Lecture 3 Flashcards
(21 cards)
Histology
the study of the microanatomy of cells and tissues and how they are organised into organs. By understanding the structure and organisation of cells and tissues, we can learn about their function
Epithelium cells
lines body surfaces and cavities. Under every epithelia is connective tissue which has lots of fibres. They are avascular. It separates the interior and exterior environment. Epithelia allows the absorption of certain molecules like a sieve. Desmosomes allow cells to adhere together and form tissue
Histology of epithelia
All epithelia rest on a basal lamina (only visible with EM). Sometimes additional reticular lamina is present and forms basement membrane (LM). Epithelial cells are polarised. Top is apical region and bottom is basal domain which is attached to basal lamina
Basal lamina
Layers of protein secreted by the epithelial cells themselves. Provides physical support and attachment to underlying tissue. Acts as filter.
Classigying epithelia
shape of nucleus usually reflects cell chape. Simple cells have receptors on apical region therefore, involved in molecule transport. Increase in cell height= secretion and absorption (increase SA:V). Bigger cells = more organelles. When there are multiple cell shapes in a stratified layer, you name it based off top layer.
Endothelium
Simple squamous epithelia that lines all blood vessels
Mesothelium
Simple squamous epithelia lining closed internal cavities (heart, lungs, abdomen) and surfaces of organs (epithelium of serosa)
Epithelial cell renewal
most epithelia have a high rate of cell turnover. Basal cells divide and migrate up where they are sloughed off at the surface
Connective tissue
holds everything together. composed of cells ans extracellular matrix. incl bone, blood and lymph vessels
Connective tissue proper
extracellular matrix contains connective tissue like collagen, elastin and reticular fibres. Subtypes based on relative abundance of cells, fibres and ground substance.
specialised connective tissue
could be specialised cells, extracellular matrix and/or function e.g blood, adipose, cartilage, bone
Resident cells
Always present in tissue e.g fibroblasts, mast cells and adipocytes
Transient cells
passes through tissue e.g lymphocytes, plasma cells and basophils
Fascicles
bundle of muscle fibre cells. They are held together by irregular connective tissue/junctions.
Smooth Muscle
Walls of viscera, vessels and airways. Involuntary movement, non striated
Cardiac muscle
located only in walls of heart. Contracts continuously and rhythmically. Striated, involuntary, branched, one central nucleus
Skeletal muscle
muscle group that enables voluntary movement. Striated and multinucleated. sarcoplasm contains myofibrils that have regularly spaced and aligned striations that compose sarcomeres.
intersection of tissue types
epithelial cells often depend on interactions with the underlying connective tissue that provides an inductive stimulus. Organs not in a body cavity or are attached to other structures share an adventitia of connective tissue.
mucosa
Epithelium and lamina propria. Lines hollow organs.
serosa
specialised simple squamous epithelia
adventitia
bridge of connective tissue joining structure
