Chapter 4 Tissue Flashcards
Tissue
Collection of specialized cells that perform limited number of functions
Histology
the study of tissues
Four main types of tissue
- Epithelial tissue (covering, surfaces, linings, glands)
- Connective tissue (support fill space, structure, strength, transport, storage
- Muscle tissue ( movement)
- Nervous tissue (Control, transmit info)
Primary Germ layers
embryonic layers, give rise to all four tissue types in adult
Epithelial Tissue (2 categories)
- Epithelia- covering
- Glands- produce fluid secretions
Features of Epithelial Tissue
- Cellularity: little extracellular matrix mostly cells
- Contacts: cells linked by strong junctions
- Polarity: apical + basal surfaces, separate functions
- Attachment: attached to CT via basal lamina
- Avascularity: diffusion from CT
- Regeneration: high turnover, stem cells at basal surface
Functions of epithelial tissue
- Provide Physical protection
- Control permeability
- Provide sensation
- Produce specialized secretions
Structure of Epithelial tissue
- Apical Surface: exposed to environment may have: microvilli: absorption or secretion
cilia: fluid movement - Basolateral Surface: attachment to neighboring cells via intercellular connections
Basal lamina ( a.k.a basement membrane)
- Lamina lucida: from epithelia
glycoproteins + fine filaments
restrict large molecule movement - Lamina densa: from CT
coarse protein fibers
provide strength
Squamous
flat, disc shaped nucleus
Cuboidal
Cube, center round nucleus
Columnar
tall, basal oval nucleus
simple
one cell layer
stratified
2 or more protection
Simple squamous epithelium
-thin, delicate
-in protected regions
-Locations:
-mesothelium
(serosa)
-endothelium
(blood vessels, heart)
-kidney tubules
-conjunctiva
-alveoli of lungs
-Functions:
absorption, diffusion, filtration or secretion