Cardio Histology/Atherosclerosis/Heart Pathology Flashcards
3 layers of the heart and types of cells:
- epicardium (simple squamous, vessels, fat, nerves)
- myocardium
- endocardium (endothelial, CT, conducting tissue)
Cardiac muscle cells describe
- small cells
- central nucleus
- branching fibers
- intercalated discs
What are located the spaces between branching cardiac muscles?
capillaries
intercalated disc uses intermediate filaments in their fascia adherens?
false. actin filaments are used
What are the Z-discs in cardiac muscles made of?
Gotcha! No Z-discs, replaced by intercalated discs
are there desmosomes in cardiac muscle?
yes, attached with intermediate filaments
Why are Gap junctions in cardiac muscles not sufficient to propagate a proper contraction?
only useful at short ranges.
T/F? the heart beat is set by the slowest beating cells? and where?
False. set by the fastest beating cells. SA/AV node.
What are Purkinje fibres full of?
glycogen
Purkinje fibres have lots of myofibrils?
Not much bro.
3 layers of blood vessels are:
- Intima
- media
- adventitia
Intima has 3 layers too, they are:
- endothelium
- on the basal lamina
- supported by CT
T/F, endothelial cells are elongated circumferentially in the vessels?
False. elongated in the direction of flow
Endothelium does 3 things:
- inhibit clotting
- store Von Willebrand’s factor for rainy days
- secrete endothelin or NO depending on it’s mood.
vessel Media is made of? how is it arranged?
smooth muscle arranged concentrically
what happens to blood pressure if you increase the lumen?
BP goes down
Usually only have 1 layer of smooth muscle in the media?
Nope, can vary from 1-50 layers yo!
What type of collagen is in the vessel media? secreted from what?
type III, and made by the smooth muscle itself
How do smooth muscles acquire elastin and ground substance?
it secretes them themselves
What kind of collagen/CT is in the adventitia of vessles?
Type I, elastin, ground substance
Adventitia secretes it’s own matrix?
Nope. Embedded fibroblasts do.
What are the blood vessels of the blood vessels called?
vasa vasorum
Where are elastic arteries found?
generally near the heart
Why isn’t diastole zero?
The elastic recoil from the large arteries passively generates continuous flow at a lower and albeit pulsatile pressure
any elastin in muscular arteries?
yes but not much.
Why have muscular arteries
to distribute and regular blood flow
size of arterioles:
less than 0.1 mm diameter
how many layers of smooth muscle do arterioles have?
1-3 layers
muscular arteries or arterioles contribute most to blood pressure?
arterioles!
what’s the intermediate vessel between arteriole and capillary?
meta arteriole with single smooth muscle cell acting as a sphincter
Average diameter of a capillary is 7.2 microns?
Nope smaller than RBC to facilitate exchange
Cells in the body are cool with being 100microns away from a capillary.
Most are within 50 microns
What are capillaries made of anyways?
single rolled endothelial cell into a tube sealed with a tight junction.
Do capillaries have a basal lamina?
Of course dummy!!
do capillaries have media?
sometimes, called pericytes
do capillaries have adventitia?
yes. a wee splash of collagen fibres
Veins have thinner whats and thicker what?
thinner medias
thicker adventitia
2 ways to move blood in tubes with low pressure?
- one way valves
2. muscle pumps
where do leukocytes prefer to diapedese?
venules
venules are affected by histamine and cytokines?
yes
venules have pericytes? or smooth muscle?
Both. Initially pericytes, soon smooth muscle
in big-ass veins what additional structure is present to help stiffen the adventitia?
longitudinal smooth muscle bundles
Leaky lymphatics collect excess fluid from the arteriole side?
Nope. venous side bro. venous side.
what do lymph vessels lack in structure?
no tight junction
do lymph vessels have valves?
yes
looking at two tubes in the microscope, what do you look for/absence of to distinguish a lymphocyte?
No RBCs present, perhaps a few WBCs
What’s the difference between ischaemia and hypoxia?
ischaemia: lack of blood to a tissue
hypoxia: lack of oxygen in tissues
What is hypoxemia?
decrease O2 in the blood
Define Embolus and Thrombus
Thrombus: blood clot in vessel
Embolus: blood clot, solid, liquid, gas free floating in the vessels messing up your shit
What happens to the intima after chronic inflammation prior to plaque formation?
can’t produce NO and prostacyclin, roughened surface, may become thrombotic
What is a foam cell?
macrophages that ate too much McDonald’s, they break down and contribute to plaque
Which bad one enters the intima? LDL, HDL?
LDL
Do you get stenosis in the initial stages of atherosclerosis?
Nope. Remodelling to accommodate but only so much
Name 3 non-modifiable risk factors for Atherosclerosis.
Age
Gender
Genetic
Name 6 modifiable risk factors for Atherosclerosis
Hypertension Diabetes Smoking obesity physical inactivity proteinuria
Why is HDL called the ‘good’ lipoprotein?
It prevent LDL oxidation and removes cholesterol from circulation
The larger and less dense the LDL, the more atherogenic it is. T/F?
False. More dense LDL = more atherogenic
What’s metabolic syndrome anyway? 5 key points.
central obesity raised triglycerides reduced HDL increased BP increase plasma glucose
Adipose is just docile annoying extra cushioning.
Nope. it’s active and releases shit that INTERFERES with insulin signalling and BP regulation.
3 complications due to atherosclerosis
- ischaemia
- infarction
aneurysm
Which thrombus plaques are most susceptible to rupture?
thin firbrous caps yo.
One side of the artery is bulging, what’s that called?
saccular aneurysm
No ballooning but has a tear in the intima, what kind of aneurysm?
dissection
what is fusiform aneurysm?
both sides bulging
what is a saccular aneurysm?
one side bulging
both sides of the artery is bulging, what’s that called?
fusiform aneurysm
what’s a false aneurysm?
hematoma in the extravascular CT
What’s a berry aneurysm?
saccular, one sided bulge
can an infection cause an aneurysm?
Yes, a mycotic aneurysm can.
What’s so bad about an Aortic dissection?
can cause heart attack or stroke from pressure build up on the outside of the aorta
What syndrome could put you at risk of aortic dissections?
Marfan’s syndrome: defect in elastin and fibrin
What is hyaline arteriolosclerosis?
from endothelial stress, try to reinforce with plasma proteins and collage on walls of vessels
Decrease flow of blood is called?
Ischaemia
Can infarction be chronic?
Nope. Acute only.
What layer of heart is most susceptible to ischaemia?
Subendocardial
Intermittent claudication occurs in arteries? or veins?
Arteries
Hypoxia is?
low O2 in environment
Hypoxemia is?
low blood oxygen
When do you get acute ischaemia?
upon exertion
Define infarction
area of necrosis caused by acute ischaemia
infarcts could be two colours
pale
red
histologically how does infarction look?
coagulative
Brain = liquifactive
How long do these last occluded?
- neurons/glials
- cardiac
- skeletal?
- minutes/hours
- 10-20 minutes
- hours
If there is only one artery to an area what is that called?
End artery
What is a response to previous chronic ischaemia?
increase collateral vasculature
3 places where blockage of end artery most likely:
Spleen
Kidney
Heart
What shape are end artery infarcts usually?
Wedge shaped
3 reasons why you normally get Haemorrhagic infarcts?
- dual circulation
- reperfusion of necrotic tissue
- venous occlusion
do you see anything histologically in infarcted tissue between 6-12 hours? Then what happens?
Nope. Then becomes hypereosinophillic
What is karyolysis?
fading of nuclei
what’s the tell tale sign you’re looking at acute infarction?
Inflammation
neutrophils
What do you see in sub-acutre infarction?
fibroblasts, granulation tissue
What is a risk of high estrogen levels
hypercoagulability
2 things that make venous thrombosis especially bad:
stasis + hypercoagulability = bad times
When do you get lines of Zhan?
thrombi in aneurysms
Colour of arterial thrombi?
pale
deep red thrombi are found where?
venous system
Fate of thrombus: 4 things:
embolism
fibrinolysis
organisation
persistence
secondary gangrene explain:
- dry
- wet
- toes, foot leg/mummification, cause not much saprophytic organisms
- acute appendicitis/cholecystitis, infarction of small bowel
