Introduction to Human Anatomy

Introduction to Human Anatomy

• Human anatomy is the study of the structure of the human body.
• The human body is divided into regions: head, neck, trunk, and limbs.
• The trunk is further subdivided into the chest (thorax) and the abdomen, and the abdomen is further subdivided into the abdomen proper and the pelvis.
• Systemic anatomy studies the organ systems, which work together for complex functions. These systems include the skin, muscular, skeletal, nervous, cardiac, respiratory, and digestive systems.

Anatomical Terminology

• The anatomical position is the standard reference position for describing structures.
• In this position, the person stands erect and faces forward, looking forward.
• The upper limbs are at the sides, with palms forward.
• The lower limbs are together, with soles on the ground and toes forward.

Anatomical Planes

• Median plane (midsagittal plane): A vertical plane dividing the body into equal right and left halves.
• Sagittal plane (paramedian plane): Any vertical plane parallel to the median plane, dividing the body into unequal right and left portions.
• Coronal (frontal) plane: A vertical plane at a right angle to the median plane, dividing the body into anterior (front) and posterior (back) portions.
• Horizontal (transverse) plane: A plane at a right angle to both the median and coronal planes, dividing the body into superior (upper) and inferior (lower) parts.

Terms of Position

• Median: Refers to any structure lying in the median plane.
• Medial: Refers to a structure nearer to the median plane than another.
• Lateral: Refers to a structure farther from the median plane than another.
• Anterior (ventral): Describes structures nearer to the front of the body.
• Posterior (dorsal): Describes structures nearer to the back of the body.
• Proximal: Refers to a structure nearer to the attachment of a limb.
• Distal: Refers to a structure farther from the attachment of a limb.
• Superior: Refers to a structure nearer to the vertex of the skull.
• Inferior: Refers to a structure nearer to the sole of the foot.
• Superficial: Refers to a structure closer to the surface of the body.
• Deep: Refers to a structure farther from the surface of the body.

Terms Related to Movement

• Flexion: Bending or decreasing the angle between bones.
• Extension: Straightening or increasing the angle between bones.
• Lateral flexion: Lateral bending movement of the trunk.
• Dorsiflexion: Lifting the top of the foot superiorly.
• Plantar flexion: Moving the sole of the foot inferiorly.
• Abduction: Movement away from the midline of the body.
• Adduction: Movement toward the midline of the body.
• Pronation: Medial rotation of the forearm.
• Supination: Lateral rotation of the forearm.
• Circumduction: A circular movement.
• Medial (internal) Rotation: Movement bringing the anterior surface closer to the midline.
• Lateral (external) Rotation: Movement taking the anterior surface away from the midline.

The Skin

• The skin is the largest organ in the body.
• It protects the body from environmental effects (e.g., UV radiation).
• It contains the body's structures.
• It regulates body temperature.
• It provides sensation.
• It synthesizes and stores vitamin D.
• It has two main parts: the epidermis and the dermis.
• The epidermis is a protective outer layer, avascular (no blood vessels).
• The dermis is composed of dense connective tissue, containing blood vessels, lymphatic vessels, collagen and elastic fibers, and nerves.
• The dermis provides skin tone and strength.
• Appendages include nails, hair follicles, sebaceous, and sweat glands.

Fascia

• Fascia is connective tissue that encloses the body.
• Two types: superficial and deep fascia.
• Superficial fascia (subcutaneous tissue): A mixture of loose areolar and adipose tissue, connecting the dermis to the deep fascia.
• Deep fascia: A dense, inelastic membranous layer, sheathing and dividing muscles into functional groups (ex. intermuscular septa).
• It is attached to the deep surface of superficial fascia.

Bone

• Bone is a living tissue.
• Provides support, protection, and leverage.
• Stores minerals.
• Produces blood cells.
• Covered by periosteum (a dense fibrous connective tissue)

Bone Classification

• Axial skeleton includes the skull, vertebral column, ribs, and sternum.
• Appendicular skeleton includes the bones of the upper and lower limbs, and the pectoral and pelvic girdles.

Types of Bones

• The table will classify bones by shape (long, short, flat, irregular).
• The description of the location and function of each bone type.
• The description of characteristics (internal structures and coverings), as well as the location.

Joints

• Joints are the unions between bones.
• Classified into fibrous, cartilaginous, and synovial types.
• Fibrous joints (synarthroses): Connected by fibrous connective tissue (e.g., sutures of the skull).
• Cartilaginous joints (amphiarthroses): Bones joined by cartilage (e.g., intervertebral discs).
• Synovial joints (diarthroses): The most common type (e.g., ball-and-socket, hinge, saddle joints with characteristics).

Muscles

• Muscles are specialized contractile tissues.
• They move body parts, or change shape of internal organs.
• Three types: skeletal (voluntary), smooth (involuntary), and cardiac (involuntary).
• Skeletal muscles are striated, voluntary, and responsible for gross movements. Have tendons and aponeuroses as attachments.

Cardiovascular System

• The heart pumps blood.
• Blood vessels (arteries, arterioles, capillaries, venules, and veins) carry blood.
• Blood is a fluid connective tissue carrying nutrients, oxygen, and waste.
• The heart has four chambers (2 atria, 2 ventricles).

Respiratory System

• The system facilitates gas exchange (oxygen in, carbon dioxide out).
• Includes conducting airways (nose and pharynx to bronchioles), and respiratory (alveoli) regions.
• Lungs are organs of breathing located within thorax.

Digestive System

• The system breaks down food, absorbs nutrients, and eliminates waste.
• Includes the alimentary tract (mouth to anus) and associated glands (salivary, liver, gallbladder, pancreas).

Lymphatic System

• Returns fluids to the bloodstream, and contributes to immunity.
• Includes lymph, lymphatic capillaries, lymphatic vessels, and lymphatic tissue/organs.

Nervous System

• The nervous system receives, integrates, and transmits information throughout the body.
• Consists of two major parts: central nervous system (CNS) and peripheral nervous system (PNS).
• The CNS consists of the brain and spinal cord.
• The PNS consists of cranial nerves, spinal nerves, ganglia and sensory receptors.

Male and Female Reproductive Systems

• These systems enable reproduction.
• Detailed descriptions of male and female reproductive organs and structures.
• Note:* This is a general summary and further details will be needed about the specific sections that require higher detail.