Fundamentals of Anatomy and Histology Flashcards
how to calculate magnification
Objective magnification x eyepiece magnification (eyepiece is 10x)
how to set up microscope (3 stages)
- focus objective lens on specimen and adjust eyepieces
- Focus condenser lens on specimen (using pencil and then blur)
- Adjust substage iris diaphragm for optimum illumination (affects resolution)
frontal (coronal) plane of body
front and back
sagittal plane of body
left and right
transverse plane of body
top and bottom
anterior
posterior
superior
inferior
medial
lateral
proximal
distal
superficial
deep
front
back
top
bottom
towards the medium plane
away from the medium plane
towards the trunk
away from the trunk
towards the surface
towards the interior
terms of location embryology:
cephalic
caudal
ventral
dorsal
cephalic - towards head
caudal - towards bottom
ventral - towards front
dorsal - towards back
for neuroanatomy, rotate labels 90 degrees anticlockwise (dorsal on top)
anatomical terms of movement:
flexion
extension
abduction
adduction
medial rotation
lateral rotation
supination
pronation
dorsiflexion
plantarflexion
inversion
eversion
circumduction
opposition
repostion
protraction
retraction
elevation
depression
flexion - movt that decreases angle between 2 body parts
extension - movt that increases angle between 2 body parts
abduction - movt away from midline
adduction - movt towards the midline
medial rotation - rotating movt towards the midline
lateral rotation - rotating movt away from midline
supination - keep elbow/shoulder still flip hand with palm facing up
pronation - flip hand with palm facing down
dorsiflexion - flexion at ankle so foot points superiorly
plantarflexion - extension at ankle so foot points inferiorly
inversion - movt of sole towards median plane
eversion - movt of sole away from median plane
circumduction - conical movt of a limb extending from the joint, controlled
opposition - movt that bring the thumb and little finger together
repostion - movt that moves the thumb and little finger away from each other
protraction - reaching out/ protruding
retraction - picking something up/retracting
elevation - movt in superior direction
depression - movt in inferior direction
how many regions are there in the abdomen
9
how to process tissue for light microscopy
- treat specimen with a fixative
(halts metabolism, inactivates enzymes, renders cellular macromolecules insoluble) - cut tissue to 10-20um one cell thick, by freezing water or replacing water with more supportive medium (eg. wax by dehydrating with graded ethanol)
- cut wax embedded tissue on a microtome
- stain tissue, but stains are usually aqueous solution immiscible with wax, so rehydrate as wax no longer needed as section cut and glass support slide
- cannot stay in aqueous phase since stain will leach out, dehydrate with graded alcohols and remove ethanol with xylene/toluene
- protect stained section with cover slip
which cellular structures are shown after staining with Haematoxylin and Eosin dyes
Haematoxylin (dark blue)
- basic dye
- binds to negative charged structure such as DNA, RNA etc.
Eosin (red)
- acidic dye
- binds to positively charged structure (most cellular proteins)
which cellular structures do trichrome dyes show up
show nuclei and cytoplasm
help differentiate collagen from smooth muscle
The light microscope
Overall tissue organisation can be seen
Individual cells distinguished
Cell nucleus visible
Resolution 200nm-10mm
Scanning electron microscope
3D views
Resolution 0.4nm-1mm
Electron beam fired at surface and are reconstructed via a detector to produce image
Transmission electron microscope
Visualise individual cells
Resolution 0.4nm-100um
Human tissue act (2004)
Regulation of post-mortem examination, anatomical examination, public display of tissue from the deceased, removal and storage of human tissue
Function of Bursae and tendon synovial sheaths
Important in reducing friction during movement
Define:
Myotome
Dermatome
Myotome:
The complete muscle mass receiving its innervation from one cranial or spinal nerve
Dermatome:
The area of skin supplied by one cranial or spinal nerve
Resolutions of the microscopes
Compound light microscope
SEM
TEM
200nm - 10mm
- 4nm - 1mm
- 078nm - 0.1nm
Unobvious components of a compound light microscope
Condenser
Diaphragm
Focuses light through specimen
Controls the amount of light entering the condenser
How to distinguish the 5 types of white blood cell under a microscope (with H-E staining)
Neutrophils Eosinophils Basophils Lymphocytes Monocytes
- contain nuclei with many different lobes
- contain red or pink granules
- contain dark blue granules
- contain a circular nucleus that fills most of the cell
- nucleus in the shape of kidney bean
Colour of staining of components using H&E staining
Nuclei
Cytoplasm
Collagen
Erythrocytes/red blood cells
Blue
Pink to red
Pale pink
Orange
Examples of artefacts
Degradation:
If enzymes haven’t be deactivated properly eg. Loss of cilia
Incomplete dehydration or rehydration:
General shrinkage, cracks in tissue
Folds:
When cut tissue section is placed onto slide
REMEMBER: some materials are removed by organic solvents eg. Lipid components such as cell membranes
Colour of staining of components using Gomori Trichrome staining
Nuclei Collagen Muscle Erythrocytes Background
Blue/grey
Green
Red
Red
Blue/green
Features of epithelium
- forms dense cellular sheets
- no blood vessels
- rests on a basal lamina complex
- polarised cells (clear apical/basal aspects)
- stain well with H&E
Classification of an epithelium
Cell shape:
- squamous (flattened)
- cuboidal
- columnar
Cell arrangement:
- simple (single layer)
- pseudostratisfied (all cells in contact with basal lamina)
- stratified (multiple layers)
Cell specialisation:
- cilia (movt)
- microvilli (absorption)
- keratinisation (protection)
- eg. Goblet cells
Microvilli
- inc SA for absorption
- shape maintained by actin filaments anchored to cell membrane
Examples of each epithelium in the body
Simple squamous:
Lining surfaces involved in passive transport of gas (lungs) or liquid (endothelium of capillaries)
Simple cuboidal:
Lines small ducts and tubules
Simple columnar:
Absorptive surfaces such as small intestine and secretory surfaces
Pseudostratisfied columnar: Upper airways (nuclei at different levels)
Stratisfied squamous (others rare) Layers for physical protection for sites subject to mechanical abrasion Oral cavity, pharynx, oesphagus
Stratisfied keratinised:
Have a cornified layer of keratinised dead cells on very surface of epithelium for physical protection
Eg. Skin (prevent desiccation/waterproof)
Transitional epithelium:
Only urinary tract
Waterproof, protective from toxicity, able to distend (stretch)
Goblet cells
- modified columnar epithelial cell that synthesises and secretes mucus
- found particularly in respiratory/gastrointestinal tracts
- stains poorly with H&E
Cilia cells
- move fluid and particles along epithelia surface
- core of 20 microtubules arranged as 9 doublets around a central pair
- bigger than microvilli
Function of cell junctions in epithelial cells (2)
Keep epithelial sheets tightly bound (anchoring junctions)
Allow functional integrity of cells
(Selective barriers - tight junctions)
(Or for intercellular communication - gap junctions)
Organisation of junctions in the cell
Tight junction
(Seals neighbouring cells tog)
-
Adherens junction
(Joins actin bundle in one cell to another)
-
Desmosome
(Joins intermediate filaments in one cell to another)
-
Gap junction
(Allows passage of small ions and molecules)
-
Hemidesmosome
(Anchors intermediate filaments in a cell to basal lamina)
Desmosomes and Hemidesmosomes continued
Anchoring junctions
- STRONG anchors for intermediate filaments
- Contain membrane-spanning proteins (desmoglein & desmocolin) that allow sheets to flex without tearing, binds homophilically
- plaque that links membrane-spanning proteins to intermediate filaments is made of plakoglobin and desmoglobin
Adherens junctions
Anchoring junctions
- transmembrane cadherin protein dimers bind homophilically to others on adjacent cells, which are connected to actin filaments
Tight junctions
Non-anchoring
- create seal between cells so NO molecules can get through
- tight-junction proteins that seal cells are Claudin and Occludin (homophilically)
Gap junctions
Non-anchoring
- allow exchange of small molecules between cells via hydrophilic pore
- protein channel gap made from 6 Connexin molecules joined together (connexon)
- channel 1.5nm in diameter
Connective tissue types (2)
Soft connective tissue:
- basal lamina
- capsule for organs
- tendons & ligaments
- areolar tissue
- adipose tissue
Hard connective tissue:
- bone
- cartilage
Cells of soft connective tissue
Permanent cells:
- fibroblasts (synthesise collagen)
- adipocytes/fat (largest store of energy, fill spaces between tissues)
Transient cells:
- phagocytic
- immunocompetent (mast, plasma, lymphocytes)
Non-cellular components of soft connective tissue (fibres)
COLLAGEN
Collagen:
- inelastic, strong, thick
- type 1 = most abundant, forms fibres, synthesised by fibroblasts formed of 3 pp chains
- type 2 = forms thin fibres (in hyaline & elastic cartilage)
- type 3 = reticular fibres
- type 4 = in basal lamina, cohere as amorphous mats
- type 5 = small amount in basal lamina
Non-cellular components of soft connective tissue (fibres)
ELASTIC FIBRES
- stretchable, resilient, thin
- hydrophobic
- cross linking
Non-cellular components of soft connective tissue (non fibre)
GROUND SUBSTANCE
- viscous, semi-fluid gel where cells and fibres of connective tissue sit
- contains mixture of glycoproteins and proteoglycans
- also acts as lubricant & barrier to foreign particles
Proteoglycans
- protein core with carb side chains
- main carbs are GAGs
- side chain extend to occupy large volume
- VERY hydrophilic (swell up from water intake, so extra cellular matrix can withstand compressive forces)
Types of soft connective tissue
Basal lamina:
- interface between epithelium & underlying connective tissue
- selectively permeable
- controls growth/specialisation
Loose:
- component of lamina propria (digestive, respiratory, glands, skin hypodermis)
- oval fibroblasts
- immunocompetent cells may be present
Dense:
- subclassified as regular or irregular depending on orientation of collagen fibres
- irregular found in dermis of skin
- oval fibroblasts & immunocompetent cells
- regular found in tendons and ligaments
Types of basic tissue (4)
Epithelia:
- protection, secretion, absorption
Connective tissue:
- support to other tissues
- divided into general connective & specialised connective
Nerve tissue:
- sensation, control to muscles & glands
- cells = neurons (involved in electrical signalling), neuroglia (support cells that wrap neurons)
Muscle tissue:
- movt
- tissues contain filaments which generate force and muscle contraction
- either striated (skeletal & cardiac) or non-striated (smooth)
-
Tissues to Organs
- liver
- brain
- intestines
- heart
- skin
Liver:
Mostly epithelia, little muscle
Brain:
Mostly nerve, little muscle
Intestines:
Mostly epithelia, muscle and connective tissue
Heart:
Mostly muscle
Skin:
Epithelia (epidermis) and connective tissue (dermis)
Functions of superficial fascia
Loose connective tissue and fat
- storage of water & fat
- protection since fat & water act as cushion
- thermal insulation from fat
- conduction to transport nerves and blood vessels to the skin
- metabolic function since fat is an energy store
Functions of deep fascia
Dense connective tissue
- movt of muscle (muscles wrapped in deep fascia can slide over eachother)
- provides attachment for some muscle since it’s so thick in some places/solid surface
- conduction, blood vessels & nerves are transported via fascias (sheaths)
- capsule around some organs
Serous membranes
- between body wall (or tissue) and mobile organs is serous membrane
- secretes fluid into a cavity
- facilitates movt and reduces friction (lungs, heart, abdominal content)
- like an organ embedding itself into semi-inflated balloon
Basic circulatory system
Arteries
- take blood away from heart
- divide until smallest (arterioles) supply the tissue bed
Veins
- take blood to the heart
The systemic circulation
(Blood to the systems)
(Left side of heart)
- aorta pumps oxygenated blood to tissues
- veins take deoxygenated blood back via vena cava
The pulmonary circulation
(To the lungs)
(Right side of heart)
- brings deoxygenated blood to the lungs via pulmonary artery
- veins bring oxygenated blood back to right side of heart (pulmonary veins)
The portal system example
Largest portal system starts in digestive system
- involves 2 capillary beds
- blood passing through their capillary network ends up in the hepatic portal vein which drains into the capillary bed of the liver
- products of digestion are removed, processed and stored
- liver can release the nutrients when desired by releasing them into the veins of systemic circulation
Structure of arteries
3 layers
INSIDE-OUT
Endothelium (epithelium) - Tunica media (smooth muscle) - Tunica externa (connective tissue)
Systole
Diastole
Systole - heart contracts, systolic pressure around 120mmHg
Diastole - heart relaxes, diastolic pressure around 80mmHg
Function of arteriovenous shunts
Shortcut between artery and vein (missing out capillary bed)
Anastomoses
Inc types of artery
Arteries can anastomose instead of ending up as a capillary
Combine with other arteries
Anastomoses are common around joints in limbs
They form an alternative route when the main flow is obstructed eg. By movt of the joint
Types of artery:
Anatomical end artery - when an artery is the sole contributor to an capillary bed (no anastomotic connections)
(Artery heading into the gut wall)
Functional end artery - when there is more than one artery supplying tissue bed but loss of main artery still leads to tissue death, that artery is this.
(Eg. 2 coronary arteries in the heart)
The lymphatic system
- Uni-directional (valves)
- 10% of fluid stays behind in tissue as lymph (90% goes back to venous side of circulation)
- lymph circulated to the root of the neck (in its own system), into large veins (subclavian veins) before going back into the heart
- on the way to the neck, lymph vessels connect to lymph nodes (packed with lymphocytes that combat pathogens found in the lymph fluid)
Sentinel node
The first set of lymph nodes draining a given territory
Predict the source of the cancer/infection
Locations of lymphatic vessels
Superficial (fascia) lymphatics follow veins
Deep lymphatics follow arteries
Syncytium define
Single cell containing many nuclei
Formed when myoblasts fuse, proliferate and form myotubes
(Skeletal muscle)
Propagation of action potential within muscle
Action potential arrives at end of motor neuron
Acetylcholine released across cleft
Impulse carried into cell via T tubules
Triggers release of Ca2+ from sad ppl admit reticulum
Calcium causes muscle fibres to contract
Cardiac myocytes
Mono or bi-nucleated cells
Individual cells connected via intercalated discs
Cells have gap junctions to allow transmission of action potentials
Many mitochondria
No satellite cells
Cartilage
Devoid of blood vessels
Chondrocytes make and maintain it
Osteons
Overlapping in compact bone
Have central Haversian canal with blood vessels
(Which are linked transversely with volkmanns canal)
Around canal is layers of lamellae (mineralised matrix)
In this are osteocytes (connected by canniculi)
Lamellar
Mineralised organic matrix
Organic: collagen type I for tensile strength
Inorganic: crystals of hydroxyapatite for compressive strength
Trabecular bone
Spongy
Rods of lamellae form trabeculae (follow lines of stress for strength)
(Less mass though)
Trabeculae form vascularised cavities
(contains red marrow)
Canaliculi connect osteocytes to these cavities
Formation of haversian systems
Osteoclasts tunnel through pre-existing bone
Tunnel invaded by blood vessels and osteoprogenitor cells
Osteoprogenitor cells -> osteoblasts
Osteoblasts lay down successive bone lamellae on walls of tunnel
Between new lamellae (interstitial systems) is remnants of old osteons
Image resolution
Number of pixels in each direction of the image
Aspect ratio
Ratio of an images width to its height
Intensity/grey-scale
The number for a pixel
Low spatial resolution
Low intensity resolution
Not able to resolve small objects
Not able to differentiate objects that look similar
Volume mode visualisation
Involves projecting 3D data set onto 2D image
3 types:
- MIP (maximum intensity projection)
- surface rendering
- volume rendering
Most common x-day contrast agent
Iodine because it’s very attenuating to x-rays
Injected into circulation
Fluoroscopy
Dynamic 2D x-day imaging
For medical application, what is the x-ray target material?
Tungsten
What x-ray energy is used in medical application
30-100 kV
How an x-ray beam is created
Current passed at low voltage through filament of tungsten (cathode)
Causes heating of wire and emission of electrons
Electrons focused and formed into narrow beam and accelerated towards the anode (tungsten)
Electrons interact with the atoms on anode and produce x-ray photons
(99% of energy converted to heat, 1% to photons)
Factors that affect the amount of x-ray transmission
Attenuation coefficient (higher atomic = higher attentuation) (Higher attenuation = brighter image)
Thickness
Alpha nuclear decay
Gives off helium atom
Beta minus decay
Neutron is converted into proton
Beta(-) particle given off (fast moving e-
Anti neutrino given off (sub-atomic particle)
Beta plus decay
Positron
Proton converted to neutron
Gives off a positron & neutrino
Positrons travel a few mm in space, combine with electron, annihilate and generate 2 gamma photons
Useful types of isotopes for imaging applications
Gamma generators (Tc) Positron generators
Most common PET isotope
Fluorine 18
Attached to glucose to make FDG to show glucose metabolism
Acoustic impedance (US)
Material property
Attentuation
Combination of scattering and absorption
Scattering causes the textured image inside tissues
Higher frequency = higher absorption
A mode vs M mode vs B mode imaging (US)
A mode:
A single amplitude time signal
(Amplitude)
M mode:
Have amplitude time signal and measure serially & multiple times and display in 2D image
(Movement)
B mode:
If take A mode image and move transducer across tissue to diff locations, can stack A mode images together to form 2D image
How does MRI work
Person put in strong magnetic field
Person Irradiated with radio waves
Person re-emits signal, MRI localises signal using magnetic field gradients to form an image
MRI
Nuclei with non-zero spin have magnetic moments
These moments typically just cancel out due to the random orientation
But when placed in external magnetic field the spins either line up with the field or against the field
Also undergo spin-top motion at Larmor frequency
(depends on strength of magnetic flux density of Bo field and the gyromagnetic ratio which is diff for each type of nucleus)
Adding radio frequency magnetic field flips some spins into anti parallel direction, reducing the size of longitudinal magnetisation
Flipped spins are put ‘in phase’ in the transverse plane, generating net transverse magnetisation
The longer the RF is applied, the more it nutates to the xy plane
Isotope with the highest NMR sensitivity
H1
High natural abundance and is present in the body in large quantities - water
Basis of contrast in MRI
After excitation, nuclear spins return to original energy levels
Longitudinal magnetisation recovers with relaxation time T1 (inc)
Transverse magnetisation recovers with relaxation time T2 (dec)
T1 & T2 values vary between tissues, so spins in diff tissues recover and decay at different rates
Free induction decay signal (FID)
Following RF excitation, The changing transverse magnetisation induces electrical voltage in a loop of conducting wire placed nearby
Types of hormone
AA derivatives (eg. Adrenalin)
Small peptides (eg. ADH)
Proteins (eg. Growth hormone, insulin)
- lots of RER, golgi, secretory vesicles
Steroids (eg. Cortisol, oestrogen)
- lots of SER, lipid droplets
Neurohypophysis/posterior pituitary
Cell bodies of these neurones lie in the hypothalamus
(Supraoptic & paraventriculae nuclei):
Both polypeptides
ADH:
Inc water retention in kidney
Oxytocin:
Contract smooth muscle (especially uterus during childbirth)
Contract myoepithelial cells of mammary glands during lactation
Transported down axons to terminals
Cell types secreting hormones
Anterior pituitary
Acidophils (pink):
- somatotrophs (growth hormone)
- mammotrophs (prolactin)
Basophils (blue):
- Thyrotrophs (TSH)
- corticotrophs (ACTH)
- gonadotrophs (FSH & LH)
Chromophobes (grey)
(Reserve cells/stem cells)
Thyroid follicular cells
Thyroid follicular cells take up iodide from blood
Synthesized to iodine & attached for tyrosine if thyroglobulin within the lumen of the follicle and stored (colloid)
On stimulation:
Follicular cells endocytose the iodinated thyroglobulin, break it down, release the iodinated tyrosine derivatives (T3 & T4)
Thyroid parafollicular cells (C)
Secrete calcitonin
inhibits Ca++ mobilisation
Adrenal cortex
Outside-in
Zona glomerulosa
secrete mineralocorticoids
(mainly aldosterone - regulates Na+ retention in distal convoluted tubule of kidney)
Zona fasciculata
Secrete glucocorticoids
(Mainly cortisol - increases glucose, lipid and protein metabolism)
Zona reticularis
Secrete some glucocorticoids and small quantities of sex steroids
Adrenal medulla
Resemble axon-less ganglion cells
Recieves cholinergic input from lesser splanchnic nerves
On stimulation secrete catecholamines directly into blood
80% of cells secrete adrenaline
The rest secrete noradrenalin
Types of islet of langerhan cells
Lining of pancreas
A/Alpha cells (20%):
Secrete glucagon
B/Beta cells (70%):
Secrete insulin
D/Delta cells (5-10%):
Secrete somatostatin
F/PP cells (1-2%):
Secrete pancreatic polypeptide
Diffuse neuroendocrine system
Scattered cells especially in gut and respiratory
Secrete amine or peptides with hormone-like or neurotransmitter activity
(Gastrin, CCK, secretin, serotonin etc)
Secrete and act locally
Imaging technologies
MRI:
- magnetic resonance imaging
- strong radio waves sent through body
- (displaces nucleus of hydrogen atoms, when move back to original positions, own radio waves are emitted which the scanner picks up and turns into image)
- pregnant or ppl with metal implant can’t have
- more detailed than CT
CT:
- computerized tomography scan
- beams of X-rays from different angles sent through body, each angle provides a thin slice of area
- 2D images onto computer are made into 3D cross sectional picture
- contrast material taken by patient to make organs easier to see
- uses = internal injuries, muscle and bone disorders, detect cancer
- high resolution pictures but can inc risk of cancer / reaction to contrast (mild hives)
- pregnant women can’t
- faster than MRI
PET:
- positron emission tomography
- uses a dye with radioactive tracers
- decay of radioactive tracers produce positrons, which react with electrons (annihilation), produces energy in the form of 2 photons in opposite directions which are detected
- measure blood flow, oxygen use, glucose metabolism
- can show problems at a cellular level
- risks = exposure to radiation, allergic reaction to tracer
- mainly used to detect cancer
- normally used in conjunction with CT/MRI
SPECT:
- rotate gamma camera detectors around patient and detect gamma ray emission from tracer
- uses radioactive substance
- primarily used to diagnose heart disease
Ultrasound:
- emir short ultrasound pulse, listen to what is reflected back
Groups of hormones
Proteins/peptides:
- majority
- synthesized by DNA transcription/translation
- small, long-chain, glycoproteins
- water soluble so in blood unbound
- therefore short half life
- produced by hypothalamus, pituitary, parathyroids, GI tract, pancreas
Steroids:
- sex hormones, adrenal cortex hormones
- three 6 carbon rings, one 5 carbon ring
- derived from cholesterol
- synthesized in mitochondria & SER
- lipids molecules so diffuse through membranes
- circulate in blood bound to proteins
- produced by adrenal gland, gonads, placenta
