1.2 Nervous & Cardiovascular Systems
Key Takeaways
The nervous system is divided into the central nervous system (CNS: brain and spinal cord) and the peripheral nervous system (PNS: cranial and spinal nerves)
The autonomic nervous system has two branches: sympathetic (fight-or-flight) and parasympathetic (rest-and-digest)
Massage therapy primarily stimulates the parasympathetic nervous system, promoting relaxation and recovery
The stretch reflex is activated when a muscle is stretched quickly, causing it to contract protectively
The Golgi tendon organ (GTO) reflex inhibits muscle contraction when excessive tension is detected, providing a protective mechanism
The heart has four chambers: right atrium, right ventricle, left atrium, left ventricle
Blood flow path: body → right atrium → right ventricle → lungs → left atrium → left ventricle → body
Normal resting heart rate for adults is 60-100 beats per minute; normal blood pressure is approximately 120/80 mmHg
The nervous system and cardiovascular system are critical for massage therapists to understand. The nervous system controls reflexes that directly affect muscle tone and pain perception, while the cardiovascular system is affected by massage techniques that influence blood flow.
The Nervous System
Organization
The nervous system is organized into two main divisions:
Central Nervous System (CNS):
- Brain — processes sensory input, initiates motor commands, controls higher functions
- Spinal cord — relays information between the brain and body, mediates reflexes
Peripheral Nervous System (PNS):
- Somatic nervous system — voluntary control of skeletal muscles, carries sensory info to CNS
- Autonomic nervous system (ANS) — involuntary control of organs, glands, smooth muscle
The Autonomic Nervous System
| Feature | Sympathetic | Parasympathetic |
|---|---|---|
| Nickname | Fight-or-flight | Rest-and-digest |
| Heart rate | Increases | Decreases |
| Blood pressure | Increases | Decreases |
| Breathing | Faster, deeper | Slower, calmer |
| Digestion | Inhibited | Stimulated |
| Pupils | Dilated | Constricted |
| Muscle tension | Increased | Decreased |
| Neurotransmitter | Norepinephrine | Acetylcholine |
Clinical Relevance: Massage therapy primarily stimulates the parasympathetic nervous system, which promotes relaxation, reduces heart rate and blood pressure, decreases muscle tension, and facilitates recovery. This is one of the key physiological mechanisms behind the stress-reducing effects of massage.
Key Reflexes for Massage Therapy
Stretch Reflex (Myotatic Reflex):
- Activated when a muscle is stretched quickly or forcefully
- Muscle spindles (proprioceptors within muscle fibers) detect the stretch
- A reflex arc causes the stretched muscle to contract protectively
- This is the reflex behind the knee-jerk (patellar) reflex
- Clinical tip: Avoid rapid, forceful stretching — it triggers the stretch reflex and increases muscle tension
Golgi Tendon Organ (GTO) Reflex (Inverse Stretch Reflex):
- Located in tendons at the muscle-tendon junction
- Activated when excessive tension is detected in the tendon
- Causes the muscle to relax (inhibition) to protect the tendon from damage
- Clinical tip: Sustained pressure or slow, sustained stretching can activate the GTO reflex, helping muscles release and relax
Reciprocal Inhibition:
- When an agonist muscle contracts, the antagonist muscle is reflexively inhibited (relaxed)
- Example: When the biceps contracts to flex the elbow, the triceps is reflexively inhibited
- Clinical tip: Used in PNF (proprioceptive neuromuscular facilitation) stretching techniques
Dermatomes and Referred Pain
A dermatome is an area of skin that is primarily innervated by a single spinal nerve root. Understanding dermatomes helps massage therapists:
- Recognize patterns of pain and numbness
- Understand referred pain patterns
- Communicate with other healthcare providers about a client's symptoms
Referred pain occurs when pain is perceived in a location different from the source. For example:
- Heart attack pain may be felt in the left arm, jaw, or back
- Trigger points in the trapezius can refer pain to the head (tension headache pattern)
The Cardiovascular System
Heart Anatomy
The heart has four chambers:
- Right atrium — receives deoxygenated blood from the body via the superior and inferior vena cava
- Right ventricle — pumps deoxygenated blood to the lungs via the pulmonary arteries
- Left atrium — receives oxygenated blood from the lungs via the pulmonary veins
- Left ventricle — pumps oxygenated blood to the body via the aorta (thickest wall, strongest pump)
Blood Flow Path
The cardiovascular system uses a double-loop circulation:
- Pulmonary circulation: Right ventricle → pulmonary arteries → lungs (gas exchange) → pulmonary veins → left atrium
- Systemic circulation: Left ventricle → aorta → body (delivers O2, picks up CO2) → vena cava → right atrium
Blood Vessels
| Vessel Type | Function | Wall Thickness |
|---|---|---|
| Arteries | Carry blood away from the heart | Thick, muscular, elastic |
| Arterioles | Small arteries that regulate blood flow | Moderate |
| Capillaries | Site of gas/nutrient exchange | One cell thick |
| Venules | Small veins that collect blood from capillaries | Thin |
| Veins | Return blood to the heart | Thinner than arteries, contain valves |
Normal Cardiovascular Values
| Measurement | Normal Adult Range |
|---|---|
| Heart rate | 60-100 beats per minute |
| Blood pressure | ~120/80 mmHg (systolic/diastolic) |
| Hypertension | >130/80 mmHg |
| Hypotension | <90/60 mmHg |
Effects of Massage on the Cardiovascular System
- Increases local blood flow to the area being massaged
- May temporarily decrease blood pressure through parasympathetic activation
- Improves venous return when strokes are directed toward the heart
- Reduces heart rate through relaxation response
- Caution: Deep tissue work and certain techniques can temporarily increase blood pressure during the session
The Lymphatic System
The lymphatic system works alongside the cardiovascular system but has unique functions:
| Feature | Description |
|---|---|
| Function | Filters and returns interstitial fluid to the bloodstream; immune defense |
| Lymph | Clear fluid similar to plasma; contains white blood cells (lymphocytes) |
| Lymph nodes | Filter stations that trap pathogens and foreign material |
| Lymph vessels | One-way vessels with valves (similar to veins); no pump — rely on muscle contraction, breathing, and gravity |
| Spleen | Largest lymphatic organ; filters blood, stores platelets and white blood cells |
| Thymus | Matures T-lymphocytes (T-cells) for immune function |
Massage and the lymphatic system:
- Manual lymphatic drainage (MLD) uses very light, rhythmic strokes to move lymph fluid
- General massage improves lymphatic circulation through mechanical compression and release
- Lymphedema (chronic swelling due to lymphatic dysfunction) requires specialized MLD training
- Direction of lymphatic strokes: toward the nearest lymph node cluster
Key Lymph Node Locations
| Location | Nodes |
|---|---|
| Cervical | Sides and front of the neck |
| Axillary | Armpit (axilla) |
| Inguinal | Groin area |
| Popliteal | Behind the knee |
| Supraclavicular | Above the clavicle |
Which branch of the autonomic nervous system is primarily stimulated by massage therapy?
Sympathetic nervous system
Parasympathetic nervous system
Somatic nervous system
Central nervous system
The Golgi tendon organ (GTO) reflex causes a muscle to:
Contract forcefully when stretched
Relax when excessive tension is detected
Spasm when touched lightly
Tighten when cold is applied
Blood flows from the left ventricle to the body through which vessel?
Pulmonary artery
Superior vena cava
Aorta
Pulmonary vein
Which proprioceptor is responsible for the stretch reflex (knee-jerk reflex)?
Golgi tendon organ
Muscle spindle
Pacinian corpuscle
Merkel disc
The two divisions of the central nervous system are the brain and the ___.
Type your answer below
What is the normal resting heart rate range for an adult?
40-60 beats per minute
60-100 beats per minute
80-120 beats per minute
100-140 beats per minute
Which of the following are effects of parasympathetic nervous system activation? (Select all that apply)
Select all that apply
Decreased heart rate
Increased blood pressure
Stimulated digestion
Dilated pupils
Decreased muscle tension
Faster, deeper breathing
A dermatome is:
A surgical instrument used to remove skin layers
An area of skin primarily innervated by a single spinal nerve root
A type of skin cancer
A muscle group innervated by the same nerve
Arteries differ from veins primarily because arteries:
Contain valves to prevent backflow
Carry blood away from the heart and have thicker, more muscular walls
Are always closer to the surface of the body
Only carry deoxygenated blood
The neurotransmitter released at the neuromuscular junction to stimulate skeletal muscle contraction is:
Norepinephrine
Dopamine
Acetylcholine
Serotonin
Arrange the path of blood flow through the heart in the correct order.
Arrange the items in the correct order
Body → superior/inferior vena cava → right atrium
Left atrium → left ventricle
Right atrium → right ventricle
Lungs → pulmonary veins → left atrium
Left ventricle → aorta → body
Right ventricle → pulmonary arteries → lungs
Manual lymphatic drainage (MLD) uses what type of pressure?
Deep, sustained pressure
Moderate to firm pressure
Very light, rhythmic pressure
Rapid, percussive pressure
Sections you finish are checked off in the contents.