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Flashcards in MOD Deck (186)
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90

What is the difference between arterial and venous thrombi?

Arterial more platelet based - pale, granular, striated with lines of Zahn
Venous more thrombin based - red and gelatinous

91

What are the outcomes of thrombosis?

Lysis
Propagation (proximally in veins, distally in arteries - direction of flow)
Recanalisation
Embolism
Reorganisation (ingrowth of fibroblasts and capillaries - granulation like tissue)

92

What is an embolism?
What is the commonest cause?

A blockage of a blood vessel by a solid, liquid or gas distant from its site of origin.
90% are thromboembolisms

93

What are common origins and sites of embolisms?

Systemic veins - lungs
Carotid arteries - cerebral arteries
Abdominal aorta - arteries of the leg
Heart - cerebral arteries

94

What are risk factors for DVTs?

Immobility
Post op hypercoagubility
Pregnancy hypercoagubility
COCP
Heart failure
Cancer

95

What are mitigations for DVT risk?

Heparin / anticoagulation
Compression stockings
Early mobilisation
Filters in IVC
Intermittent leg compression during surgery

96

Differentiate athroma, athroscleosis and arteriosclerosis

Athroma - accumulation of extra and intra cellular lipids in the intima and media of medium and large arteries

Athrosclerosis - hardening of arteries as a consequence of athroma

Arteriosclerosis - thickening hardening of arteries, e.g. Hypertension, DM

97

What are the stages of atroma formation?
What is the macroscopic appearance of each?

Fatty streak - slightly raised white or yellow streak
Simple plaque - raised yellow or white plaque
Complex plaque - raised plaque with haemorrhage, infarction, aneurysm and calcification

98

How does a complicated athroma appear histologically?

Fibrosis, necrosis, cholesterol clefts, disruption of internal elastic lamina, ingrowth of blood vessels, fissues.

99

What is the histological appearance of simple athroma?

Proliferated smooth muscle cells and foam cells

100

What are common locations of athromas with related consequences

Coronary arteries - angina / mi
Cerebral arteries - cva / cve
Superior mesenteric artery - ischemic colitis
Legs - pvd

101

What are risk factors for athroma formation?

Age
Gender
Hyperlipidemia
Smoking
Htn
Diabetes
Alcohol
Infection

102

What is the process of athroma formation?

Endothelial injury
Adhesion of platelets and release of PDGF
Proliferation of smooth muscle, macrophage arrival
Phagocytosis of lipids and ldl by smc and macrophage (foam cells)
Macrophages move into intima
Lipoproteins undergo glycosylation
Smc produce unstable matrix weakening plaque
Cytokines from macrophages recruit more inflammatory cells
Neutraphils secrete proteases causing local damage weakening plaque
Lymphocytes stimulate smooth muscle cells

103

What cells are involved in athroma formation?

Smooth muscle cells
Macrophages
Lyphocytes
Neutrophils

104

What are possible outcomes of a cell to growth signals?

Survive
Die
Divide
Differentiate

105

What are the categories of cell growth signals?

Endocrine
Autocrine
Paracrine
Contact

106

What are growth factors?
What are the odd things they effect?

Local mediators that bind to receptors to stimulate transcription of genes causing increased return from, G0 and shortening interphase.
Locomotion, contractility, differentiation, viability, angiogenesis.

107

Give some examples of growth factors

Epidermal growth factor
Vascular endothelial growth factor
Platelet derived growth factor
Granulocyte colony stimulating factor

108

What are the checkpoints in the cell cycle?

G1 end checkpoint - restriction point
G2 end checkpoint

109

What does the restriction point do in the cell cycle?

Checks cell size, environment and for dna damage

110

What does the g2 checkpoint do in the cell cycle?

Ensures all dna has replicated and the cell is of sufficient size.

111

Which cell checkpoint is the most important in the cell cycle?

Restriction point

112

How is cell movement through the cell cycle controlled?

Cyclins

113

What cyclins move the cell through the different stages?

S to G2 is A
G2 to M is B
M to G1 is D (low)
G1 to S is E

114

How do cyclins work to control cell cycle?

Bind to a cyclin dependant kinase which phosphorylates a regulatory protein.

115

How do growth factors effect cyclins?

Increase cyclin dependent kinase
Decreased cyclin dependent kinase inhibitors

116

How are cell losses in tissues replaced?

Division of a stem cell - one daughter cell remaining undiferentiated, one daughter cell replacing the lost cell.

117

In what ways can cells adapt to stress?

Regeneration
Hypertrophy
Hyperplasia
Atrophy
Metaplasia

118

What feature of regeneration aids immunity?

Replacement cells aren't immediately mature / fully functional and therefor infection may not be able to colonise or replicate within them.

119

What body parts can reconstitute?

Uterine lining
End of a finger tip below a certain age