ANAPHY

PART I: Integumentary System Reviewer

The integumentary system consists of the skin (cutaneous membrane) and its accessory structures (hair, nails, glands). It serves as the body’s first line of defense against environmental hazards.

Layers of the Skin

EPIDERMIS (Avascular, Stratified Squamous Epithelium)

- Stratum Corneum

- Stratum Lucidum (Thick skin only)

- Stratum Granulosum

- Stratum Spinosum

- Stratum Basale

DERMIS (Vascular, Connective Tissue)

- Papillary Layer (Areolar CT)

- Reticular Layer (Dense Irregular CT)

HYPODERMIS / SUBQ (Adipose & Areolar CT)

1. Epidermis

Avascular keratinized stratified squamous epithelium.

Stratum Basale (Germinativum): Deepest single layer; location of active mitosis. Contains stem cells, melanocytes (pigment production), and Merkel cells (touch sensory).

Stratum Spinosum: 8–10 layers thick; web-like system of intermediate filaments. Contains Langerhans cells (dendritic cells for immune defense).

Stratum Granulosum: 3–5 layers thick; cell death (apoptosis) begins here. Keratohyalin granules and lamellar granules (waterproofing glycolipids) accumulate.

Stratum Lucidum: Present only in thick skin (palms, soles). Clear, dead cell layer.

Stratum Corneum: Outermost layer (20–30 layers of dead, anucleate keratinized cells); acts as a physical barrier.

2. Dermis

Strong, flexible connective tissue layer containing blood vessels, nerves, and lymphatic vessels.

Papillary Layer: Upper 20%. Made of areolar connective tissue. Features dermal papillae (forming fingerprint ridges), capillaries, and Meissner’s corpuscles (fine touch).

Reticular Layer: Lower 80%. Made of dense irregular connective tissue providing tensile strength. Contains sweat/sebaceous glands, hair follicles, and Pacinian corpuscles (deep pressure/vibration).

3. Hypodermis (Subcutaneous Layer)

Technically not part of the skin. Composed of adipose and areolar connective tissue. Functions as an insulator, shock absorber, and skin anchor.

Accessory Structures & Glands

Hair: Composed of hard keratin. Associated with arrector pili muscles (smooth muscle causing goosebumps).

Sebaceous Glands: Holocrine glands attached to hair follicles; secrete sebum (oily substance preventing drying and inhibiting bacteria).

Sudoriferous (Sweat) Glands:

Eccrine (Merocrine): Thermoregulation; abundant on palms, soles, and forehead; secretes watery sweat directly to skin pores.

Apocrine: Secretes protein/lipid-rich sweat into hair follicles in axillary and anogenital regions; activated during puberty (odor caused by bacterial breakdown).

PART II: Skeletal System Reviewer

1. Overview of the Skeleton

The adult human skeleton contains 206 bones divided into two major divisions:

Axial Skeleton (80bones)

—Protects internal organs, supports head/neck/trunk

—Skull, Auditory Ossicles, Hyoid Bone, Vertebral Column, Thoracic Cage

Appendicular Skeleton (126 bones)

—Enables locomotion and manipulation of environment

—Pectoral Girdle, Upper Limbs, Pelvic Girdle, Lower Limbs

2. Microscopic & Gross Anatomy of a Long Bone (picture above)

Macro-Structures:

Diaphysis: Tubular shaft forming the long axis; constructed of dense compact bone surrounding a central cavity.

Epiphyses: Bone ends (proximal and distal); outer shell of compact bone with internal spongy (cancellous) bone. Covered by articular (hyaline) cartilage.

Metaphysis: Epiphyseal plate region (growth plate made of hyaline cartilage in children; becomes epiphyseal line in adults).

Medullary Cavity: Central hollow region in the diaphysis containing yellow bone marrow (fat storage in adults) or red bone marrow (hematopoiesis in infants/spongy bone).

Membranes:

Periosteum: Double-layered outer membrane covering the diaphysis; secured to bone by Sharpey’s (perforating) fibers.

Endosteum: Internal membrane lining the medullary cavity and spongy bone trabeculae.

3. The Skull (picture above)

—Consists of 22 bones (8 Cranial + 14 Facial).

Frontal (Anterior) View:

Bones visible: Frontal bone, Nasal bones,

Maxillae, Zygomatic bones, Mandible, Ethmoid, Sphenoid.

Landmarks: Orbits (eye sockets), Anterior nasal aperture, Mental foramen (on mandible).

Lateral View:

Bones visible: Parietal, Temporal, Frontal, Occipital, Sphenoid (greater wing), Zygomatic, Maxilla, Mandible.

Sutures:

•Coronal: Frontal + Parietal.

•Squamous: Temporal + Parietal.

•Lambdoid: Occipital + Parietal.

Landmarks:

External acoustic meatus, Mastoid process, Styloid process, Zygomatic arch (Zygomatic process of temporal + Temporal process of zygomatic).

Superior View:

Bones visible: Frontal bone anteriorly, paired Parietal bones, Occipital bone posteriorly.

Sutures: Sagittal suture (joins parietal bones along midline); Coronal suture anteriorly.

Inferior (Basal) View:

Bones visible: Palatine processes of Maxillae, Palatine bones, Sphenoid, Vomer, Temporal, Occipital.

Landmarks:

Foramen Magnum: Passes spinal cord.

Occipital Condyles: Articulate with C1 (Atlas).

Carotid Canal & Jugular Foramen: Major neurovascular passages.

4. Vertebral Column

—Composed of 26 irregular bones arranged into 5 major regions:

1. Cervical (C1–C7): Neck region. Key feature: Transverse foramina for vertebral arteries.

•C1 (Atlas): No body or spinous process; articulates with occipital condyles ("yes" motion).

•C2 (Axis): Has a vertical projection called the Dens (Odontoid process) ("no" motion).

2. Thoracic (T1–T12): Chest region. Feature costal facets for rib articulation; long, downward-pointing spinous processes.

3. Lumbar (L1–L5): Lower back. Large, hatchet-shaped spinous processes; thick bodies built for weight-bearing.

4.Sacrum (1 bone, 5 fused): Articulates with hip bones at sacroiliac joints.

5.Coccyx (1 bone, 3–5 fused): Tailbone.

Curvatures to remember:

•Primary Curvatures (Present at birth, concave anteriorly): Thoracic and Sacral.

•Secondary Curvatures (Develop postnatally, convex anteriorly): Cervical (holding head up) and Lumbar (learning to walk).

5. Thoracic Cage

—Protects thoracic organs and supports pectoral girdle.

Sternum (Breastbone): Consists of 3 fused bones:

Manubrium: Superior region; articulates with clavicles and Ribs 1–2.

Body: Midportion; articulates with costal cartilages of Ribs 2–7.

Xiphoid Process: Inferior projection (hyaline cartilage in youth, ossifies in adults).

Ribs (12 pairs):

True Ribs (1–7 / Vertebrosternal): Attach directly to sternum via costal cartilage.

False Ribs (8–12): Indirect or no attachment to sternum.

Vertebrochondral (8–10): Attach to cartilage of rib 7.

Floating Ribs (11–12 / Vertebral): No anterior attachment.

6. Upper Limb Bones & Wrist/Hand

Pectoral Girdle: Clavicle (collarbone) + Scapula (shoulder blade - landmarks: Glenoid cavity, Acromion process, Coracoid process).

Arm: Humerus (Head articulates with glenoid cavity; distal end features Trochlea and Capitulum).

•Forearm

-Radius: Lateral side (thumb side). Proximal disc-head rotates for pronation/supination.

-Ulna: Medial side (pinky side). Features Olecranon process (elbow point) and Trochlear notch.

•Wrist (Carpals - 8 bones): arranged in two rows of four.

•Mnemonic (Lateral to Medial, Proximal to Distal):

"So Long To Pinky, Here Comes The Thumb"

-Proximal Row: Scaphoid, Lunate, Triquetrum, Pisiform

-Distal Row: Hamate, Capitate, Trapezoid, Trapezium

•Hand:

-Metacarpals: 5 bones (Numbered I–V, starting at the thumb).

-Phalanges: 14 bones total (Digits II–V have Proximal, Middle, Distal; Thumb/Pollex has only Proximal and Distal).

7. Pelvic Girdle & Lower Limb Bones

Pelvic Girdle

Consists of two Coxal bones (Hip bones) that unite anteriorly at the Pubic symphysis and posteriorly at the Sacrum. Each coxal bone is formed by the fusion of 3 bones:

1.Ilium: Superior region; landmarks include Iliac crest and Greater sciatic notch.

2.Ischium: Inferior posterior part; landmark: Ischial tuberosity ("sit bones").

3.Pubis: Inferior anterior part; forms Obturator foramen with ischium.

Acetabulum: Deep socket where all three fused bones meet; receives head of femur.

Male vs. Female Pelvis Comparison:

Female: Adapted for childbearing; wider pelvic inlet/outlet, broader pubic arch (>90^\circ), shallower and lighter.

Male: Taller, narrower, deeper; acute pubic arch (<90^\circ).

8. Lower Limb Bones & Foot Bones

Thigh: Femur (Longest and strongest bone in the body; landmarks: Head, Greater and Lesser Trochanters, Condyles).

Kneecap: Patella (Sesamoid bone enclosed in quadriceps tendon).

•Leg:

-Tibia: Medial, weight-bearing bone ("shin bone"). Distal landmark: Medial malleolus (inner ankle).

-Fibula: Lateral, non-weight-bearing bone (stick-like). Distal landmark: Lateral malleolus (outer ankle).

•Foot (Tarsals, Metatarsals, Phalanges):

Tarsals (7 bones):

-Talus: Articulates with tibia and fibula (ankle joint).

-Calcaneus: Heel bone (attache

s Achilles tendon).

-Others: Navicular, Cuboid, and 3 Cuneiforms (Medial, Intermediate, Lateral).

-Metatarsals: 5 bones (Numbered I–V, medial to lateral).

-Phalanges: 14 bones (Big toe/Hallux has 2; Digits II–V have 3 each).