EMS Chapter 6 - The Human Body

Anatomy

The study of the physical structures of the human body.\\\

Physiology

The study of the normal functions and activities of the body's structures.\\\

Pathophysiology

The study of how disease or injury alters normal body function.\\\

Topographic Anatomy

The study of surface landmarks used to locate underlying organs and structures.\\\

Anatomic Position

The standard reference position in which the body stands erect, facing forward, arms at the sides, with palms facing forward.\\\

Superior

Toward the head or upper part of the body.\\\

Inferior

Toward the feet or lower part of the body.\\\

Anterior (Ventral)

Toward the front of the body.\\\

Posterior (Dorsal)

Toward the back of the body.\\\

Medial

Toward the midline of the body.\\\

Lateral

Away from the midline of the body.\\\

Proximal

Closer to the trunk or point of attachment.\\\

Distal

Farther from the trunk or point of attachment.\\\

Coronal (Frontal) Plane

A vertical plane dividing the body into front (anterior) and back (posterior) portions.\\\

Sagittal Plane

A vertical plane dividing the body into left and right portions.\\\

Midsagittal Plane

A sagittal plane dividing the body into equal left and right halves.\\\

Transverse (Axial) Plane

A horizontal plane dividing the body into upper (superior) and lower (inferior) portions.\\\

Skeletal System

The body system that supports the body, protects organs, stores minerals, and provides the framework for movement.\\\

Axial Skeleton

The central skeleton consisting of the skull, vertebral column, ribs, and sternum.\\\

Appendicular Skeleton

The skeleton consisting of the upper and lower extremities and the shoulder and pelvic girdles.\\\

Joint

The location where two or more bones meet.\\\

Ligament

A tough band of connective tissue that connects bone to bone and stabilizes joints.\\\

Tendon

A strong band of connective tissue that connects muscle to bone.\\\

Cartilage

Flexible connective tissue that cushions joints and reduces friction between bones.\\\

Synovial Fluid

Lubricating fluid within movable joints that reduces friction and allows smooth movement.\\\

Ball-and-Socket Joint

A joint allowing movement in multiple directions, including rotation (e.g., shoulder and hip).\\\

Hinge Joint

A joint allowing primarily flexion and extension (e.g., elbow and knee).\\\

Musculoskeletal System

The combined system of bones, muscles, tendons, ligaments, and joints responsible for movement, support, and protection.\\\

Skeletal Muscle

Voluntary, striated muscle attached to bones that produces body movement and generates heat.\\\

Antagonistic Muscle Pair

Two muscles that produce opposite movements, such as the biceps and triceps.\\\Respiratory System

Nasopharynx

The upper portion of the pharynx located behind the nose and above the soft palate.\\\

Oropharynx

The portion of the pharynx behind the mouth extending from the soft palate to the hyoid bone.\\\

Laryngopharynx

The lowest portion of the pharynx where the respiratory and digestive tracts separate.\\\

Larynx

The voice box that connects the pharynx to the trachea and contains the vocal cords.\\\

Epiglottis

A flap of tissue that closes over the larynx during swallowing to prevent food and liquids from entering the airway.\\\

Upper Airway

The airway consisting of the nose, mouth, pharynx, and larynx above the vocal cords.\\\

Lower Airway

The airway consisting of the trachea, bronchi, bronchioles, alveoli, and lungs.\\\

Trachea

The windpipe that carries air from the larynx to the bronchi.\\\

Carina

The point where the trachea divides into the right and left mainstem bronchi.\\\

Bronchi

The two main airways branching from the trachea into each lung.\\\

Bronchioles

Small branches of the bronchi that carry air to the alveoli.\\\

Alveoli

Tiny air sacs in the lungs where oxygen diffuses into the blood and carbon dioxide diffuses out of the blood.\\\

Pleura

A double-layered membrane surrounding the lungs; the visceral pleura covers the lungs and the parietal pleura lines the chest cavity.\\\

Diaphragm

The primary muscle of breathing that contracts during inhalation and relaxes during exhalation.\\\

Ventilation

The mechanical movement of air into and out of the lungs.\\\

Respiration

The exchange of oxygen and carbon dioxide between the blood and body tissues.\\\

Diffusion

The passive movement of molecules from an area of higher concentration to an area of lower concentration.\\\

Medulla Oblongata

The part of the brainstem primarily responsible for controlling the breathing cycle.\\\

Tidal Volume (TV)

The amount of air inhaled or exhaled during one normal breath.\\\

Residual Volume

The amount of air remaining in the lungs after maximal exhalation to keep the alveoli open.\\\

Dead Space

The portion of the respiratory system where air is present but gas exchange does not occur.\\\

Minute Volume (MV)

The total amount of air moved into and out of the lungs each minute. Calculated as Respiratory Rate × Tidal Volume.\\\

Hypoxic Drive

A backup respiratory stimulus in which low oxygen levels help stimulate breathing when carbon dioxide no longer provides the primary drive.\\\

Labored Breathing

Breathing that requires increased effort and often involves the use of accessory muscles.\\\

Accessory Muscles

Muscles of the neck, chest, and abdomen that assist breathing during respiratory distress.\\\

Retractions

Visible inward pulling of the skin between the ribs, above the clavicles, or below the rib cage during breathing, indicating increased work of breathing.\\\

Tripod Position

A position in which a patient leans forward with arms supporting the upper body to improve breathing.\\\

Agonal Gasps

Abnormal, ineffective gasping respirations that do not provide adequate ventilation and require immediate intervention.\\\

Ventilation/Perfusion (V/Q) Ratio

The relationship between airflow reaching the alveoli and blood flow reaching the pulmonary capillaries for gas exchange.\\\Circulatory (Cardiovascular) System

Systemic Circulation

The circulation that carries oxygen-rich blood from the left ventricle to the body and returns oxygen-poor blood to the right atrium.\\\

Pulmonary Circulation

The circulation that carries oxygen-poor blood from the right ventricle to the lungs and returns oxygen-rich blood to the left atrium.\\\

Atrium

The upper chamber of the heart that receives blood returning to the heart.\\\

Ventricle

The lower chamber of the heart responsible for pumping blood out of the heart.\\\

Myocardium

The muscular tissue of the heart responsible for its contractions.\\\

Chordae Tendineae

Fibrous cords that attach the heart valves to papillary muscles and prevent the valves from inverting during contraction.\\\

Stroke Volume (SV)

The amount of blood ejected by the left ventricle with each heartbeat (about 70–80 mL in an adult).\\\

Cardiac Output (CO)

The amount of blood pumped by the heart each minute. Calculated as Heart Rate × Stroke Volume (CO = HR × SV).\\\

Aorta

The largest artery in the body that carries oxygen-rich blood from the left ventricle to the systemic circulation.\\\

Pulmonary Artery

The artery that carries oxygen-poor blood from the right ventricle to the lungs.\\\

Arteries

Blood vessels that carry blood away from the heart under high pressure.\\\

Arterioles

Small branches of arteries that regulate blood flow into capillary beds by constricting or dilating.\\\

Capillaries

Microscopic blood vessels where oxygen, nutrients, carbon dioxide, and wastes are exchanged with body tissues.\\\

Veins

Blood vessels that return blood from the body back to the heart under low pressure.\\\

Superior Vena Cava

The large vein that returns blood from the head, neck, chest, and upper extremities to the right atrium.\\\

Inferior Vena Cava

The large vein that returns blood from the abdomen, pelvis, and lower extremities to the right atrium.\\\

Perfusion

The circulation of oxygenated blood through tissues to supply oxygen and nutrients.\\\

Hypoperfusion (Shock)

A state of inadequate tissue perfusion in which organs do not receive enough oxygen and nutrients to function normally.\\\

Blood Pressure (BP)

The force exerted by circulating blood against the walls of the arteries.\\\

Systole

The phase of the cardiac cycle during which the ventricles contract and pump blood into the arteries.\\\

Diastole

The phase of the cardiac cycle during which the ventricles relax and refill with blood.\\\

Mean Arterial Pressure (MAP)

The average pressure in the arteries during one cardiac cycle. MAP = CO × SVR.\\\

Systemic Vascular Resistance (SVR)

The resistance to blood flow created by the constriction or dilation of blood vessels.\\\

Red Blood Cells (Erythrocytes)

Blood cells containing hemoglobin that transport oxygen and carbon dioxide.\\\

Hemoglobin

The oxygen-carrying protein found inside red blood cells.\\\

Platelets

Blood components responsible for initiating blood clot formation.\\\

Sympathetic Nervous System

The "fight-or-flight" division of the autonomic nervous system that increases heart rate, blood pressure, and cardiac output.\\\

Parasympathetic Nervous System

The "rest-and-digest" division of the autonomic nervous system that slows heart rate and conserves energy.\\\

Alpha and Beta Adrenergic Receptors

Alpha receptors primarily cause blood vessel constriction; Beta-1 receptors increase heart rate and contractility; Beta-2 receptors dilate the bronchi.\\\Central Nervous System (CNS)

Peripheral Nervous System (PNS)

The portion of the nervous system consisting of all nerves outside the brain and spinal cord.\\\

Somatic Nervous System

The division of the nervous system responsible for voluntary control of skeletal muscles.\\\

Autonomic Nervous System (ANS)

The division of the nervous system that automatically controls involuntary body functions such as heart rate, breathing, and digestion.\\\

Sympathetic Nervous System

The division of the ANS responsible for the body's "fight-or-flight" response.\\\

Parasympathetic Nervous System

The division of the ANS responsible for the body's "rest-and-digest" functions.\\\

Cerebrum

The largest part of the brain responsible for thought, memory, sensation, reasoning, voluntary movement, and emotions.\\\

Cerebellum

The part of the brain responsible for balance, coordination, and posture.\\\

Brainstem

The part of the brain that connects the brain to the spinal cord and controls many vital life functions, including breathing.\\\

Reticular Activating System (RAS)

The network within the brainstem responsible for maintaining consciousness and alertness.\\\

Cerebrospinal Fluid (CSF)

Fluid surrounding the brain and spinal cord that cushions and protects the central nervous system.\\\

Motor Nerves

Nerves that carry signals from the brain and spinal cord to muscles and glands.\\\

Sensory Nerves

Nerves that carry information such as pain, temperature, and touch from the body to the brain and spinal cord.\\\