lecture 4 Flashcards
progenitor
a common ancestral cell
four types of tissues in the body
muscle
epithelial
connective
nervous
histology
the scientific study of tissues
general function of epithelial tissues (4)
- cover a protect the body
- line hollow organs
- form glands
- specialized for exchange with the environment
general function of connective tissue (4)
- protects and supports the body and internal organs
- connects organs
- stores energy
- aids in immunity
muscular tissue (2)
- contract to general force
- generate body heat
nervous tissue (2)
- detects and responds to stimuli
- generates electrical signals to stimulate changes in muscle or glands
tight junctions (3, structure, function, location)
- transmembrane proteins on adjacent cells
- form leakproof connections
- found in stomach, intestine, urinary bladder
adherens junction (3, SFL)
- plaque connects transmembrane proteins to microfilaments and sinches together
- resists tearing
- found in areas that contract
desmosomes junction (3, SFL)
- similar to adherens but with INTERMEDIATE filaments rather than microfilaments
- prevents tearing of epidermis, and ripping of muscle cells during heartbeats
- can be found in heart, urinary bladder
hemidesmosomes (3, SFL)
- transmembrane glycoproteins connect intermediate filaments to proteins of the basement membrane (laminins)
- anchor cells to underlying tissue (basement membrane), resists abrasion
-can be found in the skin
basement membrane layers (2) and function (2)
basal lamina - top layer
reticular lamina - bottom layer
separates overlying epithelial tissue from underlying connective tissue
provides a surface for epitehlia to anchor and grow
gap junctions (3, SFL)
- protein channels (connexons, made by connexins) that connect membranes of adjacent cells
- assist in coordination of tissue function by permitting signal sharing
- found between nerves
epithelial tissue is classified by: (2)
number of layers
and
shape of the cells in the tissue
surface epithelium
epithelium that lines body surfaces
glandular epithelium
epithelium that makes up the glands
arrangement of layers in epithelial tissues (3)
- simple - one layer
- pseudostratified - one layer that looks like many
- stratified - multiple layers
cell shapes in epithelial tissues (3)
squamous - flat and tile like
cuboidal - cube shaped
- columnar - column shaped
transitional epithelium or urothelium
variable in shape depending on if stretched
looks squamous when stretched, cuboial when at rest
polerized cells meaning and example
cells that have ends or faces
epithelial cells
apical surface
top, faces the inside of an organ, vessel, duct, or external environment
basal surface
bottom, faces underlying tissue (usually connective tissue)
lateral surface
sides, faces adjacent cells
simple squamous epithelium (3, SFL)
- single layer, flat tile like cells
- good for filtration of body fluids and diffusion of nutrients and gases
- found in lining of blood vessels and epithelial lining of serous membranes
endothelium
simple squamous epithelium that lines the blood vessels
mesothelium
simple squamous epithelium that makes up the epithelial layer of serous membranes
simple cuboidal epithelium (3, SFL)
- single layer, cube shaped tissue
- secretion of hormones and other substances, absorption of water and other solutes
- found lining kidney tubules and the thyroid gland
non ciliated simple columnar epithelium (3, SFL)
- single layer, long cells, can be with goblet cells
- secretion of mucus and absorption of nutrients
- found in digestive tracts
ciliated simple columnar (3, SFL)
- single layer, long cells with cilia, can have goblet cells
- cilia beat at apical surface to move mucus, protection from invasion and fluid loss
- found in bronchioles and oviducts
non ciliated pseudostratified columnar epithelium (3, SFL)
- single layer, irregular nulcei depths, no cilia
- absorption of substances, secretion (eg saliva)
- line epididymis and part of male urethra
ciliated pseudostratified columnar epithelium (3, SFL)
- single layer, irregular nuclei depths, cilia
- sweep mucus over tissue surface, protection from invasion
- found in upper respiratory tract
stratified squamous epithelium (4, SFL)
- can be keratinized or non
- multiple layers, flat tile like cells
- protects from abrasion, fluid loss, UV, invasion, keratinized provides strength
- found in skin (keratinized), cheek (non)
stratified cuboidal epithelium (3, SFL)
- multiple layers, cube shaped cells
- protect ducts and tubes from abrasion
- lines seal and esophageal glands, male urethra
- rare
stratified columnar epithelium (3, SFL)
- multi layer, long cells
- protect from invasion, secretion (eg, tears)
- found in conjuctiva (tear ducts), esophageal glands
transitional / urothelium (3, SFL)
- rest, cuboidal / stretched, squamous
- prevent leakage, protect from abrasion, from high pressure fluids
- found in urinary bladder, ureters, urethra
exocrine glands (2)
secrete substances a short distance, like sweat glands
secrete products into ducts
endocrine glands
secrete substances that diffusion into the blood and are circulated to tissues
hormone
chemical messenger or signal
path of hormones form an endocrine gland (3)
secrete into interstitial fluid
diffuses into blood
circulates to target tissues
unicellular gland
glands comprise of a single cell (eg. goblet cell)
sudoriferous gland
sweat glands
sebaceous gland
oil glands
mulitcellular exocrine gland classification and what it tells you (3)
merocrine
apocrine
holocrine
tells you how the secretions are released
merocrine glands
type of exocrine gland
- most of the bodys glands
- prducts leave celle via exocytosis
apocrine sweat glands are: (1)
actually merocrine glands
apocrine glands
type of exocrine gland
- secrete products only from apical surface of cells via exocytosis (chunk pinched off)
(eg, mammary glands for breastmilk)
holocrine glands
type of exocrine glands
- collect products in cytosol
- mature cells rupture - releasing contents
(eg, sebaseous glands)
two components of connective tissue
ECM (extracellular matrix)
- protein fibres and ground substance
- can be liquid, solid, or gel like
cells
- sparsely distributed throughout matrix
what makes the ECM of connective tissue?
cells of the connective tissue make it. protein fibres and ground substance is secreted
mesenchymal cells
ancestral cells for all types of connective tissue proper
fibroblasts
most common, secrete ECM of loose and dense connective tissue
macrophages
phagocytic immune cells that reside in tissues
plasma cells
immune cells that secrete antibodies
mast cells
immune cells immobilized in tissues that secrete inflammatory chemicals
apidocytes
cells of adipose tissue that store triglycerides
leukocytes (WBCs)
can migrate to connective tissue during invasion
ECM of connective tissues facts (3)
- made of protein fibres and polysaccharides
- extensively hydrated
- secreted by the connective tissue cells
ground substance
medium in which the ECM is suspended
protein fibres in the ECM (3)
collagen fibres
elastic fibres
reticular fibres
collagen fibres (3)
- makes up 25% of all protein in the body
- great tensile strength and bundle arrangement
- helps tissues resist compression
collagen fibres (3)
- makes up 25% of all protein in the body
- great tensile strength and bundle arrangement
- helps tissues resist compression
elastic fibres (4)
- thinner than collagen
- made of elastin
- can stretch and return to resting length
- resists tearing and shear
reticular fibres (4)
- made of bundled collagen + glycoprotein
- thinnest of the fibres
- supports tissues
- forms part of basement membrane
main differences between epithelial and connective tissue (3)
the ratio of extracellular matrix to number of cells
- epithelium has little/no matrix and many cells
- connective has lots of matrix + fewer cells
vascularity
- epithelium - not vascularized
- connective - vascularized
location
- epithelium - typically most superficial layer
- connective - typically underlays epithelium
types of embryonic connective tissue
mesenchyme and mucoid
mesenchymal connective tissue (2)
- contains mesenchymal cells in gel ECM + reticular fibres
- becomes nearly all types of CT
(developing skeleton)
mucoid connective tissue (3)
- sparsely distributed fibroblasts in gel ECM + collagen fibres
- provides mechanical support to overlying tissue
(umbilical cord)
types of mature connective tissue (3 main, 6 sub)
connective tissue proper (mesenchyme)
- loose
- dense
supporting CT (mucoid)
- cartilage
- bone
liquid CT (mucoid)
- blood
- lymph
loose connective tissue (3) (group, structure, what it includes)
- is mature mesenchymal
- sparsely distributed cells and fibres
- includes areolar, adipose, and reticular CT
areolar CT (5)
- widely found in the body
- all three fibres + lots of cells in gel ECM
- supports, reinforces, and provides stretch to organs
- serves as packing material for body cavities
- resembles a spider web
- loose
adipose CT
- contains adipocytes that store triglycerides in a large central droplet (white adipose tissue)
- insulates body, stores energy, supports organs
- resembles cotton balls
- loose
reticular CT
-made of tightly woven fibres + fibroblasts
- filters substances such as lymph
- called “stroma” in lymph organs
- loose
dense CT (group, structure, what it includes)
- is mature mesenchymal
- packed with protein fibres but fewer cells than loose CT
- includes Dense regular, dense irregular, and elastic
dense regular CT
- dense
- packed collagen fibres + sparse fibroblasts
- looks shiny
- great tensile strength
- part of tendons, ligaments, aponeuroses
- looks tight and wavy
aponeuroses
muscle to muscle or bone to bone attachements
dense irregular CT
- dense
- irregular arrangement of collagen fibres + few fibroblasts
- resists pulling
- found in faciae (wrap muscles) and pericardium
- looks tight but not straight, sort of like elephant print
elastic CT
- dense
- made of elastic fibres + few fibroblasts
- provides elasticity to organs
- found in lung tissue, walls of arteries, trachea, bronchial tubes
supporting CT (2)
cartilage and bone
liquid CT (2)
blood and lymph
cartilage
- thick collagen fibres embedded in gel ground substance
- ECM contains hydrated proteoglycans
- strongly resists compression
- not vascularized - heal slow
chondrocytes
special fibroblasts that resides in lacunae in cartilage
types of cartilage
hyaline
fibrocartilage
elastic
hyaline cartilage
- most common
- overlaid by perichondrium
- provides smooth surface between joints
- comprises fetal skeleton before ossification
- looks like deer hooves
perichondrium
layer of new chondrocytes containing blood vessels in cartilage
ossification
bone formation
hardening into bone
fibrocartilage
- lacks perichondrium
- strongest type of cartilage
- found at public symphysis (anterior joining of hip bones), intervertebral discs, and menisci of knees
- looks like feathers
elastic cartilage
- overlaid by perichondrium
- provides strength and stretch
- forms auricle (external ear), eustachian tubes (ear-nasal tubes), epiglottis
bone tissue
- can be compact or spongy
- compact bone consists of repeated osteons
- osteons have rings of calcified ECM with lacunae and a central canal
blood
- liquid ECM called blood plasma + blood cells
- transports O2, nutrients, gases, waste, immune cells, hormones, and platelets
lymph
- liquid tissue
- components vary based on location
- less protein than blood plasma
- Lymph nodes - have lymphocytes
- small intestine - have dietary fats
anatomical membranes
NOT biological or plasma membranes!
- sheets of flexible tissue that cover a portion of the body
- usually epithelial layer + connective tissue
- include mucous, serous, and cutaneous membranes
synovial membranes
membranes that consist of only connective tissue (no epithelium) and line joints
lamina propria
connective layer of mucous membranes
mucous membranes (SFL)
- made of areolar CT
- line body cavities that are open to the external environment
- prevents fluid loss
- protects body from invaders
- secretes enzymes to help in digestion and absorption
-lines digestive, respiratory, reproductive, and urinary tract (part of)
serous membranes (SFL)
- made of areolar CT covered by mesothelium
- mesothelium secretes serous fluid
- found in abdominal cavity, lining of lungs and heart (all have specific names)
cutaneous membranes (SFL)
- includes the skin
- epidermis / dermis - covers the surface of the body
synovial membranes (SFL)
- made of layers of synoviocytes
- deep to these are layers of areolar and adipose CT
- secrete synovial fluid to lubricate joints and nourish tissues
- found between joints
excitable cells
detect electrical impulse and respond with action potentials
- may result in a nerve impulse
muscular tissue (SF)
made of muscle fibres (myocytes)
contract to move bones and generate heat
3 types of muscular tissue
skeletal
smooth
cardiac
skeletal muscle tissue (SFL)
- long, multinucleate, striated tissue
- produces voluntary movement, maintains posture, generate heat
- attaches to bones via tendons
cardiac muscle tissue (SFL)
- branched striated fibres with single nucleus
- cells conjoin by gap junctions for more rapid electrical signal
- controls involuntary movement
- forms myocardium (heart wall)
smooth muscle (SFL)
- long , non-striated fibres in an irregularly shaped cell with one nucleus
- thicker in the middle
- gap junctions to coordinate contractions faster
- found in small intestine (peristalsis), constricts airways, contract urinary bladder and gall bladder
nervous tissue types
neurons
neuroglia
neurons (SF)
- cell body, dendrites, axon
- generates electrical signals
neuroglia (SF)
- tiny little blue things around the neuron (in pic)
- synthesize myelin
myelin
coating of neuronal axons
increases electrical signal speed
