Overview of Anatomy and Physiology Concepts

Anatomy

Anatomy is the study of the structure of the body.

External structures

Observing body parts visible on the surface.

Internal structures

Studying organs, tissues, and cells inside the body.

Relationships between body parts

Understanding how structures connect and interact (e.g., tendons attaching muscle to bone).

Physiology

Physiology is the study of the function of the body.

Mechanisms in the body

How organs and systems work together (e.g., how the heart pumps blood).

Anatomy and physiology interdependence

Anatomy makes physiology possible and physiology gives meaning to anatomy.

Macroscopic (gross) anatomy

Focuses on structures visible without magnification.

Surface anatomy

External markings (e.g., veins on the forearm).

Regional anatomy

Structures in a specific area (e.g., head, neck, abdomen).

Systemic anatomy

Body systems (e.g., cardiovascular, digestive).

Microscopic anatomy

Requires magnification to study structures like cells and tissues.

Cytology

Study of individual cells.

Histology

Study of tissues.

Comparative anatomy

Compares human anatomy with that of other species.

Inspection

Observing external appearance.

Palpation

Feeling structures through touch (e.g., swollen lymph nodes).

Auscultation

Listening to body sounds (e.g., heartbeats, lung sounds).

Percussion

Tapping the body to detect abnormalities (e.g., fluid in the lungs).

Medical imaging

Non-invasive techniques to view inside the body (e.g., X-rays, MRI).

Cellular physiology

Functions of individual cells.

Organ system physiology

How organs and systems work together (e.g., cardiovascular physiology).

Pathophysiology

How diseases disrupt normal functions.

Levels of Structural Organization in the Body

The hierarchical organization of the body from chemical to organ system level.

Chemical level

Atoms (e.g., oxygen, carbon) combine to form molecules like water, carbohydrates, proteins, and lipids.

Cellular level

Cells are the smallest living units, consisting of organelles (e.g., mitochondria for energy production).

Tissue level

Groups of similar cells performing a specific function (e.g., muscle tissue contracts to generate movement).

Organ level

Two or more tissues working together (e.g., the stomach contains muscle for churning, epithelial tissue for secretion).

Organ system level

Groups of organs performing a unified function (e.g., digestive system includes the stomach, intestines, and liver).

Organism level

The human body as a whole.

Responsiveness (irritability)

Ability to sense and react to changes (e.g., pulling your hand away from heat).

Adaptability

Long-term changes to adjust to the environment (e.g., acclimating to high altitudes).

Growth

Increase in size through cell multiplication (hyperplasia) or enlargement (hypertrophy).

Differentiation

Cells specialize to perform specific functions (e.g., stem cells becoming neurons).

Reproduction

Production of offspring or new cells (e.g., healing a wound).

Metabolism

Sum of all chemical reactions in the body.

Anabolism

Building complex molecules (e.g., protein synthesis).

Catabolism

Breaking down molecules for energy (e.g., glycolysis).

Excretion

Removal of waste products (e.g., CO₂ through respiration, urea through urination).

Homeostasis

The body's ability to maintain a stable internal environment despite external changes (e.g., stable body temperature, blood glucose levels).

Autoregulation (intrinsic)

Localized adjustments by cells or tissues. Example: Low oxygen levels in tissues cause blood vessels to dilate, increasing blood flow.

Extrinsic regulation

Controlled by the nervous and endocrine systems. Example: During exercise, the nervous system increases heart rate to pump more oxygenated blood to muscles.

Negative feedback

Most common mechanism. Reverses a change to return the body to a set point. Example: Thermoregulation—if body temperature rises, sweat glands activate to cool it down.

Positive feedback

Amplifies changes, leading to a rapid response. Example: Oxytocin release during labor increases uterine contractions until childbirth.

X-ray (radiography)

High-energy radiation passes through the body to create images of dense structures (e.g., bones). Radiopaque substances enhance visualization of hollow organs.

CT scan

Produces cross-sectional images using low-intensity X-rays. Better for detecting tumors and internal injuries.

MRI

Uses magnetic fields and radio waves to create detailed images, especially of soft tissues (e.g., brain, muscles). No radiation exposure.

PET scan

Tracks metabolic activity using radioactive glucose. Useful for detecting cancer or brain activity.

Sonography (ultrasound)

Uses sound waves to produce real-time images. Commonly used in obstetrics to monitor fetal development.

Disease

Chronic disruptions (e.g., diabetes due to unstable blood glucose levels).

Death

Inability to restore balance in critical systems (e.g., circulatory or respiratory failure).

Blood clotting cascade

Platelets attract more platelets to seal a wound.

Uterine contractions during labor

Oxytocin amplifies contractions.