Anatomy & Physiology: Introduction, Organ Systems, and Skeletal System Study Notes

Module 1.2 Overview of Anatomy & Physiology (A&P)

Characteristics of Living Organisms

Understanding the basic characteristics of living organisms is foundational in Anatomy & Physiology. These characteristics help distinguish living things from non-living matter.

• Metabolism: The sum of all chemical reactions in the body, including catabolism (breaking down molecules) and anabolism (building molecules).

• Growth: Increase in size and number of cells.

• Excitability (Responsiveness): Ability to respond to stimuli.

• Movement: Includes movement of the organism and movement within the organism (e.g., blood flow).

• Reproduction: Production of new cells or organisms.

Example: Muscle cells contract in response to nerve signals, demonstrating responsiveness and movement.

Levels of Organization

Biological systems are organized hierarchically, from the simplest to the most complex.

• Chemical level: Atoms and molecules

• Cellular level: Cells, the basic unit of life

• Tissue level: Groups of similar cells performing a common function

• Organ level: Structures composed of two or more tissue types

• Organ system level: Groups of organs working together

• Organism level: The complete living being

Example: The heart (organ) is made of muscle tissue, nervous tissue, and connective tissue, and is part of the cardiovascular system.

Approaches to Anatomy

Anatomy can be studied using different approaches:

• Systemic Anatomy: Focuses on organ systems (e.g., skeletal, muscular, nervous systems).

• Regional Anatomy: Focuses on specific regions of the body (e.g., head, arm).

• Microscopic Anatomy: Examines structures not visible to the naked eye, such as cells and tissues.

Example: Studying the muscles of the arm (regional) versus studying all muscles in the body (systemic).

Physiological Specializations

Physiology often classifies specializations by organ or organ system.

• Neurophysiology: Study of the nervous system, especially the brain and nerves.

• Cardiovascular Physiology: Study of the heart and blood vessels.

Additional info: Physiological specializations are often named for the organ or system they study (e.g., renal physiology for kidneys).

Major Organ Systems of the Human Body

Overview and Functions

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

Organ System	Main Organs	Primary Functions
Integumentary	Skin, hair, nails	Protection, body temperature regulation, water retention, vitamin D synthesis
Skeletal	Bones, joints	Support, protection, movement, stores calcium
Muscular	Skeletal muscles	Movement, heat production
Lymphatic	Spleen, lymph nodes, thymus	Immune response, fluid balance
Respiratory	Lungs, trachea, pharynx, larynx, nasal cavity	Gas exchange, acid-base balance
Digestive	Stomach, intestines, liver, pancreas, gallbladder	Breakdown and absorption of nutrients, waste elimination
Nervous	Brain, spinal cord, nerves	Control, coordination, higher mental functions
Endocrine	Thyroid, pituitary, adrenal glands	Hormone production, regulation of body functions
Cardiovascular	Heart, blood vessels	Transport of oxygen, nutrients, waste; blood pressure regulation
Urinary	Kidneys, urinary bladder, urethra	Removes metabolic wastes, balances fluids and electrolytes
Reproductive	Ovaries, testes	Production of offspring

Example: The respiratory system brings oxygen into the body and removes carbon dioxide.

Classification and Identification

• Organs are classified into organ systems based on their functions.

• Visual identification of organs in anatomical figures is a key skill.

Additional info: Some organs, like the pancreas, have roles in more than one system (digestive and endocrine).

Describing Anatomical Positions and Planes

Anatomical Position

The anatomical position is a standard reference for describing locations and directions on the human body.

• Standing upright, facing forward

• Arms at sides, palms facing forward

• Feet together

Left and Right: Always refer to the subject's left and right, not the observer's.

Directional Terms

• Superior (cranial): Toward the head

• Inferior (caudal): Toward the feet

• Anterior (ventral): Toward the front

• Posterior (dorsal): Toward the back

• Proximal: Closer to the point of origin (used for limbs)

• Distal: Farther from the point of origin (used for limbs)

• Superficial: Closer to the surface

• Deep: Farther from the surface

• Lateral: Away from the midline

• Medial: Toward the midline

Planes of Section

• Transverse (horizontal): Divides body into superior and inferior parts

• Frontal (coronal): Divides body into anterior and posterior parts

• Sagittal: Divides body into left and right parts

  • Midsagittal: Divides body into equal left and right halves

  • Parasagittal: Divides body into unequal left and right parts

• Oblique: Diagonal section

Example: A CT scan may use transverse sections to view internal organs.

Medical Imaging Techniques

Technique	Principle	Application
X-Ray	Ionizing radiation	Produces images of internal structures, especially bones
CT (Computed Tomography)	Ionizing radiation, computer reconstruction	Produces cross-sectional images
MRI (Magnetic Resonance Imaging)	Magnetic fields and radio waves	Produces detailed images of soft tissues

Additional info: MRI does not use ionizing radiation, making it safer for repeated imaging.

Module 7.1 Overview of the Skeletal System

Basic Parts of the Skeleton

The human skeleton is divided into two main parts: axial and appendicular.

• Axial skeleton: Skull, vertebral column, thoracic cage (sternum, ribs)

• Appendicular skeleton: Pectoral girdle, upper limb, pelvic girdle, lower limb

Example: The femur is part of the appendicular skeleton (lower limb).

Categories of Bones in the Skull

• Cranial bones: Enclose the brain

• Facial bones: Form the face framework

Bones of the Axial Skeleton

• Vertebral column: Vertebrae

• Thoracic cage: Sternum, ribs

Bones of the Appendicular Skeleton

• Pectoral girdle: Clavicle, scapula

• Upper limb: Humerus, radius, ulna, carpals, metacarpals, phalanges

• Pelvic girdle: Pelvic bones, sacrum

• Lower limb: Femur, patella, tibia, fibula, tarsals, metatarsals, phalanges

Distinguishing Axial vs. Appendicular Skeleton

• Axial skeleton: Central axis of the body (skull, vertebral column, thoracic cage)

• Appendicular skeleton: Limbs and girdles

Bone Markings

Bones have specific markings that serve as sites for muscle attachment, passage of nerves and blood vessels, or articulation with other bones.

Type	Description	Example
Depression	Concavity on bone surface	Fossa, sulcus
Opening	Hole or canal for passage	Foramen, canal
Projection	Outgrowth for muscle/ligament attachment	Process, tubercle, spine

Example: The foramen magnum is an opening in the occipital bone for the spinal cord.

Word Roots in Anatomy

• Word root: The base of a term, indicating its fundamental meaning

• Prefix: Added to the beginning of a word to modify its meaning

• Suffix: Added to the end of a word to modify its meaning

• Combining vowel: Used to connect word parts for easier pronunciation

Example: "Osteo-" (bone) + "-logy" (study of) = "osteology" (study of bones)

Additional info: These notes provide a structured overview of introductory concepts in Anatomy & Physiology, including organization, terminology, and the skeletal system, suitable for college-level study and exam preparation.