Cardiovascular System Histology Flashcards
major componenets of the Cardiovascular system
Heart
Blood vessels
Blood
Major function of the Cardiovascular system
Transportaions of Nutrients and oxygen, waste products, hormones
what does the left side of the heart bump
For the systemic circuit
what part of the heart receives oxygenated blood
LEft atrium
what does the right side of the heart pump
pump for the pulmonary circuit
what does the right atrium recieve
Deoxygenated blood
how much does the atrium fill the ventricles
30%, with gravity doing the rest
what is contained in the heart wall
Cardiac muscle tissue Fibrous skeleton Conducting system Coronary vasculature Serous membrane Endothelial cells with underlying connective tissues
what makes up the Fibrous skeleton on the heart
Fibrous rings (4) Fibrous Trigones (2) Membranous portion of the interventricular and interatrial septa
what do the Fibrous rings of the heart curround
The valve orifices
what connects the Fibrous rings of the heart
Fibrous Trigone
Roll of the Fibrous skeleton on the heart
Something for muscles to attach to, and electrical insulator
Roll of the Fibrous rings of the heart
Attach to the leaflets of the valves
what is in the interventricular and interatrial septa
No muscle, only connective tissue
what is between the Atria and the ventricals
the fibrous skeleton
3 layers of the heart wall
Epicardium-outer
Myocardium-middle
Endocardium-inner
What is the other name for the Epicardium
Visceral layer of serous pericardium
what makes up the myocardium
Made of mainly cardiac muscle
Fibrous skeleton of the heart
Components of the endocardium
Endothelial cells-inner
Subendothelial layer- middle
Subendocardial layer- deepest
what is found in the subendothelial layer
Contains connective tissue and smooth muscle cells
what is found in the subendocardial layer
Connective tissue layer containing the intrinsic conduction system
Parts of the PEricardium
Fibrous pericardium - outer
Parietal layer of serous pericardium - middle
Pericardial cavity
Visceral layer of serous pericardium- part of heart wall
THickest layer of the heart wall
Myocardium
what fibers are contained within the subendocardial layer
Perkinji fibers
the 4 valves associated with the hear
Tricuspid valve
Bicuspid or mitral valve
Aortic semilunar valve
Pulmonary semilunar value
what are teh atrioventricular valves
Tricuspid valve
Bicuspid or mitral valve
what are the semilunar valves
Aortic semilunar valve
Pulmonary semilunar valve
what do the Atrioventricular valves do
Prevent backflow into the atria
what do the Semilunar valves do
PRevent backflow into the ventricles
what enforces one way blood flow through the heart
Heart valves
why do heart valves open or close
REsponse to pressure changes
valves that protect the entrnaces of the venae cavae, coronary sinus, and pulmonary veins
No valves
What are the heart valves made of
Connective tissue with overlying endocardium
3 layers of the heart valves
Spongiosa
Fibrosa
Ventricularis
what makes up the Spongiosa of the heart valves
Loose connective tissue covered in endothelim made of loosely arranged collagen and elastic fibers infiltrated with proteoglycans
where is spongiosa located
On the atrial or blood vessel side of the valve
roll of the Spongiosa
Shock absorber
where is the Fibrosa of the heart valve
the core of the valve
what does the Fibrosa contain
Fibrous extensions from the dense irregular connective tissue of the skeltal rings of the heart
what is the Ventricularis of the heart valve
Dense connective tissue with layers of elastic fibers covered in endothelium
where is the Ventricularis of the heart valve
Adjacent to the ventricular side of the valve
what is found on the surface of heart valves
Endothelial cells
can the heart depolarize and contract without impulses from the nervous system
YES!
the ability of the heart to depolarize and contract without impulses from the nervous system
Intrinsic cardiac conduction system
what is the intrinsic conduction system composed of to send electonics to contract
1% noncontracile cardiac cells (cardiac conducting cells/autorhythmic cells)- self excitable
what does it mean to say that noncontractile cardiac cells are self excitable
can generate an action potential without nervous system input
Types of Cardiac conducting cells
Nodal cardiac Cells
Purkinje fibers
what are Cardiac conducting cells organized into
Nodes and highly specialized conducting fibers/tracts
what are the cardiac conducting cells responsible for
the initiation and distribution of impulses throughout the heart
what sets the rate of the intrinsic cardiac muscle contracts
by the pacemaker cells
what alters the rate of the intrinsic cardiac muscle contractions
Sympathetic (accelerates the heartbeat)
Parasympathetic (decelerates the heartbeat)
also hormones for the intrinsic rate
what is the excitation sequence that takes place in collections of autorhthmic cardiac cells
Sinoatrial node Atrioventricular Node Atrioventricular bundle/bundle of His Right and Left Bundle Branches Purkinje Fibers
what is the pacemaker of the herat
Sinoatrial node
Roll of the Sinoatrial Node
Determines heart rate through its sinus rhythm
how do impulses from the Sinoatrial node travel to the atrioventricular node
Via the internodal pathway or tracts
what happens to impulses at the atrioventricular node
Delayed for .1sec to allow for the atria to contract
what is the only electrical connection between the atria and the ventricles
Atrioventicular bundle/bundle of His
What does the Atrioventicular bundle/bundle of His travese across
Across the fibrous skeleton
what are the branches of the atrioventricular bundle
Right and left bundle branches
where doe the Right and left bundle branches course towards
To the apex of the heart through the interventricular septum
where do the Purkinje fibers travel
Finish path in interventricular septum, around apex of heart, and head back towards atria
where is the SA node
in the roof of the right atrium
where are nodal cardiac muscle cells found
in the SA and AV nodes
what are Nodal cardiac muscle cells derived from
Modified cardiac muscle cells
size of Nodal Cardiac muscle cells
Smaller than surroudning atrial contractile cardiac cells
what do nodal cardiac muscle cells lack to separate them from normal cardiac muscle
Fewer myofibrils
lack intercalated disks
where are Purkinje fibers
in the av bundle
Bundle brnaches
Subendothelial branches
what are Purkinje fibers
Modified cardiac muscle
Size of Purkinje fibers
Larger than surrounding ventricular contractile cardiac cells
what is found at the periphery of purkinje fiber cells
Myofibrils
what do Purkinje fiber Nuclei look like
Round and larger than nuclei of regular cardiac fibers
what is found inbetween Purkinje fibers
Associated intercalated disks
what kind of staining do Purkinje fibers respond to due to the large amount of glycogen in them
PAS staining
how do Purkinje fibers look with H and E stain
Glycogen rich center of cell appears homogenous and stains pale
Layers of the Ventricular wall of the heart starting with blood side
endocardial layer: Endothelial cells Subendothelial layer( connective tissue + smooth muscle cells) Subendocardial layer( connective tissue) Myocardium:
Size of cells in the Subendocardial layer
Very large
Description of Endocardial cells
Large with central round nucleii
Pale/nonstaining due to glycogen
Perifery may have myocardiacdial cells
Size of nodal cells compared to contractile cells
Much smaller
size of cells in the heart
Purkinji fibers the largest
myocardium contractile cells
Nodal cells
The tree major types of blood vessels
Artiers
Capillaries
Veins
what is the smallest artery
Arteriole
what is the smallest blood vessel
Capillaries
Main roll of capillaries
Exchange of materials between blood and body tissue
Smallest vein
VEnule
where is the pressure lowest in the circulatory system
The largest veins (decreases as blood goes toward the heart
where is the pressure the highest in the circulatory system
Right after the heart
3 layers of blood vessel
Tunical Interna
Tunica MEdia
Tunica Externa
parts of the tunica interna
Endothelium Basal Lamina Subendothelial layer (also internal elastic membrane in some artiers and aterioles)
What has an internal elastic membrane
some arteries and artieroles
what does the Tunica media contain
Rings of smooth muscle cells
Sheets/lamellae/laminae of elastin
(external elastic membrane for ateries)
what is the roll of the smooth muscle of the Tunica Meida
VAsocontstriction and vasodilation
what is found in the Tunica Externa/adventitia in large vessel
Vasa vasorum and nervi vascularis
what is the endothelium of Blood vessels
Simple ssquamous cells
what is the subendothelial layer of the blood vessels
Loose connective tissue
largest layer in the artieries
Tunica media
largest layer in the veins
TUnica Externa
what is the direction of epithelial cells in the blood vessels
Along the direction of blood flow
How do blood vessels and arteries look in cross section
Arteries more oprn
Veins more collapsed
Lumen of vein is much larger
4 types of arteries
Elastic/conducting arteries (large arteries)
Muscular/distributing arteries (medium arteries)
Small arteries
arterioles
the largest diameter arteries
Elastic/conducting arteries (10mm)
what is found in the walls of elastic/conducting arteries
LArge amount of elastic fibers
why would elastic/conducting arteries have a lot of elastic fibers in them
expand and recoil
what is the roll of elastic/conducting arteries
Propel blood onward while ventricles relax (pressure reserve)
size of muscular distributing arteries
2-10mm (meidum)
what is found in the walls of muscular distributing arteries
lots of smooth muscle
Roll of muscular/distributing arteries
regualte the blood flow to specific regions
roll of muscles of muscular/distributing arteris
in a cicular origin to contract or release
size of small arteirs
.1-2mm
what makes up the tunica media of small arteries
8 layers of smooth muscle at most
size of arterioles
10 micrometeres to 100.
what is found in the unica media of arterioles
1-2 layers of smooth muscle
what is found on the tunica intima of elastic/conducting artiers
inconspicuous internal elastic membrane
what separates the smooth muscle of the tunica media of elastic/conducting arteries
Elastic lamellae
what may be found in the tunica adventitia of elastic/conducting arteires
Vasa vasorum/nervi vascularis
thickness of tunica intima of muscular/distributing artiers
Thinner than muscular/distruiting artiers
what is found in the tunica intima of Muscular/distruting artiers
Prominent internal elastic membrane
what is found in the tunica media of muscular/distributing artiers
Smooth muscles with limitedelastic material
prominent external elastic membrane
Thickness of Tunica adventitia of muscular distributing arteries
Relatively thiccc
what is found in the tunica adventitia of muscular/distributing arteries
possibly Vasa vasorum or nervi vascularis
what is found in the tunica intima of small arteries
Internal elastic membrane (typically)
size of tunica adventitia of Small artiers
Thin and ill defined
what may be missing from the arterioles tunica intima
May be missing the internal elastic membrane
size of tuniva adventitia of arterioles
Thin, ill defined
what makes up the wal of capillaries
Thin wall
What are the 3 types of capillaries based on morphology
Continuous capillaries
Fenestrated capillaries
Discontinuous cappilaries (AKA sinusoidal capillaries)
size of capillaries
4-10 micrometers (RBC is 7.5microns)
where are continuous capillaries found
Muscles
Lungs
CNS
what is the endothelium of Continous cappilaries
Uninterrupted endothelial with tight/occluding junction
how does stuff move across continuous cappilaries
Must be selected for
what cells are associated with Continous cappilaries
Pinocytotic vessels
Asociated perictes
Roll of Pinocytotic Vessels for Cotinuous capillaries
Go in and help transport
where are the pericytes of continuous capillaries
In the basal lamina
what are pericytes
Undeveloped cells to form more endothelial cells or smooth cells
ROll of pericytes
Aid in growth some contractiong controlled by NO
why have fenestrated capillaries
help stuff more
Where are fenestrated capillaries found
ENdo glands
Sites of fluid and metabolite absorption
what also is associated with Fenestrated capillaries
Pinocytotic vessels
where are discontinuous capillaries foudn
in the liver/spleen/bone marrow
Size and shape of discontinous capillaries
LArge diameter and irregular shape with large fenestration
The flow of blood from an arteriole through a capillary network to a postcapillary venule
Microcirculation
what forms the functional unit of a microcirculatory bed
Arteriole, capillary network, and post capillary venule
types of Capillary vessels
True capillaries
Ateriovenous anastomes/shunts
roll of the ateriovenous anastomes/shunts
By pass a capillary bed
what happens if more precapillary sphincters relax
The more blood will pass through the true capillaries in the capillary bed
What happens if omre precapillary sphincters contract
the more blood will plass through the arteriovenous anastomoses and bypass the true capillaries
what is found at the enterence of true cappilaries in the cappilary bed
Precapillary sphincters
types of VEnules
Postcapillary Venule
Muscular venule
what makes up the postcapillary venule
Endothelial cell with basal lamina and pericytes
what layers does the post capillary venule lack
No tunica media and no adventitia
what is found in the Muscular Venule that the postcapillary venule
A tunica media with 1-2 layers of smooth muscle
Thin Tunica adventita
what does the muscular venule lack that the post capillary venule has
Pericytes
sieze of small veins
.1-1 mm
size of Medium veins
1-10mm
size of large veins
greater than 10mm
what makes up the tunica intima of medium veins
Endothelium and basal lamina
Thin subendothelial layer with an occasional smooth muscle cell
also possibly a thin internal elastic emebrane
what makes up the tunica media of medium veins
Several layers of smooth muscle (generally circular) with interspersedd collagen and elastic fibers
size of the tunica adventitia of medium veins
Thicker than the intima and media
what makes up the tunica adventitia
Collagen and networks of elastic fibers
what is found in the tunica intima of large veins
Endothelium and basal lamina
Thin subendothelial alyers with some smooth muscle
size of tunica media of large veins
Relatively thin
what is found in the tunica media of large veins
Circular smooth muscle
size of tunica adventitia of large veins
THicker than intima and media
what is found in the tunica adventia of large veins
Collagen and elastic fibers with occasion smooth muscle
what veins have valves
Those in limbs
what makes up the valve of a vein
Tunica intima(endothelial cells on a thin layer of connective tissue
