Cardiac And Vascular Histology Flashcards
SM have what Hallmarks
compared to dense regular CT
- elongated nuclei
- has cross section unstained regions
- not wavy
what are Dense bodies made of and what is the function
Desmin + Vimentin + intermediate filaments
anchor the thin and thick filaments to the plasma membrane and eachother
Cardiac Muscle Hallmarks
- striations + INTERCALATED DISCS*
- central nuclei
- LIPOFUSCIN GRANULES (lysosomal residues) near some nuclei
Cardiac Muscles have how many nucleus
and BF
and intercalated discs
1-2
a lot of capillaries
junctions between the cells for electrical current passage
Purkinje cells
modified CM cells and acts like pacemaker for heart
2 pericardiums around heart
fibrous pericardium (dense CT) serous pericardium (3 layers)
Serous pericardium
- Parietal layer = line inner fibrous pericardium
- Visceral layer = outer surface of heart
- Pericardial Cavity = space between parietal and visceral layers
CM found where
myocardium
what is endocardium and epicardium made of
areolar CT
epicardium has
fat and ANS, lined by mesothelium, viseral pericardium on top of it
the epicardium fat get blood supply from
coronary arteries
Coronary Microvascular Dysfunction
problems with coronary artery branches
= low BS to heart
4 characteristics of myocardium
- intercalated discs
- striations
- Lipofuscin granules
- Dyad T-tubules system
3 parts that myocardium has
AV and SA node
myoendocrine cardiocytes
cardiocytes (contractile)
where can you see the intercalated discs
at the Z=line
Fascia adherens
actin
transmit contractile forces
Transverse Region
Desmosomes
intermediate filaments of cytoskeleton
Transverse Region
Gap (nexus) junction
low electrical resistance sites (allows excitation of cells passage)
Longitudinal Region
what is a Dyad T-Tubule made of
1 T-tubule + 1 SR cisterna
Dyad T-Tubule function
invaginations into sarcolemma at the Z lines
for uniform contraction of myofibrils within a 1 cardiocyte
nodal cardiocytes
cells in the SA and AV node
ANS—-> to it
modify CM contractions
Purkinje Fibers
conduct electrical impulse fro coordinated contractions LOW amount of myofibruls HIGH glycogen amounts -most have X T-tubules - larger and near periphery
Lipofuscin Granules
with age small bodies accumulate in non-diciding cells
= residual bodies after lysosomal digestion)
Arterial Granules
= myoendocrine cardiocytes
ATRIAL CELLS that have granules (most in RA)
(has precursor for ANF –> Atrial Natriuretic factor)
ANF function
goes to kidneys to DECREASE NA+, H2O retention (absorption, so they get excreted)
Endocardium
endothelium + CT thin layer of loose CT
Endocardium in ventricle
SUBENDOCARDIAL Layer
= CT + SM merging with myocardium
= has purkinje fibers
Endocardium in atrium
NO real suberndocardial layer
= purkinje fibers closer to endothelium
= intermixed with myocardium
Cardiac Skeleton
Danse irregular CT at endocardium
- anchor valves
- surround AV canals (maintain shape)
- part of interventricular and interatrial septa
- extends to valve cusps + chordae tendineae (CM attach here , electrical insulator between A and V) *
Heart Valves
fibroelastic CT (VALVE RING) covered by endothelium continuous with cardiac skeleton
valve ring
central part of valve
Tunica intima
- Endothelium: simple squamous
- Basal lamina : collagen proteoglycans, glycoproteins
- Subendothelial layer : loose CT
= internal elastic membrane ——> sheet like fenestrated elastic with arteries and arterioles
Endothelial cell location and function
Innermost of tunica intima
- Blood coagulation and thrombosis
- Cell junctions many
- Local vasodilation and vasoconstriction
Tunica media
Layer of SM
Thick arteries
From internal elastic membrane to the external elastic membrane
Layer of elastin that separates tunica media and Adventitia
Tunica Adventitia
Collagen and elastic fibers
Loose CT around vessels
1. Vasa vasorum : vessels of tunica adventitia—> vascular tunics (Large Arteries + Veins)
2. Nervi Vasorum (vascularis) : ANS input —> vascular SM
LARGE Arteries
ELASTIC
Has elastin in between SM
Medium Arteries
MUSCULAR More SM (spiral) then elastin INTERNAL ELASTIC MEMBRANE* You can see the external elastic membrane also* Thick adventitia
small Arteries and Arterioles
Up to 8 layers of SM + internal elastic membrane (arteries)
1-2 layers of SM + maybe an IEM (arterioles)
ARTERIOLES : Sympa (vasoconstriction) and para (vasodilation) ——> tunica media*
Capillaries
Metabolic exchange, has endothermic (only tunica intima)
D can be smaller then RBCs
* PERICYTES : contractile cells of capillaries, continuous with endothelium and controlled by NO, promote capillary stability
Continuous capillaries
Has pericyte and TJs
Diffusion + transcytosis
Muscles, brain, exocrine glands, peripheral N
PANCREAS
Fenestrated Capillaries
Fenestrated, basal lamina is continuous, TJs
Small molecules exchanged
Endocrine glands, fluid metabolite absorption organs (GB, Kidney)
JEJUNUM
Discontinuous Capillaries
Basal lamina is discontinuous + large fenestrations, sinusoidal*
Exchange of macromolecules + cells
BM, spleen
LIVER hepatocytes
Metarteriole
First branch from arteriole to make capillary (has SM)
Precapillary sphincter
Regulates capillary BF
True Capillaries
No SM + pericytes*
Branched off the metarterioles
Thoroughfare channel
End of the metarteriole after all its branching of true capillaries, no SM
——> postcapillary venule
When pericapillary sphincters close
The blood doesn’t flow through all the true capillary branches and goes straight through from the metarteriole to the postcapillary venule (FASTER VENOUS RETURN)
Order of veins
Venules (postcapillary- intima and muscular-mediaSM+ adventitia) Small veins (3 layers) Medium V (3 layers), valves Large V (3 layers) *tunica intima can have valves
Veins are usually
Collapsed in lumen, have large lumen and thin walls
What travels with muscular arteries
Medium veins
LARGE veins
Longitudinal SM in adventitia
Circular SM in media
Thin intima
Lymph
Send fluids only away from tissues ——> venous supply
Lymph capillaries 3 characteristics
- Incomplete Basal Lamina : high permeability
- 1 way valve
- Closed ended tubes
———> make collecting lymph vessels
* endothelial cells held by anchoring cells *
Lymphatic vessels 3 characteristics
- Valves
- 3 layers of tunics
- TJs, no leakage
—> lymph trunks
Pathway of lymph from lymph capillaries
Lymph capillaries Lymph vessels Lymph trunks RIGTH lymphatic duct (RIGTH UEX) Thoracic Duct (all other body parts) Subclavian V + Internal jugular V junction
The right lymphatic duct —>
Right subclavian V and internal jugular V
Thoracic Duct —>
Left subclavian V + internal Jugular V
