ClipArt ETC
"Cross-section of an orange. a, axis of fruit with dots showing cut-off ends of fibro-vascular bundles; p, partition between cells of ovary; S, seed; c, cell of ovary filled with a pulp composed of irregular tubes full of juice; o, oil reservoirs near outer surface of rind; e, corky layer of epidermis." -Bergen, 1896

Orange

"Cross-section of an orange. a, axis of fruit with dots showing cut-off ends of fibro-vascular bundles;…

Human red blood corpuscles. Highly magnified.

Blood Corpuscles

Human red blood corpuscles. Highly magnified.

Blood corpuscles of a frog. Highly magnified. The appearance of blood cells in different animals varies in shape and size.

Frog Blood Corpuscles

Blood corpuscles of a frog. Highly magnified. The appearance of blood cells in different animals varies…

Label: a, axis cylinder of a nerve.

Nerve Cells

Label: a, axis cylinder of a nerve.

Diagram to show the relationship of nerve cell (NC) to Muscle (M) through its nerve fiber.

The Relation of Nerve Cells to Muscle

Diagram to show the relationship of nerve cell (NC) to Muscle (M) through its nerve fiber.

Blood plasma passing out of capillary to feed the body cells.

The Course of Blood

Blood plasma passing out of capillary to feed the body cells.

A diagram exhibiting the relative position of the elements of Serous and Mucous membranes. Labels: 1, Epithelium, composed of nucleated cells. 2, Basement layer. 3, Fibrous layer, in which arteries and veins (4) terminate in a capillary network.

Serous and Mucous Membranes

A diagram exhibiting the relative position of the elements of Serous and Mucous membranes. Labels: 1,…

The development of muscular fibers from cells. Labels: a, simple cell. b, a pair of cells fused together. c, Three cells fused and their contents assuming the striated character. d, A muscular fiber exhibiting its original composition of cells.

The Development of Muscular Fibers from Cells

The development of muscular fibers from cells. Labels: a, simple cell. b, a pair of cells fused together.…

The bronchia. Labels; 1, Outline of the right lung. 2, Outline of the left lung. 3, Larynx. 4, Trachea. 5, 6, 7, 8, Bronchial tubes. 9, Air-cells.

The Bronchia

The bronchia. Labels; 1, Outline of the right lung. 2, Outline of the left lung. 3, Larynx. 4, Trachea.…

Diagram of the two primary lobules of the lungs, magnified. Labels: 1, Bronchial tube. 2, A pair of primary lobules connected by elastic tissue. 3, Intercellular air-passages. 4, Air-cells. 5, Branches of the pulmonary artery and vein.

Diagram of the Two Primary Lobules of the Lung

Diagram of the two primary lobules of the lungs, magnified. Labels: 1, Bronchial tube. 2, A pair of…

The respiratory apparatus of other mammals is similar to humans in both structure and function. The lungs fill the cavity of the chest, and have the same general composition of lobes, lobules and air-cells. Labels: 1, Trachea. 2, Lungs. 3, Heart. 4, Diaphragm. 5, Liver. 6, Stomach. 7, Esophagus. 8, Kidney. 9, Intestines. 10, Bladder. 11, Cerebrum. 12, Cerebellum. 13, Medulla spinalis. 14, Vertebrae.

The Respiratory System of a Small Mammal

The respiratory apparatus of other mammals is similar to humans in both structure and function. The…

A diagram of the skin. Labels: 1, The lines or ridges of the cuticle, cut perpendicularly. 2, The furrow or wrinkles of the same. 3, The cuticles. 4, The colored layer of the cuticle. 5, The cutis vera. 6, The papillae, each of which answers to the lines on the external surface of the skin. 7, Small furrows between the papillae, 8, The deeper furrows between each couple of the papillae. 9, Cells filled with fat. 10, The adipose later, with numerous fat vesicles. 12, Two hairs. 13, A perspiratory gland, with its spiral duct. 15, Another perspiratory gland, with a duct less spiral. 15, Oil-glands with ducts opening into the sheath of the hair.

A Diagram of the Skin

A diagram of the skin. Labels: 1, The lines or ridges of the cuticle, cut perpendicularly. 2, The furrow…

"Lizard's tail (Saururus cernuus). Portions of leaf-epidermis; U, upper epidermis; L, lower epidermis; ep, epidermal cell; st, guard-cells of the stomata." -Gager, 1916

Leaf Epidermis

"Lizard's tail (Saururus cernuus). Portions of leaf-epidermis; U, upper epidermis; L, lower epidermis;…

"Fern prothallus; cross-sections showing antheridia (an), sperms (sp), and rhizoids (rh). Below at the right is a sperm (sp) greatly enlarged." -Gager, 1916

Fern Prothallus

"Fern prothallus; cross-sections showing antheridia (an), sperms (sp), and rhizoids (rh). Below at the…

A microscopic view of a muscle showing, at one end, the fibrillae; and at the other, the disk, or cells of the fiber.

Microscopic View of a Muscle

A microscopic view of a muscle showing, at one end, the fibrillae; and at the other, the disk, or cells…

Magnified views of the cuticle. Labels: A, represents a vertical section of the cuticle. B, the lateral view of the cells. C, flat side of scales like d, magnified, showing the nucleated cells transformed into broad scales.

Magnified View of the Cuticle

Magnified views of the cuticle. Labels: A, represents a vertical section of the cuticle. B, the lateral…

A hair. Labels: s, the sac (follicle); P, the papilla, showing the cells and the blood vessels (V).

Hair Papilla

A hair. Labels: s, the sac (follicle); P, the papilla, showing the cells and the blood vessels (V).

A hair. Labels: A perspiratory tube with its gland; B, a hair with a muscle and two oil-glands; C, cuticle; D, the papillae; E, fat-cells.

A Hair

A hair. Labels: A perspiratory tube with its gland; B, a hair with a muscle and two oil-glands; C, cuticle;…

The circulation of the blood in the web of a frog's foot. A, an artery; B, capillaries crowded with disks, owing to a rupture just above, where the disks are jammed into an adjacent mesh; C, a deeper vein; the black spots are pigments cells.

Circulation of Blood in a Frog's Foot

The circulation of the blood in the web of a frog's foot. A, an artery; B, capillaries crowded with…

A vertical section of the duodenum, highly magnified. Labels: 1, a fold-like villus; 2, epithelium, or cuticle; 3, orifices of intestinal glands; 5, orifices of duodenal glands; 4, 7, more highly magnified sections of the cells of the duodenal gland.

A Magnified Section of the Duodenum

A vertical section of the duodenum, highly magnified. Labels: 1, a fold-like villus; 2, epithelium,…

Next to the choroid and comprising about 1/4 the entire thickness of the retina is a multitude of transparent, colorless, microscopic rods (a) evenly arranged and packed side by side, like the seeds in the disk of a sunflower. Among them at regular intervals, are interspersed the cones (b). Delicate nerve fibers pass from the ends of the rods and cones, each expanding into a granular body (c) thence weaving a mesh (d) and again expanding into the granules (f). Last is a layer of fine nerve fibers (g) and gray, ganglionic cells (h) like the gray matter of the brain, whence filaments extend into the fibers of the optic nerve (i).

The Structure of the Retina

Next to the choroid and comprising about 1/4 the entire thickness of the retina is a multitude of transparent,…

The smooth muscle fibers consist of long spindle-shaped cells, the end of which are frequently spirally twisted, and in the center of which exists a long rod-shaped kernel or nucleus. Unlike striated muscle, they do not form separate muscular masses, but occur scattered, or arranged in more or less dense layers or strata, in almost all organs.

Smooth Muscle Fibers

The smooth muscle fibers consist of long spindle-shaped cells, the end of which are frequently spirally…

Gastric glands are often branched at the bottom end. Labels: a, the peptic cells; b, the inert cells.

Branched Gastric Gland

Gastric glands are often branched at the bottom end. Labels: a, the peptic cells; b, the inert cells.

A, A young vegetable cell, showing cell cavity entirely filled with granular protoplasm enclosing a large oval nucleus with one or more nucleoli. B, An older cells from the same plant showing distinct cellulose wall and vacuolation of protoplasm.

Vegetable Cell

A, A young vegetable cell, showing cell cavity entirely filled with granular protoplasm enclosing a…

A transverse section through an embryo chick (26 hours). Labels: a, epiblast; b, mesoblast; c, hypoblast; d, central portion of mesoblast, which is here fused with epiblast; e, primitive groove; f, dorsal ridge.

Cells of an Embryo Chick

A transverse section through an embryo chick (26 hours). Labels: a, epiblast; b, mesoblast; c, hypoblast;…

Squamous epithelium is found arranged as a single layer of flattened cells as the pigmentary layer of the retina. Shown is the pigment cells from the retina. A, cells still cohering, seen on their surface; a, nucleus indistinctly seen. In the other cells the nucleus is concealed by the pigment granules. B, two cells seen in profile; a, the outer or posterior part containing scarcely any pigment.

Pigment Cells from the Retina

Squamous epithelium is found arranged as a single layer of flattened cells as the pigmentary layer of…

Columnar epithelium consists of cells which are cylindrical or prismatic is form containing a large oval nucleus. Shown are the columnar epithelial cells from the intestinal mucous membrane of a cat. Labels: a, b, small cells of the lowest layer; c, superficial layer; d, goblet cells.

Columnar Epithelial Cells from a Cat

Columnar epithelium consists of cells which are cylindrical or prismatic is form containing a large…

A vertical section of an intestinal villus of a cat. Labels: a, the striated basilar border of the epithelium; b, columnar epithelium; c, goblet cells; d, centrai lymph vessel; e, unstriped muscular fibers; f, adenoid stroma of the villus in which are contained lymph corpuscles.

Intestinal Villus of a Cat

A vertical section of an intestinal villus of a cat. Labels: a, the striated basilar border of the epithelium;…

The spheroidal ciliated cells from the mouth of a frog.

Spheroidal Ciliated Cells from a Frog

The spheroidal ciliated cells from the mouth of a frog.

Ciliated epithelium from the human trachea. Large fully formed cell. Labels: b, shorter cell; c, developing cells with more than one nucleus.

Ciliated Epithelium

Ciliated epithelium from the human trachea. Large fully formed cell. Labels: b, shorter cell; c, developing…

Epithelium of the bladder. Labels: a, one of the cells of the first row; b, a cell of the second row; c, cells in situ, of first, second, and deepest layer.

Epithelium of the Bladder

Epithelium of the bladder. Labels: a, one of the cells of the first row; b, a cell of the second row;…

The vertical section of the stratified epithelium of the cornea of a rabbit. Labels: a, Anterior epithelium showing the different shapes of the cells at various depths from the free surface; b, a portion of the substance of cornea.

Epithelium of the Rabbit's Cornea

The vertical section of the stratified epithelium of the cornea of a rabbit. Labels: a, Anterior epithelium…

The jagged cells from the middle layers of pavement epithelium, from a vertical section of the gum of a newborn infant.

Pavement Epithelium

The jagged cells from the middle layers of pavement epithelium, from a vertical section of the gum of…

Ramified pigment cells, from the tissue of the choroid coat of the eye. Labels: a, cell with pigment; b, colorless fusiform cells.

Pigment Cells

Ramified pigment cells, from the tissue of the choroid coat of the eye. Labels: a, cell with pigment;…

Flat, pigmented, branched connective tissue cells from the sheath of a large blood vessel of a frog's mesentery. The pigment is not distributed uniformly throughout the substance of the larger cell, consequently some parts of it look blacker than others (uncontracted state). In the two smaller cells most of the pigment is withdrawn into the cell body, so that they appear smaller, blacker, and less branched.

Connective Tissue Cells from a Frog

Flat, pigmented, branched connective tissue cells from the sheath of a large blood vessel of a frog's…

Fibrous tissue of cornea, showing bundles of fibers with a few scattered fusiform cells (A) lying in the interfascicular spaces.

Fibrous tissue of Cornea

Fibrous tissue of cornea, showing bundles of fibers with a few scattered fusiform cells (A) lying in…

Mature white fibrous tissue of tendon, consisting mainly of fibers with a few scattered fusiform cells.

White Fibrous Tissue of the Tendon

Mature white fibrous tissue of tendon, consisting mainly of fibers with a few scattered fusiform cells.

The cells in the tendons are arranged in long chains in the ground substance separating the bundle of fibers, and are more or less regularly quadrilateral with large round nuclei containing nucleoli, which are generally places so as to be contiguous in two cells. Show is the caudal tendon of young rat. Note arrangement, form, and structure of tendon cells.

Structure of Tendon Cells

The cells in the tendons are arranged in long chains in the ground substance separating the bundle of…

The branched character of the cells is seen. Shown is a transverse section from a cross section of the tail of a rabbit, showing sheath, fibrous septa, and branched connective tissue corpuscles. The spaces left white in the drawing represent the tendinous fibers in transverse section.

Branched Tendon Cells

The branched character of the cells is seen. Shown is a transverse section from a cross section of the…

Tissue of the jelly of Wharton from a umbilical cord. Labels: a, connective tissue corpuscles; b, fasciculi of connective tissue; c, spherical formative cells.

The Tissue of Whartonian Jelly

Tissue of the jelly of Wharton from a umbilical cord. Labels: a, connective tissue corpuscles; b, fasciculi…

In the embryo the place of fibrous tissues is at first occupied by a mass of roundish cells, derived from the mesoblast. These develop into a network of branched cells or into groups of fusiform cells. Shown is a portion of submucous tissue of a uterus during pregnancy. Labels: a, branched cells, more or less spindel-shaped; b, bundles of connective tissue.

Tissue Growth of the Uterus

In the embryo the place of fibrous tissues is at first occupied by a mass of roundish cells, derived…

The ordinary fat cells of a fact tract in the omentum of a rat.

Fat Cells of a Rat

The ordinary fat cells of a fact tract in the omentum of a rat.

A group of fat cells (F, C) with capillary vessels (C).

Fat Cells with Capillary Vessels

A group of fat cells (F, C) with capillary vessels (C).

A lobule of developing adipose tissue from an eight month fetus. Labels: a, Spherical or, from pressure, polyhedral cells with large central nucleus surrounded by a finely reticulated substance staining uniformly with haematoxylin. b, Similar cells with spaces from which the fat has been removed by oil and cloves. c, Similar cells showing how the nucleus with enclosing protoplasm is being pressed towards periphery. d, Nucleus of endothelium of investing capillaries.

Developing Adipose Tissue in Fetus

A lobule of developing adipose tissue from an eight month fetus. Labels: a, Spherical or, from pressure,…

Branched connective tissue corpuscles, developing into fat cells.

Branched Connective Tissue Corpuscles

Branched connective tissue corpuscles, developing into fat cells.

The cells of hyaline cartilage are irregular in shape and are generally grouped together. Shown is the ordinary hyaline cartilage from the trachea of a child. The cartilage cells are enclosed singly or in pairs in a capsule of hyaline substance.

Hyaline Cartilage Cells

The cells of hyaline cartilage are irregular in shape and are generally grouped together. Shown is the…

The matrix of hyaline cartilage has a dimly granular appearance like that of ground glass, and in man and higher mammals has no apparent structure. In some cartilages of the frog, however, even when examined in the fresh state, is is seem to be mapped out in polygonal blocks or cell-territories, each containing a cell in the center, and representing what is generally called the capsule of the cartilage cells. Shown is the fresh cartilage from a Triton.

Hyaline Cartilage Cells

The matrix of hyaline cartilage has a dimly granular appearance like that of ground glass, and in man…

The costal cartilages also frequently become calcified in old age. Fat globules may also be seen in many cartilages. Shown is the costal cartilage from an adult dog with fat globules in the cartilage cells.

Costal Cartilage

The costal cartilages also frequently become calcified in old age. Fat globules may also be seen in…

The cells in yellow elastic cartilage are rounded or oval, with well marked nuclei and nucleoli.

Yellow Elastic Cartilage

The cells in yellow elastic cartilage are rounded or oval, with well marked nuclei and nucleoli.

White fibrocartilage is composed of both cells and a matrix, but is almost exclusively composed of fibers resembling those of white fibrous tissue.

White Fibrocartilage

White fibrocartilage is composed of both cells and a matrix, but is almost exclusively composed of fibers…

Red marrow occupies the spaces in the cancellous tissue; it is highly vascular, and this maintains the nutrition of the spongy bone, the interstices of which it fills. Shown are the cells of the red marrow of the the guinea pig. Labels; a, a large cell, the nucleus of which appears to be partly divided into three by constrictions; b, a cell, the nucleus of which shows an appearance of being constricted into a number of smaller nuclei; c, so called giant cell, or myeloplaxe, with many nuclei; d, a smaller myeloplaxe, with three nuclei; e-i, proper cells of the marrow.

Cells of the Red Marrow

Red marrow occupies the spaces in the cancellous tissue; it is highly vascular, and this maintains the…

Osteoblasts from the parietal bone of a human embryo, thirteen weeks old. Labels: a, bony septa with cells of the lacunae; b, layers of osteoblasts; c, the latter in transition to bone corpuscles.

Osteoblasts

Osteoblasts from the parietal bone of a human embryo, thirteen weeks old. Labels: a, bony septa with…

Longitudinal section of ossifying cartilage from the humerus of a fetal sheep. Calcified trabeculae are seen extending between he columns of cartilage cells (c).

Ossifying Cartilage Showing Calcification

Longitudinal section of ossifying cartilage from the humerus of a fetal sheep. Calcified trabeculae…

Transverse section of femur of a human embryo about eleven weeks old. Labels: a, rudimentary Haversian canal in cross sections; b, in longitudinal section; c, osteoblast; d, newly formed osseous substance of a lighter color; e, that of greater age; f, lacunae with their cells; g, a cell still united to an osteoblast.

Formation of Compact Bone in a Human

Transverse section of femur of a human embryo about eleven weeks old. Labels: a, rudimentary Haversian…

Part of section of developing tooth of a young rat, showing the mode of deposition of the dentine. Labels: a, outer layer of fully formed dentine; b, uncalcified matrix with one or two nodules of calcareous matter near the calcified parts; c, odontoblasts sending processes into the dentine; d, pulp; e, fusiform or wedge-shape cells found between odontoblasts; f, stellate cells of pulp in fibrous connective tissue. The section is stained in carmine, which colors the uncalcified matrix, but not the calcified part.

Deposition of Dentine

Part of section of developing tooth of a young rat, showing the mode of deposition of the dentine. Labels:…

Unstriped muscle, or plain muscle, forms the proper muscular coats. Shown is unstriped muscle cells from the mesentery of a newt. The sheath exhibits transverse markings. B, from a similar preparation, showing that each muscle cell consists of a central bundle of fibrils, F, (contractile part), connected with the intranuclear network, N, and a sheath with annular thickenings, St. The cells show varicosities due to local contraction, and on these the annular thickenings are most marked.

Unstriped Muscle of a Newt

Unstriped muscle, or plain muscle, forms the proper muscular coats. Shown is unstriped muscle cells…

Unstriped muscle, or plain muscle, forms the proper muscular coats. Shown is a plexus of bundles of unstriped muscle cells from the pulmonary pleura of the guinea pig. Labels: A, branching fibers; B, their long central nuclei.

Unstriped Muscle of a Guinea Pig

Unstriped muscle, or plain muscle, forms the proper muscular coats. Shown is a plexus of bundles of…

Muscular fiber cells from the heart. The fibers which lie side by side are united at frequent intervals by short branches.

Muscular Fiber Cells from the Heart

Muscular fiber cells from the heart. The fibers which lie side by side are united at frequent intervals…

From preparation of the nerve termination in the muscular fibers of a snake. A, End plate seen only broad surfaced. b, End plate seen as narrow surface.

Muscular Fiber Cells of a Snake

From preparation of the nerve termination in the muscular fibers of a snake. A, End plate seen only…

Nerve cells, also known as nerve corpuscles, comprise the second principle element of the nervous tissue. The are not generally present in the nerve trunk, but are found in collections of nervous tissue called ganglia. Shown are the ganglion nerve corpuscles of different shapes.

Ganglion Nerve Corpuscles

Nerve cells, also known as nerve corpuscles, comprise the second principle element of the nervous tissue.…