Human Anatomy and Physiology: Practice Exam Study Notes (Unit 1)

Body Organization and Directional Terminology

Directional Terms

Directional terms are used to describe the locations of structures in relation to other structures or locations in the body. These terms are essential for clear communication in anatomy.

• Superficial: Toward or at the body surface.

• Deep: Away from the body surface; more internal.

• External: Outside or outer part of a structure.

• Internal: Inside or inner part of a structure.

• Parietal: Pertaining to the wall of a body cavity.

• Visceral: Pertaining to the organs within the body cavities.

• Ipsilateral: On the same side of the body.

• Contralateral: On the opposite side of the body.

Example: The heart is medial to the lungs.

Body Planes

Body planes are imaginary lines that divide the body into sections and are used to describe locations or directions.

• Frontal (coronal) plane: Divides the body into anterior (front) and posterior (back) portions.

• Sagittal plane: Divides the body into right and left portions. The midsagittal plane divides the body into equal right and left halves.

• Transverse (horizontal) plane: Divides the body into superior (upper) and inferior (lower) portions.

Major Organ Systems

The human body is organized into organ systems, each with specific functions.

• Integumentary: Skin, hair, nails; protection and temperature regulation.

• Skeletal: Bones, cartilage; support, protection, movement.

• Muscular: Muscles; movement, posture, heat production.

• Nervous: Brain, spinal cord, nerves; control and communication.

• Endocrine: Glands; hormone production and regulation.

• Cardiovascular: Heart, blood vessels; transport of nutrients and waste.

• Lymphatic: Lymph nodes, vessels; immunity and fluid balance.

• Respiratory: Lungs, airways; gas exchange.

• Digestive: Stomach, intestines; breakdown and absorption of food.

• Urinary: Kidneys, bladder; waste removal and water balance.

• Reproductive: Ovaries, testes; production of offspring.

Body Cavities and Planes

Body Cavities

Body cavities protect organs and allow for changes in organ size and shape.

• Dorsal (posterior) cavity: Includes cranial and vertebral (spinal) cavities.

• Ventral (anterior) cavity: Includes thoracic and abdominopelvic cavities.

• Thoracic cavity: Contains heart and lungs.

• Abdominopelvic cavity: Contains digestive, urinary, and reproductive organs.

Example: The heart is located within the thoracic cavity.

Classification of Bones by Shape

Bone Shapes

Bones are classified according to their shapes, which relate to their functions.

• Sutural bones: Small bones located within sutures of the skull.

• Flat bones: Thin and broad; e.g., sternum, skull bones.

• Long bones: Longer than they are wide; e.g., femur, humerus.

• Irregular bones: Complex shapes; e.g., vertebrae.

• Sesamoid bones: Embedded in tendons; e.g., patella.

• Short bones: Cube-shaped; e.g., carpals, tarsals.

Microscopic Structure of Bone

Bone Tissue Components

Bones are composed of different tissues and structures that provide strength and flexibility.

• Compact bone: Dense outer layer providing strength.

• Osteon: Structural unit of compact bone.

• Central canal: Contains blood vessels and nerves within osteons.

• Bone lamella: Layers of bone matrix within osteons.

• Periosteum: Outer fibrous covering of bone.

• Lacunae: Small spaces housing osteocytes.

• Spongy bone: Porous inner bone, contains trabeculae.

• Trabeculae: Network of bony struts in spongy bone.

• Endosteum: Membrane lining the internal bone surfaces.

Example: Osteons are found in compact bone and are essential for nutrient delivery.

Skull Terminology and Structures

Major Skull Bones and Sutures

The skull consists of several bones joined by sutures, with distinct landmarks important for identification.

• Parietal, Temporal, Occipital, Frontal, Zygomatic, Mandible, Maxilla, Nasal, Sphenoid, Ethmoid, Vomer: Major bones of the skull.

• Coronal, Sagittal, Lambdoid, Squamous sutures: Joints between skull bones.

• External auditory meatus, Mastoid process, Styloid process, Pterion, Alveolar process, Condylar process, Mandibular notch: Key landmarks for identification.

Example: The coronal suture separates the frontal and parietal bones.

Foramina and Sinuses

Foramina are openings for nerves and blood vessels; sinuses are air-filled cavities that reduce skull weight and resonate sound.

• Foramen magnum: Passage for spinal cord.

• Optic canal: Passage for optic nerve.

• Frontal, Sphenoidal, Ethmoid, Maxillary sinuses: Paranasal sinuses.

Summary Table: Bone Shapes

Bone Shape	Example	Main Function
Sutural	Small bones in skull sutures	Fill gaps between larger bones
Flat	Sternum, skull	Protection, muscle attachment
Long	Femur, humerus	Movement, support
Irregular	Vertebrae	Complex functions
Sesamoid	Patella	Reduce friction, modify pressure
Short	Carpals, tarsals	Stability, support

Additional info: These notes expand upon the brief points in the practice exam, providing definitions, examples, and context for key anatomical terms and structures relevant to introductory college-level Anatomy & Physiology.