Tissue in the human body:

1. Epithelial: Is made of cells arranged in a continuous sheet with one or more layers, has apical & basal surfaces.
   • A basement membrane is the attachment between the basal surface of the cell & the underlying connective tissue.
   • Two types of epithelial tissues: (1) Covering & lining epithelia and (2) Glandular Epithelium.
   • The number of cell layers & the shape of the cells in the top layer can classify epithelium.
   • Simple Epithelium - one cell layer
   • Stratified epithelium - two or more cell layers
   • Pseudostratified Columnar Epithelium - When cells of an epithelial tissue are all anchored to the basement Membrane but not all cells reach the apical surface.
   • Glandular Epithelium – (1) Endocrine: Release hormones directly into the blood stream and (2) Exocrine - Secrete into ducts.
   
   
2. Connective: contains many different cell types including: fibroblasts, macrophages, mast cells, and adipocytes. Connective Tissue Matrix is made of two materials: ground substance - proteins and polysaccharides, fiber – reticular, collagen and elastic.
   
   Classification of Connective Tissue:
• Loose Connective - fibers & many cell types in gelatinous matrix, found in skin, & surrounding blood vessels, nerves, and organs.
• Dense Connective - Bundles of parallel collagen fibers& fibroblasts, found in tendons& ligaments.
• Cartilage - Cartilage is made of collagen & elastin fibers embedded in a matrix glycoprotein & cells called chondrocytes, which was found in small spaces.
• Cartilage has three subtypes:
  • Hyaline cartilage – Weakest, most abundant type, Found at end of long bones, & structures like the ear and nose,
  • Elastic cartilage- maintains shape, branching elastic fibers distinguish it from hyaline and
  • Fibrous Cartilage - Strongest type, has dense collagen & little matrix, found in pelvis, skull & vertebral discs.
3. Muscle: is divided into 3 categories, skeletal, cardiac and smooth.
   
   • Skeletal Muscle – voluntary, striated, striations perpendicular to the muscle fibers and it is mainly found attached to bones.
   • Cardiac Muscle – involuntary, striated, branched and has intercalated discs
   • Smooth Muscle – involuntary, nonstriated, spindle shaped and is found in blood vessels & the GI tract.
4. Nervous: Consists of only two cell types in the central nervous system (CNS) & peripheral nervous system (PNS):
   • Neurons - Cells that convert stimuli into electrical impulses to the brain, and Neuroglia – supportive cells.
   • Neurons – are made up of cell body, axon and dendrites. There are 3 types of neurons:
     • Motor Neuron –  carry impulses from CNS to muscles and glands,
     • Interneuron - interpret input from sensory neurons and end responses to motor neurons
     • Sensory Neuron – receive information from environment and transmit to CNS.
   • Neuroglia – is made up of astrocytes, oligodendrocytes, ependymal cells and microglia in the CNS, and schwann cells and satellite cells in the PNS.

Development: All tissues of the body develop from the three primary germ cell layers that form the embryo:

• Mesoderm – develops into epithelial tissue, connective tissue and muscle tissue.
• Ectoderm - develops into nervous tissue and epithelial tissue.
• Endoderm – develops into epithelial tissue.

Cell Junctions:

• Tight Junctions - Form a seal between cells, define apical and basal sides of an epithelial cell
• Gap Junctions - An open junction between two cells, which allows ions, & small molecules to pass freely between the cells.
• Adherens Junctions - Link actin cytoskeletal elements in two cells.
• Desmosomes - Link keratin filaments in adjoining cells and resist shearing forces.
• Hemidesmosomes - Anchor keratin fibers in epithelial cells to the basement membrane through integrin anchors.

This tutorial covers the four main types of tissue in the human body. It also includes a description of the anatomical location of those tissues within the body.

All 4 types of tissue originate from 3 primary layers in the developing human embryo. There are a number of cell junctions used by the various tissue types for contact with surrounding cells and the basement membrane, communication and for structural integrity. 

Specific Tutorial Features:

• A detailed description of the epithelial tissue in the body is presented including a histological description, subtype classification and location within organs and glands and the function.

Series Features:

• Concept map showing inter-connections of new concepts in this tutorial and those previously introduced.
  
• Definition slides introduce terms as they are needed.
  
• Visual representation of concepts
• Examples given throughout to illustrate how the concepts apply.
  A concise summary is given at the conclusion of the tutorial.

The four types of tissue in the human body: A tissue is a group of cells that is from similar embryological origin and is specialized for a particular function. Four types: epithelial, connective, muscle and nervous.

Epithelial
Connective
Muscle
Nervous

Development

Cell Junctions

Epithelial Tissue

• General Aspects
• Two Sub-types

Glandular Epithelium

Connective Tissue and Cartilage:

• Connective tissue
• Hyaline cartilage
• Elastic cartilage
• Fibrous cartilage

Tissues of the Human Body:

• Muscle Tissue
• Skeletal muscle
• Cardiac muscle
• Smooth muscle