basic histology

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Zoology 100 Lab

Metazoan HistologyHistology - study of tissues and its microstructure Tissues - group of cells specialized for a common function 4 kinds of tissues: 1. Epithelial 2. Connective 3. Muscular 4. Nervous

HISTOLOGY: Key facts and ImagesMa. Victoria B. PangilinanUST - College of Science Department of Biological Sciences

Epithelial Tissues sheet

Epithelial Tissues firmly bound to underlying connective tissue by a thin membrane called basal lamina or basement membrane. Lacks vascular supply, but nourished by diffusion from capillary bed in underlying connective tissues

of cells that covers external surfaces of the body or lines cavities. also forms glands of the body. tightly packed due to junctional complexes on cell surfaces (little extracellular spaces in between).



Epithelial TissuesAccording to shape: 1. Squamous flat 2. Cuboidal - box 3. Columnar - tall According to number of cell layers: 1. Simple 1 layer 2. Stratified several layers 3. Pseudostratified one layer, appearing several layers 4. Transitional relative single layer

Simple Squamous flat clear cytoplasm oval nucleus cell outlines range from wavy, serrated to smooth. lines blood capillaries, lungs. permits passive diffusion of gases and nutrients into and out of cavities .

Lung alveolus

Scraped Cheek Cells

Simple Cuboidal single layer

Simple Columnar single layer found in highly absorptive

short, box-like rounded nucleus

lines small ducts and tubules (salivary glands and kidneys) have secretory and absorptive functions

tall version of cuboidals rectangular elongated nucleus located near base

surfaces (intestinal tract) cells bear microvilli in female reproductive tract ciliated.

Kidney Tubules

Stomach lining

Small intestine lining



Stratified Squamous two to many layers of squamous

Pseudostratified Ciliated Columnar tall rectangular cells in a single with goblet cells in some

cells withstand mild mechanical distortion

lines the esophagus, anal canal, vagina. basal cells undergo continous mitosis

layer, appearing two. elongated nucleus with microvilli or cilia

basal cells render the double layer.




Transitional Epithelium number of cells vary depending

Connective Tissues bind, anchor, and support tissues composed of relatively few cells, many extracellular fibers, fluid and a ground substance or matrix Ground substance or matrix amorphous, transparent, colorless surrounding the fibers and cells Three major types: 1. Loose connective tissues 2. Dense connective Tissues 3. Specialized Connected tissues First two types are classified under connective tissue proper

on whether the organ in contracted or not cells shapes are not strictly squamous, cuboidal or columnar.

specialized to accommodate great

stretching found in urinary tract and bladder relaxed 4 - 5 layers : stretched 2 - 3 layers

Urinary bladder



Fibroblasts have large, ovoid, nuclei. have dispersed cytoplasmic processes. synthesize fibers, the

Types of FibersCollagen fibers thick, unbranched, and in spreads (B) Elastic fibers thinner than collagen fibers, less wavy and branched (C). Reticular fibers thinnest among the three, fine, delicate, branch extensively to form a network (D)

ground substance, as well as macrophages.

Connective Tissue Proper: Loose Connective Tissue also called areolar connective tissue. packing material of the body, anchoring blood vessels, nerves and body organs. contains fibroblasts, fibers, matrix, and macrophages

Connective Tissue Proper: Dense Connective Tissue forms tendons, ligaments and fasciae (bands of tissue surrounding the skeletal muscle. collagenous fibers are long and tightly packed together.




Specialized Connective Tissues: Adipose Tissue have abundant adipocytesstore fats as large droplets of triglycerides nucleus at the periphery (signet ring configuration) provides insulation, act as cushions, fill in crevices in organs

Specialized Connective Tissues: Cartilage soft and pliable. chondrocytes cartilage cells. lacunae spindle shaped cavities where chondrocytes are located. 3 types of cartilage: 1. Hyaline possess clear, homogenous matrix. (trachea) 2. Elastic possess elastic fibers (epiglottis, external ear) 3. Fibrocartilage with network of collagen fibers, and chondrocytes.




Specialized Connective Tissues: Bone Tissue for support, protection, movement, forming blood cells. Parts of a compact bone: 1. lamellae matrix 2. Haversian canal longitudinal 3. Osteocytes bone cells 4. Lacunae cavities housing osteocytes 5. Volkmanns canals at right angles #s 1 4 are collectively the Haversian system or osteon

Specialized Connective Tissues: BloodRBC circular cells without nucleus in humans, nucleated in frogs. Granulated WBCs 1. Eosinophil two-lobed nuclei, reddish color in stain. 2. Basophil - S-shaped nucleus, blue cytoplasm. 3. Neutrophil 3-5 lobed nuclei, lavender cytolasm Agranulated WBCs 1. Lymphocytes large nucleus indented on one side, thin cytoplasm 2. Monocytes oval or kindney-shaped nuclei, irregular cytoplasm Platelets minute cytoplasmic fragments, stain blue



Specialized Connective Tissues: Blood

Muscle Tissues connected to the skeleton, VOLUNTARY, striated. concerned with body movement skeletal muscles are cylindrical, striated, multinucleated, the nucleus being oval and located at the periphery of the cell. fasciculi muscle bundles endomysium tissue covering single fiber perimysium tissue covering fasciculi epimysium tissue covering entire muscle mass

Red Blood Cells


Cross section muscle bundle

Teased skeletal muscle

Muscle Tissues found as part of walls of viscera / visceral organs, INVOLUNTARY. individual muscle cell appear as spindle-shaped cells, with single centrally located nucleus at the widest part of the cell. cytoplasm is fairly homogenous, unstriated.

Muscle Tissues composes the contractile wall of the heart, INVOLUNTARY. arranged as branching networks interspersed with capillaries. nucleus centrally located, one per cell, cells striated. With interacalated discs boundaries between neighboring cells.

Smooth Muscle

Cardiac Muscle



Nervous Tissues

Nervous Tissues

Nervous system is divided into: 1. Central nervous system (CNS) which includes the brain and spinal cord, and the 2. Peripheral nervous system (PNS) which includes nerves and ganglia. *Nerves consist of axons in the PNS bundled together. *Ganglia are collections of neuron cell bodies.

Nerve cells include neurons and neuroglia(supporting cells). Neurons (cells) are specialized to produce and conduct electrochemical impulses. Neuroglia=do not conduct electrical impulses but instead support and insulate neurons and eliminate foreign materials in and around neurons. Myelin sheath - insulating covering of neuroglia cells wrapped around axons Nodes of Ranvier - separate adjacent neuroglia cells

Nervous Tissues

Nervous Tissues


X-S of Nerve Trunk

Teased Nerve

Multipolar and Bipolar Neurons

Unipolar Neurons



Nervous TissuesX-S of Nerve Trunk



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