Integrating Cells Into Tissues , organs and systems Flashcards
What. Is the definition of an organ?
- two or more tissues that are combined to create a structural unit.
What are the three cells that remain separated from each Their?
1) ova
2) spermatozoa
3) blood corcupsles
How are cell types actually formed?
During early embryo development.
- three layers of an embryo are formed.
- outer layer ( ectoderm)
- middle layer ( mesoderm)
- inner layer ( endoderm)
What part of the. Embryo are epithelial cells formed from?
ALL parts - ectoderm, ( epidermis) mesoderm( inner linings of body cavities) endoderm ( inner and outer linings of GI tract).
What part of the embryo are nerve cells derived from?
- ectoderm
What part of the embryo are muscle and connective tissue formed from?
- mesoderm.
How do cells join together?
During embryogenesis.
- cells of the same type congregate together and produce cell surface proteins which anchor cells together.
- cells are woven by ic/ECF proteins to create tissue
- the presence of ecm includes connective tissue which connects to muscle cells
- these muscle cells then connect to nerve cells which then connect to blood vessels.
Name two fibres that are present in collagen
- collagen
2) elastin
3) recticular fibres
Name 3 cells that are found in connective tissue
1) fibroblasts
2) mesenchyma( stem cell) which interconverts between different cell types
3) adipocytes
Name 3 functions of connective tissue
1) protection
2) insulating
3) separation of tissue ( eg tendons)
What is the main ground substance in connective tissue ?
Aminoglycans such as. Hyaluroic acid.
What is the main role of epithelial tissues ?
Lines all cavities and free surfaces.
How Arne epithelial cells held together ?
Cell to cell adhesions
Name 4 lateral surface adhesion junctions
1) tight junctions ( top )
2) adhesion belt
3) desmosome
4) gap junctions
What is the role of tight junctions ?
Prevents the movement of larger substances and ions through the outer layer
What is the role of adhesion belt?
- joins actin bundle in one cell to one similar in another cell.
- only found in epithelial and endothelial cells
- found in pairs
- additional transport barrier
What is the role of desmosomes ?
- found in the middle
- provides mechanical strength
- prevents tissue disintegration .
What is the role of gap junctions?
- closest to basal surface
2) found mainly in cardiac and smooth muscle cells so they can quickly communicate changes in electrolyte balance / energy changes.
3) allows small molecules to pass through eg ions , sugars , amino acids
What is the mucosalmembrane ?
- lines all moist hollow organs
- continuous with the skin at various body openings
- secrete mucus ( mucins , lysosomes , immunoglobins , anti septic enzymes)
- prevents pathogens entering body
- prevents dehydration
Where is the mucosal membrane mainly found ?
- respiratory tract
- urinary tract
- GI tract
What are the 5 layers of mucosa in the GI tract?
1) muscles lines the lumen
2) muscularis mucosa which is thin smooth muscle layer that supports the mucosa
3 submucosa which is connective tissue that contains veins and capillaries
4) muscularis externa : smooth muscle layer : inner is circular and outer is longitudinal
5) serosa : connective tissue which contains collagen , elastin , smaller arteries and veins .
What is the function of mucosa in the GI tract specifically?
1) absorb substances from the lumen through specialisations such as microvilli, folds of the mucosa
2) prevent pathogen entry through peristaltic actions , the lamina propia which contains lymphatic tissue
3) move contents and expel waste - muscularis externa performs peristalsis
In the kidneys , what type of epithelial cells surround the walls of the bowman capsule ?
Simple squamous epithelial
In the kidneys , what type of epithelial cells surround the ducts ?
Simple cuboidal epithelial
Is there a muscle layer in the kidneys ?
no , it first appears in the bladder and ureter
What type of epithelium is found in the bladder ?
Transitional epithelium
What is the role of mucus in specific to the bladder ?
Protects the bladder from damage by acidic urine
What is the role of tight junctions in the bladder ?
They were well packed to prevent the leakage of urine to inner cells
What is one difference in terms of epithelial structure between the bladder and urethra?
1) in the urethra the epithelium changes from transitional to Stratified squamous.
What is the urinary tract summary ?
1) prevent entry of pathogens
2) absorption of nutrients in the kidney
3) removal of waste products
