Chapter 4: Histology

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146 Terms

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Histology
the study of tissues
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collagen fiber
knowt flashcard image
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elastic fiber
knowt flashcard image
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Definition of tissues
the collections of specialized cells and the extracellular substance surrounding them
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the purpose of a biopsy
for diagnostic purposes (Ex: to diagnose Celiac)
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What is an autopsy?
examination of organs to determine cause of death or to study the changes caused by disease
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Which of the following is not used to classify epithelial tissues?
A. Matrix
B. Structure
C. Function
D. Location
D. Location
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epithelium characteristics
A. made almost entirely of tightly packed cells (not much matrix)
B. Covers body surfaces and forms glands (skin, digestive tract, respiratory tract, heart and blood vessels, many body cavities)
C. Most have a free and a basal surface (lateral surface is in between cells)
D. Basement membrane
E. Avascular
F. Capable of regeneration mitosis
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T or F: Epithelium cannot undergo mitosis because it is avascular.
False
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What is the basement membrane of an epithelial cell?
an extracellular material formed by secretions from epithelial and connective tissue cells
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What does the basement membrane do?
1. helps attach epithelial cells to the underlying connective tissues
2. guides cell migration for tissue repair
3. filters (in the nephrons of the kidney)
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Do all epithelium cells have a basement membrane?
No
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the function of epithelial tissues
(Before you go, Don't Forget Some Apples Peel)
Barrier, Diffusion, Filtration, Secretion, Absorption, Protection
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the free surface of an epithelial cell can be/have: (and what do they do?)
1. Smooth to reduce friction (blood vessels)
2. Microvilli/brush border to increase surface area for absorption or secretion
3. Cilia to move materials across the cell surface
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simple squamous epithelium locations
lining of blood vessels & heart, lymphatic vessels (endothelium), and alveoli of lungs
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function of simple squamous epithelium
diffusion (oxygen in lungs), filtration (kidneys), some secretion, some protection
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simple cuboidal epithelium locations
microvilli in kidney tubules & terminal bronchioles in lungs
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functions of simple cuboidal epithelium
secretion & absorption
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simple columnar epithelium locations
microvilli in GI tract & cilia in lungs
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functions of simple columnar epithelium
secretion and absorption in intestine & particles out of bronchioles in the cilia in the lungs
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stratified squamous epithelium locations
non-keratinized: mouth, throat, esophagus
keratinized: skin
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non-keratinized stratified squamous epithelium
living cells in the deepest and outermost layers that are covered with a layer of fluid on the outer layer (they are moist)
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keratinzed stratified squamous epithelium
living cells in the deepest layers, and dead cells containing the protein keratin in the outer layers (they are dry, durable, and moisture-resistant)
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functions of stratified squamous epithelium
protection from abrasion, chemicals, water loss, and infection
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stratified cuboidal epithelium locations
sweat gland ducts
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functions of stratified cuboidal epithelium
secretion, absorption, & protection against infection
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stratified columnar epithelium locations
mammary gland duct, larynx, portion of male urethra
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function of stratified columnar epithelium
secretion and protection
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pseudostratified columnar epithelium characteristics
almost always ciliated, have goblet cells, & are mucous
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pseudostratified columnar epithelium locations
nasal sinuses, bronchi of lungs, trachea
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functions of pseudostratified columnar epithelium
secrete and move mucus
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transitional epithelium locations
lining of urinary bladder and ureters
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functions of transitional epithelium
stretch with volume changes of organ & protects against caustic effects of urine
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transitional epithelium shape
cube when not stretched, squamous when stretched
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cell connectors
desmosomes (& Hemidesmosomes), tight junctions, adhesion belts, gap junctions
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function of a desmosome
bind cells together
bind cells together
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function of a hemidesmosome
bind cells to basement membrane
bind cells to basement membrane
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function of a tight junction
holds cells together & forms a permeability layer
holds cells together & forms a permeability layer
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function of an adhesion belt
help the tight junctions anchor the epithelial cells to each other
help the tight junctions anchor the epithelial cells to each other
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function of a gap junction
intercellular communication
intercellular communication
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endocrine glands
secrete hormones directly into the bloodstream (no ducts), which means its secretions are separated from the epithelium of origin
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exocrine glands
has ducts, which means its secretions maintain open contact with the epithelium from which it developed
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goblet cells
unicellular glands that secrete mucus
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How are multicellular exocrine glands classified?
the structure of their ducts or by their method of secretion
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T or F: most glands are multicellular
true
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simple structure glands
ducts with a few branches
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compound structure glands
ducts with many branches
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tubular structure glands
secretory regions shaped like tubes
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acinar (alveolar) structure glands
sac-like structures
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merocrine secretion
no loss of cellular material (like sweat)
no loss of cellular material (like sweat)
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apocrine secretion
part of cell pinches off (like mammary glands)
part of cell pinches off (like mammary glands)
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holocrine secretion
whole cell is part of secretion (like sebaceous gland)
whole cell is part of secretion (like sebaceous gland)
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T or F: connective tissue is found in every organ.
true
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functions of connective tissue, and examples of connective tissues that do those things
1. enclose/encapsulate organs (ex: muscles, arteries, veins)
2. connect tissues (ex: tendons and ligaments)
3. support and movement (ex: bones provide rigid support)
4. storage (ex: fat stores high energy molecules, bone stores minerals like Ca and P)
5. cushion/insulation (ex: fat)
6. transport (ex: blood)
7. protection (ex: immune system cells, bones)
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what connective tissue function does the word stem "blast" identify?
create matrix
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what connective tissue function does the word stem "cyte" identify?
maintain matrix
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what connective tissue function does the word stem "clast" identify?
break down matrix (for remodeling)
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types of connective tissue cells
1. adipose/fat cells (adipocytes)
2. mast cells - contain heparin, histamine, and proteolytic enzymes & are released in response to injury/infection
3. white blood cells - respond to injury/infection as well
4. macrophages - phagocytize to provide protection (can be fixed or wandering
5. undifferentiated mesenchyme (stem cells)
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What are the 3 parts of the extracellular matrix of connective tissue?
protein fibers, ground substance, & fluid
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3 different types of protein fibers of the matrix of connective tissue
collagen, reticular, & elastic
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collagen protein fiber characteristics
most common protein in the body (approx. 6% of body weight) & very strong and flexible but very inelastic
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reticular protein fiber characteristics
these are fine collagen fibers that form a branching network and fills spaces between tissues and organs & it is not as strong as most collagen fibers
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elastic protein fiber characteristics
returns to original shape
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ground substance of connective tissue extracellular matrix
the shapeless background in a microscope
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3 types of ground substance in the matrix of connective tissue
hyaluronic acid, proteoglycans, & adhesive molecules
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hyaluronic acid
a polysaccharide that is the lubricant for joint cavities
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proteoglycans
protein + polysaccharide that traps large amounts of water and provides cartilage with its resilient nature
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adhesive molecules
hold proteoglycans together
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What is the component that is not part of the extracellular matrix of Connective Tissues?
A. Fluid
B. Protein fibers
C. Holocrine tissue
D. Ground substance
C. Holocrine tissue
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loose (areolar) connective tissue
the loose packing material of most organs and tissues that attaches skin to underlying tissues
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dense regular connective tissue
has abundant collagen fibers and resists stretching
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tendons
muscle to bone
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ligaments
bone to bone
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dense irregular collagenous connective tissue
has collagen fibers that are randomly oriented and is tough
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what connective tissue makes up most of the dermis of the skin, as well as scars?
dense irregular collagenous connective tissue
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What tissue makes up the epidermis?
stratified squamous epithelium
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What tissue makes up the dermis?
dense irregular collagenous CT
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What tissue makes up the hypodermis (subcutaneous)?
loose (areolar) CT
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adipose tissue
made of adipocytes, and can be yellow/white or brown
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yellow/white adipose tissue
Most abundant type and is white at birth then yellows with age
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brown adipose tissue
in axillae and neck and is more abundant in babies
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reticular tissue
provides a super structure for lymphatic and hemopoietic tissues like lymph nodes, spleen, and bone marrow, & the spaces in between cells contain white blood cells and dendritic cells
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cartilage characteristics
firmest structure in the body except bone, avascular, no blood/nerve supply, and heals very slowly
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perichondrium
dense irregular connective tissue that surrounds nearly all cartilage and secretes cartilage cells
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When do cartilage cells become chondrocytes?
when surrounded by the matrix and are located in spaces called lacunae
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the 3 types of cartilage
hyaline, fibrocartilage, elastic
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hyaline cartilage structure
collagen fibers and proteoglycans in the matrix
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hyaline cartilage locations
where strong support and some flexibility is needed (rib cage, trachea, bronchi), on articulation surfaces, embryo skeletons, & bone growth zones
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fibrocartilage structure
thick collagen fibers in matrix that are slightly compressible and tough
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fibrocartilage locations
areas of pressure on joints (knees, interverbal disks)
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elastic cartilage structure
elastic and collagen fibers and proteoglycans in the matrix that are rigid but elastic
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elastic cartilage location
external ears
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bone
hard connective tissue made of osteocytes (living cells) + mineralized matrix
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bone matrix
provides strength/rigidity and is made up of organic collagen fibers and inorganic hydroxyapetite (Ca++ and PO4)
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Where are bone osteocytes located?
in lacunae
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types of bone
cancellous/spongy bone & compact bone
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cancellous/spongy bone
trabeculae of bone with spaces that is found inside the bone, skull, vertebrae, sternum, and ends of long bones
trabeculae of bone with spaces that is found inside the bone, skull, vertebrae, sternum, and ends of long bones
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compact bone
concentric layers around a central canal and is around the periphery of the bone
concentric layers around a central canal and is around the periphery of the bone
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blood matrix
liquid/fluid plasma (lacks fibers) that allows materials like food, oxygen, and waste products to move quickly through the body
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formed elements in blood
red cells, white cells, & platelets