The Brain Flashcards
the brain
one of the largest organs in the body
consists of about 100 billion neurons and 10-50 trillion neuroglia
2% of total body weight
requires 20% of the body’s oxygen supply
4+ minutes of oxygen deprivation may permanently injure brain neurons
protected by blood- barrier
protected by the cranium and cranial meninges
cerebrospinal fluid
blood brain barrier
from harmful substances and pathogens; prevents passage of many substances from blood into brain tissue; consists of tightly sealed blood capillaries, assisted
by astrocytes
cranium and cranial meninges
dura mater, arachnoid mater, and pia mater
cerebrospinal fluid
Clear, colorless liquid that protect against chemical and physical injury
Carries oxygen, glucose, and other needed chemicals from the blood to neurons and neuroglia and removes wastes and toxic substances
Circulates through the subarachnoid space, around the brain and spinal cord, and ventricles (cavities in the brain)
4 ventricles
choroid plexuses
how many ventricles cereospinal fluid travel through
4 ventricles: 2 lateral ventricles, 1 third ventricle, 1 fourth ventricle
choroid plexuses
specialized networks of capillaries in the walls of the ventricles that produce
CSF
arachnoid villi
fingerlike extensions of the arachnoid mater that allow CSF to be gradually reabsorbed into the blood
superior sagittal sinus
the primary vein into which CSF drains
4 major parts of the brain
brain stem
diencephalon
cerebrum
cerebellum
brain stem
continuous with the spinal cord; medulla oblongata, pons, midbrain
diencephalon
above the brain stem; thalamus, hypothalamus, pineal gland
cerebrum
the bulk of the brain above the diencephalon and brain stem
cerebral cortex
cerebral white matter
Internal region of cerebral white matter
Gray matter nuclei deep within the white matter
Read, write, speak
Calculate, compose music, create
Remember the past and plan for the future
4 lobes named after the bones that cover them: frontal lobe, parietal lobe, temporal lobe, and occipital lobe
Gyrus (gyri)
Plus a 5th lobe that lies deep and cannot be seen at the surface: insula
Regulates the muscle tone required for specific body movements and control subconscious contractions of skeletal muscles such as automatic arm swings while walking
cerebral cortex
thin layer of gray matter on the surface
outer rim of gray matter
cerebral white matter
beneath the cortex
cerebellum
posterior to the brain stem
consists of 2 cerebellar hemispheres; located posterior to the medulla and pons and inferior to the cerebrum
cerebellar cortex
white matter
cerebellar nuclei
cerebellar peduncles
Compares intended movements programmed by the cerebral cortex with what is actually happening; receives sensory impulses from muscles, tendons, joints, equilibrium receptors, and visual receptors
Helps to smooth and coordinate complex sequences of skeletal muscle contractions
Regulates posture and balance and is essential for all skilled motor activities
medulla oblongata
continuation of the spinal cord; inferior part of the brain stem
contains all sensory and motor tracts extending between the spinal cord and the brain
contains several nuclei (masses of gray matter where neurons form synapses with one another)
2 major nuclei
cardiovascular center
medullary rhythmicity area
Nuclei of touch, pressure, vibration, conscious proprioception; and reflexes for
swallowing, vomiting coughing, hiccupping, and sneezing
Nuclei of 5 pairs of cranial nerves: vestibulocholear (VIII), glossopharyngeal (IX), vagus (X), accessory (XI), and hypoglossal (XII)
cardiovascular center
regulates the rate and force of the heartbeat and the diameter of blood vessels
Medullary rhythmicity area
adjusts the basic rhythm of breathing
pons
above the medulla and anterior to the cerebellum
Consists of both nuclei and tracts (just like medulla)
Some connect right and left sides of the cerebellum
Others a part of sensory and motor tracts
Several nuclei are the sites where signals for voluntary movements that originate in the
cerebral cortex are relayed into the cerebellum
Some nuclei help control breathing
Nuclei of 4 pairs of cranial nerves: trigeminal (V), abducens (VI), facial (VII), and
vestibulochochlear (VIII)
midbrain
connects the pons to the diencephalon
cerebral peduncles
substantia nigra
red nuclei
Nuclei of 2 pairs of cranial nerves: oculomotor (III) and trochlear (IV)
4 nuclei that appear as rounded bumps on the posterior surface
2 superior colliculi
2 inferior colliculi
cerebral peduncles
makes up the anterior part of the midbrain; a pair of large tracts; contain axons of motor neurons that conduct nerve impulses from the cerebrum to the
spinal cord, medulla, and pons
substantia nigra
nucleus that is large and darkly pigmented; loss of these neurons is associated with Parkinson’s disease
red nuclei
– reddish due to rich blood supply; cerebellum and cerebral cortex form
synapses here to coordinate muscular movements
2 superior colliculi
tracking and scanning movements of the eyes and reflexes that govern movements of the eyes, head, and neck in response to visual stimuli
2 inferior colliculi
part of the auditory pathway, relaying impulses from the receptors for audition in the ear to the thalamus; reflex centers for the startle reflex
startle reflex
sudden movements of the head and body that occur when you are surprised by a loud noise
reticular formation
small clusters of neuronal cell bodies (gray matter) intermingled with small bundles of myelinated axons (white matter) that make up much of the brain stem
Netlike arrangement of white and gray matter
Have sensory and motor functions
reticular activating system
ascending part of the reticular formation which consists of sensory axons that project to the cerebral cortex
When stimulated, nerve impulses pass upward to widespread areas of the cerebral cortex resulting in consciousness
Helps maintain consciousness and is active during awakening from sleep
Inactivity produces sleep
main motor function
helps regulate muscle tone in normal resting muscles
thalmus
paired oval masses of gray matter organized into nuclei with interspersed tracts of
white matter
Major relay station for most sensory impulses that reach the cerebral cortex from the
spinal cord and brain stem
Contributes to motor functions by transmitting info from the cerebellum and basal nuclei to motor areas of the cerebral cortex
Relays nerve impulses between different areas of the cerebrum
Plays a role in the maintenance of consciousness
hypothalamus
small portion that lies below the thalamus and above the pituitary gland
big role in homeostasis
Control of the autonomic nervous system; regulates contraction of smooth and cardiac
muscle and secretions of many glands; heart rate, movement of food during digestion,
contraction of urinary bladder
Control of pituitary gland and production of hormones; primary connection between the
nervous system and endocrine system; also produces antidiuretic hormone and oxytocin
which are stored in pituitary
Regulation of emotional and behavioral patterns; along with the limbic system, regulates
rage, aggression, pain, and pleasure, and behavioral patterns related to sexual arousal
Regulation of eating and drinking
Control of body temperature; stimulates activities that promote heat loss, production, or retention depending on the blood temperature
Regulation of circadian rhythms and states of consciousness; patterns of awake and sleep
feeding center
promotes eating
satiety center
sensation of fullness and cessation of eating
thirst center
sensation of thirst caused by rising osmotic pressure of the extracellular fluid; drinking water restores the osmotic pressure to normal
pineal gland
size of a small pea protruding from the posterior midline of the third ventricle
Secretes the hormone melatonin (promotes sleepiness and contributes to circadian
rhythm)
Part of the endocrine system
cerebellar cortex
surface of the cerebellum consisting of gray matter
white matter
beneath the cortex resembling the branches of a tree
cerebellar nuclei
masses of gray matter deep within the white matter
cerebellar peduncles
bundles of axons that attach the cerebellum to the brain stem
Compares intended movements programmed by the cerebral cortex with what is actually happening; receives sensory impulses from muscles, tendons, joints, equilibrium receptors, and visual receptors
Helps to smooth and coordinate complex sequences of skeletal muscle contractions
Regulates posture and balance and is essential for all skilled motor activities
gyrus
folds of the cerebral cortex
precentral gyrus
precentral gyrus
located immediately anterior to the central sulcus; motor area
postcentral gyrus
located immediately posterior to the central sulcus; somatosensory area
fissures
deep grooves between folds
longitudinal fissure
separates the cerebrum into cerebral hemispheres
sulcus (sulci)
shallow grooves between folds
central sulcus
separates the frontal and parietal lobes
cerebral hemispheres
right and left halves of the brain separated by the longitudinal fissure
corpus callosum
broad band of white matter containing axons that extend between the hemispheres to connect internally
basal nuceli/ basal ganglia
helps initiate and terminate movements; 3 nuclei within each cerebral hemisphere:
Globus palidus, Putamen, Caudate nucleus
limbic system
a ring of structures on the inner border of the cerebrum and floor of the
diencephalon that encircles the upper part of the brain stem and the corpus callosum; “emotional
brain”; plays a primary role in a range of emotions: pain, pleasure, docility, affection, and anger;
controls most involuntary aspects of behavior related to survival; major role in controlling the
overall pattern of behavior; functions in memory
Sensory areas (function areas of cortex)
receive sensory info and are involved in perception
perception
the conscious awareness of a sensation
motor areas
initiate movements
association areas
deal with more complex integrative functions such as memory, emotions, reasoning, will, judgment, personality traits, and intelligence
primary somatosensory area
posterior to the central sulcus of each cerebral hemisphere in the postcentral gyrus of the parietal lobe
Receives impulses for touch, proprioception, pain, itching, tickle, and temperature
and is involved in the perception of these sensations
Allows one to pinpoint where sensations originate
primary visual area
located in the occipital lobe, receives visual info and is involved in visual perception
primary auditory area
located in the temporal lobe, receives info for sound and is involved in auditory perception
primary gustatory area
located at the base of the postcentral gyrus, receives impulses for gustation and is involved in gustatory perception
primary olfactory area
located on the medial aspect of the temporal lobe, receives impulses for olfaction and is involved in olfactory perception
primary motor area
located in the precentral gyrus of the frontal lobe in each hemisphere; controls voluntary contractions of specific muscles on the opposite side of the body
broca’s speech area
located in the frontal lobe close to the lateral cerebral sulcus
Localized in the left hemisphere in 97% of the population
Translates thoughts into words and plans complex language for speaking
somatosensory association area
posterior to the primary somatosensory area; integrates and interprets somatic sensations such as the exact shape and texture of an object; storage of memories of past sensory experiences for comparison
visual association area
located in the occipital lobe; relates present and past visual experiences and is essential for recognizing and evaluating what is seen
auditory association area
located below the primary auditory area in the temporal cortex; allows you to recognize a particular sound as speech, music, or noise
wenicke’s area
a broad region in the left temporal and parietal lobes; interprets the meaning of speech by recognizing spoken words; active as you translate words into thoughts
The regions in the right hemisphere that correspond to Wernicke’s and Broca’s
areas also contribute to verbal communication by adding emotional content to spoken words
common integrative area
receives and interprets nerve impulses from the sensory areas
premotor area
immediately anterior to the primary motor area; generates nerve impulses that cause a specific group of muscles to contract in a specific sequence
frontal eye field area
in the frontal cortex; controls voluntary scanning movements of the eyes, such as those that occur while reading
prefrontal cortex
anterior portion of the frontal lobe; concerned with personality, intellect, complex learning abilities, recall of info, initiative, judgment, foresight, reasoning, conscience, intuition, mood, planning for the future, and development of abstract ideas
hemispheric lateralization
functional asymmetry between the hemispheres; specializations in certain function
Left hemisphere receives signals from and controls the right side of the body and vice
versa
Left is more important for spoken and written language, numerical and scientific skills, ability to use and understand sign language, and reasoning
Right is more important for musical and artistic awareness, spatial and pattern perception, recognition of faces and emotional content of language, and for generating mental images of sight, sound, touch, gustation, and olfaction
Memory
the process by which info acquired through learning is stored and retrieved; it must produce structural and functional changes in the brain
parts of the brain involved with memory
Association areas of the frontal, parietal, occipital, and temporal lobes
Parts of the limbic system
The diencephalon
parts of the brain involved with memory of motor skills
basal nuclei
cerebellum
cerebral cortex
analgesia
pain relif
anethesia
loss of sensation
nerve block
loss of sensation due to injection of a local anesthetic
neuraglia
attacks of pain along the entire length of a local anesthetic
