Jose Luis Calvo

Jose Luis Calvo

Spain
Spain

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1,880 stock photos, vectors, and illustrations are available royalty-free.

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Cross-sectioned spinal cord surrounded by meninges showing, from outside inside, dura mater (thick), subdural space, arachnoid matter (very thin) and subarachnoid space with nerve roots. Silver stain
Very low magnification micrograph of a distal ileum showings a large aggregate of lymphoid follicles or Peyer’s patch.

Cross-striation of striated skeletal muscle fibers with dark A bands and light I bands. The clear zone in the center of A bands is the H zone. The nuclei are located in the cell periphery
Pyramidal neurons of the cerebral cortex stained with the Golgi silver chromate. From the conic shaped soma, a large apical dendrite and multiple basal dendrites originate.
Human karyotype, light micrograph. Human chromosomes stained with Giemsa (G bands).
White adipose tissue stained with HE. Adipocytes (fat cells) contains a large lipid droplet surrounded by a thin layer of cytoplasm. The nucleus is flattened and located on the periphery
Thyroid follicles lined by a flat cuboidal epithelium and filled with eosinophilic colloid. Light microscope picture. H&E stain
Thin skin showing the epidermis with its different strata, resting on the dermis.
Aortic wall showing the limit between the tunica media, with their typical elastic lamellae, and the adventitia (bottom right), formed by a loose connective tissue with some adipocytes.
Epithelial lining of the exocervix. It is a non-keratinized stratified squamous epithelium, whose most superficial cells retain their nuclei
Very low magnification light microscope micrograph of a thymus gland stained with HE. The thymic parenchyma is composed by small lobules with a dark peripheral cortex and a central clear medulla.

Mucosa layer of the jejunum showing intestinal villi and Lieberkühn crypts. Each villus contains a central axis of lamina propria covered with single columnar intestinal epithelium.
Cross sectioned skeletal striated muscle stained with Azan method. The myofibrils of muscle fiber appear stained in red color. The endomysium appears as blue lines surrounding the muscle fibers.
Human vagina mucosa showing a non-keratinized stratified squamous epithelium (with basal and parabasal layers) and a lamina propria. The superficial cells appear vacuolated due to glycogen storage
Light microscope micrograph showing a network of trabeculae of cancellous or spongy bone separated by large spaces occupied by adipose tissue of yellow bone marrow.
The reticular dermis is a dense irregular connective tissue with fibroblasts and densely packed collagen fibers, organized in intertwined fascicles. High magnification micrograph.
Striated skeletal muscle fibers showing the cross-striation with dark A bands and light I bands. The Z line stands out in the center of I bands. High magnification light micrograph.
Wall of the trachea showing from right to left: mucosa layer with respiratory epithelium and lamina propria with some mucous glands, hyaline cartilage ring and adventitia layer
Urinary bladder wall showing a very folded mucosa layer and a muscular layer with smooth muscle cells arranged in thin bundles separated by connective tissue septa with large blood vessels
Early tertiary follicle with an antrum well visible. The oocyte, located in a cumulus oophorous is surrounded by zona pellucida and corona radiata. The nucleus of oocyte is in another cut plane.
Immature young hand showing, from left to right, methacarpal bones, joined to first and second falanges by diarthrosis type joints. All bones show diaphyseal and secondary or epiphyseal centers.
Interstitial or Leydig cells located among seminiferous tubules. They are polyhedral epithelioid cells with a round nucleus and an acidophilic cytoplasm.
Low magnification micrograph of a silver stained cerebellum. Each folium shows the three layers of cerebellar cortex (molecular, Purkinje and granular) surrounding a central axis of white matter.
Striated skeletal muscle fibers showing the cross-striation with dark A bands and light I bands. The Z line stands out in the center of I bands. High magnification light micrograph.
Epidermis of thin skin. From the depth to the surface it can be identified the  the basale, spinosum, granulosum and corneum strata. The presence of melanin granules is observed in the deeper layers
Smooth muscle fibers of the small intestine, longitudinally sectioned, showing typical fusiform nuclei.
Papillary renal cell carcinoma is a malignant neoplasm derived from renal tubular epithelium with predominantly papillary or tubulopapillary architecture. It is the second most common renal carcinoma
Transitional epithelium (urothelium) of the ureter. The epithelium shows a basal cell layer 2-3 intermediate cell layers and large superficial cells.
Pyramidal neurons of the cerebral cortex stained with the Golgi silver chromate. From the conic shaped soma, a large apical dendrite and multiple basal dendrites originate.
Mucosa of urinary bladder lined by transitional epithelium (urothelium). The superficial layer shows large cells with big nuclei, sometimes binucleated.
Lieberkühn crypts of a human colon mucosa showing abundant goblet cells of pale cytoplasm.
Epiphysis of a developing long bone. A growth plate is located between the primary diaphyseal (down) and secondary epiphyseal (up) ossification centres.
Panoramic view of a cross-sectioned dorsal spinal cord. The central grey matter shows very thin dorsal and ventral horns and is surrounded by the white matter. Silver stain.
Cross section of the cochlea showing vestibular, cochlear and tympanic ducts. The cochlear duct shows, from right to left, the spiral ganglion, tectorial membrane, organ of Corti and stria vascularis
Autonomic sympathetic ganglion stained with Cajal’s silver nitrate showing a mixture of multipolar neuronal cell bodies and nerve fibers.
Striated muscle fibers of the heart myocardium. The cardiac myocytes have a central single nucleus, peripheral striated myofibrils and are joined by intercalated disks. Light microscope micrograph
Very low magnification micrograph showing the large intestine (colon) wall. The mucosa layer show Lieberkühn crypts. The submucosa shows many adipocytes. Below are the two muscular layers
Retina layers. From top to bottom : nerve fiber, ganglion cell, inner plexiform, inner nuclear, outer plexiform, outer nuclear, rods and cones, and pigment epithelium layers. (Bird retina)
Large intestine (colon) wall stained with the PAS method. The mucosa layer show Lieberkühn crypts with goblet cells. The submucosa shows many adipocytes. Below are the two muscular layers.
Growth or epiphyseal plate of a developing long bone showing the following layers, from top to bottom: resting hyaline cartilage, zones of proliferation, hypertrophy, calcification and ossification.
Mucosa of urinary bladder. Transitional epithelium (urothelium) resting on a connective tissue lamina propria. The superficial layer shows large cells with big nuclei, and a rounded apical surface
Thin skin with brown melanin granules located in melanocytes and keratinocytes, being more abundant in the deeper regions of the epidermis.
Ciliated pseudostratified columnar epithelium of the trachea (respiratory epithelium). Light microscope micrograph. Pasini method.
The key pathologic change of the Duchenne muscular dystrophy is the myonecrosis. At an early phase, necrotic fibers appear swollen, homogeneous and deeply eosinophilic.
Light micrograph of a long young bone in process of ossification showing a diaphyseal primary center, a secondary center in one of the two epiphysis and two develoing bone joints.
Cerebellar cortex The Purkinje cells are located between the molecular and granular layers, showing a rounded soma that sends dendrites to the molecular layer. Cajal silver nitrate
High magnification of keratinocytes of the stratum spinosum of the epidermis. Surrounding each keratinocyte are numerous spiny-like structures, each of which correspond to a desmosome.


Protoplasmic astrocytes located in the grey matter showing many processes, almost all of the same length., Vascular end feet are visible as a long, thick process in two of them. Golgi method
Dense irregular connective tissue of reticular dermis showing densely packed bundles of collagen fibers (stained in red). Under the epidermis (blue), the papillary dermis show a more loose tissue.
Multipolar neurons of the anterior horn of the spinal cord stained with the Cajal's silver nitrate method.
Cornea showing, from top to bottom, a non-keratinized stratified squamous epithelium, Bowman's layer, corneal stroma with collagen fibres and keratocytes, Descemet's membrane and endothelium
Actinic or senile keratosis. Light  micrograph showing disordered epithelial layers, atypical keratinocytes hyperkeratosis and lymphocyte infiltrates in the upper dermis beneath the epidermis.
A pyramidal neuron shown with the Golgi silver chromate. The apical dendritic trunk and the basilar dendrites contain  many spines. From the bottom of cell body, the finest and spineless axon arises.
Epithelium of the small intestine. It is a simple columnar epithelium with a well-developed brush border located at its apical pole.
Stratified columnar epithelium. It is a rare type of epithelium composed of columnar cells arranged in several layers (usually only two or three). Large excretory duct of a human parotid gland.
Cross sectioned striated muscle fibers of the heart atrium myocardium. The cardiac myocytes have a central  single nucleus and peripheral myofibrils. Mallory's phosphotungstic hematoxylin.
Minipig testis. Seminiferous tubules and Leydig cells (polyhedral epithelioid cells with round nucleus and acidophilic cytoplasm). In this species, the Leydig cells are much more abundant than humans
Seminiferous tubule. The germinal epithelium shows Sertoli cells, primary spermatocytes in meiosis, and highly differentiated spermatids organized in small bundles.
Human fallopian tube (uterine tube) showing a very folded mucosa. Outside are located the muscular and the serosa layer, with abundant blood vessels. The tissue on the right side is the mesosalpinx.
Longitudinal section showing the opening of a pilosebaceous unit: in the center, the hair, in the bottom the sebaceous glands.
False colour TEM micrograph of a protein-synthetizing cell packed with parallel cisterns of RER with the lumen labelled in blue colour. The cytoplasm, full of ribosomes, is labelled in green color.
Low magnification micrograph of a human uterus showing the endometrium in a secretory phase with very dilated and tortuous glands resting on the miometrium.
High magnification micrograph showing the typical aspect of the lung parenchyma with many alveoli of very thin walls, which contain numerous small capillaries.

Muscular layer of the small intestine with of two layers of smooth muscle fibers. From left to right: submucosa, inner circular layer, outer longitudinal layer, and the serosa layer
High magnification of keratinocytes of the stratum spinosum of the epidermis. Surrounding each keratinocyte are numerous spiny-like structures, each of which correspond to a desmosome.
Cross sectioned nerve fiber fascicles of an autonomic nerve. Each fascicle is surrounded by a thin perineurium.
Ciliated pseudostratified columnar epithelium of the trachea (respiratory epithelium). Light microscope micrograph. H&E stain
Cross-sectioned rabbit ureter showing from the lumen: transitional epithelium (urothelium), lamina propria, smooth muscle fibers of muscular layer, adventitia, and adipose tissue of retroperitoneum
Spermatic cord showing from outside: a thick connective tissue capsule, an empty cavity (tunica vaginalis), deferens duct (on top, with star shaped lumen) and many blood vessels of pampiniform plexus
Mucosa of urinary bladder. The transitional epithelium (urothelium) rests on a connective tissue lamina propria. The superficial layer shows large cells with big nuclei, and a rounded apical surface
Transmission electron microscope micrographs  showing the aspect of muscle fiber sarcomere components in longitudinal (below) and transverse (above) sections at the Z-line, I and A bands and H zone
Epiphyseal growth plate. From right to left: resting hyaline cartilage, zone of proliferation (chondrocyte columns), zone of hypertrophy (large lacunae), zone of calcification, and ossification zone
Epithelial lining of the lingual or superior surface of epiglottis. It is a non-keratinized stratified squamous epithelium. Below is the connective tissue of lamina propria. H&E stain.
Oogonium. False colour TEM micrograph showing the nucleus (green), nuclear envelope (pink), an atypical nucleolus (dark blue). Mitochondria (red) and lipid droplets (yellow) in the cytoplasm (cian).
False colour transmission electron microscope (TEM) micrograph showing mitochondria (blue), glycogen (pink), rough endoplasmic reticulum (red) in the cytoplasm of a hepatocyte.
Epiphyseal ossification. Mixed trabeculae showing a bluish center of calcified cartilage, covered by bone tissue stained with eosin and an external row of osteoblasts.
Four proximal convoluted tubules covered by a simple cuboidal epithelium with apical brush border. Two distal convoluted tubules (at the top and right border of the image) lack of brush border.
High magnification micrograph showing the inner layers of retina. From left to right: inner nuclear layer showing amacrine cells, inner plexiform layer, ganglion cell layer and nerve fiber layer
Striated cardiac myocytes showing yellow pigment lipofuscin granules near the central nucleus. The myocytes are joined by intercalated disks. Light micrograph. H&E stain.
The mast cell or mastocyte it is a connective tissue cell characterized by its cytoplasm filled with large granules rich in histamine and heparin. Bundles of collagen fibers can be seen outside
The reticular dermis is a dense irregular connective tissue with densely packed collagen fibers. Some small blood vessels can also be seen .
Renal medulla showing collecting ducts lined by a simple columnar epithelium. Among them, they are many cross-sectioned capillaries and Henle's loops.
Transmission electron microscope (TEM) micrograph showing a brush border in longitudinal section (inset: light microscope appearance). The microvilli are parallel and tightly packed.

Cross-striation of striated skeletal muscle fibers with dark A bands and light I bands. The clear zone in the center of A bands is the H zone. The nuclei are located in the cell periphery.
The umbilical cord contains a mucous connective tissue known as Wharton jelly with few elongated cells and an intercellular gelatinous substance, largely made up of mucopolysaccharides.
Liver cells (hepatocytes) seen with the light microscope. Their nuclei show a very large nucleolus stained in red.
Human cerebellum stained with Luxol fast blue and cresyl violet. Each cerebellar folium show the molecular and granular layers and the central axis of white matter with blue stained myelinated fibers
Sagittal section of a rabbit cerebellum showing many ramified cerebellar folia. In each folium the molecular and granular layers and the central axis of white matter can be seen. HE stain
Silver stained cerebellar cortex in a case of Creutzfeldt-Jakob disease. There are a severe loss of granular and Purkinje cells, and a notable activation of microglia cells in the molecular layer
Cornea showing, from top to bottom, the non-keratinized stratified squamous corneal epithelium, a thin acellular Bowman’s layer, and the corneal stroma with collagen fibers and interspersed keratocyte
High magnification light microscope micrograph showing fibroblasts. These cells show an elongated nuclei with one or two small nucleoli
Light microscope micrograph of cerebral cortex of a senile cerebrum. The pyramidal neurons show neurofibrillary tangles. This is a type of lesion characteristic of Alzheimer disease. Silver stain.
The perichondrium is a layer of dense irregular connective tissue, with abundant eosinophilic collagen fibers, that surrounds the cartilage, which show its typical basophilia.
Satellite cell (yellow) located between the basal lamina (pink) and the sarcolemma of striated muscle fibers (blue). They are stem cells, involved in the normal growth and regeneration of muscle
Thin skin showing the epidermis with its different strata, resting on the papillary dermis.
Panoramic view of a sagittal section of a rat cerebellum stained with Luxol fast blue counterstained wih cresyl violet. Myelinated fibers of the white matter appear stained in blue color.
Anterior or ventral horn of spinal cord showing multipolar motor neurons. The white matter (left) is crossed by many radiating fascicles of motor neuron axons. Cajal's silver nitrate
Mucosa of urinary bladder lined by transitional epithelium (urothelium) resting on a connective tissue lamina propria. The superficial layer shows large cells with big nuclei (one of them binucleated)
High magnification micrograph of the tunica media of a human aorta. The thick elastic sheets are stained in pink by eosin. Among them, nuclei of smooth muscle cells are seen. HE stain
Root hair of a hair follicle showing a enlargement (hair bulb), with the dermal papilla. The hair matrix show many melanocytes with cell processes loaded with melanin granules.
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