Histology Flashcards
What are the 3 classes of filaments
Microfilaments, Intermediate filaments and Microtubules
What are microfilaments made of
Actin
What are microtubules made of
Two tubulin subunits; Alpha and Beta
What proteins attach to microtubules and serve as the ‘motorway network of cell’
Dynein and Kinesin; both are ATPase
Dynein moves toward cell centre
Kinesin moves away from cell centre
Location of synthesis of RNA in a cell
mRNA and tRNA - Transcribed in Nucleus
rRNA - Transcribed in Nucleolus
Differentiate Euchromatin and Heterochromatin
Euchromatin - Actively undergoing transcription, light grainy colour, unwound
Heterochromatin - Condensed, wound, not transcripting
Role of Smooth Endoplasmic Reticulum
Process proteins produced in RER
Synthesis of lipids
3 types of intercellular junctions
Occluding junctions - Zona Occludends/Tight junctions, prevent diffusion
Anchoring junctions - Zone Adherens/Adherent junctions
Macula Adherens - Desmosomes, common in skin to provide mechanical stability
Communicating junctions - Gap junctions; have connexon protein; heart and smooth muscle to spread excitation
Common stain in preparing slides
Haematoxylin and Eosin - Stains acidic molecules like DNA purplish blue and stains basic molecules like plasma proteins pinkish red
4 basic tissue types
Epithelium, muscle, nervous and connective
Types of connective tissue
Soft - Tendons, ligaments, epidermids
Hard - Bone and cartilage
Blood and lymph - Specialized form
Types of soft connective tissue
Loose soft connective tissue - Loosely packed fibres separated by abundant ground substance
Dense soft connective tissue - Densely packed bundles of collagen fibres; regular or irregular
Types of bone
Outer shell of dense cortical bone - Diaphysis
Cancellous or trabecular bone - Epiphyses
Types of cardiac muscle
Smooth, skeletal and cardiac
What ‘coat’ covers nervous tissue
Meninges in CNS
Epineurium in PNS
Types of neurons
Multipolar - Many dendrites, one axon
Bipolar - One dendrite, one axon
Pseudounipolar - Short processes, axon in both direction
Types of Glia
CNS - Astrocytes - Support, ion transport, induce blood brain barrier Oligodendrocytes - Produce myelin Microglia - Immune surveillance Schwaan Cells - Myelin in PNS
Major salivary glands
Parotid - More serous secreting cells
Submandibular - Equal number of cells
Sublingual - More mucus secreting cells
Function of striated ducts in salivary glands
The ducts pump salt out of the fluid so that it’s hypotonic to blood
4 parts of the digestive tract
From lumen out -
Mucosa - Epithelium, lamina propria, muscularis mucosae
Submucosa
Muscularis externa - Inner circular and outer longitudinal layer of smooth muscle
Serosa or Adventitia
What is the enteric nervous system?
The digestive tract has its own nervous system called Enteric nervous system
Basic structure of the liver
Liver is made up of a large number of lobules. Each lobe has liver cells called hepatocytes. Each corner has a hepatic portal vein and hepatic artery. Central vein in the centre drains to these via Hepatic sinusoids.
What is the portal triad?
The hepatic portal vein + Hepatic artery + Bile duct
Endocrine vs exocrine glands
Exocrine glands release their products via ducts or into the lumen/ body surface
Endocrine glands release their products towards the basal laminae into capillaries (no ducts)
3 layers of blood vessels
From lumen to out -
Tunica Intima - Simple squamous epithelium
Tunica Media - Smooth muscle
Tunica Adventitia - Connective tissue
What are elastic arteries
The major arteries such as the aorta have many sheets of elastic fibres in tunica media to provide elastic recoil
What is vasa vasorum
Elastic arteries have their own vascular supply termed vasa vasorum
Compare diameter of RBCs and capillaries
RBC - 7 micron, Capillaries - 4 to 8 micron
3 types of capillaries
Continuous - Muscle, lungs, skin
Fenestrated - Gut, endocrine glands, kidney
Discontinuous or Sinusoidal - Liver, spleen, marrow
Which vessels are important sites for exchange
Post - Capillary Venules
What is the buffy coat found after blood has been spun in a centrifuge?
The buffy coat consists of leukocytes and platelets
What organ removes aged RBC ( > 4 months)
Spleen and liver
Histological appearance of Neutrophils
Don’t stain with acidic or basic dyes, multi-lobed
Histological appearance of Eosinophils
Affinity for acidic red dye Eosin, bilobed nucleus
Histological appearance of Basophils
Affinity for basic bluish purple Methylene blue, bilobed nucleus often obscured
Histological appearance of Monocytes
Seem non-granulated, non lobulated nuclues, kidney bean shaped
Histological appearance of Lymphocytes
Round nucleus, surrounded by thin to moderate rim of cytoplasm, non-granulated
Embryological location of haematopoiesis
Liver and spleen to some extent
