Cardiovascular pathology 4 Flashcards
The vascular system is divided into which 4 components?
- Arterial
- Capillary
- Venous
- Lymphatic
Describe the features of arteries
- Largest = elastic arteries
- Muscular arteries: fewer layers of smooth muscle cells without elastic laminae
Describe the 3 layers of elastic arteries and the components of each
- Tunica intima: inner endothelial layer over a basal lamina and subendothelial connective tissue
- Tunica media: thick, fenestrated, elastic laminae, smooth muscle cells and ground substance
- Tunica adventitia: collagen, elastic fibres and connective tissue with blood vessels (outer layer)
Describe the features of capillaries
- 5-10mm diameter
- Continuous epithelium
- Fenestrated
Describe the features of veins
Thinner walled than arteries
Adventitia is the thickest layer
Valves to prevent retrograde blood flow
What is an aneurysm?
- Localized dilation of a thinned and weakened portion of a vessel.
- Usually arteries affected (large elastic arteries), but can occur in veins
Which deficiency in pigs can lead to aneurysms?
Copper deficiency
- copper is necessary for the development of elastic tissue
What are usually the consequence of aneurysms?
Rupture => fatal
Give 2 examples as to why vessels would rupture?
Horses - sudden rupture of ascending aorta due to trauma to ventral thorax from fall
Cattle - rupture of the middle uterine artery may occur during parturition, uterine torsion or prolapse
What causes arterial hypertrophy?
Sustained increased in pressure of volume loads?
Which vessel is most affected by arterial hypertrophy?
Muscular arteries are mainly affected with hypertrophy of smooth muscle of the tunica media
Give 3 examples of arterial hypertrophy
Cats - pulmonary arteries in parasitic infections e.g. Toxocara spp, Dirofilaria immitis
Cows - Pulmonary arteries, hypoxia induced vasoconstriction and pulmonary hypertension from exposure to high altitude
All - CV abnormalities that shunt blood left to right lead to pulmonary hypertension and hypertrophy
Arterial medial calcification is associated with?
Concurrent endocardial mineralisation and fibrosis
Arterial medial calcification could be seen with which conditions?
- Vitamin D toxicosis
- Renal insufficiency
- Johne’s disease
- Calcinogenic plant toxicosis
How does arterial medial calcification appear grossly?
Solid, dense, pipelike structures with raised, solid, white, intimal plaques.
How does arterial medial calcification appear histologically?
Prominent basophilic, granular mineral deposits occasionally admixed with iron (siderocalcinosis).
What is a normal finding in the subendothelium of muscular arteries and arterioles of horses?
Arterial intimal calcification
Describe fibrinoid necrosis
Deposits of an amorphous, homogeneous, eosinophilic protein material composed of serum proteins and fibrinogen.
Describe the pathogenesis of fibrinoid necrosis
Endothelial and muscular damage of the arterial wall with extravasation of proteins and deposition in the vessel wall.
The smooth muscle of the tunica media has been replaced by an amorphous to fibiliary eosinophilic protein
Give 2 examples of when you’d see fibrinoid necrosis
Pigs - vitamin E deficiency
Dogs - uraemia