4. cardiovascular system Flashcards
role of cardiovascular system?
= transport system responsible for delivering oxygen, hormones, carrying waste products and nutrients around the body
- Heart acts as a pump to push the blood around the body, the blood transports oxygen and waste around the body and the blood vessels contain the blood and maintain the pressure
- Any disruptions in these three components can lead to the development of coronary hear disease
Cellular changes that occur in cardiac muscles in response to increase workload?
Increased workload = increases the affects on the heart
- when there is increased workload the muscles need more oxygen = heart muscles pump harder
- muscles send signal saying they need more oxygen - heart pumps harder and you breathe faster to get more oxygen into lungs
Define the term shock and explain how it may develop?
Shock = the supply of blood to the tissue is inadequate to meed the metabolic demand of the body
- all types of shock result in acute circulatory failure which causes tissue hypoperfusion which leads to cellular hypoxia which may lead to tissue damage/ organ failure
- Shock can result from heart failure, fluid loss, sepsis or an allergic reaction
Homeostasis
= the body’s ability to maintain stable internal conditions despite the changes to external environment
main systems that control homeostasis?
Most commonly, the nervous and endocrine systems restore homeostasis in the body.
- Nervous system acts by sending electrical signals (nerve impulses/action potentials) to organs to counteract the imbalance
- Glands in the Endocrine system secrete hormones into the blood.
- nerve impulses - rapid change, hormones = slower change
Feedback systems?
- stimulus
- Receptor
- afferent pathway
- control centre (brain
- efferent pathways
- effector
difference between positive and negative feedback?
Negative feedback reverse a change in a controlled condition.
Positive feedback strengthen or reinforce a change in a controlled condition
How does the body maintain blood pressure in a person with sever bleeding
Adequate blood pressure is needed for blood flow and hence the transport of all nutrients and wastes to and from regions such as.
- Three negative feedback pathway loops for blood pressure = indicate that three different processes must be active to keep blood pressure sufficient
- When sodium is retained by the kidneys so that it remains in the blood instead of exiting the boding in the urine, water is also retained = increase in blood volume and corresponding increase in blood pressure
Three classifications of anemia?
- microcytic
- normocytic
- macrocytic
Causes of microcytic anemia ?
= small pale RBC, normal or low RBC count
causes:
- iron deficiency
- thalassemia trait - genetic defect in hb, alpha or beta chains of hb affected
Causes of Normocytic anemia?
= cells normal in size and colour but low RBCC
causes:
- blood loss
- haemolytic anemia - immune complexes, faulty heart valve
- sickle cell disease - malaria
Causes of macrocytic anemia?
=. large RBC, low RBC, no central pallor
- Megaloblastic anaemia – folate or B12 deficiency, may be genetic
- Aplastic anaemia: bone marrow failure = abundant red bone marrow in femur of young child compared to apparent absence of marrow in femur of child who died from aplastic anaemia
What is a myocardial infarction?
=. occurs when there. is an obstruction in the coronary artery
- resulting in lack of blood supply (ischemia) and inadequate oxygen (hypoxia) to the heart muscles
= tissue death (infarction) of heart muscles, compromising or stopping the heart functioning
What can cause a myocardial infarction?
- Atherosclerosis : narrowing of the coronary arteries, due to a build-up of cholesterol and fat (plaque) in the arterieso Build up cause’s arteries to become harder and more restricted, decreasing the blood flow through the artery
o If plaque breaks off it causes occlusion in artery = stopping blood supply to heart = ischemia, hypoxia and cell death – a myocardial infarction - Blood clot (thrombosis) = blocking the blood flow
- Coronary artery disease
Heart failure
= defined as cardiac impairment with inability to fill or eject blood volume
- thus the heart can no longer pump enough blood around the body
- cam occur on left ventricular failure (congestive heart failure) and right sided heart failure