© 2011 National Safety Council 5-1
THE HUMAN BODYLESSON 5
© 2011 National Safety Council 5-2
Introduction
• Body is composed of different organs and tissues working together
• Minor injury or illness may damage only a specific body part or function
• Serious injury or sudden illness can threaten vital body functions
• Understanding human body can help you recognize effects of injuries and illnesses
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Body Regions and Directions
• Special terms are used by health care providers for body regions
• Directional and positional terms used to describe relationship of body structures
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Body Regions and Cavities
• Extremities refers to both arms and legs
• Thorax refers to chest area enclosed by the ribs
• Thoracic cavity is area inside chest
• Abdomen refers to area immediately below thoracic cavity
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Body Regions and Cavities (continued)
• Abdominal cavity includes stomach, intestines, other organs
• Pelvis refers to area below abdomen: pelvic bones between hip and lower spine
• Pelvic cavity contains bladder and other organs
• Spine, or spinal column, refers to bones of neck and back and nerves, or spinal cord, that run through vertebrae
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Abdominal Quadrants
Used to describe specific injuries or signs and symptoms
• Upper and lower quadrants divided by line passing through umbilicus
• Quadrants based on anatomical position, with face forward and palms facing forward
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Directional Terms
All positional and directional terms are based on anatomical position:
• Right and left refer to patient’s right and left, divided by midline down center of body
• Lateral and medial
• Anterior and posterior
• Proximal and distal
• Superior and inferior
• Prone and supine
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Body Systems
• Organs have one or more specific functions
• The organs that work together for a specific function are called a body system
• Body systems are closely interrelated and work together
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Examples of Interrelated Body Systems
• Blood carries oxygen from lungs to body cells
• Nerve sensors detect amount of oxygen and carbon dioxide in the blood and speed up or slow down heart beat and breathing to change oxygen level
• If body temperature drops, muscles in extremities start shivering to produce heat, which is carried by blood to vital organs
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Key Body Systems
• Most fundamental for life are the respiratory and cardiovascular systems
• Body cells need a constant supply of oxygen
• Any failure of breathing or blood circulation threatens life within minutes
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Pathophysiology
• “Patho” refers to an abnormality
• Understanding what can go wrong in each body system from injury or illness is important for giving emergency care
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Respiratory System
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Functions of Respiratory System
• To bring air into lungs
• To allow oxygen from air to enter blood
• To remove carbon dioxide from blood into air breathed out (exhaled)
• This process is called respiration
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Respiratory System: Primary Organs
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The Breathing Process
Breathing depends on muscular movements under control of nervous system:
• When the diaphragm contracts/moves down, thoracic cavity and lungs expand, pulling air into lungs
• Intercostal muscles assist with ventilation
• In lungs, oxygen enters blood and carbon dioxide leaves blood
• When diaphragm relaxes and moves up, thoracic cavity contracts, and air carrying carbon dioxide flows back out of lungs
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Emergency Conditions Related to the Respiratory System
• Respiration can be affected by different injuries and illnesses
• An airway obstruction is blockage of airway preventing air flow
• Inadequate oxygenation due to low oxygen, poison gas, lung infection, etc.
• A broken rib may puncture a lung, making breathing ineffective
• A penetrating injury into lungs may alter lung pressures keeping lungs from filling with air
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Emergency Conditions Relatedto the Respiratory System (continued)
• Poisoning or drug overdose may depress nervous system functions, slowing or stopping breathing
• Asthma is a common illness in which airway tissues swell making it hard to breathe
• In infants and children, anatomical structures are smaller and airway is more easily obstructed
• Uncorrected respiratory problem is the primary cause of cardiac arrest in infants and children
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Cardiovascular System
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Functions of the Cardiovascular System
• To transport oxygen and nutrients in the blood to all parts of body
• To remove carbon dioxide and other wastes
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Cardiovascular System: Primary Organs
• Heart
• Blood
• Blood vessels
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The Blood
• Red blood cells carry oxygen to body cells
• White blood cells are an important part of the immune system
• Plasma is the liquid substance of blood
• Blood also carries glucose to body cells for energy
• Blood clotting factors help control bleeding
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Pathway of Blood
Ventricles pump blood through 2 loops or cycles in body:
• Right ventricle pumps blood to lungs picking up oxygen and releasing carbon dioxide
• Blood returns to left atrium, from which it moves to left ventricle
• Left ventricle pumps oxygenated blood into body to release oxygen and pick up carbon dioxide for removal
• Blood returns to right atrium, moving to right ventricle to be pumped again to lungs
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Pulses
• Pulsing blood pressure changes occur in arteries that can be felt as pulse
• Commonly measured pulses:
- Carotid
- Femoral
- Radial
- Brachial
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Heart Rate
• Heart rate, measured as pulse, is affected by many factors
• Average resting heart rate in adult males is 6472 beats/minute; in females, 7280 beats/minute
• Heart rate of infants and children is higher
• With exercise, fever or emotional excitement, heart rate increases to meet body’s greater need for oxygen
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Emergency Conditions Related tothe Cardiovascular System
• Cells begin to die in vital organs such as brain after only a few minutes without oxygen
• Shock is a life-threatening condition that occurs when vital body organs are not receiving enough oxygen
• Oxygen delivery diminished by injury or illness affecting heart, blood, or blood vessels
• Severe bleeding leaves not enough blood in circulation to provide body with oxygen
• Arterial bleeding is most severe blood may spurt out under pressure, leading to life-threatening shock
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• Bleeding from veins generally slower but can still be serious or life threatening if it continues
• Capillary bleeding usually minor and stops by itself as blood clots
• Problems affecting blood volume (bleeding, repeated vomiting or diarrhea, or burns) affect circulation
• Blood vessel problems (inability to constrict) cause poor circulation; may occur with spinal cord injuries, infection or anaphylaxis
Emergency Conditions Related to the Cardiovascular System (continued)
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Cardiovascular Illnesses
• Stroke is problem involving arteries in brain; reduced circulation may cause mental and physical impairments
• If heart muscle does not receive enough oxygenated blood because of blocked cardiac arteries, cardiac muscle tissue may die
• The heart may stop (cardiac arrest)
• Dysrhythmia (or arrhythmia), an irregular heartbeat, may reduce heart’s pumping ability
• Fibrillation, a serious dysrhythmia, common after heart attack
• Any problem affecting the heart rate or strength of contractions can cause poor circulation and shock (poisoning, heart disease)
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Musculoskeletal System
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Functions of the Musculoskeletal System
• Skeletal system provides shape and support for body as a whole
• Muscles act on bones, allowing for movement
• Groups of bones protect vital internal organs:
- Ribs protect heart and lungs
- Skull protects brain
- Vertebrae protect spinal cord
- Pelvic bones protect bladder and other organs
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Musculoskeletal System: Primary Organs
• Bones
• Muscles
• Tendons
• Ligaments
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Types of Muscles
• Skeletal muscles create body movements and also produce heat usually under voluntary control
• Smooth muscles such as in the esophagus and blood vessels are usually under involuntary control
• Cardiac muscle is also involuntary but is unique in that the heart produces its own stimuli to contract
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Emergency Conditions Related tothe Musculoskeletal System
• Most fractures are not life-threatening
• In a dislocation, one or more bones move out of position in joint
• Sprain is stretching and tearing of ligaments and other structures in a joint
• Strain is muscle or tendon tear usually caused by overexerting muscle
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Musculoskeletal InjuriesAssociated with Other Injuries
• Vertebral fractures likely to injure spinal cord and cause nervous system damage
• Fractures of femur often cause much soft-tissue damage, bleeding and femoral artery damage
• Pelvis fracture may damage bladder/other organs in pelvic cavity or femoral arteries
• A skull fracture may cause brain damage
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Nervous System
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Nervous System: Primary Functions
• Sensory receptors gather information about environment and send to brain
• Brain integrates and analyzes information
• Nerve signals from brain lead to actions throughout body to accomplish tasks or maintain homeostasis
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Nervous System: Primary Organs
• Brain
• Spinal cord
• Sensory receptors
• Nerves
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Emergency Conditions Related to the Nervous System
• Head and spinal injuries
- Serious or life threatening
• Injury to part of brain or stroke
- May destroy or impair one or more functions
• Damage to spinal cord
- Complete loss of function to body area or paralysis
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Emergency Conditions Related to the Nervous System
(continued)
• Altered mental status from:
- Head injuries
- Any injury causing decreased oxygenation
- Sudden illness (e.g., stroke, seizure, diabetes)
- Severe infection or fever
- Poisoning or drug overdose
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Nervous System Effects Associated with Other Injuries
• Injuries and some illnesses also affect nervous system
• Pain results from damage to nerve fibers in many areas of body
• Crushing pain in chest may be caused by heart attack
• Abdominal pain that begins in umbilicus and settles into lower abdomen on right side may be a sign of appendicitis
• Pain should always be taken seriously
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Other Body Systems
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Integumentary System: Primary Functions
• Protect body
• Help regulate body temperature
• Help prevent water loss
• Sensation (e.g., touch, pressure, pain, temperature)
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Emergency Conditions Related to the Integumentary System
• Cuts and scrapes
- Bleeding
• Openings in skin
- Allow pathogens into body
• Heat and chemical burns
- Loss of body heat
- Loss of body fluid
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Importance of Skin Condition
• Skin often reveals important information about body condition
• Skin of hypothermia patient
• Skin of heatstroke patient
• Skin of patient with low blood oxygen levels
• Skin of patient in shock
• Many sudden illnesses cause sweating and skin color changes (flushed or pale)
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Gastrointestinal System
• Digests food and extracts nutrients
• Organs easily injured by traumatic forces
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Emergency Conditions Related to the Gastrointestinal System
• Abdominal cavity not protected by bones, gastrointestinal organs may be easily injured by traumatic forces
• In closed injury, pain or tenderness along with swollen, rigid abdomen may suggest internal injury
• In an open wound, internal organs may be exposed, raising risk of infection
• Ingested poison is absorbed in the same manner as nutrients from food and enters the bloodstream to affect body
• Various illnesses may cause vomiting or diarrhea, which can lead to dehydration especially in infants
• Vomiting blood is likely sign of a serious internal injury
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Functions of the Urinary System
• Removes metabolic wastes from body in urine
• Helps body maintain fluid and electrolyte balances
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Urinary System: Primary Organs
• Blood transports wastes to kidneys
• Kidneys filter wastes and produce urine
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Emergency Conditions Related to the Urinary System
• Traumatic injury may damage organs
- Look for blood in urine
• Health problems
- May cause change in urination
• Dehydration
- Lack of urination
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Reproductive System
• Female
- Produces eggs
- Supports and nurtures fetus in uterus
- Childbirth
- Lactation
• Male
- Produces and transports sperm
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Emergency Conditions Related to the Reproductive System
• Abdominal injuries may damage genitals or reproductive organs – such wounds may require special care, including concern for patient’s privacy
• Complications may develop in pregnancy
• Childbirth may occur unexpectedly away from a health care facility
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Endocrine System
• Glands that produce hormones
• Most problems develop slowly and are rarely emergencies
• Diabetes can cause emergencies
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Lymphatic System
• Helps defend against disease
• Part of immune system
• Problems seldom cause emergencies
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Growth and DevelopmentThrough the Life Span
• Basic body functions are similar in people at all ages
• Many significant changes occur in the body throughout the lifespan
• Be aware of such differences when assessing and caring for patients