Brain-Lower Flashcards
The major parts of the brain?
Brain stem
Cerebellum
Diencephalon
Cerebrum
The brain stem consists of?
Medulla oblongata
Pons
Midbrain
Posterior to the brain stem
Cerebellum
Superior to the brain stem
Diencephalon
Diencephalon comprises mainly
Thalamus
Hypothalamus
The _____ is supported on the diencephalon and brain stem, largest part of the brain
Cerebrum
The meninges consist of 3 sections?
Dura Mater (outer) Arachnoid Mater (middle) Pia Mater (inner)
The cranial dura mater has two layers, whereas the spinal dura matter has?
One layer
The cranial dura mater consists of
External Periosteal Layer
Internal Meningeal Layer
The two cranial dura mater layers are fused together except where they separate to enclose the dural venous sinuses that drain blood into the ?
Internal Jugular Vein
Separates the two hemispheres (sides) of the cerebrum
Falx cerebri
Separates the two hemispheres of the cerebellum?
Falx Cerebelli
Separates the cerebrum from the cerebellum?
Tentorium Cerebelli
Some parts of the brain lack the blood brain barrier (BBB)?
Pineal gland
Pituitary gland
Hypothalamus (median eminence)
The BBB is formed by a combination of _____ of the endothelial cells of brain capillaries and _____ foot processes
Tight junctions
Astrocyte
Substances that cross the BBB very slowy
Creatinine
Urea
Most Ions
Some substances do not cross BBB at all, ex:
Proteins
Most antibiotic drugs
Lipid soluble substances cross easily, ex:
Oxygen
CO2
Alcohol
Most anesthetic agents
Some water-soluble substances (such as glucose) cross the BBB by ?
Active transport
Protects the brain and spinal cord against chemical and physical injuries
Carries oxygen, glucose, and other needed chemicals from the blood to neurons and neuorglia
Continuously circulates through cavities in the brain and spinal cord, and around the brain and spinal cord in the subarachnoid space (between arachnoid mater and the pia mater)
Cerebrospinal Fluid (CSF)
Ventricles are four CSF filled cavities within the brain
The _____ ventricles together comprise the 1st and 2nd
The 3rd ventricle is a narrow cavity surrounded by the right and left halves of the _____?
The 4th ventricle is between the brain stem and _____?
Lateral ventricles (1st and 2nd)
Thalamus (3rd)
Brain stem and cerebellum (4th)
A thin membrane called the _____ separates the lateral ventricles
Septum Pellucidum
Cerebral Spinal Fluid (CSF) is produced in the?
Choroid Plexuses in walls of ventricles
These are networks of capillaries covered by ependymal cells that form CSF from blood plasma filtration (and some secretion)
Choroid Plexuses in walls of ventricles
The ependymal cells are joined by tight junctions thereby preventing materials from leaking between the cells, and forcing materials that might potentially enter the CSF to be subjected to _____?
Ependymal Cell Selectivity
from the choroid plexuses, CSF flows into the 3rd ventricle through two small openings called the ___ ____?
Interventricular Foramina
Then the roof of the 3rd ventricle produces more CSF and then it flows into the 4th Ventricle through the ___ ___? Where choroid plexus in the 4th ventricle produce more CSF.
Cerebral Aqueduct
From the 4th ventricle, CSF enters the ___ ____ through three openings in the roof of the 4th ventricle.
Subarachnoid space
Three openings in the roof of the 4th ventricle?
Median aperture
Two lateral apertures (pair on each side)
CSF is reabsorbed into the blood through ___ ___, which project into the CSF circulatory spaces
Arachnoid Villi
Condition in which excess cerebrospinal fluid builds up in the brain?
Hydrocephalus
Hydro= water Cephalus= head
A limited number of patients having obstructive hydrocephalus can be treated with a procedure called ___ _____. Aided by a neuroscope, a small hole is made in the floor of the third ventricle, allowing the CSF to bypass the obstruction
Third Ventriculostomy
A network of interspersed gray and white matter called the ___ ___ extends throughout the brain stem
Reticular formation
The ____ is called the vital brain because it regulates functions upon which life is most dependent, and which occur without our voluntary action: control of breathing, heart rate, blood pressure, and reflex centers for coughing, swallowing, & vomiting that respond without cognitive processing
Medulla Oblongata
The medulla begins at the ___ ___, and is a continuation of the___ ___
Foramen Magnum
Spinal Cord
White matter of the medulla contains all ascending ( or ?) and descending (or ?) tracts between the spinal cord and other parts of the brain
ascending = sensory
descending = motor
The ____ are bulges of white matter on the anterior of Medulla Oblongata where the largest motor tracts pass from the cerebrum to the spinal cord.
They represent the corticospinal tracts
Pyramids
Most of the axons in the left pyramid cross to the right side (____?), and vice versa.
Decussate
in the Medullary nuclei, the ___ ___ regulates rate and force of the heartbeat and blood vessel diameter
Cardiovascular Center
In the Medullary nuclei, the ___ ___ area (part of the respiratory center) adjusts the basic rhythm of breathing
Medullary rhythmicity
In the Medullary nuclei, the The ___ ___ of the medulla promotes swallowing of a mass (bolus) of food that has moved from the mouth into the pharynx (throat)
deglutition center
The vomiting center (___ ___) of the medulla causes vomiting, the forcible expulsion of the contents of the upper gastrointestinal tract through the mouth
Area Postrema
The ___ ____ comprises part of the gustatory pathway from the tongue to the brain, receiving input from taste buds of the tongue
gustatory nucleus
____ nuclei receive auditory input from the cochlea of the ear, and are therefore part of the auditory pathway
Cochlear
____nuclei are components of the equilibrium pathway from the inner ear to the brain, receiving sensory information from vestibular apparatus of the inner ear
Vestibular
Lateral to each pyramid is an oval-shaped swelling called an ___.
The inferior ___ nucleus within each ___ relays impulses to the cerebellum from the cerebral cortex, red nucleus of the midbrain, and spinal cord proprioceptors that monitor joint and muscle position
Olive
Olivary
Olive
The right and left gracile nucleus and cuneate nucleus are in the ___ part of the medulla
They are associated with sensastions of touch, conscious proprioception, pressure and vibration
Posterior
First order sensory neurons having their cell bodies in ___ ___ of the spinal cord ascend in the posterior columns of the posterior nuclei of the medulla.
The second-order neurons ascend to the thalamus in a band of white matter called the medial lemniscus (lemniscus = ribbon)
The medial lemniscus extends through the medulla, pons, and midbrain
The tracts of the posterior columns and axons of the medial lemniscus are collectively known as the ___ __-__ ___ pathway
Dorsal Roots
Posterior column-medial lemniscus
? is superior to the medulla
Consists of both nuclei, sensory tracts, and motor tracts (like the medulla)
It is a bridge that connects one part of the brain with another
The Pons
Nuclei comprising the pneumotaxic area and apneustic area help control ____, in conjunction with the medullary rhymicity area of the medulla
Breathing
Action of ___ muscles is controlled by bilateral clusters of neurons in both the medulla oblongata and pons, collectively called the respiratory center and comprising
- Medullary rhythmicity area
- Pneumotaxic area
- Apneustic area
Respiratory
The ____ area turns off the inspiratory area before the lungs become too full
Pneumotaxic
The ____ area prolongs inhalation by sending stimulatory impulses to the inspiratory area
Apneustic
The ____ (VIII) nerve has nuclei in two parts of the brain stem, pons and medulla
Vestibularchochlear
CN VIII, The ____ branch has sensory axons that end in the vestibular nuclei in the pons (although some enter the cerebellum via the inferior cerebellar peduncle)
Vestibular
CN VIII, The ____ branch has sensory axons that end in nuclei in the medulla oblongata
Cochlear
The ____ is also termed the mesencephalon
Connects the pons to the diencephalon (thalamus, hypothalamus, etc.)
It consists of both nuclei and tracts (like the medulla and pons)
Midbrain
The ____ ____ are a pair of tracts containing axons of motor neurons that conduct nerve impulses from the cerebral cortex to the spinal cord (corticospinal), medulla (corticobulbar), and pons (corticopontine), as well as axons of sensory neurons that extend from the medulla to the thalamus
Cerebral Peduncles
The ____ (roof) contains two pairs of rounded elevations collectively called the corpora quadrigemina
Tectum
Comprise the superior colliculi and inferior colliculi (ko-LIK-ū-lī ; little hills; singular = colliculus)
Corpora Quadrigemina
___ ___ are reflex centers for visual reflexes and for visually tracking moving objects
Superior colliculi
___ ___ are part of the auditory pathway as well as reflex centers for auditory stimuli
Inferior colliculi
This is the center responsible for involuntary turning of the head when an object is detected “out of the corner of the eye”
Superior Colliculi
Part of the auditory pathway that relays impulses from hearing receptors in the inner ear to the thalamus
This is the center responsible for the startle reflex, which is the involuntary turning of the head in response to an unexpected sound
Inferior Colliculi
Large darkly pigmented nuclei that release dopamine
Helps control subconscious muscle activities
Loss of these neurons is associated with Parkinson disease
Substantia Nigra
Reddish due to rich blood supply and iron-containing pigment in neuron cell bodies
Axons from cerebellum and cerebral cortex synapse with the red nuclei, functioning in the coordination of muscular movements
The rubrospinal tract originates in the red nucleus
The red nucleus controls crawling of babies and swinging of arms in normal walking. It and the rubrospinal tract are primarily involved in control of large muscles of the shoulder and arm, with sparse control over the hands, but not fine control of the fingers which is performed by the corticospinal tract. It does not affect the lower limbs since the rubrospinal tract terminates in the superior thoracic region of the spinal cord
Red Nuclei
Much of the brainstem consists of small clusters of neuronal cell bodies along with small bundles of myelinated axons.
This fairly extensive region of interspersed gray and white matter in the brain stem is termed the ___ ___.
Reticular formation
Part of the reticular formation called the ___ ___ ___ consists of sensory axons that help maintain consciousness and participate in awakening from sleep
Reticular Activating System (RAS)
Second largest part of the brain?
Cerebellum
In the Cerebellum, the central constricted area is termed ___?
Vermis (worm)
In the Cerebellum, the surface has many ridges, or convolutions, called ___?
Folia (leaves)
The cerebellar cortex is gray matter, also exhibiting the foliar ridges
The white matter forms the ___ ___ (tree of life)
Arbor Vitae
___ ___ are bundles of white matter comprising axons that conduct impulses between the cerebellum and other parts of the brain
Cerebellar Peduncles
How many pairs of Cerebellar Peduncles?
Three
Superior
Middle
Inferior
____ peduncles are anterior structures that conduct nerve impulses from the cerebrum to the spinal cord, medulla, and pons.
____ peduncles are posterior structures that conduct impulses between the cerebellum and other parts of the brain.
Cerebral
Cerebellar
The main function of the ___ is to evaluate how well movements initiated by motor areas in the cerebrum are actually being carried out, by comparing what was intended with what is actually being done
Cerebellum
When discrepancies are detected this sends feedback signals to motor areas of the cerebral cortex, thereby providing for smooth, coordinated movement
The ____ is also the main region of the brain that regulates posture and balance
Cerebellum
Cerebellum, The ___ and ___ ___ mediate unconscious refinements of skeletal muscle movements
Anterior and Posterior Lobes
Cerebellum, The ____ lobe contributes to equilibrium and balance
Floculonodular
____ (meaning without order; incoordination) is an inability to coordinate muscular movements
____ describes a symptom of incoordination associated with cerebellar infections, injuries, diseases, or degenerative changes
Ataxia
Comprises: Thalamus Hypothalamus Epithalamus Subthalamus
Diencephalon
Surrounds the third ventricle
Extends from brain stem to cerebrum
Diencephalon
Makes up most of the diencephalon
Thalamus
Consists of paired oval masses of gray matter organized into NUCLEI, plus some white matter tracts.
The two halves are connected across the third ventricle by a bridge of gray matter called the intermediate mass.
Thalamus
The ____ is the main RELAY station for most sensory impulses that reach the primary sensory areas of the cerebral cortex from the spinal cord, the brain stem, or the midbrain.
Thalamus
The ___ ___ is a thick band of white matter lateral to the thalamus which separates the thalamus and caudate nucleus from the lentiform nucleus
Internal Capsule
The ____ is a small portion of the diencephalon located inferior to the thalamus
It controls many body activities, and is a major regulator of homeostasis
Hypothalamus
____ bodies serve as relay stations for reflexes related to the sense of smell
Mammillary Bodies
The ____ is the major structure of concern for the tuberal region
It is the stalk that connects the pituitary gland to the hypothalamus
Infundibulum
The ____ is the main visceral control center of the body, and is one of the major regulators of homeostasis. Few tissues in the body escape its influence.
Hypothalamus
The small ____ comprises the habenular nuclei and pineal gland, and is superior and posterior to the thalamus
Epithalamus
___ ___ are involved in olfaction, especially emotional responses to odors
Habenular Nuclei
The ___ ___ secretes the hormone melatonin, and is part of the endocrine system
Pineal Gland
The ____ is a small area containing tracts and the paired subthalamic nuclei, lying immediately below the thalamus
It works with other structures of the brain to control body movement
Subthalamus
Symptoms of injury to the medulla include paralysis and loss of sensation on the ___ side of the body, and irregularities in breathing or heart rhythm
Opposite
When the inspiratory center is active, it generates nerve impulses to the ____ intercostal muscles and the ____, resulting inspiration.
external intercostal
Diphragm
During forceful breathing, impulses from the expiratory area are sent to the ____ intercostal muscle and ____ muscles. Contraction of these muscles causes forceful exhalation.
Internal intercostal
Abdominal
Mammillary bodies are part of the ____ (of the diencephalon)
Hypothalamus
Pupillary reflex?
adjusts size of eyes
_____ reflex refers to the shape of lens for close or distant viewing
Accomodation
