Chapter 12 study guide
acetylcholine
A CNS & PNS neurotransmitter which is a derivative of choline; it is synthesized, stored and released at the ends of nerve fibers at the neuromuscular junction. in the somatic and parasympathetic nervous systems, and in the brain where it may also act as a neuromodulator.
denticulate ligament
A band of fibrous pia mater extending along the spinal cord on each side between the dorsal and ventral roots of the spinal nerves; it pierces the arachnoid and is attached to the dura mater at 21 points; this* stabilizes the spinal cord within the vertebral canal and decreases the likelihood of cord damage when physical trauma occurs.
contusion
A bruise; an injury limited to some disorganization of the subcutaneous tissue and effusion of blood beneath the skin, but without an apparent open wound.
Raynaud's syndrome = Raynaud's disease
A circulatory disorder involving improper autonomic regulation of blood flow, which affects the hands and feet, caused by vessel spasms, when exposed to cold, from an emotional upset, smoking cigarettes or working with vibrating machinery, which lead to insufficient blood supply to these parts and resulting in cyanosis, numbness, pain, and, in extreme cases, gangrene.
dynorphins
A class of opioid peptides which have modulatory effects on several CNS functions, including memory acquisition, stress and movement.
medullary rhythmicity area
A collection of neurons in the reticular formation within the medulla oblongata involved in establishing or modifying the pattern for breathing; within this area are two key components: (1) the ventral respiratory group (VRG) (formerly the inspiratory area) which autorhythmically stimulates spontaneous ventilation, resting or tidal breathing (eupnea), and (2) the dorsal respiratory group (DRG) (formerly the expiratory area) which responds to situations beyond those of the resting or tidal breathing (eupnea) to alter the pattern for ventilation in response to the physiological needs of the body for O2 and CO2 exchange and for blood acid-base balance.
pontine respiratory center
A collection of neurons in the reticular formation within the pons which limit inspiratory duration by sending inhibitory signals to the medullary rhythmicity area reducing duration of inspiratory impulses causing shorter cycles which increases ventilation rate; these pontine respiratory neurons receive input from higher brain centers and peripheral receptors, and their output fine tunes the breathing rhythm during activities such as speaking, sleeping, or exercising.
ischemia
A decrease in the blood supply, and, therefore, oxygen and nutrients, to a body organ, tissue, or part caused by constriction or obstruction of the blood vessels.
electroencephalogram
A diagnostic test which records a graphic record of the electrical activity of the brain (the frequency and amplitude of brain waves, e.g., alpha, beta, delta waves) using highly sensitive electrodes attached to the scalp and connected to an electroencephalograph; commonly used in the evaluation of neurological diseases, e.g., seizures, epilepsy, etc.; aka encephalogram
reticular formation
A diffuse network of nerve fibers and neurons collected in various nuclei in parts of the brainstem, which receives afferent axons from a variety of sources, especially from the face; this system is important in arousal, maintaining consciousness, wakefulness and muscle tone and contributes to sensory adaptation by filtering out repetitive stimuli.
Cerebral palsy
A disorder usually caused by motor area brain damage occurring at or before birth and marked by muscular impairment, a loss or deficiency of motor control with involuntary spasms; often accompanied by poor coordination, it sometimes involves speech and learning difficulties; it may congenital, e.g., fetal hypoxia, placental dysfunction, or acquired after birth, e.g., from head injury, jaundice, Rh incompatibility, and rubella (German measles); nickname spastic paralysis.
neurosecretory cells
A diverse group of specialized cells derived from nervous tissue which produce regulatory hormones which are secreted into the blood stream to circulate and reach their target organs to trigger a response; within the central nervous system, neurosecretory cells are found primarily in the hypothalamus where the secretions are transferred to the pituitary gland and in the pineal body; within the peripheral nervous system, neurosecretory cells are found in the adrenal medulla and within the walls of the gastrointestinal tract.
tentorium cerebelli
A fold of the dura mater forming a roof over the cerebellum within the posterior cranial fossa, except for an anterior median opening through which the mesencephalon passes, and separating the cerebellum from the basal surface of the occipital and temporal lobes of the cerebral cortex; it supports the occipital lobes of the cerebrum, and has its posterior and lateral border attached to the skull and its anterior border free.
ramus / rami
A general anatomical term for a branch which may be applied to a nerve, a blood vessel, or a region of a bone; in the peripheral nervous system, especially the first branches from each spinal nerve.
limbic system
A group of interconnected subcortical structures, (e.g., the hypothalamus, the hippocampus, and the amygdala) involved in olfaction, emotion, motivation, behavior, and various autonomic functions.
Nucleus (grey matter)
A group of specialized nerve cells, or a localized mass of gray matter, carrying out specific functions in the brain; a term less often applied to gray matter in the spinal cord.
poliomyelitis = polio
A highly infectious viral disease that chiefly affects children, whose early symptoms include fever, sore throat, headaches and vomiting, often with stiffness of the neck and back; and, in its severe acute form, causes inflammation of somatic motor neurons of the ventral horn of the spinal cord and of brainstem, leading to paralysis, muscular atrophy, and often deformity; through vaccination, the disease is preventable
laceration
A jagged wound caused by tearing or cutting tissue.
substantia nigra
A layer of large pigmented nerve cells in the midbrain (mesencephalon) which produce dopamine and whose destruction is associated with Parkinson's disease; it is involved in metabolic disturbances associated with Parkinson's disease and with Huntington's disease.
Dyslexia
A learning disorder marked by impairment of the ability to recognize and comprehend written words.
cardiovascular center
A major autonomic nucleus located deep inside the medulla which received visceral sensory information about blood pressure, blood oxygen levels, blood pH, etc., and integrates this information to regulate the rate of the heartbeat and the level of muscular tension in the blood vessels primarily via autonomic sympathetic visceral motor impulses.
median aperture
A median opening permitting CSF to move from the fourth ventricle to the subarachnoid space.
Thalamus
A pair of large ovoid masses of gray matter situated in the posterior part of the diencephalon on either side of the third ventricle which process sensory impulses (except olfaction) by gating out irrelevant sensory information while directing relevant information to the cerebral cortex and it is also important in motor control; it is divided into two major part: dorsal and ventral, each of which contains many nuclei.
lateral apertures
A pair of lateral openings permitting CSF to move from the fourth ventricle to the subarachnoid space.
aphasia
A partial or total loss of the ability to articulate ideas or comprehend spoken or written language, resulting from damage to the brain caused by injury or disease, although the vocal organs remain intact, and the intellect is preserved.
blood- CSF barrier = blood- brain barrier
A physiological mechanism that alters the permeability of brain capillaries, so that some substances, such as certain toxins and drugs, are prevented from entering brain tissue, while other substances are allowed to enter freely; physically it consists of the capillary endothelial cells and their basement membranes and the processes of astrocytes associated with the capillary beds that serve the brain and spinal cord tissue.
Parkinson's disease
A progressive nervous disease, sometimes with a hereditary component, occurring most often after the age of 50, associated with the destruction of brain cells that produce dopamine and characterized by muscular tremor, slowing of movement, partial facial paralysis, peculiarity of gait and posture, and weakness; nickname shaking palsy.
gas neurotransmitters
A recently discovered group of novel neurotransmitters which are small soluble molecules synthesized on demand (when the action potential arrives) by certain neurons; these compounds then diffuse into nearby neurons or even back into the sending neuron to stimulate a variety of effects; e.g., nitric oxide (NO) and carbon monoxide (CO).
basal nuclei
A series of four to six paired (right and left) subcortical nuclei occupying space within the interior of the boundary area between frontal and temporal lobes of the cerebral hemispheres which receive input from cortical motor and somatosensory areas and provide output to the thalamus and midbrain; these connections (along with output from the cerebellum) are essential for execution of normal smooth coordinated voluntary movements.
brain lateralization
A significant division of labor recognized in the cerebrum in which (1) somatic sensory information from and somatic motor commands to the left side of the body are routed from/to the right cerebral hemisphere and vice versa; (2) the left side of the brain is dominant for language skills in 95% of right-handed individuals and in 60-70% of left-handed individuals; (3) for a majority of individuals the left cerebral hemisphere is also dominant for math skills and logic; (4) for a majority of individuals the right cerebral hemisphere is dominant for spatial abilities, face recognition, visual imagery, and musical skills.
pineal gland
A small endocrine organ situated in the diencephalon beneath the back part of the corpus callosum in the roof of the third ventricle of the brain which secretes the hormone melatonin; in the human it appears to play a role in sleep-wake cycles and may contribute to the regulation of the onset of puberty.
pituitary gland = hypophysis
A small oval endocrine gland attached to the base of the brain by the infundibulum and housed in the sella tursica fossa of the sphenoid bone; it is regulated by the hypothalamus; it consists of an anterior and a posterior lobe, the secretions of which control many of the other endocrine glands and influence growth, metabolism, and maturation; anterior lobe hormones include growth hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, prolactin, luteinizing hormone, follicle-stimulating hormone and melanocyte-stimulating hormone and posterior lobe hormones include antidiuretic hormone = vasopressin and oxytocin. nickname - the master gland.
mammillary region
A small portion of the inferior surface of the hypothalamus containing nuclei associated with memory.
frontal eye field
A specific motor area within the frontal cortex which controls the voluntary scanning movements of the eyes, such as tracking a bird in flight, by sending impulses to the extrinsic muscles of the eyes.
stroke = cerebrovascular accident = CVA
A sudden loss of brain function resulting when the rupture or occlusion of a blood vessel leads to oxygen starvation in the brain, characterized by loss of muscular control, diminution or loss of sensation or consciousness, dizziness, slurred speech, or other symptoms that vary with the extent and severity of the damage to the brain.
transient ischemic attack
A temporary blockage of the blood supply to the brain caused by a blood clot and usually lasting ten minutes or less, during which dizziness, blurring of vision, numbness on one side of the body, and other symptoms of a stroke may occur; nickname ministroke.
Epithalamus
A thin mass of nervous tissue (gray and white matter) forming the roof of the third ventricle, and including the pineal gland*; its gray matter is involved in emotional and visceral responses to odors and its white fibers form a link between the limbic system and other parts of the brain.
concussion
A traumatic injury to an organ, especially the brain, produced by a violent blow and followed by a temporary or prolonged loss of function; some symptoms of a concussion are: persistent low-grade headaches; having more trouble than usual remembering things, concentrating, or making decisions; feeling tired all the time; feeling sad, anxious, or listless; or becoming easily irritated for little or no reason.
hydrocephalus
A usually congenital (less often acquired, e.g., from tubercular meningitis) progressive condition in which an abnormal accumulation of cerebrospinal fluid in the cerebral ventricles causes enlargement of the skull and compression of the brain, destroying much of the neural tissue, and possibly increasing the size of the fontanelles and even the top of the head in newborns where skull bones have not united. aka water on the brain.
Reye's syndrome
An acute encephalopathy characterized by fever, vomiting, fatty infiltration of the liver, disorientation, and coma, occurring mainly in children and usually following a viral infection, such as chicken pox or influenza; while the cause and cure remain unknown, research has established a link between Reye's Syndrome and the use of aspirin and other salicylate-containing medications.
intermediate mass = massa intermedia
An apparently functionless mass of gray matter in the midline of the third ventricle that is found in many but not all human brains and is formed when the surfaces of the thalami protruding inward from opposite sides of the third ventricle make contact and fuse.
cervical enlargement
An expansion in the mass and diameter of the spinal cord in the region of C3-4 - T1-2 where motor neurons located in prominent ventral horns supply the upper limb muscles and where there are large number of axons entering and leaving the spinal cord to innervate the upper extremitiea.
lumbar enlargement
An expansion in the mass and diameter of the spinal cord in the region of T10-12 - L1-2 where motor neurons located in prominent ventral horns supply the lower limb muscles and where there are large number of axons entering and leaving the spinal cord to innervate the lower extremities.
Alzheimer's disease
An organic brain disease marked by the loss of cognitive ability, generally over a period of 10 to 15 years, and associated with the development of abnormal tissues, tangled nerve fiber masses, cortical atrophy and protein deposits in the cerebral cortex; a progressive form of presenile dementia that is similar to senile dementia except that it usually starts in the 40s or 50s; first symptoms are impaired memory which is followed by impaired thought and speech and finally complete helplessness.
encephalitis
Any inflammation of the brain, usually caused by a virus; symptoms include headache and neck pain and drowsiness and nausea and fever.
endorphins
Any of a group of large peptide neurohormones that bind to opiate receptors and are found mainly in the brain; they reduce the sensation of pain (analgesic effect) and affect emotions
neuropeptides
Any of various short-chain peptides (oligopeptides) found in brain tissue, such as endorphins; many neuropeptides are also synthesized and released as hormones by non-neuronal cells; these neuroactive molecules coordinate, integrate, and regulate physiological processes in all organisms, throughout all phases of development; acting as neurohormones, neurotransmitters, and/or neuromodulators, they maintain physiological homeostasis and influence important behavioral patterns.
brain waves
Brain waves, or the "EEG", are electrical signals that can be recorded from the brain, either directly or through the scalp; the kind of brain wave recorded depends on the behavior of the subject, and is the visible evidence of the kind of neuronal (brain cell) processing necessary for that behavior; the most common coherent patterns are classified as alpha (subject relaxed), beta (subject concentrating, alert, anxious, panicky), delta (sleep or disconnection from body), and theta (creative, pleasurable or confused states).
feeding center
Collections of neurons in the hypothalamus which evaluate and respond to changes in the blood levels of various nutritional metabolites, e.g., blood glucose, by issuing commands to brain stem centers that initiate behaviors leading to ingestion of foods; aka hunger center.
1. stroke = cerebrovascular accident (and transient ischemic attack) 2. Alzheimer's disease 3. Parkinson's disease 4. Cerebral palsy 5. Dyslexia 6. Reye's syndrome 7. encephalitis 8. meningitis
Eight brain disorders
enkephalins
Either of two closely related CNS neuropeptides (pentapeptides) having opiate qualities (producing pain relief by central inhibition of incoming pain impulses) and occurring in the brain, spinal cord, and other parts of the body.
frontal lobe, temporal lobe, parietal lobe, occipital lobe, insula
Five lobes of the cerebral hemisphere
midbrain-visual reflex centers; auditory reflex centers; reticular activating system pons-respiratory nuclei; reticular activating system medulla oblongata-cardiovascular center; respiratory centers; reticular activating system; centers controlling vomiting, hiccupping, swallowing, coughing, and sneezing
Important functional area associated with each part of the brain stem
meningitis
Inflammation of the meninges of the brain and the spinal cord, most often caused by a bacterial or viral infection and characterized by fever, nausea and vomiting, intense headache, and stiff neck; bacterial forms tend to have more severe prognosis.
neuromodulators
Molecules which potentiate or inhibit the transmission of a nerve impulse but are not the actual means of transmission itself; while they are similar to neurotransmitters, they do not directly trigger impulse transmission, but facilitate or suppress the initiation of impulse transmission; another difference is that neuromodulators may simultaneously affect larger regions within the CNS than simply an individual synapse.
choroid plexus
One of the delicate fringelike processes, consisting almost entirely of blood vessels, which project into each of the four ventricles of the brain which are lined by specialized ependymal cells which secrete cerebrospinal fluid.
(central canal) → (1) gray commissure → (2) white matter (fasiculus gracilis) → (3) pia mater → (subarachnoid space with CSF) → (4) arachnoid → (5) dura mater → (6) epidural space with adipose tissue → (7) spinous process of vertebral arch → (supraspinous ligament of superficial fascia) → (hypodermis) → (8) dermis → (9) epidermis
Sequentially, the structures encountered when exiting the body posteriorly from the central canal of the spinal cord.
circumventricular organs
Several small structures located around the edges of the third and fourth ventricles, lacking the regular blood-brain barrier and thus serving as significant sites for neural-endocrine interaction.
1. body temperature 2. food intake/hunger 3. water and electrolyte balance 4. thirst 5. biological rhythms and drives 6. regulates output of pituitary gland = hypophysis
Six aspects of internal homeostasis coordinated by the hypothalamus
1. heart rate 2. blood vessel diameter 3. respiratory rate and depth 4. the vomiting reflex 5. the cough reflex 6. control of swallowing
Six aspects of internal homeostasis coordinated by the medulla oblongata
association areas
Specific areas of the cerebral cortex which integrate sensory information with emotional states, memories, learning and rational thought processes.
Sensory areas
Specific areas of the cerebral cortex which receive and interpret somatic sensory impulses, e.g., olfaction in the frontal lobe, cutaneous sensations in the parietal lobe, visual sensations in the occipital lobe, taste, hearing, and equilibrium in the temporal lobe; visceral sensory impulses are received and interpreted in the diencephalon, cerebellum, and brain stem.
motor areas
Specific areas of the cerebral cortex, diencephalon, cerebellum, brain stem and spinal cord which generate impulses which innervate all effectors in the body, e.g., voluntary skeletal muscles, involuntary muscles, and glands, both endocrine and exocrine.
tracts (fasciculi)
Specific groups of neuron processes (axons and/or dendrites) which carry similar functional types of impulses to and from similar destinations within the central nervous system (CNS); individual ascending and descending white fiber tracts which are grouped into three regional (dorsal/posterior, lateral, ventral/anterior) columns (funiculi) on each side of the spinal cord; in general, their names combine and indicate both their origin and destination; they transmit nerve impulses between upper and lower regions of the cord and to and from the brain; they are best observed in cross sections of the spinal cord and brain stem.
pons
The "bridge" between the midbrain and the medulla oblongata consists of gray matter nuclei, including the pneumotaxic area and apneustic area which help control breathing rate, and white fiber tracts.
spinal nerves
The 31 pairs of mixed (m/s) nerves which arise from the various spinal segments of the spinal cord, which originate as dorsal and ventral roots which combine the in the region of the intervertebral foramen and shortly thereafter branch into various rami to innervate various regions of the body, the trunk, arms, legs, and internal organs.
lobe
The anatomic subdivision of a cerebral hemisphere, with the boundary usually marked by a slightly deeper sulcus or an even deeper fissure; its tissues consist of surface gray matter and some embedded nuclei of gray matter and various expanses of white matter.
subdural space
The anatomical location between the dura and the arachnoid is merely a "potential" space because under normal circumstances, the arachnoid is directly attached to the dura mater.
epidural space
The anatomical location external to the dura is merely a "potential" space in the cranium, since the dura is fused to the cranial periosteum, while, in contrast, in the vertebral canal, it generally contains adipose tissue.
frontal lobe
The anterior lobe of the cerebral hemisphere named for the overlying frontal bone, this lobe receives and interprets olfactory sensation, initiates voluntary commands to skeletal muscles; it is also a main location for personality traits and higher thought processes including learning, problem solving, memory, etc.; its tissues consist of surface gray matter and some embedded nuclei of gray matter and various expanses of white matter.
corpus callosum
The arched bridge of commissural white fibers, situated above the thalamus, which forms the roof of the lateral and third ventricles and which connects the two cerebral hemispheres, allowing communication between the right and left sides of the brain.
cerebral aqueduct
The canal connecting and transporting CFS from the third to the fourth ventricle which is located in the midbrain.
Gray commissure
The central crossbar of gray matter, observable in every segment of the spinal cord, which encloses the central canal and connects with the masses of gray matter on each side.
Functional areas (of cerebral cortex)
The general classification of regions of the cerebral cortex by main function; there are three types of functional areas: (1) sensory areas which receive and interpret somatic sensory impulses including cutaneous sensations, the five special senses, and some aspects of proprioception (however, little visceral sensory information is routed to the cortex), (2) association areas which integrate sensory information with emotional states, memories, learning and rational thought processes, and, (3) motor areas which generate impulses which innervate voluntary skeletal muscles.
1. CSF is synthesized by Choroid Plexus cells lining portions of the lateral ventricles. 2. CSF is synthesized by Choroid Plexus cells lining portions of the third ventricle. 3. CSF is synthesized by Choroid Plexus cells lining portions of the fourth ventricle. 4. CSF flows from the lateral ventricles (through the interventricular foramen) into the third ventricle. 5. CSF flows from the third ventricle through the cerebral aquaduct into the fourth ventricle. 6. CSF flows from the fourth ventricle (through the median and lateral apertures) into the subarachnoid space where it circulates of the surface of the brain and spinal cord. 7. A small quantity of CSF flows from the fourth ventricle into the central canal of the spinal cord. 8. CSF is reabsorbed by various arachnoid villi and transferred to the blood stream in the large venous sinuses located in folds of the dura mater.
The circulation of the cerebrospinal fluid including its origin and reabsorption
posterior root = dorsal root = sensory root
The collection of afferent sensory processes, emanating from the soma/cell bodies of the somatic and visceral sensory (afferent) neurons which reside in the posterior/dorsal/sensory root ganglion, which merge with the anterior root/ventral/motor root to form the spinal nerve laterally and which emerge from the posterior/dorsal horn at a particular spinal segment.
anterior root = ventral root = motor root
The collection of efferent motor processes, emanating from the soma/cell bodies of the somatic and autonomic/visceral motor (efferent) neurons which reside in the lateral and anterior/ventral horns of the gray matter, which merge with the posterior root/dorsal/sensory root to form the spinal nerve laterally and which emerge from the anterior/ventral horn at a particular spinal segment.
reticular activating system
The combination of the reticular formation in the brain stem and its connections which functions to produce arousal by responding to sensory stimuli (visual, auditory, cutaneous, olfactory, etc.) with impulses sent to higher centers; this system is suppressed by general anesthetic gases; efferent impulses are also transferred in descending pathways to control respiratory and cardiac rhythms.
diencephalon
The connection between the cortex and the brain stem which consists of the thalamus, hypothalamus, epithalamus and pineal gland, and third ventricle; it contains a variety of ascending and descending white fiber tracts as well as gray matter organized into nuclei which function in regulating internal homeostasis, in memory processing and in emotional response.
Longitudinal fissure
The deep groove which separates the left and right hemispheres of the cerebral cortex and it is occupied by the superior and inferior venous sagittal sinuses which are housed within an extension of the dura mater.
brain stem
The distal portion of the the brain, extending from the diencephalon to the spinal cord, and connecting to the cerebellum by several pairs of cerebellar peduncles, the brain stem consists of the reticular formation, midbrain, pons, and medulla oblongata; it contains major ascending and descending white fiber tracts, is the origin for several pairs of cranial nerves, and contains gray matter nuclei involved in regulating internal homeostasis, e.g., state of arousal (asleep versus awake), respiratory rate, heart rate, vasomotor tone, and coordination of swallowing, vomiting, coughing, sneezing, and hiccupping.
olfactory bulbs
The enlarged ventral projections of the frontal lobes, adjacent to the cribiform plate of the ethmoid bone, where the olfactory nerves begin.
posterior/ dorsal/ sensory root ganglion
The enlargement found on each posterior/dorsal/sensory root which houses the soma/cell bodies of the somatic and visceral (afferent) sensory neurons serving a particular spinal segment.
arachnoid villi
The finger-like projections of the arachnoid membrane which project into the cranial venous sinuses within the dura mater along the major fissures of the brain where they are in close proximity to the venous blood and where cerebrospinal fluid can be transferred from the subarachnoid space back into the bloodstream.
meninx/ meninges
The first layers of protection over the brain, spinal cord, and cranial and spinal nerves are three layers of fibrous connective tissue; the dura mater (tough and thick), arachnoid membrane (delicate), and pia mater (tough and thin).
Gyrus/gyri = convolution
The folds of gray matter which form the cerebral cortex; having the gray matter distributed in folds and grooves increases the surface area of the cortex to facilitate diffusion of nutrients, respiratory gases, and wastes between the nervous tissue and the adjacent cerebrospinal fluid and the blood stream.
folia
The folds or ridges of gray matter which form the cerebellar hemispheres; having the gray matter distributed in folds or ridges and grooves increases the surface area of the cortex to make room for additional neurons, and to facilitate diffusion of nutrients, respiratory gases, and wastes between the nervous tissue and the adjacent cerebrospinal fluid and the blood stream.
fourth ventricles
The fourth of the ventricles of the brain, a narrow space between the pons and upper medulla oblongata anteriorly and the cerebellum posteriorly which receives CSF from the cerebral aquaduct and passes CSF on to the central canal of the spinal cord and outward into the subarachnoid space; contain a choroid plexus which secretes CSF.
Cerebral cortex
The gray matter on the surface of the cerbrum which is from 2 - 4 mm thick and is subdivided into six cellular layers; the cerebral cortex is the seat of consciousness where all forms of sensory information are received and interpreted and where voluntary commands are issued to skeletal muscles; it is also a location for emotional processing and higher thought processes including learning, problem solving, memory, etc.
anterior median fissure = ventral median fissure
The groove along the anterior midline of the spinal cord that incompletely divides it into symmetrical halves; it increases the surface area of the spinal cord for exchange of nutrients and oxygen with the blood stream and the cerebrospinal fluid.
posterior median sulcus = dorsal median sulcus
The groove along the posterior midline of the spinal cord that incompletely divides it into symmetrical halves; it increases the surface area of the spinal cord for exchange of nutrients and oxygen with the blood stream and the cerebrospinal fluid.
melatonin
The hormone, a derivative of the amino acid tryptophan, produced by the pineal gland; in humans rising levels induce sleep; it also inhibits the stimulation of gonadotropin (LH) activity before puberty.
temporal lobe
The inferior lateral lobe of the cerebral hemisphere named for the overlying temporal bone, this lobe receives and interprets auditory sensation and equilibrium sensation; it is also a main location for coordination of auditory and visual aspects of language; its tissues consist of surface gray matter and some embedded nuclei of gray matter and various expanses of white matter.
spinal cord
The inferior portion of the Central Nervous System; the thick, whitish, cylindrical (slightly flattened dorso-ventrally) mass of nervous tissue that extends from the medulla oblongata down through the upper two-thirds of the spinal canal in the vertebral column to the upper lumbar region and from which the spinal nerves branch off to various parts of the body; the nervous tissue consists of nerve fibers and nerve cells, the latter being confined to the gray matter of the central portions of the cord, while the peripheral white matter is composed of nerve fibers only; the center of the cord is traversed by a slender canal connecting with the ventricles of the brain which contains cerebrospinal fluid.
pia mater
The inner layer of the meninges, a thin but tough membraneous covering which adheres smoothly to the surface of the brain and spinal cord and conforms to all the irregularities of their surfaces; it is composed of a very thin layer of dense irregular fibrous connective tissue; the smaller surface blood vessels of the brain and spinal cord are contained within this layer; at spinal levels, the pia mater gathers laterally, pierces the arachnoid and attaches to the dura, forming the denticulate ligament -- this* stabilizes the spinal cord within the vertebral canal and decreases the likelihood of cord damage when physical trauma occurs.
fissure
The larger deeper grooves on the surface of the cerebral hemispheres which tend to be partial dividers of the hemisphere into its specific lobes; these grooves also increase the surface area of the brain surface which makes room for more gray matter and also provides access to the blood supply in the nearby pia mater and subarachnoid space.
lateral ventricles
The largest pair (right and left) of the ventricles of the brain which are irregular with projecting horns which are located in the interior of the cerebral hemispheres; contain a choroid plexus which secretes CSF which circulates through them and passes to the third ventricle.
insula
The lobe of the cerebral hemisphere which is located deep within the lateral cerebral fissure under the parietal, frontal, and temporal lobes; it is a location for visceral and autonomic function, including taste; its tissues consist of surface gray matter and some embedded nuclei of gray matter and various expanses of white matter.
primary motor cortex (precentral gyrus of frontal lobe)
The location, just anterior to the central sulcus in the frontal lobe of the cerebral cortex, of the gray matter motor neurons which initiate impulses routed through the medulla and spinal cord which represent the conscious voluntary commands to the prime movers of skeletal muscle groups for specific actions; it is highly organized with specific regions representing each part of the body.
primary sensory cortex (postcentral gyrus of parietal lobe)
The location, just posterior to the central sulcus in the parietal lobe of the cerebral cortex, of the somatic sensory neurons which receive impulses routed through the thalamus, medulla and spinal cord which respond with the first conscious perceptions/awareness of cutaneous sensations arriving from stimulated receptors in the skin and subcutaneous tissues; it is highly organized with specific regions representing each part of the body.
medulla oblongata
The lower portion of the brain stem, connecting the pons to the spinal cord and the location of the pyramids; it contains major ascending and descending white fiber tracts and the location where most such tracts, sensory and motor, cross from right to left within the CNS; and it contains gray matter nuclei involved in the regulation of heart rate, vasomotor tone, respiratory rate, and coordination of swallowing, vomiting, coughing, sneezing, and hiccupping.
Cerebrum, diencephalon, brain stem, cerebellum
The main four parts, the largest subdivisions, of the brain
anterior gray horn = ventral gray horn
The mass of gray matter, observable in every segment of the spinal cord, which houses the soma/cell bodies of the somatic motor (efferent) neurons (and various interneurons) and from which motor (efferent) axons emerge, exiting the cord, to form the anterior/ventral root of each spinal nerve.
posterior gray horn = dorsal gray horn
The mass of gray matter, observable in every segment of the spinal cord, which houses the soma/cell bodies of the various interneurons which receive sensory (afferent) impulses, which enter the cord via the posterior/dorsal root of each spinal nerve, from the somatic and visceral sensory (afferent) neurons which reside in the posterior/dorsal/sensory root ganglion.
cerebellum
The mass of nervous tissue inferior to the occipital lobes (separated from them by the transverse fissure) and posterior to the medulla and pons which consists of two hemispheres connected by a central vermis; cerebellar gray matter is found on the surface and within the white matter ("arbor vitae") and this gray matter is involved in (1) the subconscious movement and coordination of skeletal muscles for skilled movements, for posture and balance, (2) the sense of equilibrium, and (3) contributes to emotional states.
lateral gray horn
The masses of gray matter, observable in only the thoracic, lumbar and sacral segments of the spinal cord, which houses the the soma/cell bodies of the autonomic/visceral motor (efferent) neurons (and various interneurons) and from which visceral motor (efferent) axons emerge, exiting the cord, to form the anterior/ventral root of each spinal nerve; this is a major control center for the Autonomic Nervous System (ANS).
arachnoid
The middle layer of the meninges, a thin, spongy membraneous covering of the brain and spinal cord with a spider-web-like appearance which does not conform to the irregularities of the surfaces of the brain and spinal cord; it is composed of a delicate loose fibrous connective tissue; the space under the arachnoid and above the pia mater, the subarachnoid space, contains cerebrospinal fluid.
central canal
The narrow tube originating posteriorly from the fourth ventricle which runs throughout the center of the medulla oblongata and the spinal cord; it is lined by ependymal cells and contains cerebrospinal fluid which is flowing posteriorly.
dura mater
The outermost and thickest, most fibrous, layer of the meninges covering the brain and spinal cord, composed of dense irregular fibrous connective tissue, a structure which contain some of the larger blood vessels, particularly the venous sinuses; it forms a protective physical barrier for the CNS.
Hypothalamus
The part of the brain which lies below the thalamus, forming the major portion of the ventral region of the diencephalon and which functions to regulate bodily temperature, water balance, carbohydrate and fat metabolism among other metabolic processes, and autonomic activities and also contributes to the regulation of internal homeostasis by neurosecretory functions which control the activity of the pituitary gland.
vertebral canal = spinal canal
The passage formed by the vertebral foramen in the articulated successive vertebrae through which the spinal cord and its membranes pass.
cranial meninges
The portion of the three meninges protecting the CNS in the dorsal body cavity; these layers cover the brain within the brain case of the skull; the first layers of protection over the brain and cranial nerves are these three layers of fibrous connective tissue; the dura mater (tough and thick), arachnoid membrane (delicate), and pia mater (tough and thin).
spinal meninges
The portion of the three meninges which cover the spinal cord and spinal nerves within the spinal canal of the vertebral column in the dorsal body cavity; the first layers of protection over the spinal cord and spinal nerves are these three layers of fibrous connective tissue; the dura mater (tough and thick), arachnoid membrane (delicate), and pia mater (tough and thin).
occipital lobe
The posterior lobe of the cerebral hemisphere named for the overlying occipital bone, this lobe receives and interprets visual sensation; its tissues consist of surface gray matter and some embedded nuclei of gray matter and various expanses of white matter.
CSF = cerebrospinal fluid
The protein-poor serous plasma filtrate which is secreted by choroid plexus cells in each of the four ventricles of the brain and which circulates through the ventricles of the brain, the central canal of the spinal cord, and the subarachnoid space, and returns to the blood stream at the arachnoid villi; it functions as a shock absorption fluid cushion for the brain and spinal cord and as a second circulatory fluid delivering oxygen and nutrients to the nervous tissue.
thirst center
The region of the hypothalamus which is close to the site of production of ADH; this center receives input from osmoreceptors, possibly the same ones responsible for control of ADH release; the threshold for thirst is a plasma osmolarity of about 295 mOsm/L and is rapid in onset; this center also receives input from baroreceptors when blood volume decreases and this center is responsive to angiotensin II; this center generates a conscious stimulus to seek out liquid to drink.
anterior white commissure = ventral white commissure
The relatively narrow crossbar of white matter, observable in every segment of the spinal cord, which lies anterior/ventral to the gray commissure and posterior/dorsal to the anterior median fissure, and which contains various nerve fibers crossing from one side of the cord to the other.
posterior white commissure = dorsal white commissure
The relatively narrow crossbar of white matter, observable in every segment of the spinal cord, which lies posterior/dorsal to the gray commissure and anterior/ventral to the posterior median sulcus, and which contains various nerve fibers crossing from one side of the cord to the other.
spinal tap = spinal puncture = lumbar puncture
The removal of cerebrospinal fluid from the subarachnoid space of the lumbar region of the spinal cord for diagnostic or therapeutic purposes, e.g., to inject anesthetic drugs.
cerebral hemispheres
The right and left halves of the cerebrum which are subdivided into 5 lobes: frontal, parietal, temporal, occipital, and insula; the two hemispheres are anatomically and functionally asymmetrical with the contralateral hemisphere having slightly enlarged parietal and occipital lobes, the differences is related largely to which hand is dominant (handedness); their tissues consist of surface gray matter and some embedded nuclei of gray matter and various expanses of white matter.
decussation of the pyramids
The routing pathway within medulla oblongata where the largest descending white fiber motor tracts to skeletal muscles cross over from right to left sides of the body and vice versa.
falx cerebri
The scythe-shaped mid-saggital fold of the dura mater occupying the longitudinal fissure between the two cerebral hemispheres and which contains the sagittal venous sinuses.
(brain) ventricles
The series of four interconnecting cavities of the brain, lined by ependymal cells and with a specialized choroid plexus which produce the cerebrospinal fluid that fills these chambers.
dural sinuses
The series of large, somewhat irregular, blood-filled venous spaces with roughly triangular cross-sections which are located within the dura mater where the dura follows the contours of the major fissures of the brain; typically there are four major dural sinuses, the superior sagittal, straight, and two transverse sinuses; these venous spaces are the locations for the arachnoid villi through which cerebrospinal fluid = CSF is reabsorbed to be returned to the venous blood supply of the brain.
cranial nerves
The series of twelve pairs of nerves which originate in various portions of the brain and exit the skull through specific foramina to serve the tissues and structures of the head and neck and certain thoracic and abdominal viscera.
Vertebral column
The series of vertebrae forming the axis of the skeleton and protecting the spinal cord; divided into five groups by location: cervical, thoracic, lumbar, sacral and coccygeal groups. aka. spinal column, spine.
conus medullaris
The short tapered end of the spinal cord which is found just inferior to the lumbar enlargement of the cord in the region of L1-2.
filum terminal
The slender threadlike prolongation of the spinal cord below the origin of the lumbar nerves and the last portion of the pia mater; this* stabilizes the spinal cord within the vertebral canal and decreases the likelihood of cord damage when physical trauma occurs.
sulcus/ sulci
The smaller shallower grooves on the surface of the cerebral hemispheres which divide the surface of each hemisphere into its specific convolutions = gyri; having the gray matter distributed in folds and grooves increases the surface area of the cortex to facilitate diffusion of nutrients, respiratory gases, and wastes between the nervous tissue and the adjacent cerebrospinal fluid and the blood stream.
subarachnoid space
The space in the meninges covering the brain and the spinal cord located under the arachnoid and above the pia mater which contains cerebrospinal fluid.
cauda equina
The spinal nerve roots with a common covering of meninges which extend out from the end of the spinal cord and go down the spinal canal through the lower part of the spine canal in the region of the lower lumbar vertebrae, sacrum and coccyx; it looks somewhat like a "horse's tail."
infundibulum
The stalk connecting the hypothalamus to the pituitary gland and the route for the vessels of the hypothalamic-hypophysial portal system.
spinal segment
The structural subdivisions of the spinal cord defined by the origin of a pair of spinal nerves from each subdividion or level within the cord (spinal segment); each subdivision is roughly equivalent to the individual vertebrae of the spinal/vertebral column (cervical, thoracic, lumbar and saccral), but in the adult are located somewhat superior to the comparable bone.
parietal lobe
The superior lateral lobe of the cerebral hemisphere named for the overlying parietal bone, this lobe receives and interprets cutaneous and somatic sensations and taste; it is also a main location for general association areas; its tissues consist of surface gray matter and some embedded nuclei of gray matter and various expanses of white matter.
third ventricles
The third of the ventricles of the brain, a narrow vertical space within the thalamus of the diencephalon which receives CSF from the lateral ventricles and passes CSF on via the cerebral aquaduct to the fourth ventricle; contain a choroid plexus which secretes CSF.
sensory areas -- motor areas -- association areas
The three fundamental categories of functional area of the cerebral cortex.
columns (funiculi)
The three regional (dorsal/posterior, lateral, ventral/anterior) collections of white matter on each side of the spinal cord which are further subdivided into various specifically named ascending and descending white tracts (fasciculi); they transmit nerve impulses between upper and lower regions of the cord and to and from the brain; they are best observed in cross sections of the spinal cord and brain stem.
Cerebrum
The two cerebral hemispheres which form the bulk of the brain have a surface consisting of folds = gyri and grooves = sulci and fissures; its tissues consist of surface gray matter and some embedded nuclei of gray matter and various expanses of white matter; each hemisphere is divided into five lobes, the frontal lobe, the temporal lobe, the parietal lobe, the occipital lobe and the insula; the cerebrum is the seat of consciousness where all forms of sensory information are received and interpreted and where voluntary commands are issued to skeletal muscles; it is also the location for emotional processing and higher thought processes including learning, problem solving, memory, etc.
interventricular foramina
The two openings or short tubes which drain the CSF from the lateral ventricles into the third ventricle.
midbrain
The upper portion of the brain stem, connecting the diencephalon to the pons, which contains the cerebral aquaduct which connects the 3rd and 4th ventricles; it contains major ascending and descending white fiber tracts, and contains gray matter nuclei involved in the reflex movements of the head and trunk in response to visual, auditory and other stimuli.
association fibers
The various interneuron processes (axons and dendrites) which transmit nerve impulses between the various gyri and nuclei within a single cerebral hemisphere.
commissural fibers
The various interneuron processes (axons and dendrites) which transmit nerve impulses from the various gyri and nuclei within a single cerebral hemisphere to corresponding locations in the opposite hemisphere; e.g., many of the fibers in the corpus callosum and anterior and posterior commissures.
projection fibers
The various interneuron processes (axons and dendrites) which transmit nerve impulses from the various gyri and nuclei within the cerebral hemispheres to and from various locations in other parts of the brain and spinal cord; e.g., the various ascending and descending tracts of white matter connecting the cerebrum to the rest of the CNS.
satiety center
The ventromedial region of the hypothalamus which is activated by hyperglycemia and by stretching sensations from the stomach to act to inhibit the feeding center of the hypothalamus, thus inhibiting food intake.
pyramids
The visible features of the ventral surface of the medulla oblongata which contain the largest descending white fiber motor tracts to skeletal muscles and the site where these fibers cross over from right to left or vice versa (crossing to the contralateral side is called called decussation in the brain stem).
descending (motor) tracts
The white fiber tracts/fasciculi in the brain stem and spinal cord which carry primarily somatic and visceral motor (efferent) information inferiorly to lower centers with synaptic connections lower in the cord.
ascending (sensory) tracts
The white fiber tracts/fasciculi in the brain stem and spinal cord which carry primarily somatic and visceral sensory (afferent) information superiorly to higher centers with synaptic connections higher in the cord or within the brain.
arbor vitae
The white matter or myelinated nerve tissue of the cerebellum, which has a treelike outline in a median section.
midbrain, pons, medulla oblongata
Three parts of the brain stem
epithalamus, thalamus, hypothalamus
Three parts of the diencephalon
association fibers- transmit nerve impulses between the various gyri and nuclei within a single cerebral hemisphere commissural fibers- transmit nerve impulses from the various gyri and nuclei within a single cerebral hemisphere to corresponding locations in the opposite hemisphere projection fibers- transmit nerve impulses from the various gyri and nuclei within the cerebral hemispheres to various locations in other parts of the brain and spinal cord (the various ascending and descending tracts of white matter connecting the cerebrum to the rest of the CNS)
Three types of myelinated fibers bundled into tracts, distinguished by where they transmit information within the CNS, that make up the white matter in the cerebrum and list their functions, in terms of where they transmit their nerve impulses.
proprioception -- visual information -- equilibrium (static and dynamic)
Three types of sensory information integrated by the cerebellum.
biogenic amines
a wide variety of small compounds derived by simple enzymatic modification of various individual amino acids which have active physiological properties such as serving as hormones, local hormones, neurotransmitters, neuromodulators, etc.
(spinal cord) → (1) pia mater → (subarachnoid space with CSF) → (2) arachnoid → (3) dura mater
the protective coverings of the spinal cord from deep to superficial.
