Brain Flashcards
major parts of the brain
cerebrum, brain stem, diencephalon, cerebellum
cranial meninges superficial to deep
scalp epicranial aponeurosis loose CT and periosteum of cranium cranium dura mater arachnoid mater subarachnoid space cerebral cortex covered by pia mater
space between the periosteal and meningeal layers contains
large veins known as sinuses
brain sinuses
veins of the brain open up into the sinuses, all of the dural sinuses interconnect and drain into the internal jugular vein
falx cerebri
between the cerebral hemispheres
tentorium cerebelli
between cerebrum and cerebellum
falx cerebelli
between the cerebellar hemispheres
diaphragm sellae
line the sella turcica and encloses pituitary gland
what are the four areas where the meningeal layer of the dura mater extends into the cranial cavity?
1) falx cerebri
2) tentorium cerebelli
3) falx cerebelli
4) diaphragm sellae
what do the four areas of meningeal layer of dura mater extensions do?
provide additional support and stability
arachnoid layer
covers brain and serves as a roof over the cranial blood vessels, contains fingerlike projections of the arachnoid (arachnoid granulations/villi) penetrate the dura mater and this is where CSF is resorbed into the venous blood
subarachnoid space
where CSF circulates
pia mater
tightly attached to the brain surface, anchored by astrocytes, floor for blood vessels. blood vessels penetrate the brain within channels lined by pia mater
ventricles of the brain are
fluid filled cavities
ventricles in the brain are lined with
ependymal cells that secrete CSF
what are the lateral ventricles separated by?
septum pellucidum
each lateral ventricle is connected to the 3rd ventricle by the
interventricular foramen
the 3rd ventricle is between the ____ in the ____
thalami, diencephalon
the aqueduct of the midbrain connects the…
3rd and 4th ventricles
the fourth ventricle is between the ____ and the ____ and is continuous with the _____ _____ of the spinal cord
pons, cerebellum, central canal
cerebrospinal fluid does what? (generally)
surrounds and bathes exposed surfaces of the central nervous system (brain and spinal cord)
functions of CSF
shock absorber (preventing contact of neural tissue with bone chemical protection (optimal chemical environment for nerve signaling) circulation (nutrients, waste products; diffusion occurs between CSF and the interstitial fluid surrounding neural cells
how is CSF formed?
choroid plexus (capillary network + ependymal cells) found in each of the ventricles, derived from plasma but not identical to it
CSF travels…
from the ventricles and central canal into the subarachnoid space through foramina in the fourth ventricle (median aperture and lateral apertures)
CSF returns to the venous blood through…
the arachnoid granulations into the dural sinuses such as the superior sagittal sinus, which is where the veins of the brain open up
what are circumventricular organs?
areas of the brain that are outside of the blood brain barrier, this allows them to monitor chemical changes in the blood.
examples of CVOs
hypothalamus, pineal gland, pituitary gland
what is the cerebrum made of?
gray matter on the outside (cortex), an internal region of white matter and nuclei (gray matter) embedded in the white matter
cerebrum has how many hemispheres separated by ____ _____
2, longitudinal fissure
lobes of the cerebrum
frontal, parietal, temporal and occipital
cortical region folds are called
gyri
the grooves between gyri are called
sulci
what are the deeper grooves in the cerebrum are called
fissures
the sensory areas of the brain are involved in..
perception of sensory information
motor areas control…
muscular movement
association areas deal with…
more complex integrative functions such as memory, personality traits and intelligence
the basal nuclei coordinate…
gross, automatic muscle movements and regulate muscle tone
limbic system functions…
in emotional aspects of behavior related to survival
frontal lobe is in charge of
personality/emotions, intelligence attention/concentration judgement body movement problem solving speech (speak and write)
parietal lobe is in charge of
sense of touch, pain and temperature
distinguishing size, shape and color
spatial perception
visual perception
occipital lobe is in charge of
vision
temporal lobe is in charge of
speech (understanding language) memory hearing sequencing organization
precentral gyrus (primary motor area) is…
anterior to the central sulcus, neurons direct voluntary movements by controlling somatic motor neurons in the brain stem and spinal cord
postcentral gyrus (primary somatosensory cortex)
posterior to the central sulcus, neurons receive somatic sensory information for touch, pressure, pain, taste, and temperature from the dorsal columns and spinothalamic tracts
cerebral association areas
interpet sensory and motor information from other areas of the cerebral cortex (ex. premotor cortex, visual association area, auditory association area, somatin sensory association area, etc.)
right hemisphere
receives somatic sensory signals from and controls muscles on left side of body, musical and artistic awareness, space and pattern perception, recognition of faces and emotional content of facial expressions, generating emotional content of language, generating mental images to compare spatial relationships, identifying and discriminating among odors
left hemisphere
receives somatic sensory signals from and controls muscles on right side of body, reasoning, numerical and scientific skills, ability to use and understand sign language, spoken and written language
what is cerebral white matter made of?
myelinated nerve fibers that form nerve bundles
association fibers
interconnect portions of cerebral cortex in the same hemisphere (arcuate fibers and longitudinal fasciculi)
commissural fibers
interconnect corresponding lobes of different cerebral hemispheres (corpus callosum and anterior commissure)
projection fibers
interconnect cerebrum to other brain regions
what is the cerebral gray matter (nuclei)
paired masses of gray matter within cerebral hemispheres, function in subconscious control and integration of muscle tone, coordination of learned movement patterns and relaying information to thalamus from the cortex
where is the limbic system located
between the cerebrum and the diencephalon just superior to the corpus callosum
function of the limbic system
establishes emotional states, links the conscious functions with the unconscious autonomic functions, facilitates memory storage and retrieval
parts of the limbic system
- cingulate gyrus, parahippocampal gyrus, hippocampus
- dentate gyrus
- amygdala
- septal nuclei
- mammillary bodies
- anterior nucleus, medial nucleus
- olfactory bulbs
- fornix, stria terminalis, stria medullaris, medial forebrain bundle, mammillothalamic tract
parts of diencephalon
thalamus, hypothalamus, epithalamus
job of thalamus
relays almost all sensory input to the cerebral cortex. provides crude perception of touch, pressure, pain, and temperature. includes nuclei involved in movement planning and control
job of hypothalamus
controls and integrates activities of the autonomic nervous system and pituitary gland. regulates emotional and behavioral patterns and circadian rhythms. controls body temperature and regulates eating and drinking behavior. helps maintain the waking state and establishes patterns of sleep. produces hormones oxytocin and antidiuretic hormone (ADH)
job of the epithalamus
consists of pineal gland, which secretes melatonin, and the habenular nuclei
thalamus is part of the
diencephalon
what does the thalamus consist of?
egg shaped bodies form the walls of the diencephalon and surround the third ventricle
thalamus does what?
functions as the relay center for sensory and motor pathways. act as an information filter, passes only a small portion of the sensory information
includes how many major groups of nuclei on either side?
7
where is the third ventricle located?
between the two thalami
what does the pineal gland do?
secretes melatonin, and is a part of the epithalamus, which is the roof of the diencephalon
hypothalamus forms the _____ of the third ventricle, and is _____ to the thalamus
floor, inferior
the _____ extends inferiorly and connects the hypothalamus to the pituitary gland
infundibulum
what does the hypothalamus do?
1) control autonomic functions (heart rate, respiration, etc.)
2) secretion of hormones (ADH and oxytocin); regulation of the AP gland
3) regulation of body temperature
4) regulation of emotional and behavioral patterns
5) regulation of eating and drinking
6) control circadian rhythms
hypothalamus has nuclei in what 4 major regions?
mammillary regoin, tuberal region, supraoptic region, preoptic region
where is the midbrain located
superior to the pons and overlapped by the large cerebral hemispheres
the midbrain contains…
several nuclei (gray matter)
midbrain nuclei include
1) process visual (superior colliculus) and auditory (inferior colliculus) information and generate reflexive responses to these stimuli
2) red nucleus that integrates information from cerebrum and cerebellum and issues involuntary motor commands for muscle tone and posture
3) of the reticular formation that is involved in maintaining alertness
4) substantia nigra regulates motor output of the cerebral nuclei. makes dopamine which inhibits excitatory neurons in basal nuclei from being active at rest
what does the pons do?
relays impulses from one side of the cerebellum to the other and between the medulla and midbrain, pontine respiratory group, together with the medulla, helps control breathing. contains nuclei of origin for trigeminal (V), abducens (VI), facial (VII), and vestibulocochlear (VIII) nerves
pons contains ____ matter that contains…
gray, respiratory centers (ex. pontine/pneumotaxic center) and nuclei for cranial nerves V, VI, VII, and VIII
white matter of pons is
ascending and descending tracts that interconnect portions of the CNS; transverse fibers
cerebellum consists of ____ hemispheres separated by the _____
2, vermis
includes gray matter (?) and white matter (?)
cortex and nuclei, arbor vitae and peduncles
lobes in the cerebellum
anterior/posterior
flocculonodular
anterior/posterior lobes of cerebellum do what?
subconscious aspects of skeletal muscle movements
flocculonodular lobe of the cerebellum does what?
equilibrium and balance
cerebellar cortex does what?
subconscious coordination of movements, contains purkinje fibers
arbor vitae does what?
connects cerebellar cortex with cerebellar peduncles
cerebellar peduncles contain which three lobes that do what?
1) superior: connect cerebellum with mesencephalon, diencephalon, and cerebrum
2) middle: communicate between cerebellum and pons
3) inferior: connect cerebellum with the medulla oblongata
as a whole, what does the cerebellum do?
compares intended movements with what is actually happening to smooth and coordinate complex, skilled movements. regulates posture and balance. may have a role in cognition and language processing
medulla oblongata forms…
inferior part of the brainstem, begins at the foramen magnum and extends to the inferior border of the pons
how many cranial nerves associate with the medulla?
5
olive of medulla
contain inferior olivary nuclei that relay impulses from proprioceptors to the cerebellum
pyramids of the medulla
form protrusions on the anterior surface, contain the motor tracts (white matter) that are passing from the cerebrum to spinal cord. 90% of these axons cross over to the other side right before entering the spinal cord
what are the four medullary nuclei
nucleus gracilis and cuneatus, olivary nuclei, reflex centers, CN nuclei (8-12)
what do the nucleus gracilis and cuneatus do?
relay the sensation of touch, conscious proprioception, pressure and vibration to the thalamus on the contralateral side of the brain.
what do the olivary nuclei do?
relays information from proprioceptors to the cerebellum.
reticular formation….
Extends from the diencephalon to the spinal cord and has sensory and motor functions.
reticular formation fibers…
Fibers project to cerebral cortex and includes the reticular activating system (RAS) which is responsible for maintaining consciousness and awakening from sleep.
what stimulates the reticular activating system?
Incoming impulses from ears, eyes and skin stimulate the RAS.
cranial nerves are…
Part of the peripheral nervous system that connect to the brain. Each cranial nerve attaches to the brain near the associated sensory or motor nuclei
how many pairs of cranial nerves are there?
12
how are the cranial nerves numbered?
with Roman numerals, according to their position along the longitudinal axis of the brain beginning with the cerebrum
where do the cranial nerves arise from?
Cerebrum: I Diencephalon II Midbrain III, IV Pons: V, VI, VII, VIII Medulla Oblongata: VIII-XII
