SP

Chapter 6: The Human Body Notes

Topographic Anatomy

  • Superficial landmarks serve as guides to structures that lie beneath.
  • Topographic anatomy applies to a body in the anatomic position.
    • The patient stands facing you, arms at the side, palms forward.
  • Planes of the body: Imaginary straight lines that divide the body
    • Coronal plane: front/back
    • Transverse plane: top/bottom
    • Sagittal (lateral) plane: left/right

The Axial Skeleton

  • The axial skeleton is the foundation to which the arms and legs are attached.
    • It includes:
    • Skull
    • Spinal column
    • Thorax
  • Skull
    • Cranium: made up of 4 bones
    • Face: made up of 14 bones
  • Spinal column
    • Composed of 33 bones (vertebrae)
    • Divided into 5 sections:
    • 7 Cervical
    • 12 Thoracic
    • 5 Lumbar
    • Sacrum
    • Coccyx
    • Thorax
    • Formed by 12 thoracic vertebrae and 12 pairs of ribs
    • The thoracic cavity contains:
      • Heart
      • Lungs
      • Esophagus
      • Great vessels

The Appendicular Skeleton

  • Arms, legs, their connection points, and pelvis
  • Occur wherever bones come in contact
  • Hinge joint
    • Motion restricted to one plane
  • Ball-and-socket joint
    • Allows rotation and bending

The Upper Extremities

  • Composed of arms, forearms, hands, and fingers
    • Shoulder girdle
    • Clavicle
    • Scapula
    • Humerus
  • Arm
    • Humerus is the supporting bone
    • Forearm
    • Radius on the lateral side
    • Ulna on the medial side
  • Wrist and hand
    • Ball-and-socket joint
    • Principal bones:
    • Carpals
    • Metacarpals
    • Phalanges

The Pelvis

  • Closed bony ring consisting of three bones
  • Sacrum
  • Two pelvic bones
    • Each pelvic bone is formed by the fusion of the ilium, ischium, and pubis.
  • Posteriorly, the ilium, ischium, and pubis bones are joined by the sacrum.
  • Anteriorly, the pubic symphysis is where the right and left pubis are joined.

The Lower Extremities

  • Main components: thigh, leg, and foot
    • Femur (thighbone)
    • Femur connects to the pelvic girdle by a ball-and-socket joint
  • The knee connects the upper leg to the lower leg
    • Kneecap (patella)
  • Lower leg
    • Tibia (shinbone)
    • Fibula
  • Ankle
    • A hinge joint
    • Allows flexion/extension of the foot
  • Foot
    • 7 tarsal bones
    • 5 metatarsal bones
    • Toes are formed by phalanges

The Skeletal System: Physiology

  • Functions of the skeletal system
    • Gives the body its shape
    • Protects fragile organs
    • Allows for movement
    • Stores calcium
    • Helps create blood cells

The Musculoskeletal System: Anatomy

  • The musculoskeletal system provides:

    • Form
    • Upright posture
    • Movement
    • Protection for vital internal organs

  • 3 types of muscle

    • Skeletal (voluntary) muscle - not striated
    • Smooth muscle - digestive system
    • Cardiac muscle - the heart

The Musculoskeletal System: Physiology

  • Contraction and relaxation of this system make it possible to move and manipulate the environment.
  • A by-product of this movement is heat.
  • Another function of the muscles is to protect the structures under them.

The Respiratory System: Anatomy

  • Structures of the body that contribute to respiration (the process of breathing)
Upper AirwayNoseMouth (oral cavity)TongueJaw (mandible)LarynxPharynxNasopharynxOropharynxLaryngopharynxTracheaEpiglottisEsophagusLower AirwayThyroid cartilageAdam’s appleCricoid cartilage: immediately below the thyroid cartilageCricothyroid membrane Trachea Ends at the carina, dividing into right and left bronchi leading to bronchiolesDivided into lobesContain bronchi, bronchioles, and alveoliAllow for gas exchange

Muscles of Breathing

  • The diaphragm and intercostal muscles are the primary muscles of breathing.
  • Other muscles involved in breathing:
    • Neck (cervical muscles)
    • Abdominal muscles
    • Pectoral muscles

The Respiratory System: Physiology

  • Functions to provide the body with oxygen and eliminate carbon dioxide
  • Ventilation and respiration are two separate, interdependent functions of the respiratory system.
  • Respiration: the exchange of oxygen and carbon dioxide in alveoli and tissues
    • Provides oxygen to the cells and removes waste carbon dioxide
    • Diffusion: the passive process in which oxygen molecules move from an area with a higher concentration of molecules to an area of lower concentration.
    • The brainstem controls breathing.
  • Ventilation: simple air movement into and out of the lungs
    • Tidal volume
    • Residual volume
    • Dead space
    • Minute volume

Characteristics of Normal Breathing

  • Normal rate and depth (tidal volume)
  • Regular rhythm or pattern of inhalation and exhalation
  • Clear, audible breath sounds on both sides of the chest
  • Regular rise and fall movement on both sides of the chest
  • Movement of the abdomen
  • Inadequate breathing patterns in adults:
    • Labored breathing
    • Muscle retractions
    • Pale, cyanotic, cool, damp skin
    • Tripod position
    • Agonal gasps (gasping breaths)

The Circulatory System: Anatomy

  • A complex arrangement of connected tubes
    • Arteries, arterioles, capillaries, venules, veins
  • Two circuits
    • Systemic circulation (body)
    • Pulmonary circulation (lungs)

The Heart

  • Made of specialized cardiac muscle
  • Works as two paired pumps
    • The septum divides the right and left sides
    • Each side is divided into:
    • Atrium (upper chamber)
    • Ventricle (lower chamber)
  • Circulation
    • The heart receives its blood from the aorta.
    • The right side receives deoxygenated blood from the veins.
    • The left side receives oxygenated blood from the lungs.
  • Normal adult resting heart rate (HR): 60–100 beats/min
  • Stroke volume (SV)
    • Amount of blood moved by one beat
  • Cardiac output (CO)
    • Amount of blood moved in 1 minute
    • HR × SV = CO
  • Electrical conduction system
    • Causes smooth, coordinated contractions
    • Contractions produce the pumping action

Arteries

  • Arteries carry blood from the heart to all body tissues.
  • Pulmonary artery
    • Carries oxygen-poor blood to the lungs
  • Arteries branch into smaller arteries and then into arterioles.
    • Arterioles branch into smaller vessels until they connect to the capillaries.
  • Pulse
    • Created by the forceful pumping of blood out of the left ventricle and into major arteries
    • Palpated most easily at the neck, wrist, or groin

Capillaries & Veins

  • Capillaries connect arterioles to venules
  • Capillaries allow contact between blood and cells
  • Veins return oxygen-depleted blood to the heart
    • The superior vena cava carries blood returning from the head, neck, shoulders, and upper extremities
    • The inferior vena cava carries blood from the abdomen, pelvis, and lower extremities

Spleen

  • A solid organ located under the rib cage
  • Filters blood
  • Particularly susceptible to injury from blunt trauma
    • This can lead to severe internal bleeding
  • Solids do not rupture, but hollow organs can
  • Solid organs → internal bleeding, infection, sepsis, death
  • Hollow organs → rupture of the organ, internal bleeding, sepsis

The Blood

  • Blood composition
    • Plasma (liquid)
    • Red blood cells (erythrocytes)
    • White blood cells (leukocytes)
    • Platelets
  • Blood pressure: the pressure blood exerts against the walls of the arteries
    • Systole occurs when the left ventricle contracts
    • Diastole occurs when the left ventricle relaxes
  • Blood pressure readings
    • Systolic blood pressure: high point of wave
    • Diastolic blood pressure: low point of wave
  • Normal circulation in adults
    • Automatically adjusted and controlled
    • Perfusion: circulation of blood in an organ or tissue in adequate amounts to meet the needs of its cells
    • Blood enters organs and tissues through arteries.
    • Blood leaves organs and tissues through veins.
  • Inadequate Circulation in Adults
    • The system can adjust to small blood loss.
    • With a large loss, adjustment fails, and the patient goes into shock.
  • Functions of blood
    • Perfusion
    • Transporting oxygen
    • Transporting carbon dioxide
    • Transporting wastes and nutrients
    • Clotting (coagulation)

The Nervous System

  • The nervous system is perhaps the most complex organ in the body
  • Divided into two main portions:
    • Central nervous system (CNS)
    • Peripheral nervous system
  • Brain
  • Controlling organs of the body
  • Subdivisions
    • Cerebrum
    • Cerebellum
    • Brain stem
  • Spinal cord
    • Continuation of the brain
    • Transmits messages between brain and body

Peripheral Nervous System

  • Somatic nervous system
    • Transmits signals from the brain to voluntary muscles
  • Autonomic nervous system
    • Involuntary actions
    • Split into two areas
    • Sympathetic nervous system (fight-or-flight)
    • Parasympathetic nervous system (slows body)

The Integumentary System: Physiology

  • Two layers
    • Epidermis (superficial)
    • Dermis (deeper)
  • Below the skin lies subcutaneous tissue.
    • Fat that insulates and serves as an energy reservoir
  • The skin is the largest single organ in the body.
  • Three major functions
    • Protect the body in the environment
    • Regulate body temperature
    • Transmit the information from the environment to the brain

The Digestive System: Anatomy

  • Digestion: processing of food that nourishes the cells
  • Abdomen: the second major body cavity
    • Contains major organs of digestion and excretion
    • Quadrants are the easiest way to identify areas:
    • Right upper
    • Lower upper
    • Right lower
    • Left lower
  • Mouth
    • Lips, cheeks, gums, teeth, tongue
    • Salivary glands
  • Oropharynx
  • Esophagus
  • Stomach
  • Pancreas
  • Liver
    • Bile ducts
  • Small intestine
  • Large intestine
  • Appendix
  • Rectum

The Digestive System: Physiology

  • Enzymes are added to food.
    • By salivary glands, stomach, liver, pancreas, and small intestine
  • Enzymes convert food into basic sugars, fatty acids, and amino acids.
    • Further processed by the liver
    • Circulated via blood throughout the body