Chapter 5 - Histology Flashcards
There are ____ trillion cells of ____ different cell types
There are 50 trillion cells of 200 different cell types
Name the 4 broad categories of tissues
Epithelial tissue
Connective tissue
Nervous tissue
Muscular tissue
Define histology
The study of tissues
Define organ
A structure with discrete boundaries that is composed of two or more tissue types
Define tissue
A group of similar cells and cell products working together to perform a specific role in an organ
The four primary tissues differ from each other in what three ways?
- Types and functions of their cells
- Characteristics of the matrix (extracellular material)
- Relative amount of space occupied by cells versus matrix
The extracellular matrix is composed of what two things?
1) Fibrous proteins
2) Ground substance (clear gel)
What other names can be used for ‘ground substance’?
Tissue fluid, extracellular fluid (ECF), or interstitial fluid
What are the six functions of epithelial tissue?
Covers body surfaces and lines body cavities
Protect deeper tissues from injury and infection
Produce and release chemical secretions
Excretion and absorption
Selectively filter substances
Makes up most glands
Describe the characteristics of epithelial tissue
Cells are very close together High rate of mitosis (regenerative) Apical and basal surfaces Basal surfaces faces basement membrane Apical surfaces may have microvilli or cilia Avascular but innervated
The ______ _______ anchors the epithelium to the connective tissue below it
basement membrane
Describe the differences between simple and stratified epithelium
Simple epithelia: -Contain one layer of cells -Named by shape of cells -All cells touch basement membrane Stratified epithelia: -Contain more than one layer -Named by shape of apical cells -Some cells rest on top of others and do not touch basement membrane
In _____ epithelia, not all cells touch the basement membrane
stratified
In ______ epithelia, all cells touch the basement membrane
simple
What are the four types of simple epithelia?
Simple squamous
Simple cuboidal
Simple columnar
Pseudostratified columnar
Describe pseudostratified columnar cells
Every cell reaches the basement membrane but not all cells reach the free surface; Falsely appears stratified
What are goblet cells?
Wineglass-shaped mucus-secreting cells in simple columnar and pseudostratified epithelia
Describe simple squamous epithelium and where it can be found
- Permits rapid diffusion or transport of substances
- Secretes serous fluid
- Locations: air sacs of lungs (alveoli), inner lining of blood vessels & heart (endothelium), and serosa
Describe simple cuboidal epithelium and where it can be found
- Absorption and secretion, mucus production and movement
- Locations: Kidney tubules and certain glands (thyroid, mammary and salivary glands)
Describe simple columnar epithelium and where it can be found
- Single row of tall, narrow cells; oval nuclei in basal half of cell
- Absorption and secretion; secretion of mucus
- Brush border of microvilli, ciliated in some organs, may possess goblet cells
- Locations: lining of GI tract, uterus, and uterine tubes
Describe pseudostratified epithelium and where it can be found
- Secretes and propels mucus
- Has cilia and goblet cells
- Looks multilayered, but all cells touch basement membrane
- Nuclei at several layers
- Locations: respiratory tract
Describe stratified epithelia
- Range from 2 to 20 or more layers of cells
- Some cells rest directly on others
- Only the deepest layer attaches to basement membrane
Describe the types of stratified epithelia
- Three stratified epithelia are named for the shapes of their apical surface cells
- Includes stratified squamous (only one expected to recognize and know functions)
- The fourth type is transitional epithelium
What is the most widespread epithelium in the human body?
Stratified squamous epithelium
Describe stratified squamous epithelia and its two types
-Deepest layers undergo continuous mitosis
-Daughter cells push toward the surface and become flatter as they migrate upward
-Top layer is exfoliated
-Two kinds
Keratinized—top layer is dead
Non-keratinized—top layer not dead
Describe keratinized stratified squamous epithelium and where it’s located
Resists abrasion; retards water loss through skin; resists penetration by pathogenic organisms
Locations: epidermis; palms and soles heavily keratinized
Describe non-keratinized stratified squamous epithelium and where it’s located
Resists abrasion and penetration of pathogens
Locations: tongue, oral mucosa, esophagus, and vagina
Describe transitional epithelium and where it’s located
Permits stretching (distension); surface cells change from round to flat when stretched Locations: ureter and urinary bladder
Describe the functions of connective tissue
Binding and Support Physical protection Immune protection Movement Storage Transport
_____ tissue is the most diverse and abundant type of tissue
Connective
Give examples of each of the functions of connective tissues
Connecting organs—tendons and ligaments
Support—bones and cartilage
Physical protection—cranium, ribs, sternum
Immune protection—white blood cells attack foreign invaders
Movement—bones provide lever system
Storage—fat, calcium, phosphorus
Heat production—metabolism of brown fat in infants
Transport—blood
Describe the characteristics of connective tissue
-Cells occupy less space than matrix (usually a large amount of extracellular matrix)
-Most cells are not in direct contact with each other
-Highly variable vascularity
Loose connective tissues have many blood vessels, whereas cartilage has few or no blood vessels
List and describe the 5 basic categories of connective tissue
- Fibrous Connective Tissue (Connective Tissue Proper): most diverse category; fibroblasts produce fibers and ground substance of matrix.
- Adipose Tissue: may be classified with loose connective tissue proper
- Cartilage (has 3 types): chondroblasts form matrix
- Bone (Osseous tissue): osteoblasts form matrix
- Blood
List and describe the three types of fibers that can be found in fibrous connective tissue
- Collagen fibers: tough, flexible, and stretch-resisant
- Reticular fibers: branching collagen fibers that forms a network
- Elastic fibers (Elastin): Allows stretch and recoil
What is fibrous connective tissue made of?
Fibers and a ground substance
Describe the ground substance of fibrous connective tissues
Usually has a gelatinous to rubbery consistency
Describe collagen fibers and where they’re found
Found in fibrous connective tissue, it is the most abundant protein: 25%. Tendons, ligaments, and deep layer of the skin are mostly collagen.
What is the most abundant proteines
Collagen (25%)
Describe reticular fibers and where they can be found
Found in fibrous connective tissue, it is thin collagen fibers coated with glycoprotein. Forms the framework of the spleen and lymph nodes.
Describe elastic fibers
Found in fibrous connective tissues, they branch and rejoin each other
What are the two main types of fibrous connective tissue? Describe them.
Loose connective tissue and dense connective tissue.
Loose connective tissue has more gel-like ground substance between cells, and its two types are areolar and reticular.
Dense connective tissue has fibers that fill spaces between cells, and its two types are dense regular and dense irregular.
What are the two main types of fibrous loose connective tissue?
Areolar and reticular
What are the two main types of fibrous dense connective tissue?
Dense regular and dense irregular
Describe areolar tissue (a type of fibrous loose connective tissue) and where it’s found
All 3 fibers are found; loosely organized; abundant blood vessels.
Wraps & cushions organs; underlies epithelia, in serous membranes, between muscles, passageways for nerves and blood vessels.
Areolar tissue—loosely organized fibers, abundant blood vessels, and a lot of seemingly empty space
Possess all six cell types
Fibers run in random directions
Mostly collagenous, but elastic and reticular also present
Found in tissue sections from almost every part of the body
Surrounds blood vessels and nerves
Nearly every epithelium rests on a layer of areolar tissue
Blood vessels provide nutrition to epithelium and waste removal
Ready supply of infection-fighting leukocytes that move about freely in areolar tissue
Describe reticular tissue (a type of fibrous loose connective tissue) and where it’s found
Mesh of reticular fibers and fibroblasts
Forms supportive framework for lymphatic organs
Found in lymph nodes, spleen, thymus, and bone marrow
Describe dense regular connective tissue (a type of fibrous dense connective tissue) and where it’s found
Densely packed, parallel collagen fibers
Tendons attach muscles to bones and ligaments hold bones together