Pathology - Circulation Lectures

Question 1

What is the structure of a blood vessel?

Answer 1

Lumen, epithelial cells, basal lamina, smooth muscle, collagen

Question 2

What is found inside the lumen?

Answer 2

RBS’s, WBC’s, plasma, platelets

Question 3

What is serum?

Answer 3

Plasma without clotting factors

Question 4

Where are clotting factors made?

Answer 4

In the liver and by endothelial cells

Question 5

What are the steps involved in blood clotting cascade? (P)

Answer 5

Prothrombin to thrombin
Thrombin converts fibrinogen to fibrin
Fibrin is mesh

Question 6

Where is tissue factor released from during clotting?

Answer 6

Smooth muscle cells

Question 7

How are plasma clotting factors activated?

Answer 7

When there is a trauma, they interact with collagen from the interstitial fluid and lead to the production of thrombin from prothrombin

Question 8

What is the purpose of tissue factor (Tf)?

Answer 8

Interacts with a specific clotting factor in plasma and triggers the activation of the clotting cascade

Question 9

How are platelets formed and what’s their purpose?

Answer 9

Fragments cut off from Megakaryocytes. Coagulation.

Question 10

Thrombus formation vs clot formation?

Answer 10

Thrombus formation occurs in flowing blood, by platelets and collagen forming a mesh fibrin clot.
Clot formation occurs in stationary blood - with blood and collagen forming fibrin mesh.

Question 11

What is the role of plasminogen?

Answer 11

Converts to plasmin and breaks up fibrin, by process of thrombolysis

Question 12

What 3 situations are prt of virchow’s triad?

Answer 12

Change in intimacy surface of vessels
Change in pattern of blood flow
Change in blood constituents

Question 13

What is the purpose of virchow’s triad?

Answer 13

The physiology that leads to a venous thrombus formation

Question 14

What can occur to lead to thrombus in a cigarette smoker?

Answer 14

Cigarette chemicals make blood platalets stickier (change in blood constituents), causing atheroma on vessel surface, altering blood flow (change in blood flow), and if the atheroma ruptures through endothelial wall (change in intimal surface), then clot and thrombus will form

Question 15

What is an infarct?

Answer 15

Necrosis as a result of ischaemia

Question 16

What is ischaemia?

Answer 16

Poor blood supply to tissue. Can be due to partial or full blockage of artery or blood vessel supplying the tissue with blood and thus o2 - hypoxia

Question 17

Ischaemia vs hypoxia?

Answer 17

Ischaemia is poor blood supply to tissue. Hypoxia is poor o2 supply to tissue

Question 18

What is an embolism?

Answer 18

A mass of material moving throgh the vascular system with the potential to cause a blockage

Question 19

What’s the most common embolism?

Answer 19

Thromboembolism. It’s a pulmonary embolism where slow flow in leg veins lead to clot formation, breaking off and travelling to pulmonary artery

Question 20

What are 2 other common causes of embolism?

Answer 20

Marrow embolism - fracture leads to bone fragments travelling through vein to lung vessels
Air embolism - air enters vein and embolises to heart.

Question 21

How does circulatory shock occur?

Answer 21

Failure of blood flow leading to perfusion of vital organs (lack of blood flow)

Question 22

How does vessel diameter react to different levels of blood?

Answer 22

When little blood present, smooth muscle contracts. Vice versa.

Question 23

What is normal blood pressure an what does its stability rely on? (3)

Answer 23

120/80. Relies on enough blood in circulation (5L), smooth muscle ‘tone’ and heart pumping blood

Question 24

How do our bodies detect blood pressure and o2?

Answer 24

2 carotid bodies and 2 carotid sinuses on either side of neck
Bodies detect o2 pressure and sinuses detect blood pressure, sending signals to brain stem

Question 25

What happens when ur carotid sinuses detect low blood pressure?

Answer 25

Sends signal to brainstem to direct heart to pump faster and harder. Sympathetic response activated by brainstem, increasing vessel tone in limbs so blood is pumped to vital organs. Also secretes adrenaline

Question 26

What are the vital organ which require blood in sympathetic/circulatory shock?

Answer 26

Heart, lungs, brain

Question 27

What are the signs that circulatory shock is present?

Answer 27

Low blood pressure but high pulse

Question 28

What are the three main causes of circulatory shock?

Answer 28

Hyovolaemic, septic or cardiogenic shock