Field Guide to Tissues

Epithelial Tissue

Epithelial tissue lines cavities, cover walls, and make glands. They are supported by connective tissue, avascular but innervated, and have regeneration properties. They filtrate/ exchange and absorb/secrete. They also have sensory reception.

Simple Squamous 

Shape: flat pancakes

Function: absorption and diffusion of materials, secretes lubricant

Structure to function: Thin layer allows for diffusion and lets materials pass through.

Organ: lining of the heart

citation: https://commons.wikimedia.org/wiki/File:Emphysema_low_mag.jpg 

Simple Cuboidal 

Shape: little cubes, almost like slightly squished building blocks

Function: absorb/secrete

Structure to function: Again single layer allows for diffusion.

Organ: ovary surface

citation: from the book, Human Anatomy and Physiology Lab Manual, Fetal Pig Version

Simple Columnar

Shape: stretched out ovals, almost mimics fingers

Function: absorption/secretion, some have cilia propelling the cells, protection

Structure to function: Longer cells build a barrier for substances like bacteria.

Organ: bronchi (ciliated) in the lungs, digestive tract (nonciliated)

citation: https://commons.wikimedia.org/wiki/File:Normal_Small_Intestine_Mucosa_(5916217283).jpg 

Pseudo-stratified Columnar

citation: https://www.flickr.com/photos/pulmonary_pathology/3661529896/ 

Stratified Squamous 

Shape: layers of horizontally stretched building blocks

Function: protection from any cuts or severe injuries 

Structure to function: The layers are what provide the protection because even if a cut gets through 2 layers there are more underneath protecting tissues.

Organ: esophagus - non-keratinized, skin - keratinized

citation: from book, Human Anatomy and Physiology Lab Manual, Fetal Pig Version

Connective Tissue

Connective tissue arises from mesenchyme, can be avascular or vascularized, and has nonliving matrixes that separate the cells. Each cell type has an immature and mature version. Some connective tissues have fibers that provide strength, stretch, and networks. There are 4 major classes: proper, cartilage, bone, and blood.

Areolar

Shape: I like to think of this tissue as strings of varying widths with knots throughout. 

Function: support organs, binding tissue, holds fluid, macrophages take care of bacteria

Structure to function: The fibers allow the tissue the strength for support with elasticity. 

Organ: under epithelial, around organs or capillaries

citation: from book, Human Anatomy and Physiology 11e

Adipose

Shape: squished ovals (fat cells)

Function: insulates heat, protects, stores energy

Structure to function: The tissue being made of adipocytes allows for lipids to be stored. The minimal gaps improve insulation.

Organ: around kidneys and eyes, in breasts

Adipose tissue does have a thin layer of ground substance with fibers separating each cell. This layer is extremely thin, with only a few fibers.

citation: https://www.pathologyoutlines.com/topic/softtissueadiposewhitefat.html 

Dense Regular

Shape: organized strings densely compacted (collagen fibers +fibroblasts) 

Function: attaches muscle-bone, muscle-muscle, and bone-bone, able to withstand stress

Structure to function: The density of the fibers gives the tissue its ability to withstand force.

Organ: tendons + ligaments

citation: https://commons.wikimedia.org/wiki/File:Dense_connective_tissue-400x.jpg 

Blood

Shape: round red and white blood cells

Function: carry and transport materials (gases, nutrients, waste)

Structure to function: The caved centers of the red blood cells help with carrying gases. 

Organ: blood vessels

citation: https://histology.siu.edu/intro/bldcells.htm 

Osseous (Bone)

Shape: looks like if were to cut a log in half, circular branched patterns

Function: support, stores minerals, surface for muscles, surround bone marrow

Structure to function: The collagen fiber and calcification give the tissue the strength it needs to provide support.

Organ: bone

In osseous tissue, there are collagen fibers. They are located within the matrix. 

citation: https://histology.siu.edu/ssb/NM035b.htm 

Hyaline Cartilage

Shape: small cells within a matrix, more circular than other cell types (chondrocyte)

Function: resist compression, cushion, and support

Structure to function: The matrix allows for movement, but the collagen gives it strength and shape.

Organ: in the nose, along the ribs

Hyaline cartilage contains collagen fibers. They are so faint under a microscope that they cannot be seen. They are located within the ground matrix. 

citation: from the book, Human Anatomy and Physiology 11e

Elastic Cartilage

Shape: small cells within a matrix, more fibers

Function: flexible but dense enough to keep shape

Structure to function: The abundance of elastic fibers gives it flexibility.

Organ: external ear, epiglottis 

Elastic cartilage contains elastic fibers. They are located within the ground matrix. 

citation: https://commons.wikimedia.org/wiki/File:Elastic_cart_100X.JPG 

Fibrocartilage

Shape: small cells within a matrix, less firm matrix

Function: absorb shock and tensile strength 

Structure to function: The matrix allows for shock to be absorbed, and the collagen gives it strength and shape.

Organ: intervertebral discs, pubic symphysis, discs of knee joint 

Fibrocartilage contains collagen fibers. They produce the blue color under a microscope. They are located within the ground matrix. 

citation: https://commons.wikimedia.org/wiki/File:Connective_Tissue_Fibrocartilage_(41140134634).jpg 

Muscle Tissue

Muscle tissue helps the body move through its contractions. There are three types: skeletal, cardiac, and smooth. Skeletal muscle is under voluntary control and around bones. Cardiac muscle is for the heart and contracts to propel blood. Smooth muscle lines cavities or hollow organs. Skeletal and cardiac muscles have striations when smooth muscle does not.

Skeletal Muscle Tissue

Shape: long, multinucleate cells 

Function: used for areas where there is voluntary control, movement

Structure to function: The connective tissue between layers allows for the cells to contract and protect them.

Organ: attached to bone

Cardiac Muscle Tissue

Shape: branching, uninucleate 

Function: for involuntary control, as cells contract blood is pushed to flow

Structure to function: The branching and connections between cells allow for controlled and efficient contractions. 

Organ: heart (specifically the walls)

citation: https://commons.wikimedia.org/wiki/File:Cardiac_myocyte_showing_lipofuscin_pigment.jpg 

Smooth Muscle Tissue

Shape: spindle shape, uninucleate, form layers

Function: used for involuntary control, contractions propel substances

Structure to function: The layer formation of smooth muscle cells help keep the muscle keep its form and produce contractions. 

Organ: walls of hollow organs, visceral cavities, mainly visceral area

citation: https://commons.wikimedia.org/wiki/File:Smooth_muscle_-_histology.jpg 

Nervous Tissue

Nervous tissue regulates and controls body functions. There are two types of cells: neurons and supporting cells. The neurons generate and conduct nerve impulses and transmit electrical signals. The supporting cells support, insulate, and protect neurons. The cell bodies have branches that form networks to other cell bodies. This tissue is in the brain and spinal cord.

citation: http://blogs.berkshirecc.edu/bccoer/mammalian-histology-nervous-tissue/