Tissues And Organs Flashcards
What holds cells together? (4)
- Cell to cell adhesion molecules
- Extracellular matrix proteins
- internal external scaffolding
- pressure caused by close proximity
What do epithelial cells line?
All cavities and free surface
Organ definition
More than 1 tissue coming together
What do epithelia rest on?
Supporting bed of connective tissue
Which attaches the epithelial layer to other tissue
What are the lateral surface adherence systems in epithelia? (3)
Tight junctions
Desmosome
Gap junctions
What are the basal surface adherence systems in epithelia? (5)
Hemi desmosome
Focal adhesions
Integrins
Role of tight junctions
Where are they found? (2)
Prevent movement of large molecules through lumen into deep tissue layers
Intestines
Blood brain barrier
What is paracellular transport?
When solvent move across an epithelial cell layer through the tight junctions between cells
Role of adhesion junctions
What are they made of?
How are they found?
Tissue stability and transport barrier - adhesion belt
Intracellular actin filaments
In pairs
What is the strongest method of adhesion?
Desmosome
What is the function of desmosome?
Where are they found?
Mechanical strength and prevent tissue destrucitons
Tissue that experiences mechanical stress - like the skin
Function of gap junctions
Where are they found?
Communicate changes in intercellular molecular composition - allows free movement of small molecules, allows waves of electrical impulses
Cardiac and smooth muscle cells
What attaches a hemidesomsome to the basal lamina?
Role?
Intergrin
Anchors epithelial cells to basal lamina and prevents loss to external surface
What is the basal lamina attached to?
Connective tissue
Function of basal surface focal adhesion?
What links cells to the basement membrane?
Anchor actin filaments to the basement membrane
Integrins
Name the three types of muscle cells
Skeletal
Cardiac
Smooth
What is the role of integrins?
Give an example of one
Hold tissue together, work as an alpha beta dimer
Skin
What are the two layers of the basement membrane?
Basal Lamina - clear and dense
Reticular - denser
What are the four types of tissue?
Connective tissue, epithelial tissue, muscle tissue, and nervous tissue
Define the mucosal membrane
The moist, inner lining of some organs and body cavities
Functions of the mucosal membrane
Lubricates
Keeps tissue moist
Stops pathogens and dirt entering the body
Two points about the mucosal membrane
Lines hollow internal organs
Continuous with the skin
What are the five layers of the GI tract?
Mucosa
Muscularis mucosae
Submucosa
Muscularis externa
Serosa
Describe the mucosa
Epithelial cell lining
Supports the mesenchymal layer
Describe the musularis
Thin discontinuous smooth muscle layer
Describe the submucosa
Connective tissue layer
Contains arteries and veins
Which layer in the GI tract contains arteries and veins?
Submucosa
Describe the muscularis externa
Smooth muscle layer that has muscle fibres in two different directions - inner circular and outer longitudinal
Which layer in the GI tract supports the mesenchymal layer?
Mucosa
Describe the serosa
Connective tissue layer
Has collagen, small arteries and veins
Explain three oesophageal structure function relationships
Epithelium - stratified squamous to withstand abrasion
Submucosa - contain mucus secreting glands
Muscularis externa - smooth muscle layer to return to original dimension (peristalsis)
Three functions of the mucosa in the GI tract
Absorb substances from lumen
Prevents ingress of pathogens
Move contents and expels waste
What helps the mucosa to move contents and expels waste
Muscularis externa performs peristalsis
What helps the mucosa absorb substances from lumen
Epithelial cell specialisations
Muscularis mucosae folds mucosa to increase surface area
What helps the mucosa prevent ingress of pathogens
Epithelial cell specialisations
Lamina propria contains lymphatic tissue to aid process
Muscularis mucosae folds mucosa to increase surface area
What are the two sections of the respiratory tract?
Conducting - nasal cavity to bronchioles
Respiratory - respiratory bronchioles to alveoli
How is the structure of the trachea and bronchi different?
Bronchi have a cartilage ring
Name two key feature of the structure of bronchi that relates to the function
Mucosa - covered in cilia
Submucosa + epithelium - secrete mucus, serum proteins to lubrixate, lysozyme to destroy bacteria
What does the bronchi not have?
Outer layer of smooth muscle
Three key properties of the alveolus connected to the function
Folds - allow for expansion
Collagen at the junctions provide to the mucosa - allow to recoil
