Don't use (Unit 2 - Tissues) Flashcards
What are the 4 broad categories of tissues?
Epithelial
Connective
Neural
Muscular
3 types of tissue sections
Longitudinal
Cross section or transverse section
Oblique section
2 non-sectioned preparations
Smear
Spread
How do the four primary tissues differ from one another?
Cells
Matrix (extracellular material)
Space occupied by cells vs. matrix
What is the matrix (extracellular material) composed of?
Fibrous proteins
Gel
What does human development begin as?
A single cell - fertilized egg. First tissues appear when cells start to organize themselves into layers
3 primary germ layers
Ectoderm
Endoderm
Mesoderm
Outer germ layer
Ectoderm
Inner germ layer
Endoderm
Middle germ layer
Mesoderm
2 epithelial tissues
Epithelia
Glands
What do epithelial tissues’ basement membrane’s contain (3)?
Collagen
Laminin and fibronectin
Heparin sulfate
What do epithelial tissues’ basement membrane do?
Anchors epithelium to connective tissue
What are the two surfaces of the basement membrane on epithelial tissues?
Basal surface
Apical surface
5 characteristics of epithelial tissue
Cellularity Polarity Attachment Avascularity Regeneration
4 functions of epithelial tissue
Provide physical protection
Control permeability
Provide sensation
Produce specialized secretion
3 ways epithelia maintain integrity
Intercellular connections
Attachment to basal lamina
Maintenance and repair
3 cell junctions at intercellular connections of epithelia
Tight junctions
Gap junctions
Desmosomes
Adjacent cells bound together by fusion of outer phospholipid layer of plasma membranes
Tight junction
Patch that holds cells together – resists mechanical stress
Desmosomes
What do hemidesmosomes do?
Anchor basal cells of epithelium to underlying basement membrane
Formed by a ring-like connexon – ions, glucose, amino acids, and other solutes pass from one cell to next
Gap junctions
What makes up a tight junction? (3)
Plasma membrane
Membrane protein
Intercellular space
What makes up a desmosome? (5)
Intermediate filaments Glycoprotein Protein plaque Intercellular space Plasma membrane
What makes up a gap junction? (2)
Pore
Connexon
What is a basal lamina composed of? (2)
Lamina lucida
Lamina densa
3 components of a simple epithelium
Contains 1 layer of cells. Named by shape of cells. All cells touch the basement membrane.
3 components of a stratified epithelium
Contains more than one layer of cells. Named by shape of apical cells. Some cells rest on top of others and do not touch the basement membrane.
4 types of simple epithelia
Simple squamous
Simple cuboidal
Simple columnar
Pseudostratified columnar
4 types of stratified epithelia
Stratified squamous
Stratified cuboidal
Stratified columnar
Transitional epithelium
Two kinds of stratified squamous epithelia
Keratinized
Nonkeratinized
What happens to the deepest layers of stratified epithelia?
Undergo continuous mitosis
Where does tattoo ink get injected below?
The basement membrane
7 functions of connective tissues
Support Protection Immune function Movement Storage Heat production Transport
Connective tissues: structural framework of body through bones and cartilage
Support
Connective tissues: cranium, ribs, sternum, protect delicate organs
Protection
Connective tissues: white blood cells attack foreign invaders
Immune function
Connective tissues: bones provide lever system
Movement
Connective tissues: fat, calcium, phosphorous
Storage
Connective tissues: metabolism of brown fat in infants
Heat production
Connective tissues: fluids and dissolved material throughout body
Transport
9 cell types in fibrous connective tissue
Fibroblasts Macrophages Leukocytes (WBC) Plasma cells Mast cells Adipocytes Mesenchymal cells Melanocytes Microphages
What do fibroblasts produce?
Fibers and ground substance
Wat do macrophages do?
Phagocytize foreign material and activate immune system when sense foreign matter (antigens)
What do plasma cells synthesize?
Disease fighting antibodies
Where are mast cells found?
Alongside blood vessels
What do adipocytes store?
Triglycerides
3 Fiber Types in Fibrous Connective Tissue
Collagenous
Reticular
Elastic
What are collagenous fibers?
most abundant of the body’s proteins – 25%
tough, flexible, and resist stretching
What are reticular fibers?
thin collagen fibers coated with glycoprotein
form framework of such organs as spleen and lymph nodes
What are elastic fibers?
thinner than collagenous fibers
allows stretch and recoil
3 Fluid Components of Fibrous Connective Tissue
Glycosaminoglycans (GAG)
Proteoglycan
Adhesive glycoproteins
What are glycosaminoglycans (GAG)?
play important role of regulating water and electrolyte balance in the tissues
What are glycosaminoglycans (GAG) composed of?
chondroitin sulfate
hyaluronic acid
What does hyaluronic acid lubricate?
Joints
What is proteoglycan?
structural bond between cells and extracellular macromolecules
What do adhesive glycoproteins bind?
Components of tissues together
2 Types of Fibrous Connective Tissue
Loose connective
Dense connective
What are the two types of loose connective tissue?
Areolar
Reticular
What are the two types of dense connective tissues?
Dense regular connective tissue
Dense irregular connective tissue
What are the 4 elements of areolar tissue?
Ground substance
Elastic fibers
Collagenous fibers
Fibroblasts
What is areolar tissue?
Loosely organized fibers, abundant blood vessels, and empty space
What does areolar tissue underly?
All epithelia, in serous membranes, between muscles, passageways for nerves and blood vessels
Collections of specialized cells with specific functions
Tissues
The study of tissues
Histology
What does epithelial tissue line?
Digestive, respiratory, urinary and reproductive tracts. Also, fluid or gas-filled internal cavities and passageways such as the chest cavity, inner surfaces of blood vessels and chambers of heart.
Cells are tightly bound together by cell junctions
Cellularity
The structural and functional differences between the exposed (apical) and attached (basal) surfaces of the tissue.
Polarity
The base of the epithelia is bound to a basal lamina or basement membrane.
Attachment
Epithelia are avascular (lacking blood vessels)
Avascularity
A high rate of cell replacement by stem cells in the epithelium.
Regeneration
What do the apical surfaces of cells lining internal passageways have on their surfaces?
Microvilli which increase surface area to aid in absorption, secretion and transport
What moves fluids across the surface of the epithelium?
Cilia
What does cilia in the respiratory tract move?
Mucus, containing particles such as smoke, out of the lungs
What are neuroepithelia specialized for?
The sensations of smell, taste, sight, equilibrium, and hearing.
In glandular epithelium, what do most cells produce?
Secretions
Individual epithelial cells may be specialized for: (3)
Movement of fluid over epithelial surface (protection or lubrication).
Movement of fluid through the epithelium (permeability).
Production of secretions (protection or chemical messengers).
3 factors make the epithelium an effective barrier:
intercellular connections, attachment to basal lamina, and maintenance and repair.
Connections between large areas of opposing cell membranes are formed by…?
Transmembrane proteins called cell adhesion molecules (CAMs).
Adjacent cell membranes may be bonded by a thin layer of proteoglycans called…?
Intercellular cement
Specialized areas of attachment between cells
Cell junctions
What is a squamous cell shape?
Simple squamous epithelium is thin and flat. Only 1 layer thick, it is the most delicate epithelium. It is found in smooth, protected areas where absorption or exchange takes place (linings of lungs, blood vessels).
What is a cuboidal cell shape?
Square
What is a columnar cell shape?
Tall
How are epithelia sorted into categories?
By cell shape and number of cell layers
simple squamous epithelium lining ventral body cavities (pleura, peritoneum, pericardium).
Mesothelium
simple squamous epithelium lining heart and blood vessels.
Endothelium
What do the stratified squamous epithelium line?
The mouth, esophagus, and anus
2 types of cuboidal epithelia
Simple
Stratified
Where does simple cuboidal epithelium occur?
Where secretion or absorption takes place (e.g. lining of kidney tubules).
Where are stratified cuboidal epithelium found?
Ducts of sweat glands and mammary glands
What do transitional epithelia tolerate?
repeated cycles of stretching without damage (e.g. urinary bladder)
Why is transitional epithelia called “transitional”?
cell layers change appearance (from stratified to simple) as they stretch.
3 types of columnar epithelia
Simple
Psueodstratified
Stratified
cells, or collections of cells, specialized for secretions ranging from sweat to hormones.
Glands
What do endocrine glands release?
hormonal secretions into interstitial fluids.
What do hormones control?
Specific tissues, organs, and organ systems
2 examples of endocrine glands
Thyroid gland
Pituitary gland
Do endocrine glands have ducts?
No
What do exocrine glands release?
secretions into ducts which carry the secretions onto an epithelial surface such as the skin, or an internal passageway that communicates with the outside environment.
4 examples of exocrine secretions
digestive enzymes, sweat, tears and milk.
3 methods of glandular secretion
merocrine, apocrine, and holocrine.
Most common glandular secretion
Merocrine
Example of a merocrine secretion
Sweat gland
How are merocrine secretions released?
From secretory vesicles by exocytosis
What happens during apocrine secretion?
part of the cell cytoplasm is released along with the secretory product.
Example of apocrine secretion
Mammary glands
What secretions does milk production involve?
Apocrine and merocrine secretions
What does holocrine secretion do?
Fills a gland cell and causes it to burst, killing the cell
Example of holocrine secretion
Sebaceous glands which produces oil in hair follicles
What must replace holocrine cells?
Stem-cell division
3 types of secretions from exocrine glands
Watery secretions
Mucins
Serous and mucous secretions
2 potential structures of exocrine glands
Unicellular
Multicellular
What are the only unicellular exocrine glands?
Goblet cells, which secrete mucins
