Introduction into cellular pathology Flashcards
Give an overview of the histology of tissues
- Introduction to Histology
- Epithelial tissues.
- Connective tissues.
- Muscle tissues.
- Nerve tissues.
Describe multicellular, histology and histopathology
From cells to tissues:
• Cells - living, more or less self-sufficient entities that may form more complex structures. In Eukaryotes, cells are surrounded by a membrane.
• Tissues – the “more complex structures”. Interwoven masses of cells and extra cellular material.
• Histology is the study of tissues and their structure
• There are four levels of structure:
Tissue structure - how cells combine together with extracellular material and each other to form a tissue
Cellular structure - how a cell is shaped, and how the components inside cells are organized to support that cells specific function
Sub-cellular structure - detailed analysis of organelles and inclusions
Histochemical structure - molecular analysis of cellular structure
Using histology to understand pathology:
Histopathology - the study of tissues affected by disease. Useful in making a diagnosis and in determining the severity and progression of a disease.
Understanding the normal structure and function of different tissues is essential for interpreting the changes that occur during disease.
Describe the structure of epithelial tissue and how it is classified
• Is made of cells arranged in a continuous sheet with one or more layers; has apical & basal surfaces above and below the cells. Single or more than 1.
A basement membrane separates the epithelial layer from the underlying connective tissue.
Two types of epithelial tissues: 1) Covering & lining epithelia; 2) Glandular epithelium (endocrine and exocrine).
The number of cell layers & the shape of the cells in the top layer are used to classify epithelium.
• Classification:
Number and distribution of cell layers
Simple Epithelium - one cell layer.
Stratified Epithelium - two or more cell layers.
Pseudostratified Epithelium - 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).
• Shape of the top layer of cells
Cuboidal, columnar, squamous
What are the two main groups of connective tissue?
1) Connective tissue proper;
2) Specialised connective tissue.
What cells types are within connective tissue?
Contains:
• Many different cell types including: fibroblasts, macrophages, mast cells, and adipocytes.
What are the two materials of the connective tissue matrix?
1) ground substance - proteins and polysaccharides; 2) fibres – reticular, collagen and elastic.
How do we classify connective tissue proper?
- Loose Connective – fibres & many cell types in gelatinous matrix, found in skin & surrounding blood vessels, nerves and organs.
- Dense Connective – bundles of parallel collagen fibres & fibroblasts, found in tendons and ligaments.
What are the two components of cartilage?
- collagen and elastic fibres embedded in a matrix of glycoproteins.
- Cells called chondrocytes
What are the 3 types of cartilage?
Hyaline Cartilage - weakest, most abundant cartilage. Found at the end of long bones and structures like ears and nose.
Elastic cartilage - maintains shape, branching elastic
fibres distinguish it from hyaline.
Fibrous Cartilage - strongest type, has dense collagen and little matrix, found in pelvis, skull and vertebral matrix.
Describe the structure of bones
Bone is composed of bone cells - osteoprogenitor cells, osteoblasts, osteocytes and osteoclasts – suspended in a matrix consisting of collagen fibres and minerals.
Describe the two types of bone development
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.
What are the two types of mature 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.
What are the 3 muscle tissues and discuss them?
Skeletal Muscle – voluntary, striated, striations perpendicular to the muscle fibers and it is mainly found attached to bones. Organized in myofibres with nuclei peripherally located. Forms a lined up banding pattern from one cell to another when observed longitudinally.
Cardiac Muscle – involuntary, striated, branched and has intercalated discs. Cells smaller than skeletal muscle with nuclei centrally located.
Smooth Muscle – involuntary, non-striated, spindle shaped and is found in blood vessels & the GI tract. Cells vary in size and have a fusiform shape. Nuclei observed in different positions
What are the two main cell types in nerve tissue?
1) Neurons - cells that convert stimuli into electrical impulses to the brain; 2) Neuroglia – collection of different cell types with supportive role
Define motor, sensory, interneuron and the cells of neuroganglia
- 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.
