Jose Luis Calvo

Jose Luis Calvo

Spain
Spain

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1,664 stock photos, vectors, and illustrations are available royalty-free.

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Epithelial lining of the exocervix. It is a non-keratinized stratified squamous epithelium, whose most superficial cells retain their nuclei
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
The reticular dermis is a dense irregular connective tissue with fibroblasts and densely packed collagen fibers, organized in intertwined fascicles. High magnification micrograph.
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.
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
Smooth muscle fibers of the small intestine, longitudinally sectioned, showing typical fusiform nuclei.
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.
Thin skin showing the epidermis with its different strata, resting on the dermis.
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
Urinary bladder wall showing a very folded mucosa layer, a muscular layer with smooth muscle cells arranged in thin bundles separated by connective tissue septa, and a very thin adventitia layer
Hematopoietic bone marrow (red marrow). (vascular compartment). Among sinusoid capillaries, there is the very cellular hematopoietic compartment. Here stand out some giant cells, the megakaryocytes
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.
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.
Endochondral ossification. Mixed bone trabeculae, showing a bluish centre of acellular calcified cartilage, covered by pink primary bone tissue with osteocytes. Bone marrow is located among trabeculae
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.
Bone diaphysis showing the cortical zone of compact bone and central hematopoietic red bone marrow (bottom).
Endochondral ossification. Mixed bone trabeculae, showing a bluish centre of acellular calcified cartilage, covered by pink primary bone tissue with osteocytes. Bone marrow is located among trabeculae
Ciliated pseudostratified columnar epithelium of the trachea (respiratory epithelium). Light microscope micrograph. Pasini method.
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
The reticular dermis is a dense irregular connective tissue with densely packed collagen fibers. Some small blood vessels can also be seen .

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
High magnification micrograph showing the typical aspect of the lung parenchyma with many alveoli of very thin walls, which contain numerous small capillaries.
Cross sectioned striated muscle fibers of the heart myocardium. The cardiac myocytes have a central  single nucleus and peripheral myofibrils. Light micrograph. H&E stain.
Proximal convoluted tubules, PAS stain. They have cells with abundant cytoplasm, apical PAS-positive brush border, and a larger cell volume compared with distal tubules.
False colour TEM of a capillary with a red blood cell (red). The endothelial cell (blue) shows many pinocytosis vesicles (yellow). The basement membrane is marked in pink.
High magnification micrograph of the basal half of the vaginal epithelium. The basal and parabasal layers are evident. Above, the superficial cells show a vacuolated aspect due to glycogen storage.


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
Organ of Corti showing, from right to left: spiral limbus with the tectorial membrane, inner spiral sulcus and Held cells under tectorial membrane and tunnel of Corti. Under, cochlear nerve
Ileum. In the Meckel diverticulum the mucosal lining frequently show a mixture of native ileal mucosa and heterotopic mucosa, most commonly gastric.
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.
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
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.
Stratum spinosum of epidermis stained with Mallory phosphotungstic hematoxylin showing keratin filaments and desmosomes between keratinocytes.
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.
Cross sectioned skeletal muscle fibers. The cytoplasm is full of myofibrils which appear as blue dots. Mallory phosphotungstic.
False colour transmission electron microscope (TEM). Neuron cell body showing nucleus (magenta) mitochondria (blue), lysosomes (green), multivesicular bodies (pink), RER (red) and Golgi (yellow).
Light micrograph of elastic cartilage of a human epiglottis stained with Verhoeff’s iron hematoxylin. Elastic fibres are visible in the cartilage matrix. The perichondrium at right.
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 surface epithelium of the stomach invaginates to form the gastric pits. The pits are lined by a simple columnar epithelium formed by mucous cells.
Example of a typical loose connective tissue belonging to the submucosa of the stomach. Collagen appear as isolated fibers and wavy bundles of fibers.
Thin skin showing the epidermis with their different layers resting on dermis. The epidermal ridges are very striking.
Very low magnification micrograph showing a lacrimal gland. It is an exocrine compound tubuloalveolar gland made up of many lobules separated by connective tissue.
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 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
Choroid plexus of the fourth ventricle. They are lined by a layer of cuboidal cells, resting on a narrow axis of loose connective tissue with numerous capillaries.
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.
Megakaryocytes in the hematopoietic compartment of the red bone marrow. These giant cells produce the blood platelets. Surrounding the megakaryocytes are different precursors of the blood cells.
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.
Thin skin epidermis stained with hematoxylin and eosin showing a large amount of melanin pigment granules above the nucleus of the keratinocytes of the basal and spinous layers.
Light microscope micrograph showing secretory units of a lacrimal gland. They are tubuloalveoli with serous cells and enlarged lumen. On the bottom border can be seen a thin connective tissue capsule
Very low magnification micrograph of a distal ileum showings a large aggregate of lymphoid follicles or Peyer’s patch.
Epiphysis of a developing long bone. A growth plate is located between the primary diaphyseal (down) and secondary epiphyseal (up) ossification centres.
A septum of connective tissue, with numerous adipocytes (fat cells) which contain a large lipid droplet. The sinuous structures correspond to nerves. Light micrograph. Hematoxylin & eosin stain.

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)
Low magnification micrograph showing the limit between retina and ciliary body (ora serrata).  Beneath, the pigmented vascularized choroid and the sclera can be seen.
Hematopoietic red bone marrow (top) next to the cortex of a compact bone (centre).
Hematopoietic red bone marrow (top) next to the cortex of a compact bone (bottom).
Hematopoietic bone marrow (red marrow) situated among the trabeculae of a cancellous bone. It is very cellular because of the formation of new blood cell
Epidermis of the thin skin. It can be identified the stratum basale, spinosum, a narrow stratum granulosum and a superficial well defined stratum corneum. The epidermis rest over the dermis.
TEM showing the nucleus of a protein-synthesizing cell. The nuclear envelope, chromatin  and nucleolus can be seen. The cytoplasm is full of RER.
Section of human kidney stained with a methenamine silver method to highlight the basement membranes of glomerular capillary loops and tubular epithelium.
False colour electron microscope micrograph showing an intercalated disc (blue) between heart muscle cells. The Z lines (red), mitochondria (green) and basement membranes (pink) are also labelled.
Pyramidal neurons of the cerebral cortex impregnated with the Golgi method.
Large ovarian antral follicle or tertiary follicle. In the last phase of follicle maturation, some follicles grow dramatically and one of these become the Graafian or preovulatory follicle.
Cross section of intradermal portion of excretory duct of an eccrine sweat gland, lined by a stratified epithelium formed by two layers of cuboidal cells.
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.
False colour electron microscope micrograph showing melanin granules (dark blue) in a melanocyte (yellow) and in several keratinocytes (light blue) with bundles of keratin filaments (red).
High magnification micrograph of myelinated nerve fibers longitudinally sectioned. In the central fiber, the axon and a node of Ranvier can be recognized. The nuclei are of Schwann cells.
Striated cardiac myocytes showing yellow pigment lipofuscin granules near the nuclei. The myocytes are joined by intercalated disks. Light micrograph. H&E stain.
Longitudinal section showing the opening of a pilosebaceous unit: in the center, the hair, in the bottom the sebaceous glands.
Light microscope micrograph showing desmosomes in a stratum spinosum of the epidermis. One micron-thick section stained with toluidine blue.
Light microscope micrograph showing secretory units of a lacrimal gland. They are tubuloalveoli with serous prismatic cells and an enlarged lumen. They produce tears to clean and lubricate the eyes
Sebaceous glands are holocrine gland whose cells accumulate sebum in clear oil or lipid droplets. Finally, the cells die, which is indicated by their pyknotic nuclei, visible on top half of the image.
Layers of the wall of a human esophagus: mucosa (with epithelium, lamina propria, and muscularis mucosae), submucosa, muscular (inner and outer layers) and a very thin adventitia.
The surface epithelium of the stomach is a simple columnar epithelium formed by mucous cells, Note the smooth muscle fiber bundle abutting the epithelium.
Heart muscle cells showing central nucleus, cross-striation and intercalated discs. Toluidine blue stained semithin resin section 0,5 µm thick. The inset show the ultrastructure of intercalated disc
Ciliated pseudostratified columnar epithelium of the trachea (respiratory epithelium). Light microscope micrograph. H&E stain
Cross section of a collecting duct, located in the medullary region of the kidney. It is lined by a simple columnar epithelium. Semithin resin section 0,5 µm thick stained with a silver nitrate method
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).
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
Renal cortex of a kidney fixed by vascular perfusion (note the expanded glomerular capillaries). The Bowman space and the simple squamous epithelium of the Bowman's capsule are visible at the top

Light microscope micrograph of a muscular artery, showing a thick and wavy internal elastic lamina, a middle layer with many layers of smooth muscle fibers, and an outer connective tissue adventitia
Multipolar neurons of the anterior horn of the spinal cord stained with the Cajal's silver nitrate method.
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.
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
Large basal cell carcinoma. Cords and large islands of basophilic cells compose the tumor. Inside the tumoral mass, there is necrotic and hemorrhagic material. The scale bar correspond to 1 mm.
Seminiferous tubules. Human testis. Male germinal epithelium shows spermatogonia, spermatocytes in meiosis, spermatids, and spermatozoa with tails protruding into the lumen.  H&E stain.
High magnification micrograph of a seminiferous tubule. The germinal epithelium shows Sertoli cells, primary spermatocytes in meiosis, spermatids, and bundles of spermatozoa.
False colour transmission electron microscope (TEM) micrograph showing mitochondria (green), lysosomes (dark pink), glycogen (blue), rough endoplasmic reticulum (red) and a centriole (light blue).
Striated skeletal muscle fibers stained with a silver method. The sarcomeres display alternating A (dark) and I (light) bands. A clear H zone stands out in the center of A bands.
Cross sectioned spinal cord stained with Luxol Fast Blue. The central grey matter is surrounded by the white matter, which is stained in blue because it is rich in myelinated fibers.
Brunner glands of the duodenum. They are mucous-secreting glands located in the submucosa layer. The mucosa shows villi and Lieberkuhn crypts.
Light micrograph of white adipose tissue. Adipocytes (fat cells) contain a large lipid droplet. The structures that traverse diagonally the image are connective tissue septa. H&E stain
Epithelium of the small intestine. It is a simple columnar epithelium with a well-developed brush border located at its apical pole.
Electron microscope (TEM) micrograph showing many lysosomes (dark granules). Some of them, with rounded grey zones inside, are lipofuscin granules. On the left side there is a noradrenaline cell.
The reticular dermis is a dense irregular connective tissue with densely packed collagen fibers. Some small blood vessels (venules) can also be seen.
False colour transmission electron microscope (TEM) micrograph showing a brush (or striated) border in cross section. Microvilli cytoplasm: green. Cell membrane: red. Glycocalix among microvilli: blue
Secondary follicle showing oocyte cytoplasm, zona pellucida, and granulosa cells organized en several layers and showing mitosis. Outside the follicle can be seen both thecas, interna and externa.
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
False colour transmission electron microscope (TEM) micrograph showing many lysosomes (red). Those with rounded clear zones inside, are lipofuscin granules. At the left is a noradrenaline cell (blue).
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