Pg 104-106

General Terminology and Anatomical Baseline

Standardized Terminology:
- Standard terminology is established across all health professions to establish a baseline reference and facilitate a common understanding.
- This includes standard terms for locating body structures, defining internal and external regions, and describing anatomical subdivisions.
Anatomical Position:
- Serves as the standard baseline reference point for all areas and structures of the human body.
- Postural Characteristics:
  - The body is in an erect position.
  - The feet are positioned slightly apart.
  - The head is held upright.
  - The arms are placed at the sides of the body.
  - The palms of the hands are facing forward.

Body Planes and Sectioning

Definition of Body Planes:
- Body planes are imaginary flat surfaces or lines that divide the body or individual body parts at specific angles.
Specific Planes:
- Sagittal Plane: A vertical plane that divides the body or a body part into right and left sides.
- Midsagittal Plane: A specific type of sagittal plane that divides the body directly down the middle into equal right and left halves.
- Frontal (Coronal) Plane: A vertical plane that divides the body or a body part into front (anterior) and back (posterior) sections.
- Transverse Plane: A horizontal plane that divides the body or a body part into upper (superior) and lower (inferior) sections.
- Oblique Plane: Any plane that intersects the body at an angle other than a strict vertical or horizontal angle.

Directional Terminology

Relative Spatial Terms:
- Superior: Located above or toward the upper part of a structure/body.
- Inferior: Located below or toward the lower part of a structure/body.
- Anterior / Ventral: Toward or at the front of the body or structures on/within the body.
- Posterior / Dorsal: Toward or at the back of the body.
- Medial: Toward or at the midline of the body.
- Lateral: Away from the midline of the body.
- Cranial: Located toward the head.
- Caudal: Located toward the tail or lower part of the trunk (away from the head).
- Ipsilateral: Located or occurring on the same side of the body.
- Contralateral: Located or occurring on the opposite side of the body.
- Proximal: Closer to the point of attachment of an extremity to the trunk.
- Distal: Farther away from the point of attachment of an extremity to the trunk.
- Superficial: Located closer to or at the surface of the body.
- Deep: Located further internal/interior into the body.

Major Body Cavities

Dorsal Body Cavity:
- Located along the posterior aspect of the body.
- Cranial Cavity: Contains the brain within the skull.
- Spinal Cavity: Encloses the spinal cord within the vertebral column.
Ventral Body Cavity:
- Located along the anterior aspect of the body.
- Thoracic Cavity:
  - Pleural Cavities: Two separate cavities, each containing a lung.
  - Pericardial Cavity: Encloses the heart.
- Abdominopelvic Cavity:
  - Abdominal Cavity: Contains the digestive organs.
  - Pelvic Cavity: Contains the reproductive organs, the urinary bladder, and the lower gastrointestinal tract.

Types of Body Movements

Anatomical Movement Definitions:
- Flexion: Bending of a joint.
- Extension: Straightening of a joint.
- Abduction: Moving a bone or limb away from the midline of the body.
- Adduction: Moving a bone or limb toward the midline of the body.
- Medial (Internal) Rotation: Rotating a limb or bone toward the midline of the body.
- Lateral (External) Rotation: Rotating a limb or bone away from the midline of the body.
- Pronation: Rotating the forearm so that the palm faces downward (posteriorly).
- Supination: Rotating the forearm so that the palm faces upward (anteriorly).
- Dorsiflexion: Decreasing the angle between the top of the foot and the front of the leg.
- Plantar Flexion: Decreasing the angle between the bottom of the foot and the back of the leg.
- Inversion: Turning the sole of the foot inward toward the midline.
- Eversion: Turning the sole of the foot outward away from the midline.

Histology and Primary Tissue Types

Foundations of Histology:
- Histology is defined as the scientific study of tissues.
- A tissue is defined as a group of similar cells working together to execute specific functions.
Four Principal Tissue Classes:
- Epithelial Tissue:
  - Functions to cover, line, and protect the outer body surfaces and internal organs.
  - Glandular Epithelium: Specialized epithelial tissue that secretes substances including mucus, enzymes, and hormones.
- Connective Tissue:
  - Serves as the most abundant and widely distributed tissue in the human body.
  - Forms the structural framework of the body, providing essential support and structure for internal organs.
  - Subtypes:
    - Fibrous Connective Tissue: includes areolar tissue, adipose tissue, reticular tissue, and dense connective tissue.
    - Bone Tissue
    - Cartilage Tissue
    - Blood Tissue
- Nervous Tissue:
  - Neurons: Specialized nerve cells that initiate and conduct electrochemical nerve impulses.
  - Neuroglia: Connective tissue cells that protect, support, and nourish neurons.
- Muscle Tissue:
  - Possesses the ability to contract (shorten) and lengthen to generate physical force and movement.

Integumentary System Structure and Function

System Overview:
- Consists of the skin along with accessory structures and organs including hair, nails, and sensory receptors.
- The skin is the body's largest organ.
Anatomical Layers of the Skin:
- Epidermis:
  - The outermost, superficial layer of the skin.
  - Functions as a protective barrier.
  - Composed entirely of dead, keratinized epithelial cells.
- Dermis:
  - The deep underlying layer of connective tissue situated directly below the epidermis.
  - Composed of fibrous connective tissue.
  - Contains structural elements including blood vessels, sensory nerve endings, hair follicles, and glands.
- Subcutaneous Layer (Hypodermis / Superficial Fascia):
  - Rests underneath the dermis.
  - Anchors and connects the skin to the underlying muscles and bones.

Epidermal Layers and Specialized Cell Types

Layers of the Epidermis (Superficial to Deep):
1. Stratum Corneum: The most superficial layer, consisting of dead, keratinized cells.
2. Stratum Lucidum: Present in thick skin areas.
3. Stratum Granulosum: Middle cellular layer.
4. Stratum Spinosum: Layer lying above the basal layer.
5. Stratum Germinativum (Stratum Basale): The deepest layer of the epidermis, which continually undergoes active cell division (mitosis) to generate new skin cells.
Specialized Components of Epidermal Cells:
- Keratin: A tough cellular protein that waterproofs the outer layer of the skin.
- Melanocytes: Specialized cells within the epidermis that produce the pigment melanin, which absorbs and protects the body against harmful solar ultraviolet radiation.

Cutaneous Glands, Structures, and Clinical Significance

Types of Sweat Glands:
- Eccrine Sweat Glands:
  - The most widely distributed type of sweat gland across the body.
  - Regulate body temperature by secreting a watery fluid that absorbs heat and cools the skin as it evaporates.
- Apocrine Sweat Glands:
  - Located predominantly in the axilla (armpit) and inguinal (groin) regions.
  - Produce a thicker, opaque secretion that contains cellular debris and cytoplasm from the secreting cells.
  - Cellular material is digested by surface bacteria, leading to the production of human body odor.
Sebaceous Glands:
- Secrete an oily substance called sebum directly into hair follicles.
- Functions to lubricate and moisturize the skin surface.
- Prone to becoming clogged and harboring bacteria, particularly during adolescence.
Integumentary Appendages and Diagnostics:
- Hair and Nails:
  - Both are hardened structures composed entirely of plates of keratin.
- Clinical Significance:
  - Numerous systemic and localized diseases produce observable alterations in the structure, color, or texture of hair, nails, and skin.
  - Thorough physical observation and assessment of the integumentary system are vital when diagnosing clinical conditions.