Medical Systems Study Guide for California CNA Exam
For English Learners at B1 Level
1. Nervous System
What it is: The body’s control center that sends messages throughout the body.
Main function: Controls all body activities, including movement, thinking, and feeling.
Key parts:
- Brain – Controls thinking, memory, and body functions
- Spinal cord – Carries messages between brain and body
- Nerves – Carry signals to and from different body parts
Important for CNAs:
- Watch for changes in mental status (confusion, alertness)
- Report seizures, dizziness, or weakness immediately
- Help protect patients who have nerve damage or paralysis
2. Immune System
What it is: The body’s defense system that fights disease and infection.
Main function: Protects the body from germs, viruses, and harmful substances.
Key parts:
- White blood cells – Fight infections
- Lymph nodes – Filter harmful substances
- Spleen – Removes old blood cells and fights infection
- Bone marrow – Makes new blood cells
Important for CNAs:
- Use proper infection control (hand washing, gloves)
- Watch for signs of infection (fever, redness, swelling)
- Some patients have weak immune systems and get sick easily
3. Cardiovascular System
What it is: The system that pumps blood throughout the body.
Main function: Delivers oxygen and nutrients to all body parts and removes waste.
Key parts:
- Heart – Pumps blood through the body
- Blood vessels:
- Arteries – Carry blood away from the heart
- Veins – Carry blood back to the heart
- Capillaries – Tiny vessels that connect arteries and veins
- Blood – Carries oxygen, nutrients, and waste
Important for CNAs:
- Take vital signs (blood pressure, pulse)
- Watch for chest pain, shortness of breath, swelling in legs
- Help patients with heart conditions avoid overexertion
4. Integumentary System
What it is: The skin and everything attached to it.
Main function: Protects the body from injury, infection, and temperature changes.
Key parts:
- Skin – The body’s largest organ
- Hair – Helps regulate body temperature
- Nails – Protect fingers and toes
- Sweat glands – Help cool the body
- Oil glands – Keep skin moist
Important for CNAs:
- Check skin daily for pressure sores (bed sores)
- Keep skin clean and dry
- Report any cuts, bruises, rashes, or skin changes
- Help prevent skin breakdown by turning bedridden patients
5. Gastrointestinal System (Digestive System)
What it is: The system that breaks down food and absorbs nutrients.
Main function: Digests food, absorbs nutrients, and removes solid waste from the body.
Key parts:
- Mouth – Where digestion begins
- Esophagus – Tube that carries food to the stomach
- Stomach – Breaks down food with acid
- Small intestine – Absorbs most nutrients
- Large intestine (colon) – Absorbs water and forms stool
- Liver – Makes bile to help digest fats
- Pancreas – Makes enzymes to help digestion
Important for CNAs:
- Monitor bowel movements (frequency, consistency, color)
- Help with feeding and nutrition
- Watch for nausea, vomiting, abdominal pain
- Report changes in appetite or eating habits
6. Respiratory System
What it is: The system that helps us breathe and get oxygen.
Main function: Brings oxygen into the body and removes carbon dioxide (waste gas).
Key parts:
- Nose and mouth – Where air enters the body
- Trachea (windpipe) – Carries air to the lungs
- Bronchi – Tubes that branch into the lungs
- Lungs – Where oxygen and carbon dioxide are exchanged
- Diaphragm – Muscle that helps with breathing
Important for CNAs:
- Count respirations (breathing rate)
- Watch for difficulty breathing, coughing, or chest pain
- Help patients with breathing exercises
- Keep airways clear (help with coughing, positioning)
7. Musculoskeletal System
What it is: The bones, muscles, and joints that give the body structure and allow movement.
Main function: Supports the body, allows movement, and protects internal organs.
Key parts:
- Bones – Give structure and protect organs
- Muscles – Allow movement and maintain posture
- Joints – Where bones meet and allow movement
- Tendons – Connect muscles to bones
- Ligaments – Connect bones to other bones
- Cartilage – Cushions joints
Important for CNAs:
- Help with safe movement and transfers
- Watch for signs of fractures (broken bones)
- Report joint pain, swelling, or limited movement
- Help with range-of-motion exercises
8. Urinary System
What it is: The system that removes liquid waste from the body and maintains water balance.
Main function: Filters blood, removes waste, and maintains proper fluid balance.
Key parts:
- Kidneys – Filter waste from blood and make urine
- Ureters – Tubes that carry urine to the bladder
- Bladder – Stores urine until it’s ready to leave the body
- Urethra – Tube that carries urine out of the body
Important for CNAs:
- Monitor urine output (amount, color, odor)
- Help with toileting and incontinence care
- Report burning, pain, or difficulty urinating
- Keep accurate intake and output records
9. Reproductive System
What it is: The system responsible for producing offspring.
Main function: Produces sex hormones and allows for reproduction.
Key parts:
- Male: Penis, testes, prostate gland
- Female: Ovaries, uterus, fallopian tubes, vagina
Important for CNAs:
- Provide respectful, private care for reproductive organs
- Report unusual discharge, bleeding, or pain
- Understand that reproductive health affects overall well-being
- Maintain patient dignity during personal care
10. Endocrine System
What it is: The system of glands that produce hormones (chemical messengers).
Main function: Regulates body functions through hormones that control growth, metabolism, and reproduction.
Key parts:
- Thyroid gland – Controls metabolism (how fast the body works)
- Pancreas – Produces insulin to control blood sugar
- Adrenal glands – Produce stress hormones
- Pituitary gland – “Master gland” that controls other glands
Important for CNAs:
- Monitor blood sugar levels in diabetic patients
- Watch for signs of hormone imbalances (extreme tiredness, mood changes)
- Help patients take medications on time (especially insulin)
- Report sudden weight changes or unusual symptoms
Key Terms to Remember
- Vital signs: Temperature, pulse, respiration, blood pressure
- Symptoms: What the patient feels (pain, nausea)
- Signs: What you can see or measure (fever, swelling)
- Acute: Sudden or short-term
- Chronic: Long-term or ongoing
- Inflammation: Redness, swelling, heat, pain
Study Tips
- Practice pronunciation of medical terms
- Connect systems – understand how they work together
- Focus on CNA responsibilities – what you observe and report
- Use flashcards for key terms and functions
- Practice scenarios – what would you do if you notice certain symptoms?
Remember: As a CNA, you observe and report – you don’t diagnose or treat medical conditions!
