Flashcards in Vascular and Lymphatic system Deck (22):
Define the term preload and list the factors that determine preload.
The pressure on the walls of the ventricles of the volume of blood filling. Stroke volume
Explain what afterload is and how it is influenced.
It is the resistance to ventricular contraction. Stroke volume
Describe the baroreceptor reflex.
It is one of the body's homeostatic mechanisms that help to maintain blood pressure at nearly constant levels. The baroreflex provides a rapid negative feedback loop in which an elevated blood pressure reflexively causes the heart rate to decrease and also causes blood pressure to decrease.
Briefly explain each of the factors that contribute to blood pressure and blood flow.
Indicate the main factor that is used to alter blood flow in the short term.
Cardiac output: is the measurement of blood flow from the heart through the ventricles, and is usually measured in litres per minute.
Compliance is the ability of any compartment to expand to accommodate increased content.
The volume of the blood: As blood volume increases, pressure and flow increase
The viscosity of the blood is the thickness of fluids that affect their ability to flow.
Blood vessel length and diameter the longer the vessel, the greater the resistance and the lower the flow.
Discuss what is meant by peripheral resistance and how the autonomic nervous system controls peripheral resistance.
Peripheral resistance is the resistance of the arteries to blood flow. As the arteries constrict, the resistance increases and as they dilate, resistance decreases.Peripheral resistance is determined by three factors:
Autonomic activity: sympathetic activity constricts peripheral arteries.
Pharmacologic agents: vasoconstrictor drugs increase resistance while vasodilator drugs decrease it.
Blood viscosity: increased viscosity increases resistance.
The autonomic nervous system (ANS) controls functions of the internal viscera, blood vessels throughout the body, effectors in the skin and glands, in fact, all organs except voluntarily controlled striated muscle. Its purpose is to adjust these organs so that their activities are most favourable to their own functions and to the balance of activity of the whole body
Explain the arterial blood pressure.
Arterial blood pressure is created by ejection of blood from the heart during systole (cardiac output) and the resistance of flow from the arterial walls (systemic vascular resistance)
Describe how the rennin-angiotensin-aldosterone system influences blood pressure.
The RAS regulates blood pressure and fluid balance in the body. When blood volume or sodium levels in the body are low, or blood potassium is high, cells in the kidney release the enzyme, renin. Renin converts angiotensinogen, which is produced in the liver, to the hormone angiotensin I. An enzyme known as angiotensin-converting enzyme found in the lungs metabolizes angiotensin I into angiotensin II. Angiotensin II causes blood vessels to constrict and blood pressure to increase.
Explain how the lymphatic system is involved in fluid movements.
Fluid collects in the interstitial tissue due to reduced capillary pressure.
It is the role of the Lymphatic system to move this fluid back into the cardiovascular system.
In the circulatory system, blood flows from the heart, through the arteries, and into capillaries that surround all cells. When blood reaches the capillaries, a portion of blood plasma (the liquid portion of the blood) seeps out of the capillaries and into the space surrounding cells. That plasma is then known as tissue fluid. Tissue fluid consists of water plus dissolved molecules that are small enough to fit through the small openings in capillaries.
Outline the pathway of lymph flow, from entering the lymphatic system to entering the cardiovascular system.
Tissue fluid is transported from lymphatic capillaries to lymphatic collecting vessels, where along the length of these vessels, lymph nodes occur to filter the lymph and valves occur to prevent backflow of lymph.
Lymph flows from lymphatic vessels into
lymphatic trunks , and finally into collecting ducts where the lymph is disposed into the subclavian veins.
Describe the clinical manifestations and nursing care of a patient with Lymphedema
Enlarged lymph nodes
Increased proliferation of lymphocytes and monocytes
Thorough skin care
Clean, dry and moisturise (in between the fingers and toes).
Promoting lymphatic drainage
Compression bandaging/stockings/pneumatic devices
Elasticated graduated compression stockings (legs) compression bandage (arms)
Monitor size of the affected limb (use a measuring tape)
Monitor fluid balance and weight
Psychological support (Disturbed body image)
Discuss the pathophysiology of an arterial aneurysm.
Occurs when the wall of an artery is weakened.
Describe the difference between a true aneurysm and a false aneurysm.
• An aneurysm is a dilatation of the artery while pseudo-aneurysm is a walled off collection of blood outside a damaged artery.
• Aneurysm and pseudo-aneurysms can both expand, but pseudo-aneurysms do not rupture with dilatation.
• Mortality of aneurysms is much higher than that of pseudo-aneurysms.
List three types of an Aortic aneurysm and identify the clinical manifestations associated with each one.
back, neck or substernal pain
oedema of the face or neck
distended neck veins
pulsations abdominal masses
mild to severe midabdominal or lumbar back pain
abrupt severe, tearing pain in an area of an aneurysm
mild or maker hypertension
weak or absent pulse
Discuss the pathophysiology of atherosclerosis.
Atherosclerosis, chronic disease caused by the deposition of fats, cholesterol, calcium, and other substances in the innermost layer of endothelium of the large and medium-sized arteries. Atherosclerosis is the most common arterial abnormality characterized as arteriosclerosis, which is defined by the loss of arterial elasticity due to vessel thickening and stiffening.
What are the clinical manifestations associated with atherosclerosis?
What are the main focuses in the management for peripheral vascular disease?
Neurovascular observations (5 Ps)
What medications are used in the treatment of peripheral vascular disease?
NSAID – Pain and inflammation. Blood thinner.
300mg-600mg QID enteric coated or dispersible
Gastric irritant – take with food.
Platelet inhibitor – Prevents blood clots from developing
Can be taken in conjunction with Aspirin.
What modifiable risk factors need to be addressed with patients diagnosed with peripheral vascular disease, in order to slow its progression?
Discuss the pathophysiology of acute myocardial infarction.
ST segment elevation myocardial infarction reflects acute myocardial infarction resulting from the rupture or erosion of an atherosclerotic plaque with thrombotic occlusion of an epicardial coronary artery and transmural ischaemia.
Discuss the clinical manifestations associated with acute myocardial infarction.
Discuss the characteristics of five complications, which may arise as a result of an acute myocardial infarction.