Term
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Definition
1.Cerebrum
2.Cerebellum
3.Diencephalon
4.Midbrain
5.Pons
6.Medulla oblongata |
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Term
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Definition
-largest portion of the adult brain
-controls higher mental functions
-divided into right and left cerebral hemispheres
-neural cortex: a superficial layer of gray matter covering most of its surface
-Gyri: elevated ridges
-Sulci: shallow depressions
-Fissures: deep grooves
Conscious thoughts, sensations, intellect, memory, and complex movements all originate in the cerebrum |
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Term
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Definition
-2nd largest part of brain
-Coordinates repetitive body movements
-2 hemispheres
-covered with gray matter: cerebellar cortex
Coordinates complex somatic motor patterns
Adjusts output of other somatic motor centers in brain and spinal cord |
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Term
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Definition
-Located under cerebrum and cerebellum
-Links cerebrum with brain stem
-3 divisions:
right and left thalamus-relays and processes sensory information
hypothalamus-hormone production, emotion, autonomic function
pituitary gland: connected to the hypothalamus via the infundibulum (stalk)
-the hypothalamus and the pituitary gland integrate the nervous and endocrine systems |
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Term
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Definition
Includes the midbrain (mesencephalon), the pons, and the medulla oblongata
Processes information between spinal cord and cerebrum or cerebellum |
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Term
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Definition
| Processes sight, sound, and associated reflexes, maintains consciousness |
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Term
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Definition
Connects the cerebellum to the brain stem
Involved in somatic and visceral motor control |
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Term
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Definition
Connects the brain to the spinal cord
Relays information to the thalamus
Regulates autonomic functions: heart rate, blood pressure, and digestion
The inferior portion has a central canal resembling the spinal cord. |
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Term
| Embryological development of the brain |
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Definition
-determines organization of adult brain structure
-CNS begins as neural tube (hollow cylinder)
Neural tube enlarges into 3 primary brain vesicles:
1.prosencephalon (forebrain)
2.mesencephalon (midbrain)
3.rhombencephalon (hindbrain) |
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Term
| 5 secondary brain vesicles |
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Definition
Telencephalon-becomes cerebrum
Diencephalon-doesn't change
Mesencephalon-doesn't change
Metencephalon-forms cerebellum and pons
Myelencephalon-becomes medulla oblongata |
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Term
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Definition
Neural tube encloses neurocoel.
Neurocoel expands to form ventricles lined with ependymal cells.
Each cerebral hemisphere contains 1 large lateral ventricle
3rd ventricle: ventricle of the diencephalon
4th ventricle: extends into the medulla oblongata |
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Term
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Definition
| A thin medial partition that separates the right and left ventricles |
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Term
| Interventricular foramen (foramen of Monro) |
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Definition
| Lateral ventricles communicate with the 3rd ventricle via this |
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Term
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Definition
-extends into the medulla oblongata
-becomes continuous with the central canal of the spinal cord
-connects with 3rd ventricle via narrow canal in mesencephalon (aqueduct of midbrain) |
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Term
| What are the ventricles filled with? |
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Definition
| Cerebrospinal fluid (CSF), which continuously circulates from the ventricles and central canal into the subarachnoid space of the surrounding cranial meninges. |
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Term
| What protects and supports the brain? |
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Definition
The bones of the cranium, the cranial meninges, and CSF
Biochemical isolation:blood-brain barrier |
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Term
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Definition
dura mater:
inner fibrous layer (meningeal)
outer fibrous layer (endosteal)-fused to periosteum
venous sinuses between 2 layers
Arachnoid mater:
covers brain
contacts epithelial layer of dura mater
subarachnoid space-between arachnoid mater and pia mater
pia mater:
attached to brain surface by astrocytes |
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Term
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Definition
-surrounds all exposed surfaces of CNS
-interchanges with interstitial fluid of brain |
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Term
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Definition
-cushions delicate nervous tissues
-supports the brain-brain is floating!
-transports nutrients, chemical messengers, and waste products |
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Term
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Definition
1. Falx cerebri: superior and inferior sagittal sinuses lie within this fold
2. tentorium cerebelli: protects the cerebellum and separates the cerebral hemispheres from the cerebellum. The transverse sinus lies within this fold.
3. falx cerebelli: divides the 2 cerebellar hemispheres along the midsagittal line inferior to the tentorium cerebelli. |
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Term
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Definition
Produces CSF
specialized ependymal cells:
-secrete CSF into ventricles
-remove waste products from CSF
-adjust composition of CSF
-Produce about 500 ml/day of CSF
-Entire volume replaced about every 6 hours |
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Term
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Definition
A problem with resorption of CSF in infants. Causes enlarged skulls.
In adults, can distort and damage the brain. |
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Term
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Definition
-from choroid plexus through ventricles and fills the central canal of spinal cord.
-Reaches subarachnoid space through 2 lateral apertures and median aperture.
-Then flows through subarachnoid space around the brain, spinal cord, and cauda equina. |
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Term
| Blood supply to the brain |
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Definition
| Arterial blood reaches the brain through the internal carotid arteries and the vertebral arteries. |
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Term
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Definition
-Disorders that interfere with blood circulation to the brain
-Stroke (cerebrovascular accident, CVA):
shuts off blood to portion of brain
neurons die in minutes |
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Term
| Blood-brain barrier (BBB) |
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Definition
-Formed by capillary endothelial cells that are extensively interconnected by tight junctions.
-only lipid soluble compounds can diffuse across the membrane (CO2, O2, ammonia, steroids, prostaglandins, and small alcohols)
-Astrocytes release chemicals that control the permeability of the endothemlium
-If astrocytes are damaged or stop stimulating the endothelial cells, the bbb disappears. |
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Term
| Circumventricular organs (non-intact areas of the BBB) |
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Definition
1. portions of the hypothalamus-permits hypothalamus hormones to diffuse into the circulation.
2. Capillaries in the posterior lobe of the pituitary gland: Antidiuretic hormones and oxytocin are released into the circulation.
3. Capillaries in the pineal gland: allows pineal secretions into the general circulation.
4. Capillaries at a choroid plexus: maintains the blood-CSF barrier |
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Term
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Definition
Most inferior of the brain regions
All communication between the brain and spinal cord involves tracts that ascend or descend through the medulla oblongata.
Center for the coordination of complex autonomic reflexes and the control of visceral functions. |
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Term
| 3 groups of nuclei in the medulla oblongata |
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Definition
1. Autonomic nuclei controlling visceral activities:
Reticular formation-gray matter with imbedded nuclei
Reflex centers-receive input from cranial nerves, the cerebral cortex, and brain stem. Output control peripheral systems-
cardiovascular centers: adjust heart rate, strength of cardiac contractions, the flow of blood through peripheral tissues.
Respiratory rhythmicity centers: sets pace for respiratory movement.
2. Sensory and motor nuclei of cranial nerves (VIII, IX, X, Xi, and XII)
Provide muscle commands to muscles of pharynx, neck, back, and visceral organs of thoracic and peritoneal cavities. CN VIII carries sensory information from receptors in the inner ear
3. Relay stations along sensory and motor pathways.
nucleus gracilis and nucleus cuneatus pass somatic sensory information to the thalamus
solitary nucleus receives visceral sensory information
olivary nuclei relay information about somatic motor commands |
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Term
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Definition
| Links the cerebellum with the midbrain, diencephalon, cerebrum, and spinal cord |
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Term
| The pons contains 4 groups of components |
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Definition
1. Sensory and motor nuclei of cranial nerves V, VI, VII, and VIII.-innervate jaw muscles, anterior face, sense organs, ear.
2. Nuclei involved with the control of respiration.-centers modify activity of respiratory rhythmicity center: apneustic center and pneumotaxic center.
3. Nuclei and tracts process and relay information heading to/from cerebellum.
4. Ascending, descending, and transverse tracts: longitudinal tracts interconnect other portions of the CNS. Transverse fibers (axons) link nuclei of pons with the cerebellar hemisphere of the opposite side |
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Term
| Functions of the cerebellum |
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Definition
-adjusts postural muscles: rapid, automatic adjustments, maintain balance/equilibrium
-programming and fine-tuning conscious and subconscious movements: refines learned movement patterns (ex. riding a bike) |
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Term
| Structures of the cerebellum |
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Definition
1. Folia: surface of the cerebellum
highly folded neural cortex
2. Anterior and posterior lobes: separated
by primary fissure
3. Cerebellar hemispheres: separated at
midline by vermis (narrow band of
cortex)
4. flocculonodular lobe: lies between the
roof of the 4th ventricle and the
cerebellar hemispheres and vermis. |
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Term
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Definition
Large, branched cells found in cerebellar cortex.
Receive input from up to 200.000 synapses. |
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Term
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Definition
Highly branched, internal white matter of cerebellum.
Cerebellar nuclei: embedded in arbor vitae, relay information to Purkinje cells |
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Term
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Definition
Tracts that link the cerebellum with the brain stem, cerebrum, and spinal cord leave the cerebellar hemispheres as peduncles:
Superior cerebellar peduncle: links cerebellum with mesencephalon, diencephalon, and cerebrum
Middle cerebellar peduncle: contains transverse fibers, communication between cerebellum and pons
Inferior cerebellar peduncles: link cerebellum with medulla oblongata and spinal cord |
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Term
| Structures of the mesencephalon (midbrain) |
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Definition
Tectum: 2 pairs of sensory nuclei (corpora quadrigemina)
-superior colliculus: receives visual input
-inferior colliculus: receives auditory input
Tegmentum:
-red nucleus (many blood vessels): subconscious motor commands that affect upper limb position
-substantia nigra: pigmented gray matter
largest midbrain nucleus
pigment is melanin, a byproduct of dopamine synthesis
Cerebral peduncles: nerve fiber bundles on ventrolateral surfaces that contain
-descending fibers to cerebellum by way of pons
-descending voluntary motor command fibers |
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Term
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Definition
| characterized by the loss of neuronal activity in the substantia nigra |
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Term
| Disorders of the cerebellum |
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Definition
Ataxia: damage from trauma or stroke
intoxication (temporary impairment)
disturbs muscle coordination |
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Term
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Definition
Integrates sensory information and motor commands
-consists of thalamus, epithalamus, and hypothalamus
-posterior portion of the epithalamus contains the pineal gland which secretes melatonin
-melatonin important in regulating day/night cycles and reproductive functions |
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Term
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Definition
-part of the diencephalon
-filters ascending sensory information for primary sensory cortex
-relays information between basal nuclei and cerebral cortex
-the 3rd ventricle separates the right and left thalamus
-each consists of a rounded mass of thalamic nuclei
-interthalamic adhesion (intermediate mass): projection of gray matter extends into ventricle from each side |
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Term
| Functions of the hypothalamus |
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Definition
1. Provides subconscious control of skeletal muscle.
2. Controls autonomic function (heart rate, blood pressure)
3. Coordinates activities of nervous and endocrine systems
4. Secretes hormones: antidiuretic hormone (ADH) by supraoptic nucleus; oxytocin by paraventricular nucleus
5. Produces emotions and behavioral drives: feeding center (hunger), thirst center (thirst)
6. Coordinates voluntary and autonomic functions
7. Regulates body temperature: preoptic area
8. Controls circadian rhythms: suprachiasmatic nucleus |
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Term
| Major groups of thalamic nuclei |
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Definition
| Anterior, medial, ventral, posterior, and lateral |
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Term
| anterior group of thalamic nuclei |
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Definition
| Part of the limbic system |
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Term
| Medial group of thalamic nuclei |
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Definition
Provide an awareness of emotional states
Receives and relays sensory information |
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Term
| Ventral group of thalamic nuclei |
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Definition
-the nuclei relay information from the basal nuclei of the cerebrum and the cerebellum to somatic motor areas of the cerebral cortex
-relay sensory information about touch, pressure, pain, temperature, and proprioception |
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Term
| Posterior group of thalamic nuclei |
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Definition
integrate sensory information for projection to the cerebral cortex
-lateral geniculate nucleus: visual information
-medial geniculate nucleus: auditory information |
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Term
| Lateral group of thalamic nuclei |
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Definition
-form feedback loops with the limbic system
-affects emotional states and the integration of sensory information |
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Term
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Definition
| -is a group of tracts and nuclei that function in emotion, motivation, and memory |
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Term
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Definition
-acts as interface between the limbic system, the cerebrum, and various sensory systems
-regulates heart rate, controls "fight or flight" response, links emotions with memories |
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Term
| Limbic lobe of cerebral hemisphere |
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Definition
-consists of the superficial folds (gyri) and underlying structures adjacent to the diencephalon
-cingulate gyrus
-dentate gyrus
-parahippocampal gyrus
These gyru conceal the hippocampus, a nucleus important in learning, especially in the storage and retrieval of new long-term memories. |
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Term
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Definition
-a component of the limbic system
-tract of white matter connects hippocampus with hypothalamus |
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Term
| anterior nucleus of the thalamus |
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Definition
-a component of the limbic system
-relays information from mamillary body to cingulate gyrus |
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Term
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Definition
A component of the limbic system
-stimulation or inhibition produced heightened alertness or lethargy |
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Term
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Definition
Largest part of the brain, controls all conscious thoughts and intellectual functions.
Processes somatic sensory and motor information
Gray matter: in cerebral cortex and basal nuclei
White matter: deep to basal cortex, around basal nuclei |
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Term
| Structures of the cerebrum |
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Definition
Gyri of neural cortex-increase surface area
Insula of cortex-lies medial to lateral sulcus
Longitudinal fissure-separates cerebral hemispheres
Lobes-divisions of hemispheres
Central sulcus-divides anterior frontal lobe from posterior parietal lobe
Lateral sulcus-divides frontal lobe from temporal lobe
Parieto-occipital sulcus-divides parietal lobe from occipital lobe |
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Term
| Functional principles of the cerebrum |
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Definition
-Each cerebral hemisphere receives sensory information from, and sends motor commands to, the opposite side of the body
-The 2 hemispheres have different functions, although their structures are alike.
-Correspondence between a specific function and a specific region of cerebral cortex is not precise. |
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Term
| White matter of the cerebrum |
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Definition
-Association fibers: connections within one hemisphere
*Arcuate fibers-short fibers connect one gyrus to another
*Longitudinal fasciculi-longer bundles connect frontal lobe to other lobes in same hemisphere
Commissural fibers: bands of fibers connecting 2 hemispheres-corpus collosum and anterior commissure
Projection fibers: pass through diencephalon, link cerebral cortex with diencephalon, brain stem, cerebellum, spinal cord
-internal capsule: all ascending and descending projection fibers |
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Term
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Definition
masses of gray matter embedded in white matter of cerebrum
direct subconscious activity |
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Term
| Structures of the basal nuclei |
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Definition
-Caudate nucleus: curving, slender tail
-Lentiform nucleus:consists of a medial globus pallidus and a lateral putamen |
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Term
| Functions of the basal nuclei |
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Definition
-involved with subconscious control of skeletal muscle tone and coordination of learned movement patterns (walking, lifting)
-Do not initiate movement, but once underway, provide general pattern and rhythm
-Information arrives at caudate nucleus and putamen from sensory, motor and integrative areas of cortex, processing occurs, output through globus pallidus |
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Term
| Motor and sensory areas of cortex |
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Definition
Central sulcus separates motor and sensory areas
Motor areas:
precentral gyrus of frontal lobe-directs voluntary movements
primary motor cortex-surface of precentral gyrus
pyramidal cells-neurons of primary motor cortex, direct voluntary movements by controlling somatic motor neurons
Sensory areas:
postcentral gyrus of parietal lobe-receives somatic sensory information (touch, pressure, pain, vibration, taste, and temperature)
primary sensory cortex-surface of postcentral gyrus |
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Term
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Definition
-Visual cortex: occipital lobe, information from sight receptors
Auditory cortex: temporal lobe, information from sound receptors
Olfactory cortex: temporal lobe, information from odor receptors
Gustatory cortex: frontal lobe, information from taste receptors |
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Term
| 4 categories of brain waves |
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Definition
1. Alpha waves: found in healthy, awake adults at rest with eyes closed
2. Beta waves: higher frequency, found in adults concentrating or mentally stressed
3. Theta waves: found in children, or intensely frustrated adults; may indicate brain disorder in adults
4. Delta waves: during sleep, low frequency, found in awake adults with brain damage |
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Term
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Definition
disorder affecting the ability to speak or read.
Global aphasia results from extensive damage to the general interpretive area or to the associated sensory tracts.
Causes: severe stroke or tumor |
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Term
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Definition
| A disorder affecting the comprehension and use of written words. |
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Term
| Cranial nerve I-Olfactory |
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Definition
Primary function: smell
Pass through: Olfactory foramina in cribriform plate of ethmoid
Destination: olfactory bulbs |
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Term
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Definition
Primary function: vision
Pass through: Optic canals of sphenoid
Destination: diencephalon by way of the optic chiasm |
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Term
| Cranial nerve III-Oculomotor |
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Definition
Primary function: motor (eye movements)
Pass through: superior orbital fissures of sphenoid
Destination: somatic motor-superior, inferior, and medial rectus muscles, inferior oblique muscle, levator palpebrae superioris muscle. Visceral motor-intrinsic eye muscles |
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Term
| Cranial nerves IV-Trochlear |
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Definition
Primary function: motor (eye movements)
Pass through: superior orbital fissures of sphenoid
Destination: Superior oblique muscle |
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Term
| Cranial nerves V-Trigeminal |
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Definition
Primary function: mixed (sensory and motor) to face
Pass through: ophthalmic branch through superior orbital fissure; maxillary branch through foramen rotundum; mandibular branch through foramen ovale.
Destination: ophthalmic, maxillary, and mandibular branches to sensory nuclei in pons; mandibular branch also innervates muscles of mastication |
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Term
| Cranial Nerves VI-Abducens |
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Definition
Primary function: motor (eye movements)
Pass through: Superior orbital fissures of sphenoid
Destination: Lateral rectus muscle |
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Term
| Cranial nerves VII-Facial nerves |
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Definition
Primary function: mixed (sensory and motor) to face
Pass through: internal acoustic meatus to canals leading to the stylomastoid foramina |
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Term
| Cranial nerves VIII-Vestibulocochlear |
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Definition
Primary function: special sensory-balance and equilibrium (vestibular branch), and hearing (cochlear branch).
Pass through: internal acoustic meatus of temporal bones
Destination: vestibular and cochlear nuclei of pons and medulla oblongata |
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Term
| Cranial nerves IX-Glossopharyngeal |
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Definition
Primary function: mixed (sensory and motor) to head and neck
Pass through: jugular foramina between the occipital bone and the temporal bones
Destination: sensory: sensory nuclei of medulla oblongata. somatic motor: pharyngeal muscles involved in swallowing. Visceral motor: parotid salivary gland by way of the otic ganglion |
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Term
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Definition
Primary function: mixed (sensory and motor) widely distributed to the thorax and abdomen
Pass through: jugular foramina between the occipital bone and the temporal bones
Destination: Sensory: sensory nuclei and autonomic centers of medulla oblongata; Visceral motor: muscles of the palate, pharynx, digestive, respiratory, and cardiovascular systems in the thoracic and abdominal cavities |
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Term
| Cranial nerves XI-Accessory nerves |
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Definition
Primary function: motor to mucscles of the neck and upper back
Pass through: Jugular foramina between the occipital bone and the temporal bones
Destination: Internal branch innervates voluntary muscles of palate, pharynx, and larynx; external branch controls sternocleidomastoid and trapezius muscles |
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Term
| Cranial nerves XII-hypoglossal |
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Definition
Primary function: motor (tongue movements)
Pass through: hypoglossal canals of occipital bone
Destination: muscles of the tongue |
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