Histo - CV Flashcards
What are the 3 blood vessel walls?
- Tunica intima
- Tunica media
- Tunica adventitia
These are continuous w/ layers of the heart:
- Endocardium
- CT
- Myocardium
- smooth muscle
- Epicardium
- CT
What is this?
Tunics in a Muscular Artery
- Tunica intima
- closest to lumen
- Tunica media
- middle
- Tunica aventitia
- outter most
What is Tunica intima?
Basics:
- Endothelium + BL (non-thrombogenic)
- if not, non-thrombogenic clot will form & start atherosclerotic plaque
- Subendothelial layer (loose CT)
- fibroblasts or smooth muscle cells
- collagens, other molecules
- Internal elastic lamia
Function:
- Forms valves (in some larger veins)
Note:
- Presence of the last 3 = dependent on the size of the vessel
What is the Tunica Media?
Basics:
- Smooth muscle - deposits:
- Elastic fibers
- Reticular fibers
- Proteoglycans
Can have one of the following:
- External elastic lamina
- Muscular or medium artery
- Multiple elastic laminae
- large or elastic artery
- Pericytes
- capillaries & post-cap venules
Note:
- Not all vessels have Tunica Media
What is Tunica Adventitia?
Basics:
- Loose CT
- has vasa vasorum in LARGER vessels
- has smooth muscle in LARGE veins
What is Vasa Vasorum?
Basics:
- Vessels of the vessels
- smaller arteries & veins
- Present in tunica adventitia
- can enter the tunica media
Function:
- Provides nutrients to outer layers of large vessels
What is this?
Basics:
- Wall of vessel = thickens
- Macrophages & foam cells present
- Smooth muscle proliferates
Function:
- Blocks the lumen of a vessel
Note:
- Similar to wound situation
What is this?
Aneurysm
Basics:
- Dilation of arterial wall
- caused by weak tunica media
Causes:
- developmental defects
- lesions
- variety of diseases
- Marfan’s syndrome
What are the characteristics of non-capillary blood vessels?
Basics:
- Arteries & veins run together
- exception = LARGE vessels
Arteries
- smaller diameters
- thicker walls
Veins
- larger diameters
- thinner walls
- VALVES
- prevent backflow
- more in legs
What is this?
Large Artery
Basics:
- Thick tunica media
- >50 elastic lamina
- layers of smooth muscle
- Large tunica adventitia
- w/ vaso vasorum
- may extend into tunica media
- w/ vaso vasorum
What is this?
Medium or Muscular Artery
Basics:
- Single internal elastic lamina
- Broken up external elastic lamina
Note:
- Both are borders of the tunica media
What is this?
Small Arteries & Arterioles
Basics:
- Based on # of layers of smooth muscle
- (1-5)
- No obvious internal (or external) elastic lamina
Function:
- Essential hypertension results from INCREASED arteriolar constriction
What is this?
Capillaries
Basics:
- Single RBC in diameter
- Can have pericytes
- NO smooth muscle but can be contractile
- Diff types in diff places
Function:
- Continuous
- sealed by tight junction
- Fenstrated - small holes
- w/ diaphragm
- w/out diaphragm
- seen in kidney (glomeralus)
- Sinusoid - large holes
- discontinous w/ basement membrane
- seen in liver
- discontinous w/ basement membrane
What is this?
Pericytes
Basics:
- Capillaries can have Pericytes
- In tunica media
- outside of endothelium
Function:
- Pericytes = contractile
- Help regulate blood flow
What is this?
Venules
Basics:
- Post-capillary
- Have pericytes
- LARGER venules may have several pericytse of smooth muscle cells
Function:
- Bring blood back to heart
- Where WBC leave the blood –> enter CT
What are the 2 things in this image?
Medium vein running with Medium artery
What is this?
Large Vein with Valve
Basics:
- Found in large lumen
- Thickest wall of all veins
- May have smooth muscle in the adventitia
Function:
- Brings blood back to heart
-
May have valves
- come off of tunica intima
- prevent backflow
What is this?
Large vein
- 2 layers of smooth muscle going in opposite directions
- helps give structure
What is this?
Lymphatic Capillary
Basics:
- Filled w/ lymph NOT blood
- Thin wall of endothelial cells
- Blind-ended
Function:
- Drain interstitial fluid
What is this?
Cardiac Muscle
Basics:
- Central nuclei (1 or 2)
- Mitochondria = more abundant
-
Functional syncytium
- separate cells, but are coupled & work together via intercalated discs
- Can have lipofuscin
- brown deposits b/c long lived
- May have satellite cells
- Has desmin intermediate filaments
- vimentin in rare cases
Organization:
- Striated muscle
- Branched cells
- Has endomysium & perimysium
- perimysium = forms cardiac skeleton
-
Sarcomeric organization (same ask skeletal muscle)
- Diads at Z disk (instead of triads)
- Purkinje fibers
- specialized cardiac muscle cells
- DO NOT proliferate
What is this?
Cardiac Muscle in XS and LS
-
LS
- Branching cells of varying widths
- Central nuclei
- Intercalated discs
-
XS
- Cellular profiles of varying diameters
- Central nucei in some profiles
What is this?
Myocardial Infarction
First 24 hours:
- Myocardial ishcemia cuased by occlusion of coronary artery
- Necrosis of cardiocytes
- Start lacking intracellular striations
- Lactic dehydrogenase-1 & Creatine Kinases MB
- released from dead cells and detected in serum
3 Days later:
- Necrotic cardiocytes = surrounded by neutrophils
- After 3 weeks (not shown), capillaries, fibroblasts, macrophages, lymphocytes observed
- 3 months later = scar tissue
What is this?
Intercalated Disks in Cardiac
Transverse
- Desmosomes
- Fascia adherans
Longitudinal
- Gap junctions
- allows for synchronous muscle contractions
What is this?
Purkinje Fibers
Basics:
- Modified cardiac muscle fibers
- larger; fewer myofibrils; LOTS of glycogen
- Striated
- Intercalated disks
- Stain more lightly
Function:
- Coordinate rhythmic contraction of cells
What is this?
XS through heart
Epicardium
- aka - Viceral pericardium
- outer layer of the heart
- CT w/ ganglia, nerves, blood vessels
- Thicker than endocardium
- Lined w/ mesothelium
Myocardium
- Cardiac myofibers
- Arranged spirally
- Thicker = walls of ventricles
Endocardium
- Inner lining of heart
-
Has 3 layers:
- Endothelium + CT
- Myoelastic layer (in middle)
- w/ smooth muscle + CT
- Subendocardial layer (deep)
- merges w/ myocardium
- has purkinje fibers
- Lined by endothelium
