Chapter 1: The Human Body

Need For Terminology?

Communicate accurately with others in the class and possibly later in your profession

Anatomy- What?

• Anatomical Name

• Structure

  • Types of Anatomy

    • Gross Anatomy- can see with naked eye

      • Regional Anatomy (Ex. Left Leg)

      • Systemic Anatomy (Ex. Cardiovascular System)

    • Microscopic Anatomy- need microscope/ magnification

      • Cytology

      • Histology

    • Developmental Anatomy- Changes throughout life span

      • Growth span, soft spot closing on infant

Physiology- How? And Why?

• How does it function?

• Why does it function that way?

  • Types of Physiology

    • Cellular Level

    • Organ System

Body's Organization

1. Chemical (atoms and molecules)

2. Cellular

3. Tissue

4. Organ

5. Organ Systems

6. Organism

1. Multiple atoms form molecules

2. Cells are multiple molecules

3. Tissues are similar to cells

4. Organs are made of different tissues

5. Organ system has different organs working together

6. Organism has many organ systems working together

Rule of Threes for Survival

• Three minutes without oxygen

• Three hours without shelter in harsh environment

• Three days without water

• Three weeks without food

Homeostasis

• Literal translation means 'un-changing'

• Relatively stable internal conditions of the body

  • Goal of Homeostasis: prevent severe change

    • Controlled by:

      • Nervous System

        • Electrical impulses

        • Withdrawal reflexes

      • Endocrine System- bloodborne hormones

    • Controlled How?

      • Mainly- Negative Feedback Mechanism

        • Narrow acceptable ranges

        • CardioPulm Examples: Heart Rate, BP, Oxygen levels, etc.

        • Other examples: Body temp, blood sugar levels

      • Less Common- Positive Feedback Mechanism

        • Used during infrequent events

        • Examples:

          • Childbirth dilation and contractions

          • Blood clotting

          • Breastfeeding

    • Difference in feedback mechanisms

      • Negative Feedback- change opposite of the initial change

        • Return to ideal value

      • Positive Feedback- Change the same as the initial change

        • Cascading change

• Imbalance of Homeostasis

  • Living outside of homeostatic range

  • Increases risk of disease

  • Control systems can become less efficient as aging

Anatomical Terms for Directions, Regions, and Planes

Anatomical Position

• Body Erect

• Feet slightly apart

• Palms facing forward with thumbs pointing away from body

Orientation and Directional Terms

• Superior (Cranial)

  • Toward the head end or upper part of a structure or the body; above

    • The head is superior to the abdomen.

• Inferior (Caudal)

  • Away from the head end or toward the lower part of a structure or the body; below

    • The naval is inferior to the chin

• Anterior (ventral)

  • Toward the front of the body; in the front

    • The breastbone is anterior to the spine

• Posterior (dorsal)

  • Towards or at the back of the body; behind

    • The heart is posterior to the breastbone

• Medial

  • Toward or at the midline of the body; on the inner side of

    • The heart is medial to the arm

• Lateral

  • Away from the midline of the body; on the outer side of

    • The arms are lateral to the chest

• Proximal

  • Closer to the origin of the body part or the point of attachment of a limb to the body trunk

    • The elbow is proximal to the wrist

• Distal

  • Farther from the origin of a body part or the point of attachment of a limb to the body trunk

    • The knee is distal to the thigh

• Superficial (external)

  • Toward or at the body surface

    • The skin is superficial to the skeletal muscles

• Deep (internal)

  • Away from the body surface; more internal

    • The lungs are deep to the skin.

Divisions of the Body

Two divisions

• Axial

  • Head, neck, and trunk

• Appendicular

  • Appendages or limbs (legs and arms)

Body Planes

• Ways body is viewed or studied

• Three common Body Planes

  • Sagittal plane (sideways view)

    • Midsagittal Plane: cut was made perfectly on midline

    • Parasagittal plane or Sagittal Plane: cut was off-centered, not on midline

  • Frontal Plane (front view)

    • Divides body vertically into anterior and posterior parts (front and back)

  • Transverse (horizontal view)

    • Divides body into superior and inferior parts (top and bottom)

Body Cavities

• Many internal organs lie in membrane-lined cavities

• Closed to the outside and provide varying levels of protection

• Common two cavities:

  • Dorsal Body Cavity (cranial and vertebral cavities)

    • Houses/ protects CNS

    • Brain encased in skull, spinal cord in vertebral column

    • Brain and SC covered in meninges

  • Ventral body cavity (thoracic and abdominal cavities)

    • Houses viscera or visceral organs

    • Two Subdivisions separated by diaphragm

      • Thoracic Cavity

        • Pleural cavities each enveloping a lung

        • Pericardial cavity surrounding heart

      • Abdominopelvic Cavity

        • Abdominal contains stomach, intestines, spleen liver

        • Pelvic contains bladder, some reproductive organs and rectum

Serous Membrane and Fluid