2.3 Tissues Flashcards
what are the 4 types of tissues
epithelial, connecive, nerve and muscle
what are the characteristics of Epithelial Tissue
- Polarity
- Apilcal surfaces: can have microvilli or villia
- basement membrane: involved in anchoring epithelial later, acts as selective filter
- contains basal lamina: mostly glycoproteins and collagen secreted by epithelial cells
- reticular lamina: fine network of collagen and fibronectin fibers secreted by the underlying ECM
- Special contacts
- tight junctions and desmosomes
- Supported by connective itssue
- all epithelial sheets rest on supporting connective itssue
- provides nutrients, site for waste prod exchance
- all epithelial sheets rest on supporting connective itssue
- aascular but innervated
- contains no blood vessels but supplied by nerve fibers
- Regenerative
- Rapidly replaces lost cells by cell division
what are the different types of Epithelial Tissues?
- Simple vs Stratefied
- simple: typical where abs and filtration occur (lining of lungs)
- only one layer
- Stratified: common highly abrasive areas (skin, esophagus)
- want highly regenerative layer thats always adding more layers to skin
- simple: typical where abs and filtration occur (lining of lungs)
- Squamous, cuboidal or columnar
- squamous: cells and nucleus are flattened (ex skin, blood vessels)
- cuboidal: round nucleus (ex kidney tubules)
- Columnar: upright elongated nucelus (ex intestines)
what type of tissue is this
simple cuboidal epethelial
- nuceli relatively round and only one layer
what type of tissue is this
simple columnar epethelial tissue
what is the role of simple columnar epethelial tissue, where are they found
- function absorption, secretion of musuc, enzymes and toher substances
- can be cilliated or non cilliated
non cilliated type: lines most of digestive tract, gallbladder and excretory ducts, some glands
cilliated: line small bronchi, uterine tubes, some regions of uterus
* can contain goblet cells of mucus
where cna you find simple cuboidal epithelia tissue?
can find in kidney tubules. duct and secretory protions of small glands, overay surface
*function is for secretion and absorption
what mofoications are made to the epithelia of the digestive tract?
* talking about simple columnar
- have two modifications:
1. dense microvilli: on paical surface of absorptive cells
2. goblet cells: that secrete a protective lubricating mucus
what are pseudostratified columnar?
- cells vary in hieght, but all cells rest on basement membrane however some do not reach the free surface
*simple in nature but look multilayered, not actually stratified
- because nuclei are seen at different layers it gives the false pseudo impression that there are several layers
Noncilliated type: in males sperm carying ducts and ducts of large glands
ciliated: lines trachea, most of upper respiratory tract
describe stratified squamous epithelia
- thick membrane composed of several cell layers
- basal cells are suboidal or columnar and metabolically active, surface cells are flattened (squamous)
- function: underlying tissues in areas subjected to abrasion
Nonkeratinized type forms the moist linings of the esophagus, mounth, vagina
keratinized: forms epidermid of skin, dry membrane
describe stratified cuboidal
- cuboidally shaped cells arranged in multiple layers
- protect areas as ducts of sweat glands, male urethra and mammary glands
- typically two cell layers thick, quite rare in body
*look to see the two layers, thats how you know its not the simple cuboidal like those in kidney
describe stratified columnar
- also occurs at transition areas between two other types of epithelia
- some exocrine glands have areas of stratified columnar epithelium
*also in anoractal junction, pharynx and male urethra
- nuceli elongated and overall rectangular in shape
- as hint look for cillia, if see cillia its pseudostratefied
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describe transitional epithelia
Appearance of cuboidal and squamus, Depends on strucutre of tissue at that time
When bladder is empty looks cuboidal when full looks squamous
Found in lining of ureter, bladder
*basal cells cuboidal or columnar, suface cells dome shaped or squamours like depending on degree of stretch
*lines uteters bladder and part of urethra
** if has more than two layers it cant be stratefied cuboidal, so if more than two alyers and look cuboidal its transitional
describe the cutaneous membrane
Cutaneous - Parts you can see visually
Dry mem bc exposed to outside of the body (skin)
Combo of stratified squamous and underlying connective tissue
describe the mucous epithelial membrane
- mucosae line body cavities that open to the exterior
- mucous membranes are often adapted for absorption and secretion
- digestive and respiratory tracts secrete copious amounts of lubricating mucus
- urinary tract does not have any secretion but mucus membrane is bathed in urine
describe epithelial serous membranes
- composed of a secretory epithelial layer (serous fluid) and a connective tissue layer underneath
- Lines internal body cavities (abdominal and thoracic)
*Associated with simple squamous
Makes serious fluid, provides lubrication for the organs inside of the civity
*visceral means surounding organ itself, parietal means it surrounds the cavity it is in
describe glandular epithelia
- gland = one or more cells that makes and secretes particular product
- two key ways to classify this gland:
1. Site of product release (endocrine or exocrine)
2. Number of cells forming the gland: unicellular or multicellular (most are multi)
*some unicellular glands are along digestive tract mucosa and in brain (diffuse endocrine system)
-secretions include aa, proteins, glycopeprides, steroids
*ductless glands secret directly into blood stream or extracellular space
exocrine glands
- more numerous than endocrine
- secrete products onto body surfaces (skin) or into body cavities
- ex: mucous, sweat, oil and salivary glands, the liver (secretes bile) nd pancrease (secretes digestive enzymes)
what is goblet cells an example of
unicellular exocrine glands
- Found in simple columnar and simple cuboidal layers
found in epithelial linings of intestine and resp tract amid columnar cells
- These cells have a lot of golgi and ER, produce a ton of mucin which forms muscus in water
*mucin is secreted into lumen
what are the two features of multicellualr exocrine glands?
- epithelium derives duct
- secretory unit (acinus) consisting of secretory cells
- most have supportive connective tissue surrounding the secretory unit, blood vessels and nerve fibers
- components form a fibrous capsule
how can you classify Multicellular exocrine glands?
- Duct structure: simple (unbranched) or compound (branched)
- secretory unit structure: tubular (tubes), alveolar (flask like) or tubuloalveolar
what are the modes of secretion
Merocrine: products are secreted by exocytosis (pancrease, sweat, salivary)
*vesicels produced in cells, fuse w/ membrane and then out to lumen
Holocrine: products are secreted by the rupture of gland cells (proliferation at bottom, produces new cells and oil cells move up
ex: Sebaceous oil glands of skin (only real example)
what is connective tissue? what are the main classes?
- Found throughout the body; most abundant and widely dsitributed in primary tissues
- amount in each tissue varies (skin is primarily connective, brain has very little)
Main classes: connective tissue proper, cartilage, bone, blood
what is the structure of proteoglycans in the Ground Substance?
- proteoglycans = group of glycotroteins that consist of glycosaminoglycans (GAGs)
- control ECM volume: net (-) change attracts H2O directly and indirectly attracts cations 9esp Na+)
- Hyalauronic acid acts as a core strucutre for aggretion of proteoglycans
*depending on the combo of GAG attached to link protein, will give rise to different kinda of proteoglycan structure
Cell types of connective tissue
* connective tissue has both undifferentiated cells with suffix blast and matuer cells with suffic cyte
Primary blast cells
- Fibroblasts: connective tissue proper
- Chrondroblasts: cartilage
- Osteoblasts: bone
- Hematopoietic stem cells: blood
Other types of cells include: cells, WBC, plasma cells, macrophages and mast cells
describe areolar connective tissue proper
- type of loose connective tissue
- most widlet distributed in body
- serves as a universal packing material (wraps and sushions organs, macrophages phagocytise bacteria)
- high content of hyaluronic acid makes the ground substance quite viscous
- Reservoir of water and salts (nearly as much fluid as in entire bloodstream)
adipose (fat) connective tissue
- type of loose connective tissue
- adipocytes account for 90% of tissue’s mass (not a lot of connective tissue actually assocaited, mainly flat globules)
- triglyceride oil droplets occupy most of a fats cell’s volume and displaces the nucleus to one side
- the matrix is scanty and cells packed closely together
- brown at asipose cells contain adundant mitochondria, which use the lipid fuels to heat the bloodstream to warm
describe reticular connective tissue
- a loose connective tissue
- the ONLY fibers in the matrix of reticular connective tissue and reticular fibers (no collegen or elastic)
- forms a delicate network along which fibroblasts called reticular cells lie scattered
*network of fibers can support free blood cells in lymph nodes, spleen and bone marrow
describe dense regular connective tissue proper
- poorly vascularized and closely packed bundles of collagen fibers running in parallel to direction of pull *only resists in one direction
- provides great resistance to tension (pulling forces)
- ligaments contain more elastic fibers than tendons and are slightly more stretchy
- it also forms fascia (fibroud membrane that wraps around muscles, blood vessels and nerves) *plasic wrap esc
- can be referred to as elastic connective tissue
describe dense irregular connective tissue proper
- similar elements as regular variety
- Bundles of collagen fibers are much thicker and are arranged irregularly
- found where tension is exerted from many different dierctions (ex leathery dermis)
- forms fibrous joint capsules and fibrous coverings that surround some organs (kidneys, bones, cartilages, muscles and nerves)
what are the types of cartilage
hyaline cartilage: connection of ribs to sternum (costal cartilage), articular cartilage (coverings of longbones), trachea, larnyx, in nose
elastic cartilage: two primary sites - external ear and epiglotis
fibrocartilage: very dense and can resist pressure - bones of legs (meniscus), public symphysis, intervertebral disk
describe hyaline cartilage
- provides firm support with some pliability for the nose, connects the ribs to the sternum, and supports most of the respiratory system
- The embryonic skeleton is formed of hyaline cartilage
- Skeletal hyaline cartilage persists during childhood as epiphyseal plates (allow bones to keep growing)
- it covers ends of long bones as articular cartilage providing springy pads that absorb compression at joints
- chondroblasts product the matrix and when mature (chondrocytes) lie in lacunae (easy way to identify this tisssue)
describe elastic cartilage
- nearly identical to hyaline cartilage except there is more elastin fibers
- found where strength and exceptional stretch ability needed
- part of external ear and epiglottis
*Perichondrium is not cartilage but its connective tissue surrounding it (highly vascular to support avascular cartilage)
describe fibrocartilage
- intermediate between hyaline cartilage and dense regular connective tissues
*has a lot of collagen
- rows of chondrycytes alternate with rows of thick collagen fibers
- compressible and resists tension and is found where strong support and ability to withstand heavy pressue
- found in: inervertebral discs, pubic symphysis and spongy cartilages of knee (menisci)
**look for lacuna in slide
describe blood tissue
- classified as connective tissue because it developes from mesenchyme
- RBC and WBC (neutrophils, lymphocytes, monocytes, eosinophils, basophils
- Fibers are soluble protein molecules that precipitate, forming large visible fiberlike structures duing blood clotting
describe nervous tissue
- main component of the nervous system
- two major cell types
neurons: generate and conduct nerve impulses and typically they are branching cells with cytoplasmic extensions or processes
supporting cells: nonconducting cells that support, insulate and protect
Skeletal muscle tissue
- long, cylindical, multinucleate cells: obvious striations
functoin: voluntary movment, locomotion, maniputation of env, facial expression, voluntary contral - location: attaches to bones or ocasionally skin
describe cardiac muscle tissue
- branching, striated, generally uninucleate cells that interdigitate at specialzed junctions
*as it contracts it propels blood into circulation
ON SLIDE:
More white space -Filled with adipose tissue to provide energy to cardiac cells
Fibers have striations may think skeletal BUT look at darker stained lined going through it (up and down)
Intercalating disks
Cells also only have one nucleus
describe step 1 of tissue repair
- inflammation
- clotting occurs - surface dried and scab is formed
- severed blood vesseles bleed and inflammatory chem are released
- local blood vessels become more permeable allowing WBC, fluid, clotting factors and other plasma proteins to seep into injured areas
describe step 3 os tissue repair
- permanet repair
- regeneration and fibrosis effect permanent repair
- the fibrosed area matures and contracts: the epithelium thickens
- fully regenreated epithelium with underlying area of scar tissue results
Conrtaction can bring together the tissue areas to remove excess fluid
