Histo - CV Flashcards by Jasmine Santos

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

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What is this?

Tunics in a Muscular Artery

Tunica intima
- closest to lumen
Tunica media
- middle
Tunica aventitia
- outter most

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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

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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

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What is Tunica Adventitia?

Basics:

Loose CT
- has vasa vasorum in LARGER vessels
- has smooth muscle in LARGE veins

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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

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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

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What is this?

Aneurysm

Basics:

Dilation of arterial wall
- caused by weak tunica media

Causes:

developmental defects
lesions
variety of diseases
- Marfan’s syndrome

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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

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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

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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

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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

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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

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What is this?

Pericytes

Basics:

Capillaries can have Pericytes
In tunica media
- outside of endothelium

Function:

Pericytes = contractile
Help regulate blood flow

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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

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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 are the characteristics of Lymphatic Vessels?

Basics:

Tunica intima
- Endothelium + BL
  - in lymphatic caps, BL can be discontinous or absent
- Subendothelial layer
- Valves
  - in smaller lymph vessels
Tunica Media
- Present only in LARGE lymphatics
- Smooth muscle
- CT
Tunica adventitia
- Thin layer of CT

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:_ 1. Endothelium + CT 2. Myoelastic layer (in middle) * w/ smooth muscle + CT 3. Subendocardial layer (deep) * merges w/ myocardium * has purkinje fibers * Lined by _endothelium_

What are the 2 major Semilunar Valves in the Heart?

**Aortic Valve:** * Between L.V. and aorta **Pulmonary Trunk Valve:** * Between R.V. and pulmonary trunk **Characteristics:** * _No chordae tendineae_ * Similar to valves in veins

What are the 2 major Atrioventricular Valves in the heart?

**Tricuspid:** * R.A. --\> R.V. (atrioventricular) * Has 3 leaflets * 3 papillary muscles * connected by chordae tendineae **Mitral valve:** * L.A. --\> L.V. (atroventricular) * Has 2 leaflets * 2 papillary muscles * connected by chordae tendineae **Notes:** * _Papillary muscles:_ * specialized **striated muscles** * smaller than cardiac myofibers * _Chordae tendineae_ * **Tendons** * Prevent valves from turning inside-out * Connect papillary muscles to valves

What are the 2 types of Pericardium?

**Fibrous pericardium** * Dense CT * _Continous w/ tunica adventitial_ of great vessels **Serous pericardium** 1. Parietal layer * _adherent to the fibrous_ pericardium 2. Visceral layer * Epicardium when in contact w/ the heart **Note:** * 2 layers = continous (fibrous & serous) * between them = pericardial cavity