Microscopy And Movement Flashcards
What are the 5 ways to obtain a sample of an organ
Punch
Incisional
Excisional
Needle
Endoscopic
(All biopsies)
What are the 3 different specimen types you can obtain
Whole organs/ surgical specimens
Organ samples (biopsies)
Fluid samples
How would you prepare a slide of cells to be seen under a light microscope
Fresh tissue delicate and easily damaged
Stabilise/ fix tissue before cutting
Cut into thin slices
How would you prepare a tissue sample to be seen under an electron microscope
Freeze tissue- easier to cut- less chance of damage
Infiltrate tissue with liquid that solidifies- paraffin sections
Resin embedding for hard materials like bone
How are paraffin sections made (12 steps)
- Fresh tissue fixed before processing- preserves tissue and protect against processing
- Tissue put into formaldehyde solution from 6-24 hours
- Specimens dehydrated by increasing conc. of ethanol- allow paraffin infiltration
- Clearing agent to remove ethanol and fat- xylene
- Wax infiltration- paraffin wax and additives- liquid at 60 degrees- solid at 20
- Block formed after wax infiltration to allow sectioning
- Placed into mould- filled with molten wax with histology cassette
- Solidified with cold plate
- Ribbons of sections cut on microtome- as thin as 2um
- Flattened on warm water bath
- Mounted on glass slide
- Wax removed- dehydration reversed so can be stained
Where are frozen sections mostly used
For kidney biopsies
Why are frozen sections made instead of paraffin
If needed urgently- quicker process
If sample has high fat
How is a frozen section made
- Tissue froze rapidly at 150 degrees
- Sections cut on special microtome in cryostat (refrigerated cabinet)
What are the two methods used to stain tissues
Histochemical and immunohistochemical
What is the most commonly used stain
Haematoxylin and eosin
What colour is haematoxylin
Purple/blue
What colour is eosin
Pink/ red
What does haematoxylin stain
Acidic structure like DNA and RNA- nuclei
What stain is used to see acidic structures like nuclei
Haematoxylin
What does eosin stain
Stains basic structures like cytoplasm
What stain would be used to see basic structures like cytoplasm
Eosin
What does periodic acid-shiff stain
Carbohydrates like glycogen, basement membranes, goblet cells and fungi
What stain would be used to see glycogen
Periodic acid-shiff
What stain would be used to see goblet cells
Periodic acid-shiff
What does elastic van Gieson stain and what colour do they appear
Connective tissues
Collagen- appears red
Nuclei- appears blue
Cytoplasm- appears yellow
Elastic fibres- appears brown
What is elastic van gieson stain mostly used to see
Vessel structures and connective tissues
What stain would we use to see connective tissues or vessels
Elastic van gieson
What is immunohistochemistry
Antibodies are added to tissues to bind to their specific antigens
Antibodies have indicator attached- fluorescent or coloured product
What 4 types of cells are specialised for movement of body tissues
Muscle cells
Myoepithelial cells
Myofibroblasts
Pericytes
Characteristics of skeletal muscle
Striated
Responsible for voluntary movement and posture maintenance
Referred to as muscle fibres- myofibres
Up to 35cm in length
Powerful contraction but quick to retire
How are skeletal muscles structured
Into compartments/ groups of muscles with similar functions
Muscle- fascicle- muscle fibre
Each layer surrounded by connective tissue- fascia, epimysium, perimysium, endomysium
What 4 connective tissues surround skeletal muscles
Fascia, epimysium, perimysium and endomysium
What are the 3 compartments of the thigh and what action do they carry out
Anterior- extension
Posterior- flexor
Medial- adductor
What are the 3 compartments of the leg and what action do they carry out
Anterior- dorsiflexor
Posterior- plantarflexor
Lateral- Evertor
What tissue connects muscles to bones
Tendons
Function of a tendon
Connects muscles to bones
What is the cell membrane of a skeletal muscle fibre called
Sarcolemma
What are contractile proteins arranged into
Myofibrils
What are the two myofibrils- which one is thick- which ones thin
Actin- thin
Myosin- thick
What’s the cytoplasm if skeletal muscles referred to as
Sarcoplasm
Where are nuclei located in skeletal muscle fibres
Located peripherally- close to the sarcolemma
What are tendons composed of
Collagen fibres and fibroblasts
Why do tendons take long to heal
Because they are poorly vascularised
What are aponeuroses
Flat sheet-like tendon
Provides strength and stability to the skeleton
Attaches muscles to bones
Attaches muscles to muscles
What do aponeuroses do
They attach muscles to bones and muscles to muscles
What does a ligament do
Connects bones to bones
Increases joint stability
Characteristics of a ligament
Flexible bands of collagenous tissue
Where is smooth muscle found
Found in locations that require slow or rhythmic contractions
Eg. Walls of hollow viscera like bowel, bladder or uterus
Blood vessel walls
Secretory gland ducts
Are smooth muscle cells larger or smaller than skeletal muscle cells
Smaller
Describe the structure of a smooth muscle cell
Spindle shaped
Tapering at the ends
Single, centrally placed nucleus
Irregular branching fasiculi
Where is the nucleus of smooth muscle cells located
Single nucleus, centrally placed
How is smooth muscle contraction stimulated
By autonomic nervous system
Neurohormones
Conduction from adjacent cell
What is the organisation of actin and myosin in smooth muscle
Crisscross cells
What is cardiac muscle referred to as
Myocardium
What type of muscle is cardiac muscle
Striated
How many nuclei do cardiac muscle cells have
One- mononuclear
Describe the structure of cardiac muscle
Mononuclear
Ends of cells split into branches- connect network of myocytes
Intercalated discs
Characteristics of cardiac muscle
Not able to regenerate after damage- forms scar tissue
Less powerful than skeletal muscle but more resistant to fatigue
What are myoepithelial cells
Form secretory glands like breast tissue
What is the function of myoepithelial cells
Expel secretions from glandular tissue
What is the function of myofibroblasts
Repair defects resulting from tissue death
Secrete collagen
What is the function of pericytes
Surround blood vessels
Help with tissue healing
