Week 3 Flashcards
what is a tissue?
two or more types of cells working together to perform a specific function. they also share common embryonic origin.
what are the 4 main categories of tissues?
epithelial, connective, muscle, and nervous tissue
what is epithelial tissue?
epithelial tissue are large sheets of cells covering all the surfaces of the body exposed to the outside world and lining the outside of organs and body cavities.
hollow organs and body cavities that are not connected to the exterior of the body are lined by?
endothelium, a type of epithelium
what is the structure of epithelial tissue?
- highly cellular with little or no extracellular material present.
- apical facing surface: facing open space
- basal surface: close to underlying body structures.
if cilia is present, it is found on the apical surface
what is the basement membrane?
the basement membrane is made up of the basal lamina and reticular lamina and anchors the epithelial tissue to the underlying connective tissue.
basal lamina: glycoproteins and collagen
is epithelial tissue vascularized or no?
no, epithelial tissue is nearly completely avascular, lacking blood vessels.
what are the functions of epithelial tissue?
epithelial tissue provides the body’s first line of protection from physical, chemical, and biological wear and tear.
how can epithelial tissue be classified?
shape of cells: squamous, cuboidal, columnar shaped.
number of cell layers: simple, stratified, pseudostratified, and transitional.
what is squamous?
flat and thin cells
what is cuboidal?
cube shaped, as wide as it is tall
what is columnar?
taller than it is wide
what is simple?
one layer
what is stratified?
two or more layers
what is pseudostratified?
one layer but gives the appearance of more than one layer
what is transitional?
transitional is a form of stratified epithelium in which the shape of the cells may vary
what is the location and function of simple squamous epithelium?
flat one layer
location: alveoli of lungs, lining heart, blood vessels, lymphatic vessels, segments of kidney tubules
function: allows material to pass through diffusion and filtration, secretes lubricating substance
what is the location and function of simple cuboidal epithelium?
cube shaped one layer
location: ducts of glands, kidney tubules
function: secretes and absorbs
what is the location and function of simple columnar epithelium?
one layer of column shaped cells
location: ciliated are in bronchi, uterine tubes, uterus and nonciliated are in the digestive tract and bladder
function: absorbs and also secretes mucus and enzymes
what is the location and function of stratified squamous epithelium?
two or more layers of flat cells
location: lines esophagus, mouth, vagina, skin
function: protects against abrasion
what is the location and function of stratified cuboidal epithelium?
two or more layers of cube shaped cells
location: sweat glands, salivary glands, mammary glands
function: protective tissue
what is the location and function of stratified columnar epithelium?
two or more layers of columnar shaped cells
location: male urethra and ducts of glands
function: secretes and protects
what is the location and function of transitional epithelium?
stratified, shape varies
location: lines bladder, urethra, and ureters.
function: allows urinary organs to expand and stretch
what is the function of connective tissue?
- support and connect other tissues
- protection
- transport of fluid, nutrients, waste, and chemical messengers
are cells in connective tissue densely packed?
unlike epithelial tissue, cells are dispersed in a matrix.
whats the major component of the matrix?
ground substance and protein fibres.
what are the categories of connective tissues?
connective tissue proper, supportive connective tissue, and fluid connective tissue
what goes under connective tissue proper?
- loose connective tissue: areolar, adipose, and reticular
- dense connective tissue: regular and irregular
what goes under supportive connective tissue?
cartilage: hyaline, fibrocartilage, elastic
bones: compact, cancellous
what goes under fluid connective tissue?
blood and lymph
what are the most abundant cells in connective tissue proper?
fibroblasts: secrete protein fiber and matrix
what are adipocytes?
lipid/fat storage cells
what are mesenchymal cells?
adult stem cell that differentiate into any type of connective tissue cell needed for the healing of damaged connective tissue.
what is a macrophage?
large blood cell: essential component of immune system
what is a mast cell?
releases histamine which causes vasodilation at site of injury or infection, along with itching, swelling, redness
what are the 3 main fibers secreted by fibroblasts?
collagen, elastic, and reticular fibers.
what is adipose tissue?
- consists mainly of fat storage cells/adipocytes.
- contributes to lipid storage and insulation
what is areolar tissue?
contains all cell types and fibres in a web like fashion.
- surrounds blood/lymph vessels and supports organs in abdominal cavity
- areolar tissue underlies most epithelia
what is reticular tissue?
mesh like supportive framework for soft organs.
dense regular connective tissue?
- fibres are parallel to eachother
- ligaments and tendons made of dense regular connective tissue but in ligaments not all fibres are parallel
dense irregular connective tissue?
- the direction of fibres is random
- dermis of the skin is an example of dense irregular connective tissue
what are chondrocytes and where are they?
embedded within the cartilage matrix are the chondrocytes, and the space they occupy are called lacunae
is cartilaginous tissue vascularized?
no, avascular which is why cartilage has slow healing
what are the main types of cartilage in the body?
hyaline cartilage
what is hyaline cartilage?
- most common type of cartilage
- short dispersed collagen fibres
- rib cage, nose, embryonic skeleton
what is fibrocartilage?
- thick bundles of collagen fibres
- knee joint, jaw joint, intervertebral discs
what is elastic cartilage?
- elastic fibres and collagen
- ear lobes
is bone connective tissue?
yes, bone is the hardest connective tissue.
- provides protection to internal organs and supports the body.
- collagen fibres embedded in a ground substance containing hydroxyapatite.
without collagen, bones would?
be brittle and shatter easily
without mineral crystals, bone would?
flex and provide little support
is bone vascularized?
yes bone is highly vascularized, unlike cartilage, bone can recover from injuries in a short amount of time.
what are fluid connective tissue types?
blood and lymph
- cells circulate in liquid extracellular matrix.
- formed elements circulating in blood are derived from HEMATOPOIETIC STEM CELLS IN THE BONE MARROW.
lymph contains?
liquid matrix and white blood cells
muscle cells are?
excitable: they respond to a stimulus and they are contractile
what are the 3 types of muscle tissues?
skeletal, cardiac, and smooth muscle tissue
skeletal muscle?
- long fibre
- striated
- multinucleated
- voluntary movement
- attached to bones
cardiac muscle?
- short fibre
- striated
- mononucleated
- contracts to pump blood
- attached to heart walls
smooth muscle?
- short fibre
- no striations
- mono nucleated
- involuntary movement
- walls of major organs
what are muscle cells/muscle fibres called?
myocytes
nervous tissue is?
excitable
two main classes of cells making up nervous tissue are?
neurons and neuroglia
what are the parts of a neuron?r
cytoplasm, organelles, cell body, nucleus, dendrites, axon, myelin sheath, synapse
