Frustrations & Aspirations an RN

Innate and Adaptive Immunity

There are 2 systems of immunity - innate immunity and adaptive immunity. Thank you @coffeeloveinglazyfox, for the suggestion!

Initially, the heart tries to make up for the loss of cardiac output, by developing more muscle mass, enlarging, and pumping faster. Changes may also occur in the circulatory system, as the body adjusts to lower cardiac output. For example, the blood vessels may narrow to increase blood pressure, and blood may be diverted away from less essential tissues and organs, such as the kidneys, as the body tries to compensate for the heart’s reduced power. 

Over time, the increased workload leads to changes in the heart muscle itself (known as remodeling), causing it to stiffen, and further reducing its ability to pump blood efficiently, which leads to worsening heart failure. As the heart increasingly struggles to keep up with the body’s demand for blood and oxygen, characteristic signs and symptoms of heart failure begin to appear.

Heart failure can involve the left side, the right side, or both sides of the heart. The left ventricle is the stronger of the heart’s two pumps. Left-sided heart failure is more common, and may subsequently cause the right side to fail.

Reduced cardiac output and blood supply may have multiple effects in various organs and tissues. These include:

• An increased heart rate due to increased sympathetic nervous system activity, the part of the nervous system responsible for accelerating heart rate, constricting blood vessels and raising blood pressure. Although increased heart rate helps maintain cardiac output, it also means more oxygen is needed by the heart itself - increased cardiac perfusion may worsen coronary artery disease or cause arrhythmias, as well as stimulate increases in muscle mass leading to heart enlargement.

• Increased blood pressure due to sympathetic nervous system activity (increases the amount of work the heart has to perform). Increased blood volume and blood pressure due to secretion of antidiuretic hormone in response to sympathetic nervous system activity, which causes fluid retention in the kidneys.

• Salt and fluid retention by the kidneys caused as a result of reduced blood flow to the kidneys, which ultimately leads to the secretion of aldosterone, a hormone that stimulates the absorption of sodium (Na+) by the kidneys, and regulates the balance of salt and water in the bloodstream.

• Heart muscle remodeling caused by chronically high levels of a number of hormones including catecholamines, renin, angiotensin, and aldosterone.

• Decreased muscle strength due to skeletal muscle atrophy resulting from reduced perfusion.

“Just something that helps with blocks”

HEARTBEATS!!

The pause is to allow the atria to fully empty into the ventricle.

Heartbeat on an ECG trace

P Interval (Ventricular Diastole)

Atria and ventricles are relaxed

blood is flowing into the atria from the veins. 

Atrial pressure increases above that of the ventricle, AV valves open allowing blood to flow into the ventricle

P Wave (Atrial Systole) P-Q

Signal transduction from SA to AV nodes. 

SA node fires 

Atria contract causing atrial systole 

which forces all blood into the ventricles

emptying the atria.

Q Interval (End of Ventricular Diastole)

Depolarisation of interventricular (IV) septum 

AV valves remain open - all remaining blood squeezed into the ventricles. 

impulse from the SA node reaches the AV node 

which spreads the signal throughout the walls of the ventricles via bundles of His and Purkinje fibres

R peak is the end of ventricular diastole and the start of systole.

R Interval (Ventricular Systole)

Ventricular contraction

All blood is now within the ventricles

so pressure is higher than in the atria - AV valves close

ventricles start to contract although pressure is not yet high enough to open the SL (semilunar) valves

ST Segment (Ventricular Systole)

Ventricular contraction

Pressure increases until it equals Aortic pressure,

SL valves open

blood is ejected into the Aorta (and pulmonary artery) as ventricles contract

At this time the atria are in diastole and filling with blood returning from the veins.

plateau in ventricular arterial pressure

T Wave (Ventricular Diastole)

T= moment of Ventricular repolarisation immediately before ventricular relaxation

Ventricles relax

ventricular pressure is once again less than the aortic pressure 

ALP: 

Present in liver, bone, intestine, kidney, neutrophils and placenta. 

80% originates from bone. 

If GGT up, ALP from liver. 

If GGT normal, ALP from bones. 

ALP rises with obstruction to the biliary tract. 

ALT: 

Most present in the liver, but also found in other tissues. 

Very high levels suggest, viral hepatitis, diabetes, congestive heart failure, liver damage, bile duct problems, infectious mononucleosis or myopathy.

AST: 

Present in liver, heart, skeletal muscle, kidneys, pancreas, lungs, leukocytes and erythrocytes. 

Increased levels may indicate haemolytic anaemia, rhabdomyolysis, increased leucocyte count etc

Distinction in source can be made via CK and Troponin. 

AST<ALT = hepatic injury

AST>ALT = hepatocyte necrosis - poor prognosis (AST is found in the mitochondria, not spilled out until severe destruction) - CONSIDER MUSCLE SOURCE

AST:ALT Ratio: 

Greater than 2 = Hepatitis.

Less than 2= cholestatic disorder.

GGT: 

Found in both hepatocytes and biliary epithelial cells. 

Sensitive for hepatobiliary disease. 

5 times increase = good marker of alcohol abuse.

GST (Gluthathione S-transferase):

 Isoenzymes of GST are involved in the detoxification and conjugation of several electrophilic compounds with glutathione. 

Found to be a very good marker of acute hepatocellular damage with a half life of 90min. Not widely used.

CK: 

Found in heart, brain, skeletal muscle and other tissue. 

Released when muscle damage. 

Causes range from exercise injury to hormonal disorders.

LDH: 

Found in muscles, liver, heart, pancreas, kidneys, brain and blood cells. 

Used to used to diagnose and monitor heart attacks. 

Five types of isoenzymes can help determine location of damage. 

LDH-1 - heart, red cells, kidney, germ cells. 

LDH-2 - heart, red blood cells, kidney (lesser amounts than LDH-1).

LDH-3 - lungs and other tissues. 

LDH-4 - white blood cells, lymph nodes; muscle, liver (smaller amounts than LDH-5).

LDH-5 - liver, muscle.

Troponin: 

Highly specific marker for myocardial infarction or muscle cell death. 

Also used to diagnose other conditions which relate to cardiac muscle injury.

Lipase: 

Found in blood, gastric juices, pancreatic secretions, intestinal juices and adipose tissues.

Hydrolyses triglycerides  

Acute pancreatitis, pancreatic neoplasia, pancreatic abscesses, and pancreatic duct obstruction can result in high levels of lipase and usually are 2 to 3 times the upper limit of normal.

Amylase: 

Is made by the pancreas and by the glands in and around the mouth/throat. 

Catalyses hydrolysis of starch 

High amylase may indicate the presence of a condition affecting the pancreas. 

In acute pancreatitis the levels are 4-6 times normal and remains high until treated. 

Chronic pancreatitis, levels will be high but will decrease until problem is solved.

Acid phosphatase: