Introduction to Human Body Anatomy and Physiology

Introduction to the Human Body

• The chapter introduces anatomy and physiology.
• It discusses the organization of the human body.
• It reveals shared properties of all living things.
• It discusses homeostasis.

Anatomy vs. Physiology

• Anatomy studies the structure of body parts.
• Physiology studies how body parts function.
• Anatomy and physiology are inseparable.
• Function reflects structure.
• Structure dictates function.

Branches of Anatomy and Physiology

• Developmental biology: Studies growth and development from fertilization to death.
• Embryology: Studies development after fertilization of a human egg.
• Cell biology: Studies cellular structure and functions.
• Histology: Studies microscopic structure of tissues.
• Gross anatomy: Observable body structures without a microscope.
• Systemic anatomy: Study of specific body systems.
• Regional anatomy: Study of specific regions of the body.
• Surface (topographical) anatomy: Study of surface markings of the body.
• Imaging anatomy: Visualization of body structures with imaging techniques.
• Clinical anatomy: Application of anatomy to medical practice.
• Pathological anatomy: Structural changes related to disease.

Branches of Physiology

• Molecular physiology: Studies functions of individual molecules.
• Neurophysiology: Studies functional properties of nerve cells.
• Endocrinology: Studies hormones and how they control body functions.
• Cardiovascular physiology: Studies functions of the heart and blood vessels.
• Immunology: Studies the body's defenses against disease.
• Respiratory physiology: Studies functions of the air passageways and lungs.
• Renal physiology: Studies functions of the kidneys.
• Exercise physiology: Studies changes in cell and organ function due to activity.
• Pathophysiology: Studies functional changes associated with disease and aging.

Levels of Structural Organization

• Chemical level: Atoms combine to form molecules.
• Cellular level: Cells are the basic units of life.
• Tissue level: Tissues are groups of similar cells.
• Organ level: Organs are composed of different tissues.
• System level: Organ systems work together to perform specific functions.
• Organismal level: The human body as a whole.

Systems of the Human Body

• Integumentary system: Protects the body, regulates temperature, excretes waste, detects sensations.
• Skeletal system: Supports and protects the body, aids movement, produces blood cells, stores minerals.
• Muscular system: Enables body movement, maintains posture, produces heat.
• Nervous system: Generates nerve impulses, regulates body activities, processes information.
• Endocrine system: Regulates body activities via hormones.
• Cardiovascular system: Transports blood, oxygen, and nutrients, regulates acid-base balance, temperature, and water content.
• Lymphatic/immune system: Returns proteins and fluid to blood; fights disease, contains lymphoid tissues.
• Respiratory system: Transfers oxygen and carbon dioxide, regulates acid-base balance.
• Digestive system: Breaks down food, absorbs nutrients, and eliminates waste.
• Urinary system: Removes wastes and regulates water and electrolyte balance, maintaining blood pH.
• Reproductive system: Enables reproduction through gametes and hormones.

Basic Life Processes

• Metabolism: Sum of all chemical processes in the body.
• Responsiveness: Ability to detect and respond to changes.
• Movement: Motion of the whole body or its parts.
• Growth: Increase in body size.
• Differentiation: Development of cells from unspecialized to specialized cells.
• Reproduction: Production of new cells or organisms.

Homeostasis

• A condition of equilibrium or balance in the body's internal environment.
• Maintained by regulatory processes.
• Imbalances cause diseases, disorders, and potentially death.

Body Fluids & Homeostasis

• Body cells survive by regulating extracellular fluid composition.
• Extracellular fluid is critical for cellular function.

Control of Homeostasis

• Basic components of a feedback loop include: stimulus, receptor, control center, effector, and response.

Control of Homeostasis: Negative Feedback

• Original stimulus decrease in intensity.
• Change is opposite to original stimulus, reducing imbalances.

Examples of Negative Feedback Mechanism

• Thermoregulation: A mechanism that regulates body temperature by detecting and responding to changes in temperature.
• The Body responds to temperature changes by regulating blood flow, sweating, and shivering.

Regulation of Blood Glucose Levels

• Control of blood glucose concentration is critical for body functions, regulated by hormones like insulin and glucagon.

Control of Homeostasis: Positive Feedback

• The change amplifies the original stimulus.
• Example of positive feedback is labor.

Basic Anatomical Terminology

• Includes body positions, regional names, directional terms, planes and sections, and body cavities.

Types of Anatomical Terminology

• Body Positions: Standard, consistent way to view the body
• Regional Names: Specific body parts and regions.
• Directional Terms: Describe the positions of body structures relative to each other.

Body Positions: The Anatomical Position

• Erect, face forward, palms forward, feet flat.
• A standardized method for observing the body.
• Standardized reference for anatomical description.

Body Positions

• Prone (lying facedown)
• Supine (lying faceup)

Regional Names

• Refers to specific regions of the body for reference (e.g., cephalic, cervical, thoracic, abdominal, etc).

Directional Terms

• Terms to locate one part of the body relative to another precisely (e.g., superior, inferior, anterior, posterior, medial, lateral, proximal, distal, superficial, deep).

Planes and Sections

• Imaginary flat surfaces that divide the body (coronal, transverse, median, oblique planes).
• Cuts of the body structure to view internal structures (e.g., cross-sections, longitudinal sections).

Practicing Planes and Sections

• Example of identifying the body planes based on images given (e.g., brain sections).

Body Cavities

• Spaces within the body that protect, separate, and support internal organs (e.g., cranial cavity, vertebral canal, thoracic cavity, abdominopelvic cavity—abdominal and pelvic cavities).

Serous Membranes

• Thin, double-layered membranes lining the thoracic and abdominal cavities, reducing friction.
• Include the visceral and parietal layers, covering organs and cavity walls.
• Examples include pericardium, pleura, and peritoneum.

Serous Membranes in the Thoracic Cavity

• Pericardium for the heart and pleura for the lungs, lining the pleural and pericardial cavities.
• Cover the heart and lungs in the thoracic cavity.

Serous Membrane in the Abdominal Cavity

• The peritoneum covers many abdominal organs.
• Retroperitoneal organs lie behind the peritoneum.

Abdominopelvic Regions & Quadrants

• The abdomen and pelvis are divided into regions and quadrants for organ description purposes (the quadrants being right upper, right lower, left upper, and left lower).

Aging and Homeostasis

• Aging involves a decline in the body's ability to restore homeostasis.
• This decline impacts various systems, potentially leading to issues or diseases, such as declining organ function.