Final Exam 2 Flashcards
Tight junctions
Outer layers of the plasma membranes between two cells are fused
Creates a fluid tight seal
Prevent penetration and leakages
Important for the urinary bladder
Desmosomes
Anchoring junctions
Made of interlocking filaments
Filaments penetrate from the plaque into the cytoplasm to stabilize the bond
Important for areas with lots of stretching
Skin heart and uterus
Gap junctions
Communicating junctions
Fluid filled tunnels between the cells
Connexons: tubular channel proteins link adjoining cells
Allows rapid exchange of nutrients and ion change signals
Microvilli
Finger like projections
Non-motile
Bush border of the cell
Increases surface area for better absorption and secretion
Cilia
Thousands of hairlike structures
Motile: in a wave like motion
Helps move mucus and debris out of things like the trachea
Simple squamous epithelia
Single layer of cells
Scale like with irregular outlines
Thin
Reduces friction, filtration and nutrient exchange
Air sacs of lungs, lining blood vessels and heart, pleura/peritoneal/pericardial lining
Simple cuboidal epithelia
Single layer, cube shaped cells
Lining, secretion, absorption
No protection from abrasion
ovary, kidney tubules, pancreas
Simple columnar epithelia non ciliated
No cilia but has microvilli
Absorption, secretion and protection with goblet cells
Gastrointestinal tract
Simple columnar ciliated epithelia
Moves fluids or particles along passage ways by ciliary action
Uterine tubes, paranasal sinuses, spinal cord canal
Stratified squamous epithelia
Skin
Cuboidal/columnar at the basal layer
As the cells die and move up they become keratinized and squamous
Protection
Stratified cuboidal epithelia
Protection
Ducts of sweat glands, mammary glands, salivary glands
Stratified columnar epithelia
Protection and secretion from goblet cells
Rare: parts of urethra, pharynx
Pseudostratified columnar epithelia
All cells are attached to the basal layer but other some reach the surface
The nuclei are found at different levels and give the appearance of being stratified (actually simple)
Can be plain or ciliated
Often contain goblet cells
Upper respiratory tract or glandular ducts
Protection, secretion, movement of mucus by ciliary action
Transitional epithelia
Good in areas with lots of stretching like the urinary bladder
Start off as stratified and cuboidal/columnar and as they stretch they become squamous and simple
Permits distension without leakage
Holocrine secretion
Gland fills with secretory material and discharges entire cell contents
Completely destroys the cell
Merocrine secretion
Gland has vesicles which pass secretory material through the cell membrane without any significant loss of cytoplasm
Apocrine secretion
Secretory material gets pushed to the apex of the cell and the apex explodes releasing the secretion
Only some cytoplasm is lost
Steps of inflammation
1: very short lived vasoconstriction
2: histamine and heparin are released from mast cells and causes vasodilation this causes redness and swelling and brings nutrients to the area
3: fluid enters the area and furthers swelling and irritates the nerve
4: a clot forms and a net of fibrin forms to trap bacteria and isolate the site, if it is on the skin it is called a scab which protects and covers the wound
5: macrophages and neutrophils enter the area and clear debris and bacteria and these quickly die to form pus
6: histamine and heparin levels drop and the swelling and redness settles down
First intention wound healing
Wound edges are close in apposition and results in minimal scarring
Second intention wound healing
Wound edges separated and granulation tissue forms over the gap and a moderate scar forms
Third intention wound healing
Large extensive wound gap with severe scarring and delayed healing
Osteoblasts
Form bone
Adds Minerals to ossify
Metabolically active
Osteocytes
Osteoblasts that have been trapped in lacunae of ossified matrix
Can convert to osteoblasts when needed (injury)
Less metabolically active than osteoblasts
Osteoclasts
Cells that eat away or remove bone
Important for remodelling and growth
Allows body to withdraw calcium from bone