Anatomy and Physiology Overview

Anatomy and Physiology

• Anatomy is the study of the body's structures and their relationships.
• Physiology is the study of body functions.
• The structure of a body part often reflects its function.

Branches of Anatomy and Physiology

• Microscopic anatomy (Histology) studies structures too small to be seen with the naked eye, including cells and tissues.
• Skin, kidney, intestine, and lung are examples of microscopic anatomy.

Levels of Structural Organization

• The human body has six levels of structural organization:
  • Atoms
  • Cells
  • Tissues
  • Organs
  • Organ Systems
  • Organism

Cellular Diversity

• Epigenetics, such as methylation, acetylation, and microRNAs, lead to different gene expression profiles, resulting in various types and amounts of proteins.
• This diversity in proteins leads to differences in:
  • Cell function
  • Cytoskeleton, which provides structural support and determines cell shape
  • Cell junctions and adhesion.
  • Cellular memory (Differentiated cell)

Homeostasis

• Homeostasis is the maintenance of relatively stable conditions in the body's internal environment.
• Maintaining homeostasis is a dynamic condition that occurs through the interplay of the body's regulatory systems, mainly the nervous system and the endocrine system.
• Homeostatic control mechanisms have three components:
  • Receptor: Responds to changes in the environment (stimuli), sending information to the control center.
  • Control Center: Determines the set point, analyzes information, and determines the appropriate response.
  • Effector: Provides a means for response to the stimulus.

Feedback Mechanisms

• Negative Feedback: Reverses a change in a controlled condition, returning the variable to its "ideal" value.
  • Most homeostatic control mechanisms are negative feedback.
  • Examples include regulation of body temperature, heart rate, blood pressure, breathing rate, and blood levels of glucose, oxygen, carbon dioxide, and minerals.
• Positive Feedback: Strengthens or reinforces a change in the body's controlled conditions.
  • Positive feedback is rare in the human body.
  • Examples include blood clotting and labor contractions.

Survival Needs

• The human body needs the following for survival:
  • Nutrients: Chemicals used for energy and cell building
  • Oxygen: Required for chemical reactions
  • Water: The most abundant chemical in the human body
  • Normal Body Temperature: Maintained at 37°C (98.6°F)
  • Atmospheric Pressure: Must be appropriate for gas exchange

Basic Life Processes

• Movement: Motion of the whole body, individual organs, single cells, and even tiny structures inside cells.
• Growth: An increase in body size resulting from an increase in the size of existing cells, the number of cells, or both.
• Differentiation: The development of a cell from an unspecialized to a specialized state.
• Reproduction: The formation of new cells for tissue growth, repair, or replacement, or the production of a new individual.