A&P Chapter 5 Histology & Tissues Flashcards
(84 cards)
What is Histology?
The study of cells and tissues and how they are arranged into organs.
This allows us to see how cells are arranged in a particular tissue type and how tissues help form an organ.
What are the four primary tissue classes?
Epithelial, Connective, Nervous, Muscular
The vast majority of organs and tissues will have all four of the tissue classes.
Tissues are…
A group of similar cells derived from a common embryonic origin that are arranged in a way that allows them to carry out a particular STRUCTURAL or PHYSIOLOGICAL function.
Tissues = Cells + Extracellular Matrix
What does extracellular matrix contain? Where is it found?
Protein Fibers, Water, Minerals, Nutrients, and Waste Products
It is found in the spaces between cells.
How do tissues differ from one another?
In the types of cells that make up the tissue as well as by the type and amount of EXTRACELLULAR MATRIX that surrounds the cells.
What are the two functions of tissues?
Structural, Ex. Bone supports and protects the body, also allows the muscles to produce movement.
Physiological, Ex. Epithelial tissues lining the digestive system allows the body to absorb nutrients from the foods we eat.
MANY TISSUES HAVE BOTH A STRUCTURAL AND A PHYSIOLOGICAL FUNCTION.
What are epithelial tissues?
They are a layer of tightly bound cells that are one or more layers thick (1-20) that are bound to a BASEMENT MEMBRANE. They are usually exposed to the outside environment or to the inside of the body.
Examples: Skin, Lining of Digestive System, Lining of Lungs, Lining of Blood Vessels, Etc…
What does the Basement Membrane do?
It acts as a biological glue that holds cells to connective tissues below it.
The BM is composed of collagen, and avariety of glycoproteins and proteoglycans.
What are the shapes of epithelial cells?
Squamous, Cuboidal, Columnar
Describe Squamous cells
Thin, flat looking like a fried egg. Good for exchange of gasses, nutrients, and waste products. Found in lung and blood vessels.
These cells offer short distances between layers/areas therefore they are ideal for the exchange of things.
Describe Cuboidal cells
Typically square or round, they are found in the lining of ducts of many glands.
You will see a uniform amount of cytoplasm around the nucleus of these cells.
Describe Columnar cells
Tall and narrow, found lining the intestines. They often have small projections on the exposed (APICAL) surface called MICROVILLI that increase surface area for absorption.
What are the three functions of Epithelial tissue?
- Compartmentalization, we find epithelial tissue lining cavities/organs. It serves as a layer between things keeping things in the body seperate.
- Absorption/Secretion, stuff passes in and out of areas going through the epithelial tissue.
- Transport/Exchange, Exchange of gasses/waste products. Transportation of nutrients.
What is one layer of epithelial cells described as?
Simple, one layer is simple. All the cells connect with the basement membrane. Multiple layers is called stratified.
What are multiple layers of epithelia cells described as?
Stratified, only the bottom layer touches the basement membrane all the upper layers are bound to other cells.
Describe Pseudostratified columnar and how they look compared to stratified columnar cells.
All the cells are bound to the basement membrane but not all the cells reach the exposed surface. There is only ONE layer of cells, the nuclei will look uneven and not lined up in a single row.
What are transitional epithelial cells? Where are they found?
This is a specialized type of epithelial cell that transitions between a cuboidal shape and a squamous shape when stretched. The cells transition between the two depending on the movement of the tissue.
Found in the bladder and other organs that need to stretch.
What are the four types of epithelial tissues?
Simple, Stratified, Pseudostratified columnar, Transitional.
What types of epithelial cells will microvilli be found on?
Columnar epithelial cells.
What are goblet cells?
One celled mucous glands.
Explain keratinized, stratified squamous epithelia. Where is it found?
Keratinized = Dead cells with no nuclei. Stratified = Many layers of cells. Squamous = Thin squamous cells.
Many layers of cells, lower cells are alive and dividing, upper cells are dead and filled with keratin.
Found in the pads of the feet, hands, any place where layers are needed to protect against abrasion.
Explain Non-keratinized stratified squamous epithelia.
Many layers of cells, all alive, CAN SEE THE NUCLEI in all the cells.
Still offers resistance to abrasion like Keratinized stratified squamous cells but exit in other areas of the body like the mouth/vagina.
Connective tissues derive from?
The mesoderm.
What are the 6 major functions of connective tissue?
Connection, Connective tissues bind bone to muscle and bones to other bones, they also hold organs in place.
2. Support, Bones help support the body and cartilage supports structures like the nose and ear.
Protection, both PHYSICAL and IMMUNE. Physically connective tissues surround and protect the body. Connective tissues also contain large numbers of LEUKOCYTES AND MACROPHAGES that are immune cells protecting the body from bacteria and viruses.
4. Movement, Bones help move the body with the help of muscle.
5. Storage/Heat Production, Adipose tissue stores energy for later use and preserves/generates heat.
6. Transport, Blood transports gases, nutrients, waste, and hormones to the entire body.
