begins in the arch of the aorta and leaves through the external carotid arteries (goes to the face), common carotid arteries (goes to the brain), and vertebral arteries
- vertebral arteries feed the spinal cord
- internal carotid arteries and vertebral arteries carry blood to the Circle of Willis
- vertebral arteries carry blood to the occipital lobe
the two vertebral arteries unite to form…
basilar artery
basilar artery bifurcates into…
two posterior cerebral arteries
principal branches of the internal carotid artery
anterior cerebral artery, middle cerebral artery, posterior communicating artery
through the principal branches of the internal carotid artery…
supplies both cortical and sub-cortical structures of the brain
ophthalmic artery
gives rise to central artery of retina; supplies the retina
posterior cerebral artery
supplies posterior part of the cerebrum
feed the pons
basilar artery and pontine arteries
pontine arteries
come off of the basilar artery
internal carotid artery feeds 5 branches
- ophthalmic artery
- middle cerebral artery
- anterior cerebral artery
- posterior communicating artery
- anterior choroidal artery
anterior inferior cerebellar artery
feeds the cerebellum; comes off the basilar artery
vertebral artery
feeds the spinal cord
middle cerebral artery
feeds the two hemispheres
posterior inferior cerebellar artery
feeds the cerebellum; comes off the vertebral arteries
there are __ of each artery
2
- exception is basilar artery
central nervous system (CNS)
brain and spinal cord
peripheral nervous system (PNS)
nerves outside the CNS throughout the body
- cranial nerves, ganglia outside CNS, spinal nerves
two divisions of the peripheral nervous system
somatic nervous system and autonomic nervous system
two divisions of the autonomic nervous system
sympathetic nervous system and parasympathetic nervous system
somatic nervous system
conscious muscle movement
autonomic nervous system
not consciously controlled
sympathetic nervous system
fight or flight— high arousal
parasympathetic nervous system
low arousal; regulates movment and the internal environment
- afferent neurons transmit information to the central nervous system
- efferent neurons transmit information away from the central nervous system
neuron pathways of the spinal cord
- sensory neurons go from the skin or viscera to the dorsal root ganglion, dorsal root, then interneurons of the spinal cord
- somatic motor neurons go from the interneurons of the spinal cord to the ventral root then skeletal muscles
- preganglionic neurons go from the interneurons of the spinal cord to the ventral root, autonomic ganglion, postganglionic neuron, then viscera
viscera
internal organs
layers of the spinal cord
discs of fatty tissue (for cushioning) –> bone of spinal cord (vertebrae) –> dura mater –> arachnoid membrane –> pia mater
CSF and the spinal cord
surrounds the outside of the spinal cord as well as goes through the center of the butterfly of the spinal cord
layers of the bones (vertebrae) of the spine (from bottom to top)
coccyx and sacral vertebrae (fused) [S1-5] –> lumbar vertebrae (L1-5) –> thoracic vertebrae (T1-12) –> cervical vertebrae (C1-8)
dermatome
refers to the cutaneous area innervated by fibers from a single dorsal roots (dorsal side of the spinal cord)
What is the spinal cord made of?
gray and white matter
gray matter of the spinal cord organized in two different ways
nuclei or Rexed Laminae
nuclei organization of spinal cord
organized by nuclei (somas) based on collective function; location
Rexed Laminae organization of the spinal cord
organized by layers (laminae) within the spinal cord where cells were grouped according to their structure and function, rather than solely on location
interneurons
only located in the central nervous system
spinal cord sensory pathways
- spinothalamic tract
- dorsal columns
- medial leminiscus tract
dorsal columns
fasciculus gracilis, fasciculus cuneatus
spinothalamic tract
- major sensory pathway
- function: pain and temperature; some touch pressure
- originates: dorsal horn (laminae I, IV, V)
- courses: crosses immediately in spinal cord; synapse at thalamus
- terminates: somatosensory areas of cortex
- neurons of the arms connect to C8 through the dorsal horn
- neurons of the legs connect to L4 through the dorsal horn
dorsal columns (DCs)
- major sensory pathway
- function: touch (two-point, discriminative), vibration, position sense (static and kinesthesia)
- originates: from ipsilateral dorsal root ganglia
- courses: topographically within the dorsal funiculus (white matter)
- terminates: medulla (1st order neurons)
- crosses the spinal cord at the medulla into the medial leminiscus tract
- lower extremities course through the fasciculus gracilis; connect to L4
- upper extremities course through the fasciculus cuneatus; connect to C8
medial leminiscus tract
- begins after the dorsal columns synapse in the medulla and crosses the spinal cord
- function: touch (two-point, discriminative), vibration, position sense (static and kinesthesia)
- originates: at medulla (continuation of dorsal columns), crosses immediately to contralateral side, 2nd order neurons
- courses: ipsilateral; synapses at thalamus (VPL nucleus) and become 3rd order neurons
- terminates: somatosensory areas of cortex
first order sensory neurons
located roughly in the extremities
second order sensory neurons
located roughly in the spinal cord
third order sensory neurons
located roughly in the brain
first order motor neurons
located roughly in the brain
second order motor neurons
located roughly in the spinal cord
third order motor neurons
located roughly in the extremities
why ordered neurons are opposite directions for sensory and motor neurons
sensory is afferent whereas motor is efferent
motor pathways of the spinal cord split into two categories
direct pathway, indirect pathway
direct pathway of the motor pathways of the spinal cord
corticospinal tract
indirect pathways of the motor pathways of the spinal cord
reticulospinal tract, mesencephalospinal, vestibulospinal
all motor pathways are subject to modulation by…
cerebellum, basal ganglia
corticospinal tract (pyramidal tract)
- direct pathway of motor pathways
- function: modulates sensory afferents, controls gross limb movements and rapid movements, controls independent digit movement
- originates: motor and somatosensory cortexes (first order neurons)
- courses: ipsilateral to medulla then crosses (75-90%) in the medulla (pyramidal decussation); descends to all spinal cord levels
- terminates: dorsal horn, intermediate gray, and ventral horn (second order neurons) to the skeletal muscles (third order neurons)
upper motor neuron signs (due to lesions involving lateral corticospinal and descending motor tracts)
- loss (paralysis) or diminution (paresis) of movement
- increase in muscle tone (spasticity)
- hyperreflexia (exaggerated deep tendon [myotatic] reflexes
- clonus
- abnormal superficial reflexes
- babinski sign
- all are ipsilateral (when lesionis in the spinal cord) and below the level of the spinal cord lesion
lower motor neuron signs (due to lesions involving anterior horn cells)
- loss (paralysis) or diminution (paresis) of movement
- decrease in muscle tone (hypotonia)
- hyporeflexia (decrease) or areflexia (absent) deep tendon (myotatic) reflexes
- fibrillations and/or fasciculations (spontaneous activity of muscle fibers at rest)
- muscle atrophy
