Vital Organs You Need to Know for the NCLEX (...

Vital Organs You Need to Know for the NCLEX (2025)

The National Council Licensure Examination (NCLEX) is a crucial step for aspiring nurses to demonstrate their readiness to provide safe and effective care. One of the key areas of knowledge required for the NCLEX is a solid understanding of the human body's vital organs.

This guide covers the most important organs—heart, lungs, brain, liver, and kidneys—from a nursing perspective. We’ll break down how each is tested on the NCLEX, what to watch for in clinical situations, and what kind of questions you might see.

Want to brush up on the basics first? Check out 25 Essential Words to Know Before the NCLEX.

🫀 The Heart

The heart pumps blood throughout the body, delivering oxygen and nutrients while removing waste products. It consists of four chambers and is regulated by an electrical conduction system.

What Nurses Need to Know:

Common cardiac conditions: MI, CHF, arrhythmias
Nursing assessments: apical pulse, edema, BP trends
ECG interpretation basics: normal sinus rhythm, ST elevation, AFib
Priority interventions for chest pain: MONA (Morphine, Oxygen, Nitrates, Aspirin)

NCLEX Scenario:

A patient is admitted with chest pain and ECG shows ST elevation in leads II, III, and aVF. What is your first nursing action?

A. Prepare for defibrillation
B. Administer morphine
C. Place the patient in Trendelenburg
D. Check a troponin level

Correct Answer: B. Morphine is part of initial MI care (MONA).

Clinical Case Study:

Mr. Lopez, age 68, presents with fatigue and shortness of breath. You hear crackles in the lungs and note bilateral pitting edema. His BNP is elevated, and EF is 35%. What are your top 3 nursing priorities?

Administer prescribed diuretics
Elevate the legs and monitor intake/output
Educate on sodium restriction and daily weights

🧠 Tip: Know how to differentiate left-sided vs. right-sided heart failure—a common NCLEX topic.

🫁 The Lungs

The lungs are responsible for gas exchange: oxygen in, carbon dioxide out. They're divided into lobes (3 on the right, 2 on the left).

What Nurses Need to Know:

Respiratory diseases: COPD, pneumonia, asthma
Nursing assessments: lung sounds, O2 sat, tripod positioning
Interventions: incentive spirometry, oxygen therapy, suctioning
ABG interpretation (especially pH, CO2, HCO3)

NCLEX Scenario:

A patient with COPD has a pH of 7.32 and a PaCO2 of 55 mmHg. What is the acid-base status?

A. Metabolic alkalosis
B. Respiratory acidosis
C. Respiratory alkalosis
D. Metabolic acidosis

Correct Answer: B. Elevated CO2 and low pH = respiratory acidosis.

Clinical Case Study:

Mrs. Chen, age 70, arrives with confusion and productive cough. O2 sat is 89% on room air. Auscultation reveals crackles in the lower lobes. What are your initial steps?

Apply 2L O2 via nasal cannula
Obtain sputum sample
Administer prescribed antibiotics and monitor response

Mnemonic for early hypoxia: "RAT" — Restlessness, Anxiety, Tachycardia

📘 Also helpful: Different Types of NCLEX Questions

🧠 The Brain

The brain controls body functions, including thought, coordination, and vital signs. It’s divided into the cerebrum, cerebellum, and brainstem.

What Nurses Need to Know:

Neuro conditions: stroke, TBI, seizures, increased ICP
Assessments: GCS (Glasgow Coma Scale), PERRLA, motor strength
Priorities: maintain cerebral perfusion, elevate HOB, seizure precautions
Warning signs of stroke: FAST (Face, Arms, Speech, Time)

Quick Tip:

Know the Glasgow Coma Scale (GCS) components: eye opening, verbal response, and motor response. A GCS < 8 usually means intubation.

Clinical Case Study:

Mr. Jackson, 59, is brought to the ED with slurred speech and right-sided weakness. CT confirms ischemic stroke. What's your immediate nursing role?

Keep HOB elevated to 30 degrees
Monitor neuro status every hour
Prepare for tPA administration per protocol

Use therapeutic communication techniques for stroke patients with aphasia—explained in Therapeutic Communication Tips.

🧬 The Liver

The liver detoxifies blood, synthesizes proteins, and helps in digestion.

What Nurses Need to Know:

Conditions: hepatitis, cirrhosis, liver failure
Signs: jaundice, ascites, asterixis, elevated LFTs (ALT/AST)
Priorities: monitor ammonia levels, fall risk, skin care
Meds to avoid: acetaminophen, sedatives, NSAIDs

Key Labs:

AST/ALT > 40 = liver injury
Ammonia > 45 = risk for encephalopathy
Albumin < 3.5 = poor protein synthesis

Clinical Case Study:

Ms. Rivera, age 50, with a history of alcohol use presents with jaundice and lethargy. Her ammonia is 87. What is your next move?

Administer lactulose as ordered
Monitor for signs of hepatic encephalopathy
Implement fall precautions and assess mental status frequently

Mnemonic for cirrhosis complications: "THE LIVER IS SCARRED" — Thrombocytopenia, Hepatic encephalopathy, Edema...

📘 Mnemonics like this? See 25 Nursing Mnemonics for Complex Concepts

🩺 The Kidneys

The kidneys filter waste and regulate fluid, electrolyte, and acid-base balance.

What Nurses Need to Know:

Conditions: AKI, CKD, nephrotic syndrome
Labs: BUN, creatinine, GFR, urine output (<30 mL/hr is a red flag)
Interventions: fluid restrictions, monitor electrolytes (esp. K+), prepare for dialysis
Drugs: careful with nephrotoxic meds (vancomycin, contrast dye)

Clinical Tip:

Always report:

Urine output < 30 mL/hr
Potassium > 5.0 mEq/L
Creatinine > 1.3 mg/dL

Clinical Case Study:

Mr. Hughes, 76, is on gentamicin for sepsis. You note he’s only voided 200 mL in 12 hours. Creatinine is 2.1. What's your role?

Notify provider immediately
Monitor for further signs of AKI
Ensure patient is well-hydrated and discontinue nephrotoxic meds if ordered

📘 Related: NCLEX Categories Explained

✅ Final Tips for NCLEX Organ System Mastery

Here’s a quick checklist of red flags by organ:

Organ	Red Flag Signs	Labs to Watch
Heart	Chest pain, SOB	Troponin, BNP
Lungs	O2 sat < 90%, wheezing	ABG, pH, CO2
Brain	GCS < 8, unequal pupils	ICP, GCS
Liver	Jaundice, confusion	ALT/AST, ammonia
Kidneys	Low UO, edema	BUN, Creatinine

Create flashcards for each organ with conditions, labs, meds, and red flags
Use GoodNurse.com to drill categories and vocab
Practice case studies to integrate patho + nursing priorities
Review labs and interventions daily in your final review week

💡 Want a deeper dive? Start with our full NCLEX study guide and plan your schedule week-by-week.

Understanding the vital organs and their functions is not just NCLEX content—it’s core to becoming a safe and effective nurse. Focus on conditions, labs, symptoms, and interventions tied to each system.

You’ve got this. 🚀