pt7 Flashcards
(50 cards)
What does the term ‘neoplasia’ literally mean?
Neoplasia literally means ‘new growth,’ referring to the abnormal, unregulated proliferation of cells.
What is meant by tumour ‘differentiation’?
Tumour differentiation describes how much tumour cells resemble their normal counterparts; well-differentiated tumours closely mimic normal tissue, whereas poorly differentiated tumours do not.
What is pleomorphism, and in which context is it used?
Pleomorphism is the variation in size and shape among cells, and it is a common feature seen in anaplastic and malignant cells.
What are tumour giant cells?
Tumour giant cells are unusually large cells, often formed by the fusion of several cells, and are characteristic of anaplastic or highly malignant tumours.
Why is dysplasia considered a pre-neoplastic condition?
Dysplasia involves disordered growth and architectural disturbance; if persistent, it can progress to carcinoma in situ and eventually to invasive cancer.
What does metastasis indicate about a tumour?
Metastasis indicates that a tumour is malignant since only malignant tumours have the capacity to spread to distant sites.
How does lymphatic spread contribute to metastasis?
Tumour cells enter lymphatic vessels and travel to regional lymph nodes, where they may establish secondary tumour sites.
How does haematogenous spread differ from lymphatic spread?
In haematogenous spread, tumour cells enter the bloodstream and can form metastases in distant organs, such as the liver or lungs.
What are the five main components of the circulatory system?
Pump (heart), distributary system (aorta/arteries/arterioles), oxygenation system (pulmonary vessels/lungs), exchange system (capillaries), collecting system (veins/vena cava).
What is the primary function of the heart valves?
To maintain unidirectional blood flow through the heart chambers and great vessels.
Name the four cardiac valves.
Aortic valve, pulmonary valve, mitral (bicuspid) valve, tricuspid valve.
What tissue makes up the myocardium?
Specialized striated muscle cells called cardiac myocytes.
How are ventricular myocytes arranged, and why?
In a spiral/circumferential orientation to squeeze blood efficiently on systole and relax on diastole.
When does most coronary blood flow to the myocardium occur?
During ventricular diastole, when contracting myocardium isn’t compressing the vessels.
What are the three major epicardial coronary arteries?
Left anterior descending (LAD), left circumflex (LCX), and right coronary artery (RCA).
Why is the LAD artery clinically important?
It supplies a large portion of the left ventricle and is most often blocked in myocardial infarction.
What is the sinoatrial (SA) node?
The heart’s primary pacemaker, located at the junction of the right atrial appendage and superior vena cava.
What is the role of the atrioventricular (AV) node?
Delays impulse from atria to ventricles to allow atrial contraction and ventricular filling.
What does the Bundle of His do?
Conducts impulse from AV node into the interventricular septum before dividing into bundle branches.
What are Purkinje fibers?
Network of fibers extending through the ventricular myocardium to ensure coordinated contraction.
Why does the SA node set heart rate over other pacemakers?
It has the fastest intrinsic rate (up to ~200 bpm), overriding slower subsidiary pacemakers.
What does the P wave on an ECG represent?
Atrial depolarization.
What does the QRS complex represent?
Ventricular depolarization.
What does the T wave represent?
Ventricular repolarization.
