Test 2 Study Guide: Anatomy & Physiology

Test 2 Study Guide: Anatomy & Physiology

Chapter 5: The Integumentary System

Layers of the Skin

The skin is composed of three layers:

1. Epidermis – Superficial layer, made of keratinized stratified squamous epithelium.

2. Dermis – Deep layer, contains blood vessels, nerves, and glands.

3. Hypodermis (Subcutaneous Tissue) – Not part of the skin; adipose tissue for insulation and shock absorption.

Layers of the Epidermis (Mnemonic: "Before Signing, Get Legal Counsel")

1. Stratum Basale – Deepest layer; mitotic cells (actively dividing).

   • Contains melanocytes (produce melanin) and Merkel cells (sensory receptors).

2. Stratum Spinosum – Several layers of keratinocytes, connected by desmosomes for strength.

3. Stratum Granulosum – Cells begin to die, produce keratohyalin granules (for waterproofing).

4. Stratum Lucidum – Only in thick skin (palms, soles); transparent layer.

5. Stratum Corneum – Outermost layer, made of dead keratinized cells; provides protection.

Functions of the Skin

1. Protection – Chemical, physical, and biological barriers.

2. Temperature Regulation – Sweating, blood vessel dilation/constriction.

3. Cutaneous Sensation – Touch, pain, temperature receptors.

4. Metabolic Functions – Vitamin D production.

5. Blood Reservoir – Stores 5% of body’s blood.

6. Excretion – Removes salts & wastes through sweat.

Skin Cancer & Burns

• Basal Cell Carcinoma – Most common, least dangerous; originates in stratum basale.

• Squamous Cell Carcinoma – Can spread, originates in stratum spinosum.

• Melanoma – Most dangerous, arises from melanocytes.

  • ABCD Rule: Asymmetry, Border irregularity, Color variation, Diameter >6mm.

Chapter 6: Bones and Skeletal Tissue

Bone Textures

• Compact Bone – Dense outer layer, strong, made of osteons.

• Spongy Bone – Honeycomb-like structure with trabeculae filled with marrow; reduces weight while maintaining strength.

Structure of Bones

• Long Bones – Longer than wide (e.g., femur, humerus).

• Short Bones – Cube-shaped (e.g., wrist, ankle).

• Flat Bones – Thin, curved (e.g., sternum, skull bones).

• Irregular Bones – Complex shapes (e.g., vertebrae, hip bones).

Bone Markings

Bone markings serve as attachment points for muscles & ligaments, help form joints, or allow passage of blood vessels & nerves.

Bone Markings That Are Sites of Muscle & Ligament Attachment

• Tuberosity – Large rounded projection.

• Crest – Narrow ridge of bone.

• Trochanter – Large, irregular projection (only on femur).

• Line – Narrow ridge of bone.

• Tubercle – Small rounded projection.

• Epicondyle – Raised area on or above a condyle.

• Spine – Sharp, slender projection.

• Process – Any bony prominence.

Bone Markings That Help Form Joints

• Head – Bony expansion on a narrow neck.

• Facet – Smooth, nearly flat surface.

• Condyle – Rounded articular projection.

• Ramus – Armlike bar of bone.

Bone Markings for Passage of Vessels & Nerves

• Fissure – Narrow slit-like opening.

• Foramen – Round or oval opening through a bone.

• Notch – Indentation at an edge.

Other bone markings

Meatus: Canal-like passageway

Sinus: Bone cavity, filled with air and lined with mucous membrane

Fossa: Shallow basinlike depression in a bone, often serving as an articular surface

Hematopoietic Tissue (Red Marrow)

• Newborns: Found in medullary cavities and spongy bone.

• Adults: Located in flat bones (sternum, hip bones) and heads of femur & humerus.

Chemical Composition of Bone

• Organic Components (35%) – Cells (osteocytes, osteoblasts, osteoclasts) and collagen fibers (strength & flexibility).

• Inorganic Components (65%) – Calcium phosphate (hydroxyapatite crystals) provide hardness.

Bone Development (Ossification)

• Endochondral Ossification – Forms most bones, replaces hyaline cartilage.

• Intramembranous Ossification – Forms flat bones (e.g., skull, clavicle).

Bone Remodeling & Repair

• Controlled by:

  • Hormones (PTH & Calcitonin).

  • Mechanical Stress (Wolff’s Law) – Bones grow in response to stress.

• Fracture Healing Stages:

  1. Hematoma formation.

  2. Fibrocartilaginous callus formation.

  3. Bony callus formation.

  4. Bone remodeling.

Homeostatic Imbalances of Bone

1. Osteomalacia & Rickets – Soft, weak bones due to calcium or vitamin D deficiency.

2. Osteoporosis – Bone resorption exceeds deposit, leading to fragile bones.

   • Risk Factors: Older age, postmenopause, lack of exercise, smoking.

   • Prevention: Calcium, vitamin D, weight-bearing exercise.

3. Paget’s Disease – Excessive, unorganized bone growth, weak bones in spine, pelvis, skull.

Chapter 7: The Skeleton

Mnemonic: How to Remember the Vertebrae Regions ("Breakfast at 7, Lunch at 12, Dinner at 5")

• Cervical (C1-C7) → 7 Vertebrae (Breakfast)

• Thoracic (T1-T12) → 12 Vertebrae (Lunch)

• Lumbar (L1-L5) → 5 Vertebrae (Dinner)

Mnemonic: "The Circus Needs More Interesting Little Clowns" (Tarsal Bones in the Foot)

• Talus

• Calcaneus

• Navicular

• Medial cuneiform

• Intermediate cuneiform

• Lateral cuneiform

• Cuboid

Mnemonic: "Some Lovers Try Positions That They Can’t Handle" (Carpal Bones in the Hand)

• Scaphoid

• Lunate

• Triquetrum

• Pisiform

• Trapezoid

• Trapezius

• Capitate

• Hamate