Week 2 - Cells, Tissues, Organs Flashcards
What is Tissue
A group of cells that shares a common structure and features and are arranged in a patter
What are the types of tissue (4)
- Epithelial Tissue
- Connective Tissue
- Nervous Tissue (excitable tissue)
- Muscle Tissue (excitable tissue)
What is Epithelial tissue
sheets of cells which cover the exterior surfaces of the body, lines internal cavities and passageways and forms certain glands
What are the cell junctions (3) - in Epithelial tissue
- Tight Junction
- Gap Junction
- Anchoring Junction
Tight junction
Anchoring Junction
Gap Junction
What is a tight junction
- Prevents molecules from passing between cells
- Forms continuous seal around the cell
- stops viral infections
What are anchoring junctions (desmosomes)
- Acts like velcro
- Holds tissue together but doesn’t prevent the movement of molecules between them
- More flexible than tight
- Found in skin and heart since they have to move but have to hold together
What are gap junctions
- a intercellular passageway between cells which allows the movement of small molecules and ions
Simple Squamous
Stratified Squamous
Simple Cuboidal
Stratified Cuboidal
Simple Columnar
Stratified Columnar epithelium
Pseudostratified Columnar
Function of simple squamous
- Commonly involved in diffusion, osmosis, filtration, absorption or transport of materials
- allows for fast gas exchange (less distance for diffusion)
Example of simple squamous
alveoli of lungs
Function of stratified squamous epithelium
Protects against abrasion
- can secrete mucus to lubricate
- easily replaced
Example of stratified squamous
Skin, mouth, esophagus
Function of simple cuboidal
These epithelia are active in the secretion and absorptions of molecules.
Example of simple cuboidal
Simple cuboidal epithelia are observed in the lining of the kidney tubules and in the ducts of glands.
Function of stratified cuboidal
Protective tissue, excretion, secretion
Example of stratified cuboidal
sweat glands, salivary glands, mammary glands
Function of simple columnar
- this epithelium is active in the absorption and secretion of molecules
- Provides an impermeable barrier against any bacteria that could be ingested but is permeable to any necessary ions
- very good at absorbing nutrients due to microvilli
- Can specialize in secreting mucus that coats and protects the surrounding surface from damage
Example of simple columnar
digestive tract and parts of the female reproductive tract.
Function of stratified columnar
Secretes and protects
Example of stratified columnar
urethra (male and female) and the duct of some glands
Function of pseudostratified columnar
secrete mucus
Example of pseudostratified columnar
Exclusively to the respiratory system.
bronchi, trachea and much of the upper respiratory tract where some of these cells have cilia.
What is transitional epithelium
Epithelium which changes its shape
Appears thicker and more multi-layered when bladder is empty, and more stretched out and less stratified when bladder is full and distended
Where would you find transitional epithelium
Only found in urinary system/Bladder - expands when full and shrinks when empty
What are the types of glands
- Endocrine glands
- Exocrine glands
What are examples of endocrine glands
Pituitary, thyroid and adrenal glands (adrenalin)
- normally releases hormones
What are examples of exocrine glands
sweat (eccrine, apocrine), salivary (parotid papilla, submandibular duct, sublingal gland)
What is connective tissue
Tissue which binds and holds tissue and organs together
The function of connective tissue
- support and protect
- connect other tissues
- transport
What are the components of the tissue matrix (3)
- cells
- gels (ground substances)
- fibers
What are the types of fibers in connective tissue
Collagen fibres
Elastic fibres
Reticular fibres
Function of collagen fibres in tissue
provides structure and strength
Function of elastic fibres
Can bound back and provides elasticity and flexibility
What are the broad categories of connective tissue
- Connective tissue proper
- Supportive connective tissue
- Fluid connective tissue
What is connective tissue proper and subclasses
- tissue which anchors, holds and binds organs in the body
- Loose connective tissue (loosely arranged)
- Dense connective tissue (densely packed)
What is supportive connective tissue and subclasses
- supports the structure of your body
- cartilage
- bone
What is fluid connective tissue
- blood
- lymph
What are the excitable tissue (2)
- Nervous tissue
- Muscle tissue
what are excitable tissues
Tissues which conduct electrical impulses to generate action potentials.
What are Microvilli
- Small fingerlike projections found in the small intestine
- They increase the cell surface for easier and faster nutrient absorption
What are Cilia
- Hair like extensions of the plasma membrane into the extracellular fluid
- found on pseudostratified columnar epithelium and simple columnar epithelium
- There is motile and non-motile cilia
Cilia are microscopic extensions of the apical cell membrane that are supported by microtubules.
They often beat in unison and move fluids as well as trapped particles.
The ciliated epithelium of your airway forms a mucociliary escalator that sweeps particles of dust and pathogens trapped in the secreted mucous toward the throat. It is called an escalator because it continuously pushes mucous with trapped particles upward.
What are motile cilia
- they beat in a coordinated, whip-like manner to sweeps particles of dust and pathogens trapped in the secreted mucous toward the throat
