Renal SAQs Flashcards
Define cardiorenal syndrome
any acute or chronic problem in the heart or kidneys that could result in an acute or chronic problem of the other.
How does reduced nitric oxide bioavailability contribute to cardiorenal syndrome?
- reduce renal perfusion
- Impair sodium and water reabsorption
- Reduce glomerular filtration rate
- Impair tubuloglomerular feedback mechanism
- Impair myogenic response
- Enhance renal vasoconstrictor responses to renal sympathetic nerve activity, thereby leading to renal ischemia
- Augment the vasoconstrictor activity of the renin angiotensin aldosterone system (RAAS)
How do we define acute kidney injury functionally and structurally? You must include functional
and structural characteristics in your answer
- Abrupt deterioration in kidney function (kidney failure)
- Increase in serum biomarkers (creatinine, reduced urine output and blood urea nitrogen)
- Decreased glomerular filtration rate
- AKI is the presence of any of the following
1. Increase in serum creatinine by 0.3 mg/dl or more within 48 hours
2. Increase in serum creatinine to 1.5 time or more of baseline measured within the prior seven days
3. Urine volume less than 0.5 ml/kg/h for at least 6 hours
How does angiotensinogen get converted to angiotensin II.
Renin Release: When blood pressure drops or sodium levels decrease, specialized cells in the kidneys called juxtaglomerular cells release an enzyme called renin into the bloodstream.
Angiotensinogen Activation: Renin acts on a protein called angiotensinogen, which is produced in the liver and released into the blood. Renin cleaves angiotensinogen to produce angiotensin I.
Conversion to Angiotensin II: Angiotensin I is relatively inactive. However, it is further converted to its active form, angiotensin II, through the action of an enzyme called angiotensin-converting enzyme (ACE). ACE is primarily found in the lungs and blood vessels.
Describe the actions of angiotensin II.
Angiotensin II’s Effects: Angiotensin II is a potent vasoconstrictor, causing blood vessels to narrow, which increases blood pressure. It also stimulates the release of aldosterone from the adrenal glands, promoting sodium and water retention. Additionally, angiotensin II stimulates the release of antidiuretic hormone (ADH), which further contributes to fluid retention.
Describe the cardioprotective arm of the renin angiotensin system and its actions within the kidney
The cardioprotective arm of the renin-angiotensin system involves ACE2 converting angiotensin II to angiotensin-(1-7). This peptide promotes vasodilation, reduces inflammation, and has antifibrotic effects. Within the kidney, angiotensin-(1-7) helps maintain blood vessel function, regulate blood pressure, and counteract the harmful effects of angiotensin II.
Give TWO (2) definitions of oxidative stress: one a classical definition; and one that considers the role of the mitochondria.
Classical Definition: Oxidative stress refers to an imbalance between the production of reactive oxygen species (ROS) and the body’s ability to detoxify and neutralize their harmful effects, leading to potential damage to cellular components.
Mitochondrial Consideration: Oxidative stress with mitochondrial involvement is characterized by the excessive production of ROS within mitochondria, primarily due to electron transport chain dysfunction, which can lead to cellular damage, impaired energy production, and various health disorders.
Name the primary reactive oxygen species (ROS) in aerobic organisms; and name the most
damaging of the ROS.
Primary ROS: Superoxide radical (O2·−) is a primary reactive oxygen species generated during aerobic metabolism.
Most Damaging ROS: Hydroxyl radical (OH·) is considered the most damaging reactive oxygen species due to its high reactivity and ability to cause widespread cellular damage by attacking various biomolecules.
Explain why inflammatory cells are closely linked with oxidative stress
Inflammatory cells generate reactive oxygen species (ROS) as part of their defense response. While ROS help neutralize pathogens, their excessive production during inflammation leads to oxidative stress, causing tissue damage and contributing to chronic inflammatory conditions.
