Lab 1: Histology Flashcards
What are the four primary tissues of the vertebrate body?
- Epithelial
- Connective
- Muscle
- Nervous
What are the three functions of epithelial tissue?
- Covers the body surfaces
- Lines hollow organs, ventral body cavities, and ducts
- Forms glands
What are the four functions of connective tissue?
- Protects and supports the body and its organs
- Binds organs together
- Stores energy
- Provides immunity
Which tissue provides immunity?
Connective
Which tissue forms glands?
Epithelial
What is the function of muscle tissue?
Responsible for movement and the generation of force
What is the function of nervous tissue?
Carries information very quickly from one side of the body to the other
EVERY cell in our body belongs to one of how many tissue types?
Four (epithelial, connective, muscle, nervous)
What are the two basic types of epithelial tissues?
- Covering and lining epithelia
- Glandular epithelia
Differentiate covering and lining epithelia form glandular epithelia.
- Covering-Lining epithelial cells form a continuous layer over all the free surfaces of the body
- Glandular epithelia make up most of the glands in the body
Where are covering-lining epithelial cells found?
- Outer layer of the skin
- Inner surface of the digestive and respiratory cavities
- Inner surface of the heart and blood vessels
- Walls and organs of closed ventral body cavities
- Ducts of exocrine glands
Are epithelial cells close to each other or far away?
Close, there is little extracellular material between cells
What types of junctions unite adjacent epithelial cells? (3)
- Tight junctions
- Desmosomes
- Gap junctions
What is the apical surface? In which cells are they found? What is the exception?
- One free surface found in epithelial cells
- Exposed at the body surface or at the lumen (space) of the body cavity, duct, tube or vessel
- With the exception of endocrine glands
What does the lower surface of an epithelium rest on? What is the exception?
- The basal surface rests on a basement membrane; a non-living adhesive material secreted by the epithelium and underlying connective tissue
- With the exception of endocrine glands
Are there many or little blood vessels within the epithelial layer? What is the exception?
- There are NO blood vessels
- With the exception of endocrine glands
How often do epithelial cells divide? Why? What is the exception?
- Frequent cell division because they are exposed to wear and tear and injury
- With the exception of endocrine glands
What are the three primary functions of covering epithelia?
- Protect underlying tissues
- Allow and regulate the passage of materials
- Form sensory parts of organs
What does epithelia protect from?
Physical damage, drying out, chemical injury, infection
What materials are regulated by epithelia?
Oxygen, water, food, waste
Specialized epithelia form sensory parts of organs, such as what?
Eye, ear, mouth (taste buds), nose (olfactory epithelium)
Most glands are derived from which kinds of cells?
Epithelial cells specialized for producing secretions
What is the material secreted from glands usually made of?
Watery fluid containing substances such as salts, enzymes, hormones, mucus, fats
Give examples of products of glands.
Milk, insulin, sweat, saliva, calcitonin, tears, bile
What are the three features that allow the classification of covering and lining epithelia?
- The number of cell layers
- The shape of the cells
- Specializations of their cell surfaces
Flat epithelium cells are called ______.
squamous
Square epithelium cells are called ______.
cuboidal
Rectangular epithelium cells are called ______.
columnar
Epithelium cells that change shape depending on the degree of stretching of the tissue are called _______.
transitional
Under a microscope, if nuclei are flat and parallel to the free surface, they are ______ epithelium.
squamous
Under a microscope, if nuclei are oval and parallel to the axis of the cell and situated at its base, they are ______ epithelium.
columnar
Under a microscope, if nuclei are round and situated in the middle of the cell, they are ______ epithelium.
cuboidal
Where are simple epithelia mainly found? What is their main function?
- Areas of minimum wear and tear
- To allow passage of substances between the lumen and the surrounding tissues
What is the main function of stratified epithelia?
Protect the tissues that they cover
What are the four sub-classifications of simple epithelia?
- Squamous
- Cuboidal
- Columnar
- Pseudostratified
What are the four sub-classifications of stratified epithelia?
- Squamous
- Cuboidal
- Columnar
- Transitional
What kind of epithelium is found in the alveoli of the lungs, the kidney glomeruli, the lining of the heart, blood vessels and lymphatic vessels, and in the lining of the ventral body cavities?
Simple squamous epithelium
Which epithelium is the thinnest of them all? What does that allow?
- Simple squamous epithelium
- Well-adapted for diffusion (gas exchange, exchange of waste and nutrients, filtration, secretion)
What kind of epithelium is found in small glands, kidney tubules and ovary surface?
Simple cuboidal epithelium
What is the simple cuboidal epithelium adapted for?
Secretion and absorption of substances; giving urine its final composition as it moves in and out of the tubule
Which simple epithelium may be ciliated or non-ciliated?
- Columnar
- Pseudostratified
What do non-ciliated, simple columnar epithelium contain on the apical surface of its cells? What does that do?
- Microvilli on the apical surface of its cells
- Increase the surface area of the epithelium
What kind of epithelium is found mainly lining the digestive tract, and lining the ducts of some glands?
Non-ciliated, simple columnar epithelium
What do ciliated, simple columnar epithelium contain on the apical surface of its cells?
Cilia
What kind of epithelium is found in the small bronchi, the uterine tubes and part of the uterus?
Ciliated, simple columnar epithelium
Which cells are involved in the secretion of mucus and in moving mucus or female reproductive cells?
Ciliated, simple columnar epithelium
Explain the composition of simple pseudostratified epithelium.
- One layer of cells
- All its cells rest on the basement membrane
- Appears stratified because cells are of different heights and their nuclei are at different levels
What kind of epithelium is found lining part of the male urethra and ducts of large glands?
Non-ciliated simple pseudostratified epithelium
What kind of epithelium is found in the trachea, primary bronchi and in most of the upper respiratory tract, and is involved in the secretion and propulsion of mucus?
Ciiliated simple pseudostratified epithelium
Which epithelium is the thickest of all? What is its function?
- Stratified squamous epithelium
- Protection
Which epithelium cells may or may not contain keratin? What is keratin’s function?
- Stratified squamous epithelium
- Tough protective protein that prevents water loss
- Resistant to friction
- Repels bacteria
What epithelium forms the epidermis of the skin?
Keratinized, stratified squamous epithelium
What kind of epithelium lines wet surfaces subjected to abrasion (lining of the mouth, esophagus, tongue, part of the epiglottis, vagina)?
Non-keratinized, stratified squamous epithelium
What kind of epithelium is found in the largest ducts of sweat glands, mammary glands, salivary glands and in parts of the male urethra? What is its function?
- Stratified cuboidal epithelium
- Protection
What kind of epithelium is very rare, and lines part of the urethra, large ducts of some glands, and a portion of the conjunctiva of the eye? What are its functions?
- Stratified columnar epithelium
- Protection and secretion
What kind of epithelium is found lining surfaces of organs subjected to stretch, such as the bladder, the ureters, and part of the urethra? What is its function?
- Stratified transitional epithelium
- Allows for distension of the urinary organ
What does a transitional epithelium look like if it is stretched? What does it look like if it is unstretched?
- Stretched: stratified squamous epithelium
- Unstretched: stratified cuboidal epithelium
Differentiate endocrine and exocrine glands.
- Endocrine: products (hormones) are secreted directly into the blood
- Exocrine: release their products onto the free surface of the skin or of the open cavities of the body (digestive, respiratory, reproductive tract)
Most of the endocrine glands are _______ derivatives.
epithelial
Describe how endocrine glands are formed.
- By invagination from an epithelial sheet and initially having ducts connecting them to the free surface of the epithelial sheet
- During embryonic development, they will lose their ducts and thus are called ductless glands
Under the microscope, what do endocrine glands look like? What is the major difference?
- Stratified epithelial tissues
- They do NOT have a free surface, and are surrounded directly by other tissues
Are the cells of connective tissue close to each other or far away?
Far apart, separated by an abundant amount of extracellular matrix
Where do you find connective tissue?
Everywhere in the body
What are the four main functions of connective tissue?
- Binding, support and packaging other tissues (epithelia, muscles, nerves)
- Protection, defense and repair
- Insulation
- Transportation
What forms the three-dimensional fibrous mesh which supports cells inside large soft organs (liver, spleen)?
Connective tissue
The delicate and fragile _______ _________ _________ forms a soft packing around organs.
areolar connective tissue
What is scar tissue formed of?
Connective tissue, which fills in spaces where the original tissue does not regenerate
Inflammation is a defense response of which type of tissue?
Connective tissue
How does connective tissue function as insulation?
Fat cells or adipose tissue is a connective tissue that insulates organs and provides reserve energy fuel
How does connective tissue function as transportation?
Blood is a connective tissue (carries and delivers oxygen and nutrients to tissues)
What are connective tissues caracterized by?
Abundant amounts of extracellular matrix in which a variety of cell types are dispersed
The extracellular matrix in connective tissue usually includes _______ of one or more types embedded in what?
fibers, amorphous ground substance
What are the four classes of connective tissues?
- Blood
- Bone
- Cartilage
- Connective Tissue Proper
Differentiate -blast and -cyste cells in connective tissue.
- -blast cells retain their capacity for division and secrete the matrix characteristic to their tissue
- Undifferentiated -blast cells mature and become -cyst cells following matrix production, and are responsible for maintaining the matrix in a healthy state
What are the -blast cells in the four types of connective tissue?
- Blood: hemocytoblasts
- Connective Tissue Proper: fibroblasts
- Cartilage: chondroblasts
- Bone: osteoblasts