A&P Ch: 14 Brain and Cranial Nerves
What are the relay stations in the medulla oblongata?
- olivary nucleus - nucleus cuneatus - nucleus gracilis
Which are the autonomic centers in the medulla oblongata?
- reticular formation - cardiovascular centers - solitary nucleus
What are the four special sensory cortexes of the cerebrum?
-visual cortex - info form sight receptors -auditory cortex - info from sound receptors -olfactory cortex - info from odor receptors -gustatory cortex - info from taste receptors
What are the eight functions of they hypothalamus?
1) Provides subconscious control of skeletal muscle 2) Controls autonomic funtion 3) Coordinates activities of nervosu and endocrine systems 4) Secretes hormones - antidiuretic hormone (ADH) bu suraoptic nucleus and ocytocin (OT, OXT) by paraventricular nucleus 5) Produces emotions and behavioral drives - feeding and thirst center 6) Coordinates voluntary and autonomic functions 7) Regulates body temp - proptic area of hypothalamus 8)Controls circadian rythmns (day-night cycles) - suprechiasmatic nucleus
What are the three functional principles of the cerebrum?
1)Each cerebral hem. recieves sensory info from, and sends motor commands to, the opposite side of the body 2)The two hem.s have diff functs 3)Correspondence btwn a specific funct and a specific region of cerebra; cortex is not precise
What are the six regions of the brain?
1. Cerebrum 2. Cerebellum 3. Diencephalon 4. Mesencephalon 5. Pons 6. Medulla Oblongata
What are the three layers of cranial meninges?
1. Dura mater - inner fibrous layer (meningeal layer) - outer fibrous layer (endosteal layer) fused to periosteum - venous sinuses between two layers 2. Arachnoid mater - covers brain - contacts epithelial layer of dura mater - subarchnoid space: between anarchnoid mater and pia mater 3. Pia mater Attached to brain surface by astrocytes
What are the three types of dural folds?
1. Falax cerebri: projections between the cerebral hemispheres and contain superior and inferior sagittal sinuses. 2. Tentorium cerebrelli: spereates cerebellum and cerebrum and contains transverse cerebrum 3. Falx cerebelli: divides cerebellar hemispheres below the tentorium cerebelli
What are the structures of the cerebellum?
- Folis - surface of cerebellum that is a highly folded neural cortex - Anterior and posterior lobes - separated at midline by vermis - Vermis - narrow band of cortex - Flocculonodular lobe - below fourth ventricle -Purkinje cells - large branched cells found in the cerebrellar cortex -Arbor vitae - highly branched, internal white matter of cerebellum. Has cerebellar nuclei embedded in it which relay info to purkinje cells
What is ataxia?
A disorder of the cerebellum caused by damage from trauma or stroke, intoxication (temp impairment), and disturbs muscle coordination
What is the limbic system?
A functional group that establishes emotional states, links conscious functions of cerebral cortex with autonoic functions of brain stem, and facilitates memory storage and retrieval.
What is the function of the cerebrum?
Conscious thought processes or intellectual functions, memory storage and processing, and conscious and subconscious regulations of skeletal muscle contractions
What is the function of the mamillary body of the hypothalamus?
Controls feeding reflexes (licking, swallowing, ect)
What is the function of the cerebellum?
Coordinates complex somatic motor patterns and adjusts output of other somatic motor centers in brains and spinal cord.
What are the cerebral components of the limbic system?
Cortical areas - limbic lobe (cingulate gyrus, dentate gyrus, and parahippocampal gyrus) Nuclei - hippocampus andamygdaloid body Tracts - fornix
Where is white matter in the cerebrum?
Deep to basal cortex and around basal nuclei
What delivers and removes blood form the brain?
Delivered by internal carotid arteries and vertebral ateries Removed from dural sinuses by internal jugular veins
What is cerebrovascular disease?
Disorders that interfere with blood circulation to brain. Stroke or cerebrovascular accident (CVA) - shuts off blood to portion of brain causing neurons to die
What are arachnoid villi?
Extensions of subarachnoid spaces that extend through dura mater to superior sagittal sinus
Where is gray matter in the cerebrum?
In cerebral cortex and basal nuclei
Where are cranial nerves VII, IX, X, XI, and XII and what do they do?
In the gray mater of the medulla oblongata. Are sensory and motor nuclei of five cranial nerves; nuclei relay ascending info from the spinal cord to higher cenetrs.
What is reticular formation and where is it located on the medulla oblongata?
In the gray mater. Contains nuclei and centers that regulate vital automatic functions; extends into the pons and midbrain
Where is the nucleus gracilis and the nucleus cuneatus and what do they do?
In the gray matter of the medulla oblongata and relay somatic info to the thalamus
Where are ascending and descending tracts within columns on the medulla oblongata and what do they do?
In white mater and link the brain with the spinal cord.
What is the prefrontal cortex of the frontal love of the cerebrum?
Integrates info from sensory association area and performs abstract intellectual activities (predicting consequences of actions)
What is the function of the Diencephalon?
Integrates sensory info and motor commands
What is the function of the cerebellum?
It adjusts postural muscles and fine tunes conscious and subconscious movements
Where is the olivary nucleus and what does it do?
It is in the gray matter of the medulla oblongata and it relays info from the red nuclei, other midbrain centers, and the cerebral cortex to the cerebellum.
What are the cerebellar cortex and the cerebellar nuclei part of and what does it do?
It is part of gray matter. It controls involuntary coordination and control of ongoing body movements.
Where is reticular formations in the pons and what does it do?
It is part of the gray matter in the pons and it is automatically prosses the incoming sensations and outgoing motor commands.
Where is the descending tracts in the pons and what does it do?
It is part of the white matter and it carries motor commands from higher centers to nuclei of cranial or spinal nerves
Where is ascending tracts in the pons and what does it do?
It is part of the white matter and it carries sensory info from the brain stem nuclei to the thalamus.
Where is transverse tracts in the pons and what does it do?
It is part of the white matter and it interconnects cerebellum hemispheres.
What is the blood-brain barrier?
It isolates CNS neural tissue from general circulation and is formed by network of tight junctions. It is between endothelial cells of CNS capillaries.
What is the function of the infundibulum of the hypothalamus?
It's a narrow stalk that connects hypothalamus to the pituitary gland
Where is the tuberal area of the hypothalamus and what is the function?
It's located between the infundibulum and mamillary bodies. It helps control pituitary gland functions
What are arachnoid granulations?
Large clusters of villi that absorb CSF into venous circulation
What are the three divisions of the diencephalon?
Left thalamus, right thalamus and hypothalamus
What diffuses into the fluid of the brain and spinal cord from the blood-brain barrier?
Lipid-soluble compounds (O2, CO2), steroids, and prostaglandins diffuse into interstitial fluid of brain and spinal cord.
What is the diencephalon?
Located under cerebrum and cerebellum and links cerebrum with brainstem. It has three divisions: L and R thalamus and hypothalamus
How do ventricles of the brain originate?
Neural tube encloses neurocoel and the neurocol expands to form chambers (ventricles) lined with ependymal cells
What does the left hemisphere (dominant hemisphere) of the cerebrum generally control in most people?
Reading, writing, and math, Decision making, and speech and language
What are the reflex centers in the medulla oblongata and what do they do?
Reflex centers in the gray mater 1. cardiovascular center - Regulate heart rate and force contraction 2. respiratory rythmicity center - set the pace of respiratory movements
What is the function of the preoptic area of they hypothalamus?
Regulates body temp by control of autonomic centers in the medulla oblongata
What is the function of the thalamus?
Relay and processing centers for sensory info.
What is the function of the supraoptic nucleus?
Secretes antidiuretic hormone, restricting water loss by the kidneys
What is the function of the paraventricular nucleus of the hypothalamus?
Secretes oxytocin, stimulating smooth muscle contractions in uterus and mammary glands.
What does the right hemisphere of the cerebrum relate to?
Senses (touch, smell, taste, feel) and recognition (faces, voice inflections)
What are choroid plexus?
Specialized ependymal cells and capillaries that secrete CSF into ventricles, remove waste products from CSF and adjust composition of CSF.
What is the function of the red nucleus in the midbrain?
Subconscious control of upper limb position and background muscle tone
What makes up the walls and floor of the Mesencephalon (midbrian)?
Substantia nigra, red nucleus, and reticular formation.
What is cerebrospinal fluid (CSF)?
Surrounds all exposed surfaces of CNS and interchanges with interstitial fluid of brain. It cushions delicate neural structures, supports the brain, and transports nutrients, chemical messengers, and waste products.
What is the blood-CSF barrier?
Surrounds capillaries of choroids plexus, limits movement of compounds transferred, and allows chemical composition of blood and CSF to differ. It is formed by special ependymal cells.
What special sensory cortex of the cerebrum receives info from taste receptors?
The gustatory cortex
What is the cerebrum?
The largest part of the brain that controls all conscious thoughts and intellectual functions and processes somatic sensory and motor info
What is the cerebrum?
The largest part of the brain that is divided into the L and R cerebral hemispheres. The surface layer is made up of gray matter (neural cortex)
What part of the thalamus projects visual info to the visual cortex?
The lateral geniculate of the posterior group of the thalamus
What part of the thalamus influences emotional states?
The lateral group of the thalamus
What part of the thalamus projects auditory info to the auditory cortex?
The medial geniculate nuclei of the posterior group of the thalamus
What special sensory cortex of the cerebrum receives info from odor receptors?
The olfactory cortex
What makes up the hypothalamus of the diencephalon?
The paraventricular nucleus, peoptic area, autonomic centers, tuberal nucleus, mamillary body, suprachiasmatic nucleus, and supraoptic nucleus
What sensory area of the cerebrum receives somatic info like touch, pressure, pain, vibration, taste, and temp?
The postcentral gyrus of parietal lobe
What is the cerebellum?
The second largest part of the brain that has two hemispheres, coordinates repetitive body movements , and is covered with cerebral cortex
What makes up the gray matter in the Mesencephalon (midbrain)?
The tectum (roof) - superior and inferior calliculus, the walls and floor - substantia nigra, red nucleus, and reticular formation.
Where is the tectum (roof) and what are the parts of it?
The tectum is part of the gray matter in the mesencephalon. It has two parts: the superior colliculus and the inferior colliculus.
What are the diencephalic components of the limbic system?
The thalamus and the hypothalamus
What separates the left thalamus and the right thalamus?
The third ventricle
What are the three parts of the cerebellar peduncles and what are they part of?
The three parts are superior, middle, and inferior. They are part of white matter
What special sensory cortex of the cerebrum receives info from sight receptors?
The visual cortex
What is another name for the general interpretive area in the cerebrum?
The wernicke area
Where are the apneustic and pneumotaxic centers in the pons and what do they do?
They are in the gray matter in the pons and they adjust activities of the respiratory rhythmicity centers in the medulla oblongata.
What are the functions of cerebral nuclei?
They are involved with the subconscious control of skeletal muscle tone and the coordination of learned movement patterns (walking, lifting)
Where are the cranial nerve nuclei NV, V, VI, VII, and VIII in the pons and what do they do?
They are part of the gray matter and they relay sensory info and issue somatic motor commands.
Where are the arbor vitae in the cerebellum and what do they do?
They are part of the white matter in the cerebellum and they the connect cerebellar cortex and nuclei with cerebellar peduncles.
What is the function of the middle cerebellar peduncle?
To carry communications between the cerebellum and pons
What is the function of the lateral group of the thalamus?
To integrate sensory info and to influence emotional states
What is the function of the pulvinar nuclei of the posterior group of the thalamus?
To integrate sensory info for projection to association areas of cerebral cortex
What is the function of the medial group of the thalamus?
To integrate sensory info for projection to the frontal lobes
What is the function of the superior colliculus in the tectum (roof) mesenephalon?
To integrate visual info with other sensory input; initiate reflex responses to visual stimuli.
What is the function of the inferior cerebellar peduncle?
To link the cerbellum with the medulla oblongata and the spinal cord
What is the function of the superior cerebellar peduncle?
To link the cerebellum with the midbrain, diencephalon, and cerebrum
What is the function of the brain stem?
To process info between the spinal cord and the cerebrum or the cerebellum
What is the function of the mamillary bodies in the hypothalamus?
To process olfactory and other sensory info and to control reflex eating movements
What is the function of the medial geniculate nuclei of the posterior group of the thalamus?
To project auditory info to the auditory cortex
What is the function of the lateral geniculate nuclei of the posterior group of the thalamus?
To project visual info to the visual cortex
What is the function of the substantia nigra in the midbrain?
To regulate activity in the basal nuclei.
What is the function of the suprachiasmatic nucleus of the hypothalamus?
To regulate daily (circadian) rhythms
What is the function of the inferior colliculus of the tectum (roof) of the mesencephalon?
To relay auditory info to medial geniculate nuclei; initiate relfex responses to auditory stimuli
What is the function of the pons?
To relay sensory info to cerebellum and thalamus and subconscious somatic and visceral motor neurons. It also connects the cerebellum to the brain stem
What is the function of the medulla oblongata?
To relay sensory info to thalamus and to other portions of the brain stem and autonomic centers for regulation of visceral function ( cardiovascular, respiratory, and digestive system activities) - regulates blood pressure, heart rate, and digestion Also connects the brain to the spinal cord
What are involved with the subconscious control of skeletal muscle tone and the coordination of learned movement patterns (walking, lifting)?
basal nuclei
What is another name for cerebral nuclei?
basal nuclei
What is another name for basal nuclei?
cerebral nuclei
What are cranial meninges?
protective coverings of the brain that protect the brain from cranial trauma. They are a continuous with spinal meninges. It has three layers: Dura matter, arachnoid mater, and pia mater.
What is the function of the ventral group of the thalamus?
to project sensory info to the primary sensory cortex; relays info from cerebellum and basal nuclei to motor area of cerebral cortex
What are the three functional principles of the cerebrum?
-each cerebral hemisphere receives sensory info from, and sends motor commands to, the opposite side of the body -two hemispheres have different functions, although their structures are alike -correspondence between a specific function and a specific region of cerebral cortex is not precise
What is the function of the thalamus in the diencephalon?
-filters ascending sensory info for primary sensory cortex -Relays info between basal nuclei and cerebral cortex
What is hemisphere lateralization of the cerebrum?
-functional diffs between left and right hemispheres -each cerebral hemisphere performs certain functions that are not ordinarily performed by the opposite hemisphere
What are the parts of the gray matter in the medulla oblongata?
-olivary nucleus - reflex centers: cardiovascular center and respiratoy rhythmicity center - nucleus gracilis and nucleus cuneatus - cranial nerves VIII, IX-XII - Reticular formation
What are the sensory areas of the cerebrum?
-postcentral gyrus of parietal lobe - receives somatic info (tough, pressure, pain, vibration, taste, temp) -primary sensory cortex - surface of postcentral gyrus
What are the motor areas of the cerebrum?
-precentral gyrus of frontal lobe - directs voluntary movements -primary motor cortex - the surface of parietal gyrus -pyramidal cells - neurons of primary motor cortex
What is the general interpretive area (Wernicke area) in the cerebrum?
*present only in left hemisphere. Receives info from all sensory association areas ad coordinates access to complex visual and auditory memories
The Brain
-The brain is a large, delicate mass of neural tissue containing internal passageways and chambers filled with cerebrospinal fluid. -Ascending from the medulla oblongata to the cerebrum, brain functions become more complex and variable. -Conscious thought and intelligence are produced in the neutral cortex of the cerebral hemispheres
What is the function of the cerberal peduncles in the midbrain?
Connects primary motor with motor neuron in brain and spinal cord; carry ascending sensory info to thalamus.
What are the nuclei involved with respiration in the pons?
Apneustic center and pneumotaxic center which modify respiratory rhythmicity center activity
What are integrative centers in the cerebrum and what do they do?
Are located in lobes and cortical areas of both cerebral hemispheres. Receives info from association areas and direct complex motor or analytical activities
What are the basal nuclei of the cerebrum (cerebral nuclei)?
Are masses of gray matter embedded in white matter of the cerebrum and direct subconscious activities. They are involved with the subconscious control of skeletal muscle tone and the coordination of learned movement patterns (walking, lifting)
What thalamic nuclei make up and that is their function?
Are rounded masses that form the thalamus Relay sensory info to basal nuclei and cerebral cortex
What are the tracts in pons and what do they do?
Ascending, descending, and transverse tracts made are made up of transverse fibers (axons) and they link nuclei of pons with opposite cerebrallar hemisphere
What controls the blood-brain barrier?
Astrocytes control the blood-brain barrier by releasing chemicals that control permeability of endothelium.
What special sensory cortex of the cerebrum receives info from sound receptors?
Auditory cortex
What is the function of reticular formation in the midbrains?
Automatic processing of incoming sensations and outgoing motor commands; can initiate involuntary motor repsonses to stimuli; and helps maintain consciousness.
What is the function of the hypothalamus?
Centers controlling emotions, autonomic functions, and hormone productions.
What are basal nuclei also called?
Cerebral nuclei
What is the pituitary gland?
Connected to the hypothalamus by the infundibulum (stalk) in the diencephalon and is a major endocrine gland. It interfaces nervous and endocrine systems.
What are dural folds of the brain?
Folded inner layer of dura mater that extend into cranial cavity and stabilize and support the brain. Folds contain collecting veins (dural sinuses).
What is neural cortex (cerebral cortex)?
Folded surface that increases surface area of the cerebrum. Has elevated ridges (gyri), shallow depressions (sulci), and deep grooves (fissures).
Where is the pineal gland found and what is it's function?
Found in posterior epithalamus. Secretes the hormone melatonin
How many ventricle are in the brain and where are they?
Four 1&2: Each cerebral hemisphere contains one large lateral ventricle separated by a thin medial partition (septum pellucidum) 3: Ventricle of the diencephalon - lateral ventricles communicate with third ventricle by interventricular foramen (foramen of Monro) 4: Extends into the medula oblongata and becomes continuous with central canal of the spinal canal. Connects with the thrid ventricle by a narrow canal in mesencephalon (aqueduct of midbrain)
Where does CSF circulate?
From choroid plexus --> through ventricles --> to central canal of spinal cord --> into subarachnoid space around the brain, spinal cord, and cauda equina
What part of the hypothalamus controls relfexive eating movements?
Mamillary bodies
What are the three parts of the hypothalamus?
Mamillary bodies, infundibulum, and tuberal area
What are Basal nuclei (cerebral nuclei)?
Masses of gray matter embedded in white matter of cerebrum. They direct subconscious activities
What are the three parts of the brain that make up the brain stem?
Mesencephalon, pons, and medulla oblongata
What is the anterior group of the thalamus?
Part of the limbic group
What are transverse lines in the cerebellum and what are they part of?
Part of the white matter. They interconnect pontine nuclei with the opposite cerbellar hemisphere.
What protects the brain?
Physically: bones of the cranium, cranial menings, and cerebrospinal fluid Biochem Isolation: blood-brain barrier
What are the four breaks in the blood-brain barrier?
Portions of the hypothalamus - secrete hypothalamic hormones Posterior lobe ofpituitary gland - secrete hormones ADH and oxytocin Pineal glands - pineal secretions Choroid plexus - where special ependymal cells maintain blood-CSF barrier
What is the function of the mesencephalon? (Also called midbrain)
Processes visual and auditory data, generates reflexive somatic motor responses, and maintenance of consciousness
What is the function of the tuberal nucleus of the hypothalamus?
Produces inhibitory and releasing hormones that control endocrine cells of the anterior lobe of the pituitary gland (adenohypophysis)
What is the interthalamic adhesion (or intermediate mass)?
Projection of gray matter that extends into ventricle form each side
What makes up the posterior group of the thalamus?
Pulvinar nuclei, lateral geniculate nuclei, and medial geniculate nuclei
What are the two autonomic centers in the hypothalamus and what is their function?
Sympathetic and parasympathic. They control heart rate and blood pressure by regulation of autonomic centers in the medulla oblongata
What makes up the Diencephalon?
Thalamus, epithalamus, and hypothalamus
What part of the white matter in the medulla oblongata?
The ascending and descending tracts within columns that link the brain with the spinal cord
What separates motor and sensory areas of the cerebrum?
The central sulcus
What are the components of the limbic system?
The cerebral components, diencephalon components, and the reticular formation
What makes up the white matter in the in the midbrain?
The cerebral peduncles
What is the largest part of the brain?
The cerebrum
