Lab 1 Flashcards
What are the four primary tissue types?
epithelial: covers body surfaces, lines hollow organs, ventral cavities and ducts and form glands
connective: protects and support body and organs, bind organs together and store energy, provides immunity
muscle: movement and generating force
nervous: carries info
quickly from one side to the other
What are the two types of epithelia?
covering and lining epithelia
- outer layer of skin
- inner surface of digestive and respiratory cavities
- inner surface of heart and blood vessel
- walls and organs of closed ventral body cavities
- ducts of exocrine glands
glandular epithelia
- most glands in the body
What is the main characteristics of epithelia?
made of many cells close to each other (very little ECM)
have special types of junctional specializations
all have one free surface: apical (except endocrine glands) exposed to the lumen [body cavity/space], duct, tube or vessel
rests on a basal surface (basement membrane)
not vascularized = no blood vessels within epithelial layer
frequent divisions since exposed to wear and tear, injury needing replacement
What are the functions?
covering epithelia:
- protect underlying tissues from physical damage
- allow and regulate passage of materials
- specialized epithelia form sensory parts of organs like eye, taste buds, ear , mouth
glandular epithelia
- classified as endocrine (hormones secreted directly into blood) or exocrine (release products onto free surface or open cavities)
Classification of covering and lining epithelia?
- number of cell layers
one layer: simple
several: stratified
-shape of cells
flat: squamous
square: cuboidal
rectangular: columnar
if changes shape: transitional epithelium
-specialization of cell surfaces
microvilli
cilia
on microscope:
nuclei is flat and parallel = squamous
nuclei oval and parallel to axis on cell = columnar
nuclei is round and in the centre of cell = cuboidal
What are 2 subtypes of epithelia?
simple
one layer
found in areas of minim wear and tear
main function: allow passage of substances between the lumen and tissues
stratified
many layers
thick
main function: to protect tissues they cover
What is simple squamous?
one layer, flat cells
alveoli of lungs, glomeruli of kidneys and lining of heart, blood vessels and lymphatic vessels and ventral body cavities
thinnest = well adapted for diffusion, filtration and secretion
What is simple cuboidal epithelium for?
one layer of cuboidal cells (round centred nucleus)
found in small glands, kidney tubules and ovary surface
for secretion, absorption
What is simple columnar epithelium for?
one layer of columnar cells with oval nucleus
can be ciliated (contain microvilli on apical surface of cells to increase surface area)=have cilia on apical surface, found in small bronchi, uterine tubes and part of the uterus, involved in secretion of mucus and other substances to move mucus or female reproductive cells) or non ciliated = mainly lining digestive tract
What is simple pseudo stratified epithelium for?
one layer of many cells, rests on basal membrane
appears stratified
can be (non) ciliated (both)
ciliated= in trachea, primary bronchi, most upper respiratory tract and secretion and propulsion of mucus
non ciliated = lining of male urethra and ducts of large glands
What is stratified squamous for?
several layers of squamous cells
thickest of all
function: protection
may or may not have keratin, touch protective protein that prevents water loss = resistant to friction and repels bacteria
keratinized: forms epidermis of skin
non-keratinized: lines wet surfaces like lining of mouth, esophagus, tongue, epiglotis, vagina
What is stratified cuboidal epithelium for?
several layers of cuboidal cellsfound: largest ducts of sweat glands, mammary glands, salivary glands and male urethra
protection!!
What is stratified columnar epithelium for?
several layers of columnar cells
very rare: lines urethra, large ducts and some parts of the eye
protection and secretion!
Stratified transitional epithelium?
several layers
lines surfaces of organs subject to stretch, like bladder, ureters, parts of urethra
allows distension of urinary organs
What is the main difference between endocrine glands and exocrine glands?
endocrine: secrete hormones, circulate through the body to target areas, act as chemical messengers
most are epithelial derivatives: by invagination from an epithelial sheet and initially have ducts connecting them to free surface of the epithelial sheet
exocrine: release products into free surface or open cavities like digestive, respiratory, reproductive, products are NOT released into blood
What is the most abundant primary tissues?
connective tissue
What is a main characteristic of CT?
abundant cells in ECM, embedded in ground substances
What is the function of CT?
binding, support and packaging: form capsules around organs and form ligaments, tendons to which bone binds to each other or muscles, form 3D mesh fibres to support cells in large organs like liver and spleen
bone and cartilage support body organs
protection, defense and repair: great regenerative ability important for injury
scar tissue is formed of connective tissue which fill space of original tissue that does not regenerate
defense mechanisms: inflammation
skull is chamber that protects the brain
insulation: fat cells or adipose tissues cushions and insulates and provide energy as fuel
transportation: blood is CT and carries and delivers oxygen and nutrients to tissues
What is the main four classification of CT?
blood, bone, cartilage and CT proper
What are the three critera of division?
- secrete matric or maintain it
blast: undifferentiated cell type: division and secretes matric
cyst: once matrix is produced: capacity for cell division lost and become mature cells, less active, maintain matric in healthy state
fibroblast: primary blast cells of CT proper
hemocytoblasts: primary blast cells of blood
chrondroblasts and osteoblasts: primary blast cells of cartilage and bone
accessory cells supported by CT
fat storing cells - energy reserve fuel
WBC, mast cells, macrophages, antibody producing plasma cells: mobile and migrate CT matrix into bloodstream, involved in body defence and elimination of dead or dying cells
- fibres: provide strength ( 3 types)
- collagen: white fibers, extremely tough, stronger than steel, high tensile strength, resist longitudinal stress
- elastic fibres: yellow fibres, stretched 1.5 times their length, recoil to initial length, greater elasticity needed in lungs and blood vessels
- reticular fibers: fine collagenous, delicate branching network support soft organs like liver and spleen - ground substance or ECM: amorphous susbtance that fills space between cells and contains fibres, composed of interstitial fluid, cell adhesion proteins (allow CT to attach themselves to matrix) and proteoglycans (proteins attached to polysaccharides = can trap more or less water depending on nature and form substance that can be fluid or semi stiff hydrated gel) = determine the properties of matrix
eg. more polysaccharide = stiffer ground substance
ground substance supports cells and binds them together an funtion as a medium which nutrients and other things diffuse between capillaries and cells
What is the extracellular matrix composed of?
fibers and ground substance
Differentiate between the different tissues. (4)
epithelial: one or more layers, covers, protect, lines and moves, glandular activity
connective: sparsely arranged surrounded by a lot of ECM, supports body structures and transport
Muscle: long fibre like cells, can be branched and produces body movement
nervous: mix of many types of cells including neurons, communication
What are muscle tissues?
specialized cells for force generation and contraction, cells are elongated and can change shape to become shorter or thicker
contracting: muscle cells pull at attached ends and cause body parts to move
What is common to all muscle tissues?
made of many cells close together (little ECM)
well vascularized
elongated
contain myofilaments (contractile proteins)
What are the three kinds of muscle tissue?
skeletal: long, rod like, striated, multinucleated, some skeletal muscles attach and cover the bony skeleton other attach to the skin like facial muscles
generate heat when they contract so maintain constant body temperature
Cardiac muscle: intercalated disks only in cardiac=anchor desmosomes and gap junctions, long cylindrical, striated, shorter than skeletal
elongated, branched and striated, one nucleus sometimes two, found in heart only
contraction: squeezes blood out of heart and propels into blood vessels
Smooth muscle: spindle shaped, one nucleus, not striated
found in walls of hollow organs and generally propel substances through these organs by alternating contraction and relaxation
What are the functions of the nervous system?
constantly monitors changes inside and outside body
processes and interprets information, makes decisions about what should be done
carries order of what should be done to muscles and glands
What are histological characteristics of nervous tissue?
made of many packed closely cells (little ECM)
most cells are strongly branched
What are the two main groups of cells?
neurons: respond to stimuli, conduct electrical impulse to and from all body organs within CNS, have a cell body (with nuclei and organelles), dendrites that receive stimuli and axon that generate impulses and transmit from one part to another
glial cells: support, protect and bind neuron
Where do we find nervous tissue?
the brain, spinal cord, nerves and associated ganglia
