Brain Flashcards
part of the CNS enclosed in the
cranial cavity
Brain
•composed of 100 billion
neurons & 10 to 15 trillion
neuroglia
• ave. wt.: 1.5 kg
Brain
The average weight of the brain?
1.5 kg
• receives 15%-20% of the blood
pumped by the heart.
Brain
• highly metabolic organ
• consumes 80% of glucose &
15% of O2
that body uses
• glucose & O2 not stored in brain
Brain
• is continuous with the spinal
cord and consists of the
medulla oblongata, pons,
midbrain & reticular formation
Brain Stem
• located above the brain stem &
consists mostly of the thalamus
& hypothalamus
DIENCEPHALON
• forms the bulk of the brain,
supported on the diencephalon &
brain stem
CEREBRUM
• located posterior to the brain stem
CEREBELLUM
• bony structure protecting the
brain
SKULL/CRANIUM
• consistent with the spinal
meninges
• consists of 3 layers: the
outermost dura mater, middle
arachnoid mater & innermost
pia mater
MENINGES
• a clear, colorless liquid w/c
contains small amounts of
glucose, proteins, lactic acid,
urea, cations (Na+, K+, Ca++
,
Mg++), & anions (Cl-
, HCO3-
) &
some WBCs
CSF
Average volume of CSF
80-150 mL
• functions:
✓ carries needed chemicals from
the blood to neurons &
neuroglia
✓ removes wastes produced by
brain & spinal cord cells
✓ protects the spinal cord & brain
from chemical & physical injury
CSF
• circulates through the
subarachnoid space around the
brain & spinal cord, through
cavities in the brain known as
ventricles & through the
central canal of spinal cord
CSF
•related to CSF
Production & Absorption
•space between pia mater &
arachnoid mater
•surrounds brain & spinal cord
•where CSF circulates
Subarachnoid
•related to CSF
Production & Absorption
•CSF-filled chambers in the brain
there are four namely:
✓ two lateral ventricles (found in each
hemisphere of cerebrum)
✓ one third ventricle (found inferior
to lateral ventricle
✓ one fourth ventricle (found bet.
brain stem & cerebellum inferior to
third ventricle)
VENTRICLES
•related to CSF
•Production & Absorption
are specialized networks of
capillaries in the walls of the
ventricles lined w/ ependymal
cells
•where CSF is produced from blood
plasma
CHOROID PLEXUS
•related to CSF
•Production & Absorption
fingerlike extensions of arachnoid
mater
•gradually absorbs CSF
ARACHNOID VILLI
•related to CSF
Production & Absorption
•large veins w/in dura mater where
CSF drains & becomes blood
plasma again
CRANIAL VEINOUS SINUSES
is the part of the brain between
the spinal cord & diencephalon
BRAIN STEM
•MAJOR REGIONS of the Brainstem
• or “medulla”
• a continuation of the spinal
cord
• forms the inferior part of the
brain stem
MEDULLA OBLONGTA
• its gray matter contains
several nuclei:
•MAJOR REGIONS of the Brainstem
• within its white matter are all
ascending & descending
tracts extending between the
spinal cord & other parts of
the brain
• where most sensory & motor
fibers decussate
MEDULLA OBLONGTA
•NUCLEI of the Medulla
• adjusts the force & rate of
heart beat
CARDIAC CENTER
•NUCLEI of the Medulla
• regulates blood pressure by
adjusting diameter of blood
vessels
VASOMETOR CENTER
•NUCLEI of the Medulla
• adjusts the basic rhythm &
rate of breathing
MEDULLARY RESPIRATORY CENTER
•NUCLEI of the Medulla
• other nuclei w/c control
reflexes for swallowing,
vomiting, coughing,
hiccupping, & sneezing
REFLEX CENTER
•NUCLEI of the Medulla
• pairs of cranial nerves VIII to
XII
NUCLEI of CRANIAL NERVES
MAJOR REGIONS of the Brainstem
• located superior to the medulla
& anterior to the cerebellum
• bulges anteriorly
• a bridge whose white matter
contains tracts w/c connect parts
of the brain w/ one another
PONS
MAJOR REGIONS of the Brainstem
• its gray matter contains several
nuclei w/c are sites where
signals for voluntary movements
that originate in the cerebrum
are relayed into the cerebellum
• its other nuclei are respiratory
centers that control breathing
• also contains nuclei for pairs of
cranial nerves V to VIII
PONS
MAJOR REGIONS of the Brainstem
• connects the pons to the
diencephalon
• its white matter contains tracts
w/c conduct nerve impulses from
the cerebrum to the spinal cord
MIDBRAIN
MAJOR REGIONS of the Brainstem
• its gray matter contains nuclei
w/c are reflex centers for the ff.:
✓startle (auditory) reflex
✓visual reflex
MIDBRAIN
MAJOR REGIONS of the Brainstem
• also contains nuclei for pairs of
cranial nerves III & IV w/c
coordinate eye movements
MIDBRAIN
MAJOR REGIONS of the Brainstem
• group of nuclei scattered
throughout brain stem
• major component of the
reticular activating system w/c
maintains arousal & regulates
sleep-wake cycle
• damage causes coma
RETICULAR FORMATION
• is the part of the brain superior
to the brain stem
DIENCEPHALON
MAJOR REGIONS of the
Diencephalon
• egg-shaped structure w/c
forms bulk of diencephalon
• the relay station for all
sensations except smell
THALAMUS
MAJOR REGIONS of the
Diencephalon
• groups sensory impulses &
transmits them to the cerebrum
for localization & processing
• can suppress unimportant
sensations to permit
concentration
THALAMUS
MAJOR REGIONS of the
Diencephalon
• small part of diencephalon
located inferior to the
thalamus
• has numerous functions & is
the major regulator of
homeostasis
HYPOTHALAMUS
MAJOR REGIONS of the
Diencephalon
• functions:
✓ controls ANS
✓ produces hormones (ADH,
oxytocin & releasing hormones)
✓ regulates emotional &
behavioral patterns
HYPOTHALAMUS
MAJOR REGIONS of the
Diencephalon
✓ regulates eating & drinking
(feeding, satiety & thirst center)
✓ controls body temp.
(thermoregulatory center)
✓ acts as biological clock that
regulates circadian rhythms
HYPOTHALAMUS
• located posterior to the medulla
& pons and below the cerebrum
• consists of two cerebellar
hemispheres
CEREBELLUM
• functions:
✓ coordinates movement of
skeletal muscles
✓ regulates posture & balance
CEREBELLUM
• largest part of the brain
• the “seat of intelligence”
• divided into left & right
hemispheres
CEREBELLUM
STRUCTURES / REGIONS related
to the Cerebrum
• a region of gray matter that
forms the outer rim of the
cerebrum
• contains several nuclei
divided into functional areas
CEREBELLUM CORTEX
STRUCTURES / REGIONS related
to the Cerebrum
• the “executive suite” of the
nervous system
• the home of the “conscious
mind”
CEREBRAL CORTEX
STRUCTURES / REGIONS related
to the Cerebrum
• the convolutions or “folds “
of the cerebral cortex
• increase the surface area of
the cortex
GYRI
STRUCTURES / REGIONS related
to the Cerebrum
• singular: sulcus
• the shallow grooves between
the gyri
SULCI
STRUCTURES / REGIONS related
to the Cerebrum
• the deep grooves
FISSURES
STRUCTURES / REGIONS related
to the Cerebrum
• separates the cerebrum into
right and left halves called
cerebral hemispheres
LONGITUDINAL FISSURE
STRUCTURES / REGIONS related
to the Cerebrum
• a broad band of white matter
containing axons that connect
the two cerebral hemispheres
internally
CORPUS COLLOSUM
STRUCTURES / REGIONS related
to the Cerebrum
• the four lobes that make up
each cerebral hemisphere
• each lobe has several
functional areas across entire
cortex
FRONTAL, PARIETAL, OCCIPITAL & TEMPORAL LOBES
STRUCTURES / REGIONS related
to the Cerebrum
• separates the frontal and
parietal lobes
CENTRAL SULCUS
STRUCTURES / REGIONS related
to the Cerebrum
• a major gyrus located
immediately anterior to the
central sulcus
• contains the primary motor
area of the cerebral cortex
POSTCENTRAL GYRUS
STRUCTURES / REGIONS related
to the Cerebrum
• located internal to the cerebral
cortex (gray matter)
• made of myelinated nerve fibers
that connect the lobes of the
cerebrum to one another & to
all other parts of the brain.
CEREBRAL WHITE MATTER
STRUCTURES / REGIONS related
to the Cerebrum
• transmit impulses:
✓ between gyri in the same
hemisphere
✓ from the gyri in one
cerebral hemisphere to the
corresponding gyri in the
opposite cerebral
hemisphere via the corpus
callosum
✓ from the cerebrum to other
parts of the brain and
spinal cord
CEREBRAL WHITE MATTER
STRUCTURES / REGIONS related
to the Cerebrum
• or “basal ganglia”
• collective term for the nuclei
that lie deep within each
cerebral hemisphere
BASAL NUCLEI
STRUCTURES / REGIONS related
to the Cerebrum
• regulates the ff.:
✓ initiation & termination of
movements
✓ muscle tone
✓ subconscious contractions
of skeletal muscles
BASAL NUCLEI
STRUCTURES / REGIONS related
to the Cerebrum
• a ring of structures on inner
border of cerebrum & floor of
diencephalon
• the “emotional brain”
LIMBIC SYSTEM
STRUCTURES / REGIONS related
to the Cerebrum
• plays a primary role in a range of
emotions (e.g., pain, pleasure,
docility, affection & anger)
• hippocampus: functions in
memory together with parts of
the cerebrum
LIMBIC SYSTEM
FUNCTIONAL AREAS of Cerebral Cortex
▪ receive sensory information
from the various receptors &
sensory/ascending tracts
▪ involved in the conscious
awareness of a sensation called
“perception”
SENSORY AREAS
FUNCTIONAL AREAS of Cerebral Cortex
•Sensory Areas
• functions:
perception of touch, pressure,
vibration, proprioception, pain,
itching, tickle & temp.
allows one to discriminate where
sensations originate
a.) PRIMARY SOMATOSENSORY AREA
FUNCTIONAL AREAS of Cerebral Cortex
1. Sensory Areas
• location: occipital lobe
• function:
visual perception
PRIMARY VISUAL AREA
FUNCTIONAL AREAS of Cerebral Cortex
1. Sensory Areas
• location: temporal lobe
• function:
perception of sound
PRIMARY AUDITORY AREA
FUNCTIONAL AREAS of Cerebral Cortex
1. Sensory Areas
• location: parietal lobe
• function:
perception & discrimination of
taste
PRIMARY GUSTATORY AREA
FUNCTIONAL AREAS of Cerebral Cortex
1. Sensory Areas
• location: temporal lobe
• function:
perception & discrimination of
smell
PRIMARY OLFACTORY AREA
FUNCTIONAL AREAS of Cerebral Cortex
▪ control the execution of
voluntary movements
MOTOR AREAS
FUNCTIONAL AREAS of Cerebral Cortex
2. Motor Areas
• location: frontal lobe (pre-
central gyrus)
• function:
contraction of specific skeletal
muscles on contralateral or
opposite side of the body
PRIMARY MOTOR AREA
FUNCTIONAL AREAS of Cerebral Cortex
2. Motor Areas
• location: frontal
• impairment causes nonfluent,
expressive or Broca’s aphasia
• function:
translates thoughts into speech
BROCA’S MOTOR SPEECH AREA
FUNCTIONAL AREAS of Cerebral Cortex
▪ makes associations bet. various
kinds of sensory information
▪ also associates new sensory
inputs w/ memories of past
experiences & plans
appropriate motor responses
ASSOCIATION AREAS
FUNCTIONAL AREAS of Cerebral Cortex
3. Association Areas
• location: parietal lobe
• functions:
integrates & interprets what is
felt such as the exact shape &
texture of an object
SOMATOSENSOTARY ASSOCIATION AREA
FUNCTIONAL AREAS of Cerebral Cortex
3. Association Areas
• location: occipital lobe
• functions:
interprets what is being seen
relates present & past visual
experiences
VISUAL ASSOCIATION AREA
FUNCTIONAL AREAS of Cerebral Cortex
• location: temporal lobe
3. Association Areas
• location: temporal lobe
• function:
interprets sound
AUDITORY ASSOCIATION AREA
FUNCTIONAL AREAS of Cerebral Cortex
3. Association Areas
• location: temporal lobe
• function:
interprets the meaning of speech
by recognizing spoken words
• impairment causes fluent,
receptive or Wernicke’s aphasia
WERNICKE’S AREA
FUNCTIONAL AREAS of Cerebral Cortex
3. Association Areas
• location: frontal lobe
• function:
carries out learned motor skills by
allowing different muscles to
contract in a specific sequence
PREMOTOR AREA
FUNCTIONAL AREAS of Cerebral Cortex
3. Association Areas
• location: frontal lobe
• functions:
personality, intellect, complex
learning abilities, recall of
information, initiative, judgment,
foresight, reasoning, conscience
• functions:
intuition, mood, planning for the
future, & development of abstract
ideas
PREFRONTAL AREA
• relay sensory input from somatic
sensory receptors to the primary
somatosensory area in the cerebral
cortex
SOMATIC SENSORY PATHWAYS
• transmit motor output from primary
motor area in the cerebral cortex to
the skeletal muscles
SOMATIC MOTOR PATHWAYS
• refers to the functional
asymmetry of the two cerebral
hemispheres
HEMISPHERIC LATERALIZATION
• receives sensory signals from
and controls the right side of
the body
LEFT HEMISPHERE
• more important for spoken &
written language, numerical &
scientific skills, ability to use &
understand sign language &
reasoning in most people
LEFT HEMISPHERE
• more important for musical &
artistic awareness, spatial &
pattern perception, recognition
of faces & emotional content
of language & for generating
mental images of sight, sound,
touch, taste, & smell
RIGHT HEMISPHERE
• innervate specific areas of the
body & function could be
sensory, motor or both
CRANIAL NERVES
• part of the PNS
• 12 pairs of nerves whose cell
bodies originate from the brain
• numbered I to XII from superior
to inferior
CRANIAL NERVES
CRANIAL NERVES
sensory function:
smell
OLFACTORY NERVE (CN I)
CRANIAL NERVES
• sensory function:
vision
OPTIC NERVE (CN II)
CRANIAL NERVES
• motor function:
moves eyelid & eyeball
constricts pupil
OCULOMOTOR NERVES (CN III)
CRANIAL NERVES
• motor function:
moves eyeball
TROCHLEAR NERVE (CN IV)
CRANIAL NERVES
• sensory function:
corneal reflex
facial sensations
• motor function:
mastication
TRIGEMINAL NERVE (CN V)
CRANIAL NERVES
• motor function:
moves eyeball
ABDUCENS NERVE (CN VI)
CRANIAL NERVES
• sensory function:
taste (anterior 2/3 of
tongue)
• motor function:
facial expression
FACIAL NERVE (CN VII)
CRANIAL NERVES
• sensory function:
hearing
balance/equilibrium
VESTIBULOCOCHLEAR NERVE (CN VIII)
CRANIAL NERVES
• sensory function:
taste (posterior 1/3 of
tongue)
detects changes in BP &
pH of blood
• motor function:
swallowing
speaking
GLOSSOPHARYNGEAL NERVE (CN IX)
CRANIAL NERVES
• sensory function:
detects changes in BP &
pH of blood
• motor function:
swallowing
speaking
coughing
decreases heart rate
peristalsis
increases digestive secretions
VAGUS NERVE (CN X)
CRANIAL NERVES
• motor function:
moves head & shoulder
(innervates trapezius &
sternocleidomastoid
muscles)
• motor function:
moves tongue
HYPOGLOSSAL NERVE (CN XII)
• part of the PNS
• consists of cranial & spinal
nerves whose motor & sensory
fibers innervate smooth &
cardiac muscles & glands
• is different from the somatic
nervous system in many ways
AUTONOMIC NERVOUS SYSTEM
What does CSF stand for??
CEREBROSPINAL FLUID
