Introduction to Histology (Pathology)

The study of tissues and their structure

How cells combine together with extracellular material and each other to form a tissue

How a cell is shaped, and how the components inside cells are organised to support that cells specific function

Detailed analysis of organelles and inclusions

Molecular analysis of cellular structure

-Epithelial tissues

-Connective tissues

-Muscle tissues

-Nerve tissues

-Ectoderm

-Mesoderm

-Endoderm

-Nervous tissue and Epithelial tissue

-Epithelial tissue, Connective tissue and Muscle tissue

-Epithelial tissue

-Epithelial tissue is made of cells arranged in a continuous sheet with one or more layers; has apical and basal surfaces

+A basement membrane separates the epithelial layer from the underlying connective tissue

+Two types of epithelial tissues: 1) Covering and lining epithelia; or the PROPER epithelium 2) GLANDULAR epithelium (endocrine and exocrine)

+The number of cell layers and the shape of the cells in the top layer are used to classify epithelium

One cell layer

Two or more cell layers

Cells are all anchored to the basement membrane (i.e. one cell layer) but not all cells reach the apical surface (nuclei do not align, does not look like one cell layer)

-Cuboidal

-Columnar

-Squamous

-"connective tissue" is a term given to several body tissues that connect, support, and help bind other tissues

-There are two main groups: 1) Connective tissue proper; loose connective tissue (areolar, adipose, reticular)

2) Specialised connective tissue; types include: dense regular, irregular and elastic connective tissue

-Contains:

+Many different cell types including; fibroblasts, macrophages, mast cells and adipocytes

+Connective tissue matrix made of two materials: 1) ground substance-proteins and polysaccharides; 2)fibres- reticular, collagen and elastic.

Fibres and many cell types in gelatinous matrix found in skin and surrounding blood vessels, nerves and organs

Bundles of parallel collagen fibres and fibroblasts, found in tendons and ligaments

Cartilage is a strong, flexible connective tissue that protects your joints and bones

Cartilage is made of two main components: 1) collagen and elastin fibres embedded in a matrix of glycoproteins; 2) cells called chondrocytes.

Hyaline

Elastic

Fibrous

The weakest, most abundant type. Found at the end of long bones, and structures like the ear and nose

Maintains shape, branching elastic fibres distinguish it from hyaline

Strongest type, has dense collagen and little matrix, found in pelvis, skull and vertebral discs

-Bone is composed of bone cells- osteoprogenitor cells, osteoblasts, osteocytes and osteoclasts-suspended in a matrix consisting of collagen fibres and minerals

+Bone development can be 1) Membranous-as in flat bones clavicle or mandible; 2) Endochondral - as in limb and vertebral column bones.

+Mature bone may be 1) Compact-concentric circular layers (lamellae) organised in lacunae and a central canal (Harvesian system); 2)Trabecular-slender interlacing parallel lamellae with marrow within the spaces

The principle functional unit of muscle tissue is the muscle fibre. There are also some satellite cells (stem cells) with capacity to develop into new muscle fibres

-Skeletal

-Cardiac

-Smooth

Voluntary, striated, striations perpendicular to the muscle fibres, and it is mainly found attached to bones. Organised in myofibres with nuclei peripherally located. Forms a lined up banding pattern from one cell to another when observed longitudinally

Involuntary, striated, branched and has intercalated discs. Cells smaller than skeletal muscle with nuclei centrally located.

Involuntary, non-striated, spindle shaped and is found in blood vessels and the GI tract. Cells vary in size and have a fusiform shape. Nuclei observed in different positions

Constitutes the central nervous system (CNS) and the peripheral nervous system (PNS). Consists of two main functional cell types: 1) Neurons - cells that convert stimuli into electrical impulses to the brain; 2) Neuroglia - collective of different cell types with supportive role.

-Motor neuron

-Interneuron

-Sensory neuron

Carry impulses from the CNS to muscles and glands

Interpret input from sensory neurons and end responses to motor neurons

Receive information from environment and transmit to CNS

It is made up of astrocytes, oligodendrocytes, ependymal cells and microglia in the CNS, and Schwann cells and satellite cells in the PNS (peripheral nervous system)

Many fibres that support and bind other tissues, as well as empty space for storing tissue fluid

Contains many fat cells, which are able to store nutrients and also serve to insulate the body

Similar to areolar tissue but contains only reticular fibres and supports certain structures

Many collagen fibres packed together with fibroblasts in between which resists tension

Many collagen fibres, but not arranged in any pattern which offers resistance in many directions

Similar to regular dense connective tissue in most respects but it is more elastic

Nerve cells and blood vessels

Tissue fluid