Histology - IMMS Flashcards
What colours do haemotoxylin and eosin stain the cell nuclei an cytoplasm?
- Nuclei = blue - Cytoplasm = pink but colour varies depending on nature of cytoplasmic contents
What do these stains show: - PAS - Van Gieson - Trichrome - Alcian Blue?
- sugars, e.g. goblet cells - elastic tissue - 3 types of cell - mucins
Why do cells vary in size?
Depends on metabolic activity, e.g. lymphocytes smaller than nerve cells as aren’t as metabolically active (need less mitochondria)
What are the 6 types of cell shapes?
- rounded - polygonal - fusiform - squamous (flattened) - cuboidal - columnar
What common feature do metabolically active cells have?
Nucleoli (within nucleus, site of ribosomal RNA formation)
What is chromatin? What are the two types?
Condensed DNA wound around histones. Can’t be transcribed unless decondensed. - Heterochromatin = permanently condensed - Euchromatin = becomes decondensed in the life cycle of the cell
What is the mitochondria?
- powerhouse of cell - site of oxidative phosphorylation - have own nucleus
What is RER?
Site of protein synthesis, lots of ribosomes
What is SER?
- site of membrane lipid synthesis - processes synthesised proteins
What is the Golgi apparatus?
- processes macromolecules synthesised in ER - prominent in plasma cells (called perinuclear ‘hoff’)
What are the 3 parts of the Golgi apparatus?
- cis face = receives transport vesicles from SER, phosphorylase some proteins - medial Golgi = forms complex oligosaccharides by adding sugars to lipids and peptides - trans Golgi network (end) = sorts macromolecules into vesicles which bud from surface
What are vesicles?
Small membrane-bound organelles used for transport, storage and exchanging cell membrane between compartments. An example is a lysosome
How are lysosomes formed?
Hydrolyse vesicles fuse with endosomes to form endolysosomes
What is the cytoskeleton? What does it contain?
- supports cell’s shape - microfilaments (actin) helps this (smallest, 5nm) - intermediate filaments (6 types) spread tensile forces through tissue = cytokeratin, desmin, glial fibrillary acidic, neurofilament, laminin, vimentin - microtubules act as a scaffold for chromosomes during mitosis + meiosis (made of tubulin) (largest, 25nm)
What is lipofuscin and where is it found?
- membrane-bound orange-brown pigment, formed from peroxidation of lipids in older cells - heart and liver
Where are lipids and glycogen found?
- lipids found in adipocytes (fat cells) - glycogen found in cytoplasm
Are all the constituents of the body contained inside cells?
No, there is interstitial fluid, e.g. water + extra cellular material, e.g. tendons
A sample of liver from a patient who has a disease that makes them store excess iron in the liver is examined by a pathologist. Which stain can be used to stain iron blue? A - Alcian blue B - Haemotoxylin C - Iron haemotoxylin D - Perl’s stain E - Periodic acid-Schiff stain
D - Perl’s stain
Different cells have different lifespans. Which of the following cell types lives for the whole life of a person? A - Enterocytes (gut lining cells) B - Erythrocytes (red blood cells) C - Cardiac myocytes (heart muscle cells) D - Fibroblasts (connective tissue cells) E - Keratinocytes (skin cells)
C - Cardiac myocytes (heart muscle cells)
Which stain(s) have been used on this section? A - Alcian Blue B - Giemsa C - Haemotoxylin and eosin D - Periodic acid Schiff E - Perls Prussian Blue
D
What is the shape of these cells? A - Columnar B - Fusiform C - Polygonal D - Rounded E - Squamous
B
What is the lifespan of these cells? A - 5 days B - 120 days C - 400 days D - 3600 days E - 21000 days
B
What is chromatin? A - Mitochondrial DNA B - Nuclear DNA C - Nuclear DNA + proteins D - Nuclear RNA E - Nuclear RNA + proteins
C
What is the function of the arrowed organelle? A - DNA transcription B - Energy production C - Lipid degradation D - Protein degradation E - Protein synthesis
A
Which metabolic process takes place here? A - Fatty acid metabolism B - Lipid synthesis C - Kreb’s cycle D - Nucleotide phosphorylation E - Respiratory chain
C
Which organelle causes this pale area? A - Golgi body B - Lysosomes C - Mitochondria D - Rough ER E - Smooth ER
A
What is the function of this organelle? A - Form complex oligosaccharides B - Form membrane lipid C - Protein phosphorylation D - Proteolysis E - Synthesise protein
E
Which of these filaments has the smallest diameter? A - Actin B - Desmin C - Nuclear laminin D - Tubulin E - Vimentin
A
Which of these intermediate filaments is predominantly found in muscle? A - Cytokeratin B - Desmin C - Neurofilament protein D - Nuclear laminin E - Vimentin
B
What is this pigment? A - Bilirubin B - Haemosiderin C - Lipofuscin D - Melanin E - Rhodopsin
C
What type of tissue is this? A - Bone B - Epithelium C - Germ cells D - Muscle E - Nerve
D
What is epithelia? What are the 3 purposes of the barriers it forms?
Epithelia comprise a cohesive sheet of cell, with one or more layers, resting on a basement membrane. Form barriers for protection, e.g. skin, absorption, e.g. gut and secretion, e.g. pancreas
What are the two types of epithelia regarding layers of cells?
- Simple epithelia = single layer of cells on basement membrane - Stratified (compound) epithelia = 2 or more layers of cells on basement membrane
Explain the shape of simple squamous epithelium.
- Single layer of flattened plate-like cells - Parallel oval nuclei (1 per cell) - Lines inside of blood vessels (endothelium), outside of lungs (mesothelium) + abdominal organs (peritoneum)
Explain the shape of simple cuboidal epithelium
- Single layer of cells with similar height + width - Central spherical nuclei - Line kidney tubules, small ducts
Explain the shape of simple columnar epithelium.
- Single layer of cells taller than they are wide - May or may not have cilia (wafts material on surface across epithelium) or microvilli (microvilli increase s.a. for absorption of water + nutrients) - Lines stomach, intestines + uterus
Where do we generally find stratified epithelia?
Found at sites subject to abrasive forces, e.g. mouth
Describe the shape of stratified squamous non-keratinising epithelium.
- Multiple layer of cells, plate-like squares - Produces no keratin, so found in areas not in need of waterproofing, e.g. oesophagus
Describe the shape of stratified squamous keratinising epithelium.
- Multiple layers of cells, plate-like squames - Keratin = waterproof, so found on skin
Describe the shape of pseudostratified epithelium
- Single layer of cells of variable height. Tricks you into thinking it’s multiple layers. - All in contact with basement membrane, but nuclei at varying heights
Describe the shape of urothelium (transitional epithelium).
- Breaks the rules - looks stratified, but is a mixture of stratified and pseudostratified - In stratified, bottom layer in contact with basement membrane - In urothelium, several layers are in contact with basement membrane - Top layer (umbrella layer) and then pseudostratified (appears 3-7 layers thick)
What is the basement membrane?
- Always present in epithelia, but can’t usually see it - Can infer its presence from difference in colour between epithelium and underlying connective tissue
What is used to stain basement membrane?
PAS
What is the basement membrane made up of?
Several extra-cellular proteins including Collagen IV + Fibronectin
How are epithelial cells joined together?
Epithelial junctions
Which epithelial junctions prevent diffusion between cells?
Occluding (tight) junctions
Which type of epithelial junction spreads forces across several cells?
Desmosomes
Which epithelial junction allows the spread of ions and small molecules between adjacent epithelial cells?
Gap
Where else might this type of epithelium be found? - A. Blood vessels - B. Renal tubules - C. Salivary ducts - D. Trachea - E. Urinary bladder
A
What type of epithelium is this? - A. Pseudostratified - B. Simple cuboidal - C. Simple columnar - D. Simple squamous - E. Stratified squamous
D