Tissues Flashcards
What does epithelial tissue provide?
protective covering of surfaces inside and outside the body
Why is it helpful that blood vessels cannot penetrate epithelial tissue?
means that the cells can be sloughed off when they are dead
What is the outer layer of skin called?
epidermis
What does the function of epithelial tissue depend on?
the location and type of tissue
Name some functions of epithelial tissue?
protection, barrier, passage of substances, secretion, absorption
What are the two basic types of epithelial tissue?
simple and stratified
What are the 3 varieties of simple epithelial cells?
cuboidal, squamous, columnar
Where do stratified epithelial cells tend to be used?
where abrasion occurs
What are glands mainly formed of?
epithelium
Where do glands develop from?
the folding of the epithelium of the embryo
What do exocrine glands do?
secrete things
What are the 3 types of exocrine glands?
unicellular, simple and compound
What don’t endocrine glands have?
ducts
What are the 3 ways exocrine glands excrete their products?
merocrine, apocrine and holocrine
How do merocrine glands secrete their products?
exocytosis
How do apocrine glands secrete their products?
upper portion of the cell is shed
How do holocrine glands secrete their products?
the whole cell is lost/bursts
What are the 2 layers of epidermis?
dermis and epidermis
How is the epidermis nourished as it is avascular?
by the dermis through diffusion
Wht happens to the level of keretinisation as you move up the layers of the epidermis?
it increases
Give examples of highly keratinised cells
nails, claws, horns, hooves
What are the 3 shapes of simple epithelial tissue?
squamous, cuboidal, columnar
What is the function of single layer squamous cells?
diffusion, filtration, secretion, protection against friction
Give an example of where single layer squamous cells are used
lining of blood vessels and heart
What is the function of single layer cuboidal cells?
active transport and facilitated diffusion
give an example of where single layer cuboidal cells are used
kidney tubules and glands
what is the function of single layer columnar cells?
secretion and absorption
give an example of where single layer columnar cells are used
stomach, intestines
What are the 2 types of stratified epithelial tissue?
squamous - keratinised, squamous - non keratinised (cuboidal and columnar)
what is the function of stratified squamous cells?
protection from abrasion
give an example of where keratinised stratified squamous cells would be found
skin
give an example of where non-keratinised stratified squamous cells would be found
mouth, oesophegus, anus, vagina
What is pseudostratified epithelial tissue?
columnar cells with cilia at the surface
What is the function of pseudostratified epithelium?
secrete mucus and move mucus that contains foreign particles
give an example of where you might find pseudostratified epithelium?
lining of nasal cavities, sinus, trachea, bronchi, pharynx
What is transitional epithelium?
moves from cuboid to columnar, becomes squamous-like when stretched
What is the function of transitional epithelium?
allows for volume fluctuation, protection
Where would you find transitional epithelium?
the bladder
What are the 7 functions of connective tissue?
transporting, connecting tissues, supporting and moving, separating, protecting, enclosing, cushioning and insulating
Where does connective tissue arise from in the embryo?
mesenchyme - embryonic connective tissue
What is the correct name of the embryonic connective tissue?
mesenchyme (mesoderm and neural chrest)
What do these prefixes mean? chondro fibro osteo adipo
cartilage, fibrous, bone, fat
What do these suffixes mean?
blast
cyte
clast
germ/origin, cell, destroy
Describe the appearance of loose/areolar tissue
loose packing material, apears ‘lacey’
What is the function of loose/areolar tissue in the skin?
attaches skin to underlying tissues
What are the two types of dense connective tissue?
regular and irregular
What two subsections can regular and irregular dense connective tissue be divided into?
elastic and collagenous
What is dense regular elastic tissue used for?
ligaments of vertebra and vocal chords
Why does dense regular elastic tissue have its particular function?
it is able to stretch and recoil
What is dense regular collagenous tissue used for?
ligaments and tendons
Why does dense regular collagenous tissue have its particular function?
withstands pulling forces
What is dense irregular elastic tissue used for?
aorta
Why does dense irregular elastic tissue have its particular function?
stretch and recoil in many directions
What is dense irregular collagenous tissue used for?
dermis of skin
Why does dense irregular collagenous tissue have its particular function?
strength in many directions
What is reticular connective tissue found in?
lymph nodes
What is andipose connective tissue found in?
fat
What is the extracellular matrix like in andipose connective tissue?
there is very little extracellular matrix
What is andipose tissue used for?
packing, insulation and energy storage
What texture of connective tissue is bone?
hard
What are the two types of bone tissue?
cortical or compact (tough outer shell) and trebecular (woven or spongy)
What does trebecular bone tissue provide?
support without weight
What is cartilage made up of?
chondrocytes in lacune with a rigid matrix
What are the three types of cartilage?
hyaline, fibrocartilage, elastic
What is hyaline cartilage made up of and what does it do?
collagen fibres and proteoglycans
resists compressive forces
What is fibrocartilage made up of and where is it found?
more collagen than proteoglycans
intravertebral disks
What is elastic cartilage made up of and where is it found?
elastic fibres, collagen and proteoglycans
outer ear and epiglottis
What makes blood unusual as a connective tissue?
cell matrix is liquid
Where is blood and haematopoietic tissue found?
bone marrow in bone cavities
What are red marrow and yellow marrow made of and where are these located in the bone?
red: haematopoietic, ends of long bones
yellow: adipose, shafts of long bones
What do red and yellow marrow make?
red: red and white blood cells
yellow: replaces red as we grow
What type of connective tissue is muscle?
specialised
What are the 4 qualities of muscle?
contractibility, extensibility, elasticity and excitability
What are the three types of muscle?
skeletal, smooth and cardiac
Where is nervous tissue found?
the brain, spinal chord and nerves
What is a nerve cell called?
a neuron
When does inflammation occur?
when tissue is damaged or there is an immune response
How does inflammation present depending on cause of injury and type of tissue injured?
presents the same
Why does skin heal quickly?
because there is good blood supply
What does an immune response trigger the release of ?
inflammatory mediators
give 2 examples of inflammatory mediators
prostaglandin, histamine
What are the 3 key effects of inflammatory mediators?
dilation of blood vessels, pain receptor stimulation, increased blood vessel permeability
What does the dilation of blood cells do?
brings WBC and agents of tissue repair/infection fighting to the sight of the injury
What does increased blood vessel permeability allow?
WBC and clotting factors to reach the site
What is another effect of increasing the permeability of blood vessels aside from allowing cells to reach the site?
allows protein to leak out into tissues changing osmotic gradient between blood and tissue. This draws water along osmotic gradient into tissues causing them to swell
What is swelling of tissues due to increased water known as?
oedema
What can bruising also be known as?
contusion or haematoma
What causes bruising?
trauma results in capillaries bursting, releasing blood into tissues
What is the outwards appearence of bruising?
skin discolouration
How can bruises be treated?
cold therapy
What are the 4 basic stages of bone healing?
haematoma formation, callus formation, callus ossification, bone remodelling
What is a haematoma?
collection of blood outside blood vessels
Where does the callus form?
internally between ends of bones and externally as a collar around the break
What happens during callus ossification?
woven spongy bone replaces internal and external calluses
What happens during bone remodelling?
compact bone replaces woven bone and part of internal callus is removed. Restores medullary cavity
What do osteoclasts do?
break down dead bone
what do fibroblasts do?
produce collagen
what do chondroblasts do
cartilage precursor
What do osteoblasts do?
produce new bone
What is a healthy ligament made up of?
dense regular elastic/collegenous tissue
What happens during ligament injury?
load increases across the joint so more ligament fires are recruited and slack is removed until ligament tears
What happens in the acute phase of ligament injury?
blood collects, clot formation,platelets. Immune cells ingest and remove debris. proliferactive or regenerative phase. Immune cells release growth factors and cytokines to rebuild ligament tissue matrix
How does the tissue remodeling phase of ligament injury present?
initially appears as disorganised scar tissue with more blood vessels, fat cells, fibroblastic and inflammatory cells than normal ligament tissue
Describe normal ligament tissue
bimodal (large), callagen fibrils, cell matrix turnover is low, collagen alligned, collagen densely packed, high matrix to cell ratio, low cell density, mature collagen cross links, primarily collagen type 1, primarily small protoglycans, rare cell division
Describe scarred ligament tissue
smaller collagen fibrils, cell matrix turnover is high, collagen disorganised, flaws between fibres, lower matrix to cell ratio, higher cell density, immature collagen cross links, more collagen 3, larger protoglycans, more cell division
What are the 4 stages of wound healing?
inflammation, debridement, repair, maturation
Can more than one stage of wound healing happen at the same time?
yes
When does inflammation occur and what happens during that time?
immediatly after injury
clot forms
When does debridement occur and what happens during that time?
approximately 6 hours post trauma, part of the inflammation phase
WBC arrive
When does wound repair occur and what happens during that time?
3-5 days post trauma
granulation tissue forms, wound strength increases
When does maturation occur and what happens during that time?
approximately 3 weeks post injury
remodelling of scar which may take weeks or years to complete
What parts of the body heal quickest?
dermis and epidermis
What parts of the body heal slowest?
ligaments and tendons
Why do dermis and epidermis heal so much faster than ligaments and tendons?
are more vascular so receive necessary proteins/WBC quicker
When does contraction occur?
1 week after wounding
What do fibroblasts need to differentiate into in order for contraction to begin?
myofibroblasts
When does contraction peak in large wounds?
5-15 days
How long can contraction last?
several weeks
How much smaller can the wound become after contraction?
40-80% smaller
What are teratomas?
tumors deriving from more than one embryological germ cell layer
What are the most common germ cell layers for teratomas to derive from?
ectoderm and mesoderm
What is the most common type of ovarian germ cell tumor?
mature teratoma
What are teratomas most often in humans
congenital
Where are teratomas often found in animals?
ovaries of a variety of species
