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4 primary types of tissue, what are they?
muscle
nervous
connective
epithelial
epithelial tissue functions and locations
locations
body coverings
body linings
functions
protection
absorption
filtration
secretion
where does epithelial tissue line and cover?
covers and lines body surfaces, forms sheets with one free surface, the apical surface (top), an anchored surface, the basement membrane (bottom)
number of cell layers for simple and stratified
simple - one layer
stratified - more than one
different types of cell shapes
squamous - flattened
cubodial - cube-shaped
columnar - shaped like columns
simple epithelial tissue function and density
functions in secretion, absorption, and filtration
very thin(one layer), not suited for protection
simple squamous epithelium
single layer
usually forms membranes
lines air sacs of lungs
forms walls of capillaries
forms serous membranes, the line and cover in ventral cavity
functions in diffusion, filtration, or secretion in membranes
single cuboidal epithelium
located in glands and their ducts
walls of kidney tubules
covers the surface of ovaries
functions in secretion and adsorption like ciliated types propel mucus or reproductive cells
single columnar epithelium
single layer of tall cells
located in lining of digestive tract from the stomach to anus and mucous membranes line body cavities opening to the exterior
function - secretion and absorption
Pseudostratified columnar epithelium
Location: respiratory tract, where it is ciliated and known as pseudo-stratified ciliated columnar epithelium
Functions in absorption or secretion
Stratified epithelia
consists of two or more cell layers
function primarily in protection
Stratified squamous epithelium
Functions as a protective covering where friction is common
Locationsālining of the:
Skin (outer portion)
Mouth
Esophagus
Stratified cuboidal epitheliumā
two layers of cuboidal cells;
functions in protection
Stratified columnar epitheliumā
surface cells are columnar, and cells underneath vary in size and shape;
functions in protection
Stratified cuboidal and columnar
Rare in human body
Found mainly in ducts of large glands
Transitional epithelium
Composed of modified stratified squamous epithelium
Shape of cells depends upon the amount of stretching
Functions in stretching and the ability to return to normal shape
Location: lining of urinary system organs
Glandular epithelia
One or more cells responsible for secreting a particular product
Secretions contain protein molecules in an aqueous (water-based) fluid
Secretion is an active process
Two major gland types develop from epithelial sheets
Endocrine glands
Ductless; secretions (hormones) diffuse into blood vessels
Examples include thyroid, adrenals, and pituitary
Exocrine glands
Secretions empty through ducts to the epithelial surface
Include sweat and oil glands, liver, and pancreas (both internal and external)
connective tissue
Found everywhere in the body to connect body parts
Includes the most abundant and widely distributed tissues
Functions
Protection
Support
Binding
connective tissue variation blood supply
Variations in blood supply
Some tissue types are well vascularized
Some have a poor blood supply or are avascular
what is extracellular matrix
nonliving material that surrounds living cells
Two main elements of the extracellular matrix
Ground substanceāmostly water, along with adhesion proteins and polysaccharide molecules
Fibers
Collagen (white) fibers
Elastic (yellow) fibers
Reticular fibers (a type of collagen)
Types of connective tissue from most rigid to softest, or most fluid:
Bone
Cartilage
Dense connective tissue
Loose connective tissue
Blood
Bone (osseous tissue)
Composed of:
Osteocytes (bone cells) sitting in lacunae (cavities)
Hard matrix of calcium salts
Large numbers of collagen fibers
Functions to protect and support the body
Cartilage
Less hard and more flexible than bone
Found in only a few places in the body
Chondrocyte (cartilage cell) is the major cell type
Types
Hyaline cartilage
Fibrocartilage
Elastic cartilage
Hyaline cartilage
Most widespread type of cartilage
Abundant collagen fibers hidden by a glassy, rubbery matrix
Locations
Trachea
Attaches ribs to the breastbone
Covers ends of long bones
Entire fetal skeleton prior to birth
Epiphyseal (growth) plates in long bones
Elastic cartilage
Provides elasticity
Location: supports the external ear
Fibrocartilage
Highly compressible
Location: forms cushionlike discs between vertebrae of the spinal column
Dense connective tissue (dense fibrous tissue)
Main matrix element is collagen fiber
Fibroblasts are cells that make fibers
Locations
Tendonsāattach skeletal muscle to bone
Ligamentsāattach bone to bone at joints and are more elastic than tendons
Dermisālower layers of the skin
Loose connective tissue
Softer, have more cells and fewer fibers than other connective tissues (except blood)
Types
Areolar
Adipose
Reticular
Areolar connective tissue
Functions as a universal packing tissue and āglueā to hold organs in place
Layer of areolar tissue called lamina propria underlies all membranes
All fiber types form a loose network
Can soak up excess fluid (causes edema)
Adipose connective tissue
Functions
Insulates the body
Protects some organs
Serves as a site of fuel storage
Locations
Subcutaneous tissue beneath the skin
Protects organs, such as the kidneys
Fat ādepotsā include hips, breasts, and belly
Reticular connective tissue
Forms stroma (internal framework) of organs
Locations
Lymph nodes
Spleen
Bone marrow
Blood (vascular tissue)
Blood cells surrounded by fluid matrix known as blood plasma
Functions as the transport vehicle for the cardiovascular system, carrying:
Nutrients
Wastes
Respiratory gases
muscle tissue
function is to contract, or shorten, to produce movement
Three types of muscle tissue
Skeletal
Cardiac
Smooth
Skeletal muscle tissue
Packaged by connective tissue sheets into skeletal muscles, which are attached to the skeleton and pull on bones or skin
Voluntarily (consciously) controlled
Produces gross body movements or facial expressions
Characteristics of skeletal muscle cells
Striations (stripes)
Multinucleate (more than one nucleus)
Long, cylindrical shape
Cardiac muscle tissue
Involuntarily controlled
Found only in the heart
Pumps blood through blood vessels
Characteristics of cardiac muscle cells
Striations
One nucleus per cell
Short, branching cells
Intercalated discs contain gap junctions to connect cells together
Smooth (visceral) muscle tissue
Involuntarily controlled
Found in walls of hollow organs such as stomach, uterus, and blood vessels
Peristalsis, a wavelike activity, is a typical activity
Characteristics of smooth muscle cells
No visible striations
One nucleus per cell
Spindle-shaped cells
Nervous Tissue
Function is to receive and conduct electrochemical impulses to and from body parts
Irritability
Conductivity
Composed of neurons and nerve support cells
Support cells called neuroglia insulate, protect, and support neurons
what are the shapes for squamous, cuboidal, and columnar?
squamous - flattened
cubodial, cube shaped
columnar - shaped like columns