Tissue Basics: Structure and Histology Flashcards
Name the four main types of tissue and give examples of where in the body each is likely to be found
- Epithelial - lining the outside of the body, cavities, glands
- Connective - connected to the epithelial to form skin, bone, cartilage, blood
- Nervous - in the brain
- Muscle - heart muscle wall
Describe or identify the shared features of epithelial tissue, including glands, such as cellular polarity, intercell
junctions, and the basement membrane
Epithelial tissue:
Polarity = epithelial cells have two sides with different features:
1. Apical side - facing the outside, top surface, may have microvilli or cilia
2. Basolateral surface - inner surface attached to the basement membrane
Tight junctions - exist between epithelial cells, selectively permeable(?) only some allow for paracellular transport, while others only allow transcellular transport
Basement membrane - thin layer at the basolateral surface that connect the epithelial cells to the connective tissue
**Classify an example epithelial tissue based on key structural or physiological features
Epithelial tissue:
1) Layering:
- Simple (single layer)
- Stratified (multiple layers)
- Pseudo-Stratified (seeming to be multi-layered but is only one layer)
2) Shape:
- Squamous (flat, thin, fast absorption and diffusion)
- Cuboidal (cube-shaped, absorb nutrients, and produce secretions)
- Columnar (tall, narrow, absorb nutrients, produce secretions)
Explain the basic definition of connective tissue and classify whether a tissue is a connective tissue
Connective tissue = must contain the presence of extracellular proteins/fibres and cells in a matrix
(cells + extracellular matrix = ground substance + fibres + cells)
Function: provides structural framework for other tissues, connects body parts, binding, support, protection from invasive microorganisms, insulation, storage of energy, transportation, etc.
Compare and contrast the structure and general functions of loose and dense connective tissue proper
Loose connective tissue = fewer density of extracellular fibres, more cells, and more ground substance, airy/disperal of fibres
= consists many cells, mainly fibroblasts, supporting matrix for blood, lymph, etc.
Dense connective tissue = denser extracellular fibres, tightly packed and smooth
= consists fewer cells, mainly fibrocytes, produces tendons and ligaments via strong, rope-like structures
Describe the key features of tissue repair in proper connective tissue, and predict consequences for the organism if a component of the repair process is disrupted
What is an organ?
two or more types of tissues working together to perform specific functions
What is a tissue?
a group of similar cells and their products working together to perform specific functions
What are the four general types of tissues that all tissues in the body fall under?
- Epithelial
- Connective
- Nervous
- Muscle
What is epithelial tissue?
tissue that lines surfaces, passageways, chambers, and forms glands
- epithelia, glands (endocrine and exocrine)
- avascular: does not have a blood supply
- innervated: supplied with nerves
What is connective tissue?
defined by the presence of extracellular fibres/proteins and cells in a ground substance matrix
tissue that fills internal space/stiffens space, structural support, stores energy
What is nervous tissue?
conducts electrical impulses, sends and receives info in the form of electrochemical signals, carries information
What is muscle tissue?
contracts to produce movement and mechanical force
What do muscle and nervous tissue have in common?
contain highly specialized cells adapted for very specific physiological roles + use a lot of energy
What do epithelial and connective tissue have in common?
more diverse in their functions, specializations, and where they are found
Where can epithelial tissue be found?
covers surfaces of the body (outside, inside), cavities, passageways
What are the functions of epithelial tissue?
provide physical protection, control permeability, provide sensation, and produce specialized secretions
Describe the structure of epithelial tissue/epithelium/epithelial cells?
Epithelial Tissue is made of Epithelium, which is made of Epithelial Cells
Epithelial Cells (single or multi-layered)
- Epithelial cells are all POLAR - have different features on different sides
- Apical side - exposed to outside/inside, contains microvilli/cilia
- Basolateral side - inner surface, attached to the basement membrane
- Basement membrane - thin layer that connects epithelial cells to the connective tissue
All epithelial cells share basic features, including ____________________–they have an _______ and _______ surface
All epithelial cells share some basic features, including
POLARIZATION – they all have an APICAL surface and a
BASOLATERAL surface.
What are tight junctions? What are the two types?
Tight junctions are proteins between the epithelial cells that define how water (and solutes) can move between the lumen and ISF
There are two types of tight junctions: leaky and tight
What is the apical surface of an epithelial cell?
top surface - exposed to internal body space or external environment, in contact with lumen
What is the basolateral surface of an epithelial cell?
bottom surface, attached to the sides, and basement membrane, in contact with the interstitial fluid
Differentiate “leaky” tight junctions from “tight” tight junctions?
“Leaky” tight junctions - allow paracellular transport of water and solutes because there is some space between the epithelial cells
“Tight” tight junctions - do not allow paracellular transport, only transcellular transport is allowed because there are no gaps between the two neighbouring cells
What is paracellular transport? How is it different from transcellular transport?
Paracellular transport = between the cells
Transcellular transport = through the cell
How do you classify epithelium?
- Layering
- Shape