Lecture 5 - Tissues, Organs And Systems Flashcards
Function of tight junction
The Asshole Did Good, TADG
- Located at very top
- Prevent large molecules entering tissues
- Allow small molecules (sugars, aa, H2O) to cross: Paracellular Transport
Function of Adhesion junction
- 2nd one, found in pairs
- Linked to E-cadherin, joins an actin bundle in one cell to a adjacent bundle in neighbouring cell
Function of desmosome
- Strongest of all
- Random distribution pattern
- Found in tissues w intense mechanical stress (cardiac muscle, bladder tissue)
- Provide mechanical strength
Function of Gap junctions
- For transmission of electrical signals/impulse
- Cardiac muscle & smooth muscle
Function of hemidesmosome (vertical attachment)
- Anchors intermediate filaments in cell to basal lamina
Type of epithelium in oesophagus? Function of submucosa?
- Stratified squamous non-keratinised
- Submucosa: connective tissue containing mucus-secreting glands
GI tract: What is the function of the mucosa?
- Specialised epithelial cells (microvilli, folding of mucosa) = absorb nutrients
- Lamina propia contains lymphatic tissue = Prevent invasion of pathogens
- Muscularis mucosa folds mucosa to increase SA = stability + absorb
- Muscularis externa = peristalsis
What is the difference in structure btw proximal and distal tubule
- Proximal has ciliated surface
One feature all adhesion properties require are
Presence of Ca2+ ions
Desc. the layers of mucosal membrane in GI tract
- Mucosa: Epithelium, lamina propria (connective tissue), muscularis mucosae (smooth muscle)
- Submucosa: Connective tissue that contains blood vessels
- Muscularis externa: Smooth muscle
- Serosa: Connective tissue (contain collagen)
Sequence: epithelium –> connective tissue –> muscle –> connective tissue –> muscle –> c.t
What is the epithelium in ureter known as? Type of epithelium?
- Transitional epithelium known as urothelium
Sequence= epithelium –> lamina propia –> muscularis mucosa
What are the special adaptations in the bladder?
- Fat cells act as shock absorber for expanding bladder
- Epithelial cells secrete mucus: protect against damage from acidic urine/prevent ingress of pathogens
- Tight junctions: prevent leakage into inner cell layer
Function of urinary tract?
- Absorption of nutrients in kidney
- Prevent ingress of pathogen
- Removal of waste products
Why is the right bronchus more likely to be lodged by foreign material?
- Right bronchus is more vertical than left
Desc. sequence of cells in trachea/bronchi
- Mucosa: Epithelium –> lamina propia (X muscle)
- Pseudostratified ciliated columnar epithelium
- Very thin lamina propia - Submucosa: contains collagen and elastin fibres, produce watery mucus that thickens during infection
- C-shaped hyaline cartilage
- 2 layers: perichondrium (lays down collagen fibres) & chondrogenic layer (cartilage formation)
- Cells can interconvert (chondroblasts –> chondrocytes), hyaline & elastic cartilage can be formed
*No outer smooth muscle layer
What are the type of secretions from epithelium and submucosal glands of trachea/bronchi? What is the special adaptation?
MALS
- Mucins and water: mucus
- Serum protein: lubricate surface
- Lysozyme: destroy bac.
- Anti-proteases: inactivate bac. enzymes
- Mucociliary escalator: mucus trap pathogen, cilia beating to back of throat to be swallowed/coughed
What is the features of mucociliary escalator?
- Thick basement membrane
- Lamina propia ⬆️immune cells & elastic fibres
What is the difference btw. primary and secondary bronchi in terms of structure? Desc. sequence of layers in 2
- Secondary no cartilage present as full rings
Epithelium (pseudostratified, ciliated) –> smooth muscle –> submucosa –> airway kept open by crescent cartilage
*Again, no layer of outer smooth muscle
Desc. structure of alveolus
- Flattened specialised epithelial cells –> endothelium
- Endothelium folds into the basal lamina for expansion of air sacs during inhalation
- Mucosa has collagen & many elastin fibres: for elastic recoil during exhalation
What separates alveoli from alveoli?
Basal lamina
What cell adhesion molecule attaches blastocyst to endometrium?
Integrin
What Color is the centre of an RBC when stained by H&E? Why?
- No blue (haematoxylin): RBC no nucleus
- Eosin binds to acidic structures, Hb is an acidophilus material (thrives under acidic conditions)
- Hb on outside of the ring —> only outside of ring is red
