Disc-shaped Cells Research Articles

Comparative Analysis of Specific Gravity with Hemoglobin of the Blood - Clinicopathological Analysis

Aim: The study aims to analyze the specific gravity with the hemoglobin of the blood.
 Introduction: The ratio of the density of a substance to the density of the water at a specified temperature and pressure is known as specific gravity. Blood is a fluid connective tissue that delivers oxygen and nutrients to the cells and transports metabolic waste away from the cells. Red blood cells are biconcave disc-shaped cells produced from bone marrow. It contains proteins that transport oxygen from the lungs to all the parts of the body. The term heme reforms to the iron-containing porphyrin. The aim of the study was to analyse the specific gravity of Hemoglobin of the blood.
 Materials and Methods: 10 random blood samples were collected from the patients in Saveetha Dental College. Then the samples were centrifuged and the blood-specific gravity and hemoglobin were analyzed from the sample using a multi-reagent strip and the specific gravity and hemoglobin was determined.
 Results and Discussion: The mean specific gravity value of age group 21 - 30 years is 1.015, the mean specific gravity value of age group 31 - 40 years is 1.018, the mean specific gravity value of age group 41 - 50 is 1.016, and the mean specific gravity value of age group more than 50 years is 1.020. The mean specific gravity value of females is 1.01750 and the mean specific gravity value of males is 1.01750. The mean Hb value of females is 11.67 and the mean Hb value of males is 14.68.
 Conclusion: The value of mean specific gravity is slightly increased among different age groups and the mean Hb value is also slightly increased with different age groups. Between genders mean specific gravity is equal to both genders and mean Hb value is more in males compared with females.

Failure in the compensatory mechanism in red blood cells due to sustained smoking during pregnancy

Decrease in the bioavailability of vasoactive nitric oxide (NO), derived from the endothelial nitric oxide synthase (NOS3), underlines vascular endothelial damage. Our expanding knowledge on mature red blood cells (RBCs) makes it supposable that RBCs might contribute to vascular function and integrity via their active NO synthetizing system (RBC-NOS3). This “rescue” mechanism of RBCs could be especially important during pregnancy with smoking habit, when smoking acts as an additional stressor and causes active change in the redox status.In this study RBC populations of 82 non-smoking (RBC-NS) and 75 smoking (RBC-S) pregnant women were examined. Morphological variants were followed by confocal microscopy and quantified by a microscopy based intelligent analysis software. Fluorescence activated cell sorting was used to examine the translational and posttranslational regulation of RBC-NOS, Arginase-1 and the formation of the major product of lipid peroxidation, 4-hydroxy-2-nonenal. To survey the rheological parameters of RBCs like elasticity and plasticity atomic force microscopy-based measurement was applied. Significant morphological and functional differences of RBCs were found between the non-smoking and smoking groups. The phenotypic variations in RBC-S population, even the characteristic biconcave disc-shaped cells, could be connected to impaired NOS3 activation and are compromised in their physiological properties. Membrane lipid studies reveal an elevated lipid oxidation state well paralleled with the changed elastic and plastic activities.These features can form a basic tool in the prenatal health screening conditions; hence the compensatory mechanism of RBC-S population completely fails to sense and rescue the acute oxidative stress conditions.

Prasionema heeschiae sp. nov. (Prasiolales, Chlorophyta) from Campbell Island, New Zealand: first record of Prasionema in the southern hemisphere

ABSTRACTA new species in the genus Prasionema (Prasiolales, Trebouxiophyceae) is described from Campbell Island, in the New Zealand subantarctic region, the first record of this genus in the southern hemisphere. Prasionema heeschiae sp. nov. is filamentous, uni- to predominantly biseriate, with disc-shaped cells, and an axial plastid with a central pyrenoid. It is anchored by an enlarged pigmented basal cell. There is evidence of reproduction by both spores and fragmentation. This species was found growing on a timber wharf above the high tide level. The only other species in the genus, P. payeri Heesch, M.Pazoutová & Rindi, was described from Spitzbergen growing on soil in a high nutrient environment. The bipolar distribution of Prasionema is discussed. Based on phylogenetic analyses that included sequence data from holotype material of southern filamentous Prasiolales, we reduce Rosenvingiella australis to synonymy with R. tasmanica.

Spectral coding in auditory midbrain neurons

The data of frequency properties of single neurons in the auditory midbrain center, central nucleus of the inferior colliculus and morphologic aspects of its functional ordering are reviewed. On the basis of reconstruction of single units frequency receptive fields and morphophysiologic mapping of their location within the frequency-band lamina of the central nucleus the model of spectral coding by auditory midbrain neurons is developed. The main structural basement of spectral coding in the auditory midbrain is the tonotopic organization of its central nucleus as well as the order in its morphological structure expressed in alternation of layers of disc-shaped neurons and neuropil. The main neural mechanism of spectral coding is a critical bands mechanism. The critical bandwidth is controlled by inhibitory disc-shaped neurons which constitute an essential part of the population of the central nucleus disc-shaped cells.

Very Low Impedance Battery Architecture for Electrified Vehicles

Rolled-Ribbon is design and manufacturing method for battery cells that incorporates features of very short path length to bring current flow as well as heat from the cell and battery. Disc-shaped cells can be stacked to form a dense and efficient battery architecture for electrified vehicles. Relative to competing architectures, Rolled-Ribbon combines the low-cost winding and dimensional stability of the cylindrical format with fully-tabbed, very short electrodes of a prismatic (that is replicated by winding). The very short electrode of the cells and the quasi-bipolar arrangement approximately lower cell structural impedance (ACIR) by 50% and DC-pulse impedance by 25% for Li-ion battery. As such, Rolled-Ribbon overcomes the power/energy tradeoffs faced by competing architectures. Specific energy is increased with larger cells and high power is maintained.

Relationship of opioid receptors with GABAergic neurons in the rat inferior colliculus

The inferior colliculus is a critical structure for processing auditory information and receives ascending and descending synaptic auditory projections. In addition to GABAergic and glutamatergic innervations, other neurotransmitter systems are also reported in the inferior colliculus, including opioid peptides. In the present study, the relative distribution of each type of opioid receptor, mu (MOR), delta (DOR) and kappa (KOR) within GABAergic neurons in the inferior colliculus was examined. GABA immunoreactivity was expressed by small, medium and large neurons and distributed in the central nucleus and the pericentral nucleus of the inferior colliculus. Immunostaining for MOR, DOR and KOR receptors was found in both disc-shaped cells and stellate cells. Punctiform beta-endorphin immunolabelling was observed in the proximity of GABA-positive neurons. Co-localization of GABA and MOR receptors was observed in neurons and nerve terminals in the central nucleus, dorsal cortex and external cortex of the inferior colliculus. Quantification of the co-localization patterns determined that a higher proportion of GABA neurons was associated with MOR receptors compared with KOR or DOR receptors.

Structure of the ovary and the differentiation of follicular epithelium in the pig louse, Haematopinus suis (Insecta: Phthiraptera)

The female reproductive system of the pig louse, Haematopinus suis (Insecta: Phthiraptera) is composed of paired ovaries, lateral oviducts, and a common oviduct that leads into a vagina. Clusters of mycetocytes (= cells filled with symbiotic organisms) are associated with lateral oviducts. Each ovary is composed of five loosely arranged ovarioles of the polytrophic-meroistic type. An individual ovariole is covered by a basal lamina and is composed of a terminal filament, germarium, and vitellarium. The terminal filament is composed of large, disc-shaped cells that are orientated perpendicularly to the long axis ofthe ovariole. The basal part of the terminal filament is separated from the germarium by a well-developed transverse septum. The germarium is short and filled with clusters of oogonial cells. In each cluster the cells arejoined by intercellular bridges, filled with fusomal material. Within the cluster, only one cell, the future oocyte, enters the prophase of the first meiotic division; the other cells differentiate into nurse cells. The basal part ofthe germarium is filled with the somatic prefollicular cells. The boundary between the germarium and the vitellarium is not distinct. The vitellarium contains linearly arranged ovarian follicles in subsequent stages of oogenesis (previtellogenesis, vitellogenesis and choriogenesis). Each follicle consists of an oocyte and 7 nurse cells and is surrounded by follicular cells. During oogenesis the follicular cells diversify, so that ultimately, five morphologically distinct subpopulations of these cells can be distinguished: (1) cells in contact with the nurse cells, (2) anterior cells, (3) mainbody cells, (4) posterior cells, and (5) interfollicular cells. Interestingly, the follicular cells associated with the anterior part of the oocyte, i.e. located in space at the oocyte/nurse cell border (fold cells) are mitotically active throughout previtellogenesis. It might be suggested, in this context, that the separation of the oocyte from the nurse cell compartment is brought about by mitotic divisions, consequent multiplication and centripetal migration of these cells.

Orientation of biological cells using plane-polarized gaussian beam optical tweezers

Optical tweezers are widely used for the manipulation of cells and their internal structures. However, the degree of manipulation possible is limited by poor control over the orientation of the trapped cells. We show that it is possible to controllably align or rotate disc-shaped cells—chloroplasts of Spinacia oleracea—in a plane-polarized Gaussian beam trap, using optical torques resulting predominantly from circular polarization induced in the transmitted beam by the non-spherical shape of the cells.

Biomedicine. Nota bene: weathering the big chill.

P latelets are tiny disc-shaped cells devoid of a nucleus that are produced by the bone marrow. At sites of injury, platelets bind to von Willebrand factor (vWF) on the surface of endothelial cells, become activated by thrombin, and interact with plasma fibrin to form clots. For more than 50 years, platelet transfusions have prevented life-threatening blood loss in trauma, surgery, and bone marrow transplant patients. However, unlike red blood cells, which are amenable to cold storage, refrigerated platelets are cleared rapidly from the patient's circulation after transfusion. Unfortunately, the shelf life of platelets at room temperature is only 5 days, resulting in an acute shortage of platelets for transfusion. In a recent issue of Cell , Hoffmeister and colleagues ([1][1]) reveal why chilled, transfused platelets disappear rapidly from the circulation and propose a strategy to block this clearance. The rapid disappearance of chilled, transfused platelets has been attributed to the cold-induced loss of their normal discoid shape, presumably leading to the ensnaring of deformed platelets in capillaries. Not so, say Hoffmeister et al ., who show that even preserving the disc shape of chilled mouse platelets with drugs does not prevent their rapid clearance after transfusion into mice. The researchers next demonstrated that clearance of chilled platelets is due to their ingestion (phagocytosis) by liver macrophages called Kupffer cells. Phagocytosis of platelets depends on their binding to an integrin called CR3 on the Kupffer cell surface. When chilled mouse platelets are transfused into mice lacking CR3, they circulate with the same kinetics as transfused platelets kept at room temperature. Seeking the platelet counter-receptor that interacts with CR3, the researchers first investigated GP1ba, the platelet surface glycoprotein that binds to vWF. They found that enzymatically cleaving the extracellular portion of GP1ba from chilled mouse platelets boosted platelet survival after transfusion. Furthermore, in an in vitro assay, enzyme-treated chilled human platelets were not ingested by macrophages, implying that GP1ba is the platelet counter-receptor for CR3. Electron microscopy revealed that refrigeration induced the rearrangement of both mouse and human platelet GP1ba from neat, linear rows into clusters. This redistribution of GP1ba did not affect normal platelet behavior, because chilled platelets circulating in CR3-deficient mice were still able to bind to vWF, respond to thrombin and other mediators, and promote clot formation. If cold-induced platelet clearance could be blocked, then platelets could be stored in the cold and their shelf life dramatically extended. At a recent meeting, Hoffmeister and co-workers ( [2][2]) presented a strategy to attain this goal. By using galactose sugar residues to shield the sugar molecules on GP1ba that bind to CR3, they prevented the clearance of chilled, transfused mouse platelets. Chilled platelets with sugar-modified GP1ba circulated with a normal life-span in transfused mice and fulfilled their normal functions. The Hoffmeister et al . work is a big step toward making platelet refrigeration a reality and alleviating the acute shortage of platelets for transfusion.

Terminal filament cell organization in the larval ovary of Drosophila melanogaster: ultrastructural observations and pattern of divisions.

The adult ovary of Drosophila is composed of approximately twenty parallel repetitive structures called ovarioles. The ovarioles appear at the prepupal stage and their formation requires the presence of stacks of discshaped cells called the terminal filaments. Terminal filaments form in a progressive manner during the third larval instar. We have looked at the beginning of formation of both the terminal filaments and ovarioles at an ultrastructural level. Moreover, we studied the pattern of division of the terminal filament cell precursors using the base analog, BrdU. Two main waves of division are observed. The first wave consists of divisions of almost all the terminal filament cell precursors during a short period of time at the transition between the second and third larval instar. The second wave, in which the precursors carry out their final divisions before differentiating, occurs gradually, going from the medial to the lateral side of the ovary during the first half of the third larval instar.

Drosophila Ovary Morphogenesis: Analysis of Terminal Filament Formation and Identification of a Gene Required for This Process

The adult ovary of Drosophila is composed of approximately 20 parallel repetitive structures called ovarioles. At the anterior tip of each ovariole is a stack of 8-9 disc-shaped cells, called the terminal filament. Ovariole morphogenesis starts with the formation of the terminal filaments. Using two enhancer trap markers for terminal filament cells, we show that terminal filaments form in a progressive manner from medial to lateral across the ovary and that the number of terminal filament cells in a developing stack increases gradually. This process occurs during the second half of the third larval instar. One of these enhancer trap mutations, which is in the 0bric à brac gene, demonstrates that this gene is necessary for terminal filament formation and that a terminal filament cell cluster is required for ovariole morphogenesis to take place.

Rapid induction of type X collagen gene expression in cultured chick vertebral chondrocytes

During endochondral ossification, small rapidly proliferating chondrocytes mature into flattened discshaped cells and then into large round hypertrophic cells. These morphological changes are accompanied by a decrease in the rate of cell proliferation. Type X collagen synthesis is initiated during chondrocyte maturation and reaches very high levels in the hypertrophic cells. We have analyzed type X collagen gene expression in chick embryo vertebral chondrocytes that were allowed to mature in monolayer culture and were then switched to suspension culture. The resuspended chondrocytes changed in shape from flat to round and decreased the proliferation rate as they do in vivo. These events were accompanied by a rapid, dramatic increase in type X collagen gene expression at the levels of transcription, steady-state mRNA and protein synthesis, as well as an increase in the number of cells producing type X collagen. The amount of type X collagen gene expression in resuspended chondrocytes was comparable to that in mineralizing cartilage in vivo. These results indicate that events accompanying the switch from monolayer to suspension culture (for example, the change from a flat to a round shape and/or the decrease in proliferation rate) may play a role in the induction of type X collagen gene expression during chondrocyte maturation. Thus we have developed an in vitro system that appears to mimic the events occurring during in vivo chondrocyte maturation. This in vitro model may provide an ideal system for further examination of the parameters regulating chondrocyte maturation and type X collagen gene expression.

Dendritic and axonal morphology of HRP‐injected neurons in the inferior colliculus of the cat

The dendritic and axonal morphology of neurons in the inferior colliculus of the cat was investigated after intracellular injection of HRP, in vivo. All injected axons gave off local collaterals, and most showed a widespread distribution and lacked a specific orientation. In contrast, the dendrites of injected neurons were distinguished by their degree of orientation and the direction of the longest axis of orientation. Dendrites showed a high, moderate, or low degree of orientation. Most highly oriented cells had their longest axis in the rostrocaudal direction with fewer in the mediolateral direction. In the central nucleus, only the rostrocaudally oriented cells correspond to the disc-shaped cells identified in Golgi preparations. Unlike most cells in our sample, the two cells that were disc-shaped had axons that were parallel to the orientation of the dendritic tree. In the dorsal cortex, rostrocaudally oriented cells also were found, but they had unoriented axons. In both the central nucleus and dorsal cortex, cells with a mediolateral axis of orientation or no specific orientation correspond to stellate cells and had axons with widespread local collaterals. These results suggest that an extensive network of local axon collaterals may contribute to neural processing within the inferior colliculus. In the central nucleus, local axons may establish connections within or across the fibrodendritic laminae. In the dorsal cortex, the local and afferent axons may form a complex reticular network. Finally, some injected cells had axons terminating locally and also entering the brachium of the inferior colliculus. This suggests that cells in the inferior colliculus may function as both interneurons and projection neurons.

A bangiophyte red alga from the Proterozoic of arctic Canada.

Silicified peritidal carbonate rocks of the 1250- to 750-million-year-old Hunting Formation, Somerset Island, arctic Canada, contain fossils of well-preserved bangiophyte red algae. Morphological details, especially the presence of multiseriate filaments composed of radially arranged wedge-shaped cells derived by longitudinal divisions from disc-shaped cells in uniseriate filaments, indicate that the fossils are related to extant species in the genus Bangia. Such taxonomic resolution distinguishes these fossils from other pre-Ediacaran eukaryotes and contributes to growing evidence that multicellular algae diversified well before the Ediacaran radiation of large animals.

The ultrastructure of the central nucleus of the inferior colliculus of the Sprague-Dawley rat.

Previous studies from this laboratory have indicated that increased numbers of GABAergic neurons, as well as total neurons, occur in the central nucleus of the inferior colliculus (IC) of genetically epilepsy-prone rats (GEPRs) as compared to non-seizuring Sprague-Dawley rats. Since electron microscopic studies of the IC have not been reported for rats, we wanted to determine the ultrastructure of neurons and their processes in this brain region to serve as a basis for future studies on neuronal circuitry in the GEPRs. Both disc-shaped and stellate types were found for each of three size categories: large, medium and small. Thus, six types of neuron were distinguished by differences in somatic size, shape, organelles and dendritic orientation. Large neurons (longest diameter greater than 25 micron), which are the least frequent cell type, contained vast perikaryal cytoplasm, eccentrically located nuclei and abundant granular endoplasmic reticulum (GER) adjacent to the nucleus as well as clustered in the cytoplasm; many axosomatic, symmetric synapses were present. Medium-sized neuronal somata (15-25 micron in diameter) had smooth as well as infolded nuclear membranes and clusters of GER in their cytoplasm but no GER adjacent to the nucleus; synapses were sparse along the surface of their somata. Small neurons (10-15 micron in diameter), which are the most frequent cell type, had scant perikaryal cytoplasm, usually infolded nuclei, frequently two nucleoli, and few or no stacked cisternae of GER in the perikaryal cytoplasm; only infrequent axosomatic synapses were found. Based on previous retrograde and immunocytochemical studies, most large disc-shaped and stellate cells project to the medial geniculate body and are probably excitatory, but some large stellate neurons have been shown to be GABAergic and it is doubtful that such neurons participate in this projection. A dense plexus of terminals that form symmetric synapses covers the soma and proximal dendrites of large neurons, and may provide a strong GABAergic inhibition of this type of projection neuron. Small and medium-sized disc-shaped cells also project to the thalamus but they lack this dense axosomatic plexus. The stellate cells from these same two size categories probably do not project to the thalamus and may be GABAergic local circuit neurons. Other ultrastructural features of IC neurons that were analysed include dendrites, dendritic spines, axon hillocks, initial segments and terminals, as well as the laminae of myelinated axons. Dendrites were either beaded or smooth and few spines were observed.(ABSTRACT TRUNCATED AT 400 WORDS)

The human erythrocyte membrane skeleton may be an ionic gel. II. Numerical analyses of cell shapes and shape transformations.

In the first paper in this series (Stokke et al. Eur Biophys J 1986, 13:203-218) we developed the general theory of the mechanochemical properties and the elastic free energy of the protein gel--lipid bilayer membrane model. Here we report on an extensive numerical analysis of the human erythrocyte shapes and shape transformations predicted by this new cell membrane model. We have calculated the total elastic free energy of deformation of four different cell shape classes: disc-shaped cells, cup-shaped cells, crenated cells, and cells with membrane invaginations. We find that which of these shape classes is favoured depends strongly on the spectrin gel osmotic tension, IIGu, and the surface tensions, IIEu and IIPu, of the extracellular and protoplasmic halves of the membrane lipid bilayer, respectively. For constant ratio IIEu/IIPu greater than O large negative or positive values of IIGu favour respectively the crenated and invaginated cell shape classes. For small absolute values of IIGu, IIEu, and IIPu, biconcave or cup-shaped cells are the stable ones. Our numerical analysis shows that the higher the membrane skeleton compressibility is, the smaller are the values of IIGu needed to induce cell shape transformation. We find that the stable and metastable shapes of discocytes and stomatocytes generally depend both on the shape of the stressfree membrane skeleton and the membrane skeleton compressibility.

Formation of the notochord in living ascidian embryos

The dynamic behaviour of cells during formation of the notochord in the ascidian, Ciona intestinalis, was examined by means of Differential Interference Contrast (DIC) microscopy and time-lapse videorecording. The initial rudiment is formed in part as a consequence of the pattern of mitotic divisions as the blastopore shifts posteriorly. Vertical and horizontal rearrangements produce an elongate rod of disc-shaped cells stacked end to end. Further elongation is accompanied by a cell shape change. Some cell growth or swelling is indicated to occur later in development, but this growth appears to contribute mostly to an increase in the diameter, and only insignificantly to the length of the notochord. Intracellular vacuoles that appear around 13 h after fertilization increase in size and fuse at about 16 h form intercellular ones. These in turn merge to form the central matrix core of the notochord at around 18 to 20 h. As the notochord elongates and cells change in shape, the basal surfaces bleb actively. This surface activity may be related to formation of the perinotochordal sheath.

Rapid platelet morphological changes visualized by scanning-electron microscopy: kinetics derived from a quenched-flow approach.

Platelet activation is accompanied by distinct morphological changes from disc-shaped cells to more rounded particles with multiple blebs or psuedopodia. A quenched-flow approach has been used to follow the kinetics and nature of these morphological events. Scanning-electron micrographs revealed very rapid alterations in platelet shape. At 0.5 S after activation with ADP or thrombin, the number of resting disc-shaped particles was nearly halved and short blebbed forms were maximal at 0.5 S. By 1.7 S about 60% of particles were in fully activated or multiple-blebbed form. The calcium ionophore A-23187 caused slightly slower effects. Adrenalin was much less potent, with about 14% of platelets becoming fully activated by 10 S. Control experiments showed only small changes in particle morphology when unactivated platelets were pumped through the reaction tubing and then quenched in glutaraldehyde. The resistive volume of platelets increased by 0.42 fl at 0.5 S after ADP stimulation and was essentially independent of variations in particle shape. These results show that the quenched-flow approach can provide new information about platelet function and that morphological changes begin earlier than previously thought.

Neuron types in the central nucleus of the inferior colliculus that project to the medial geniculate body

At least four neuron types, distinguished on the basis of dendritic and cell body morphology, were labeled in the central nucleus of the inferior colliculus after horseradish peroxidase injections into the medial geniculate body of the cat. Most labeled cells had disc-shaped dendritic fields whose orientation and arrangement into layers were important identifying features. Most labeled cells were small or medium-sized disc-shaped cells with dendritic fields and cell bodies of corresponding size. These cell types appeared to have dispersed Nissl substance and infrequent axosomatic endings. Large disc-shaped cells, identified by their large dendritic fields and somata, were also labeled. These may have had a different Nissl pattern, including both perinuclear cisterns and clumps of granular endoplasmic reticulum, and numerous axosomatic synaptic endings. Stellate cells, which constituted the fourth labeled cell type, were distinguished by their spherical dendritic fields composed of dendrites radiating in all directions, especially across the layers formed by the disc-shaped cells. Stellate cells probably corresponded to neurons with stacks or clumps of granular endoplasmic reticulum, an irregular nuclear envelope, and frequent axosomatic contacts. These results suggest that many of the cell types previously identified in studies using the Golgi method send their axons to the medical geniculate body. The results also raise the possibility that Nissl pattern and dendritic morphology of central nucleus cell types are related. The presence of several types of neurons in the central nucleus with axons ascending to the thalamus may provide a structural basis for some type of parallel information processing in this part of the central auditory system.

The central nucleus of the inferior colliculus in the cat.

The central nucleus of the inferior colliculus in the cat is distinguished by its unique neuropil. In Golgi-impregnated material, it is composed primarily of neurons with disc-shaped dendritic fields arranged into parallel arrays, or laminae, complemented by the laminar afferent axons from the lateral lemniscus. Large, medium-large, medium, and small varieties of disc-shaped cells are distinguished on the basis of the size of the dendritic field and cell body size, dendritic diameter, and dendritic appendages. A second major class of neurons in the central nucleus are the stellate cells with dichotomously branched, spherical-shaped dendritic trees. Simple, complex, and small stellate cells can be distinguished by their size and by the complexity of the dendritic and axonal branching. Laminar afferent axons are recognized by the nests of collateral side branches and the grapelike clusters of terminal boutons--thick, thin, and intermediate-sized varieties are apparent. Other axon types include local collaterals of central nucleus neurons, some of which are distinguished by their frequent and complex collaterals. In the central nucleus, the configuration of the fibrodendritic laminae, the presence of subdivisions, and the banding of afferent axons suggest levels of organization which are superimposed on the synaptic arrangements of the individual cell and axon types. The laminar pattern, as studied in serial Golgi-impregnated sections, differs from previous reports. The central nucleus contains subdivisions which can be distinguished by their laminar pattern, different proportions of cell types, and the packing density of the cell bodies and axonal plexus. The patterns of degeneration observed in Nauta-stained material after lesions of caudal auditory pathways show that thick and fine afferent fibers form dense bands of degeneration separated by sparse, fine-fiber degeneration. The bands are thicker than individual laminae but smaller than the subdivisions. The intrinsic organization of the neurons and axons, combined with the laminar organization, subdivisions, and banding patterns, each may contribute different aspects to the processing of auditory information in the central nucleus.