Anatomy & Physiology Study Guide: Tissues, Skin, and Skeletal System

Introduction to Anatomy & Physiology

This study guide covers foundational topics in Anatomy & Physiology, focusing on the organization of the human body, tissues, skin, and the skeletal system. It is structured to help students understand key concepts, definitions, and relationships necessary for exam preparation.

Hierarchy of Biological Organization

Levels of Organization

• Atoms: The smallest units of matter, forming molecules.

• Molecules: Chemical structures consisting of atoms bonded together (e.g., water, proteins).

• Cells: The basic structural and functional units of life.

• Tissues: Groups of similar cells performing a common function.

• Organs: Structures composed of two or more tissue types working together.

• Organ Systems: Groups of organs that perform related functions.

• Organism: The complete living being.

Example: Muscle tissue (tissue level) forms the heart (organ), which is part of the cardiovascular system (organ system).

Body Cavities and Anatomical Regions

Major Body Cavities

• Thoracic Cavity: Contains the heart and lungs.

• Abdominal Cavity: Contains digestive organs.

• Pelvic Cavity: Contains urinary and reproductive organs.

Anatomical Directions

• Medial: Toward the midline of the body.

• Lateral: Away from the midline.

• Proximal: Closer to the point of attachment.

• Distal: Farther from the point of attachment.

• Anterior (Ventral): Toward the front.

• Posterior (Dorsal): Toward the back.

• Superior: Above.

• Inferior: Below.

Example: The heart is medial to the lungs and superior to the stomach.

Body Planes and Positions

Body Planes

• Sagittal Plane: Divides the body into right and left parts.

• Frontal (Coronal) Plane: Divides the body into anterior and posterior parts.

• Transverse (Horizontal) Plane: Divides the body into superior and inferior parts.

Body Positions

• Supine: Lying on the back, face upward.

• Prone: Lying on the stomach, face downward.

Cell Types and Tissues

Types of Tissues

• Epithelial Tissue: Covers body surfaces and lines cavities; functions in protection, absorption, and secretion.

• Connective Tissue: Supports, binds, and protects organs (e.g., bone, blood, adipose tissue).

• Muscle Tissue: Responsible for movement (skeletal, cardiac, smooth muscle).

• Nervous Tissue: Conducts electrical impulses; found in the brain, spinal cord, and nerves.

Cell Types in the Skin

• Keratinocytes: Produce keratin, a protective protein.

• Melanocytes: Produce melanin, which gives skin its color.

• Langerhans Cells: Immune cells in the epidermis.

• Merkel Cells: Sensory receptors for touch.

Skin Structure and Function

Layers of the Skin

• Epidermis: Outermost layer; provides a waterproof barrier.

• Dermis: Middle layer; contains connective tissue, hair follicles, and sweat glands.

• Hypodermis (Subcutaneous Layer): Deepest layer; made of fat and connective tissue.

Functions of the Skin

• Protection from pathogens and injury

• Regulation of body temperature

• Sensation (touch, pain, temperature)

• Excretion of wastes

• Synthesis of vitamin D

Skeletal System Overview

Functions of the Skeletal System

• Support for the body

• Protection of internal organs

• Movement (with muscles)

• Mineral storage (calcium, phosphorus)

• Blood cell production (hematopoiesis)

Classification of Bones

• Long Bones: Longer than they are wide (e.g., femur, humerus).

• Short Bones: Cube-shaped (e.g., carpals, tarsals).

• Flat Bones: Thin and broad (e.g., skull, ribs, sternum).

• Irregular Bones: Complex shapes (e.g., vertebrae, pelvis).

• Sesamoid Bones: Embedded in tendons (e.g., patella).

Bone Anatomy

• Diaphysis: Shaft of a long bone.

• Epiphysis: Ends of a long bone.

• Metaphysis: Region between diaphysis and epiphysis; contains the growth plate.

• Periosteum: Outer covering of bone.

• Endosteum: Lining of the medullary cavity.

Axial and Appendicular Skeleton

Axial Skeleton

• Skull

• Vertebral column

• Rib cage (ribs and sternum)

Appendicular Skeleton

• Pectoral girdle (shoulder bones)

• Upper limbs (arms, forearms, hands)

• Pelvic girdle (hip bones)

• Lower limbs (thighs, legs, feet)

Vertebral Column

Regions and Number of Vertebrae

Region	Number of Vertebrae
Cervical	7
Thoracic	12
Lumbar	5
Sacral	5 (fused)
Coccygeal	4 (fused)

Example: The cervical region supports the head and allows for its movement.

Joints (Arthrology)

Types of Joints

• Fibrous Joints: Immovable (e.g., sutures of the skull).

• Cartilaginous Joints: Slightly movable (e.g., intervertebral discs).

• Synovial Joints: Freely movable (e.g., shoulder, knee).

Examples of Synovial Joints

• Hinge Joint: Elbow, knee

• Ball-and-Socket Joint: Shoulder, hip

• Pivot Joint: Atlas and axis (neck)

Palpable Landmarks and Bone Identification

• Know which bones and structures are palpable (can be felt through the skin).

• Identify major bony landmarks (e.g., acromion, iliac crest, sacrum).

• Distinguish between bones of the upper and lower limbs.

• Recognize the phalanges, metacarpals, and head/base of bones.

Additional Info

• Be able to compare and contrast different types of tissues and joints.

• Understand the functional significance of anatomical features.

• Apply anatomical terminology to describe locations and relationships in the body.