Histology Flashcards
What is the inner cytosol?
Solution of proteins, electrolytes and carbohydrates
What is a cytoskeleton made of?
Thin, intermediate filaments and microtubules
Role of the plasmalemma?
Separates plasma from outside environment
Describe the arrangement of the phospholipid bilayer/plasmalemma?
Hydrophilic heads at outer and inner surfaces and hydrophobic tails at centre surrounding protein structure
What is the plasmalemma made up of?
Integral proteins
Embedded cholesterol
Phospholipid bilayer
What can the plasmalemma do?
Exocytose and endocytose material
The plasmalemma is impermeable. True or False?
FALSE
Selectively permeable
Organelles in he cytoplasm?
Mitochondria RER SER Golgi apparatus Lysosomes Nucleus
Role of mitochondria?
Generate ATP
Synthesis of certain lipids and proteins
Role of RER?
Protein synthesis
Role of SER?
Cholesterol and lipid synthesis/ detoxification
Role of golgi apparatus?
Modification and packaging of secretions
Role of lysozomes?
Hydrolytic enzymes of intracellular digestion
Role of nucleus?
Contains genetic code
Width and substance of microfilaments?
7nm
Actin
Width and substance of intermediate filaments?
> 10nm
Composed of proteins
Width and substance of microtubules?
25nm
Composed of tubulin
Where do microtubules originate from?
Centrosome
Which substances attach to microtubules and move along?
Dynein and kinesin
What is on the outer nuclear membrane?
Ribosomes
What is the site of RNA synthesis?
Nucleus= mRNA, tRNA and rRNA
Where is rRNA synthesized?
Nucleolus
Where are ribosomes formed?
In the nucleus
What is the role of ribosomes and its make up for this?
Small subunit which binds RNA and large subunit which catalyses formation of peptide bonds
What happens in RER?
Protein synthesis
Initiation of glycoprotein formation
What happens in SER?
Continues processing of proteins from RER
Site of lipid synthesis
What consists of the Golgi apparatus?
Composed of a group of flattened membrane bound cisternae
What happens in the golgi apparatus?
Transport vesicles arrive at golgi from SER
Modifies & packages macromolecules from SER
What is the membrane in mitochondria folded to form?
Cristae
Types of intracellular junctions?
Occluding/Tight junctions
Anchoring junctions (desmosomes/hemidesmosomes/adherant)
Communicating/Gap junctions
What is role of occluding junctions and their other name?
Tight junctions
- Link cells to form diffusion barrier
- Prevent diffusion
Role of anchoring junctions?
Provide mechanical strength
Adherent junctions role?
Link submembrane actin bundles of adjacent cells
Role of desomsomes?
Link submembrane intermediate filaments of adjacent cells
Hemidesmosomes?
Link submembrane intermediate filaments of cells to extracellular matrix through transmembrane proteins
Role of communicating junctions and their other name?
Allow movement of molecules between cells
Gap junctions
Where are Gap junctions found?
Epithelium, but also in smooth muscle and cardiac muscle
Structure of Communicating junction?
Circular patch studded with pores (produced by connexion proteins)
Process of endocytosis?
Membrane invaginates, fuses and a newly made endocytotic vesicle buds into cell
How is endocytosis mediated?
Receptors
Process of phagocytosis?
Bacteria binds to cell surface
Cell engulfs it to form phagosome
Binds with lysozome containing digestive enzymes
Common stain?
H&E
What is H&E?
Haematoxylin- purple basic dye
Eosin- pink acidic dye
4 basic tissues types?
Epithelium
Connective tissue
Muscle
Nervous tissue
What tissue type forms glands?
Epithelium
What do all types of epithelium have?
Basal lamina