Chapter 23: Animal Tissues and Organ Systems

Chapter 23: Animal Tissues and Organ Systems

Key Definitions

  • Organelle: Membrane-bound structure with specific functions in a cell (e.g., chloroplast).

  • Cell: Fundamental unit of life; multicellular organisms have many cells.

  • Tissue: Collection of specialized cells functioning together (e.g., epidermis of leaf).

  • Molecule: Group of joined atoms (e.g., DNA).

  • Atom: Smallest unit of a pure substance (e.g., carbon atom).

  • Organism: A single living individual (e.g., acacia tree).

  • Population: Group of same species in a specific area and time.

  • Organ: Structure made of tissues working together (e.g., leaf).

  • Organ System: Interconnected organs (e.g., aboveground part of a plant).

  • Community: All populations in a region (e.g., savanna populations).

  • Ecosystem: Living and nonliving components of an area (e.g., savanna).

  • Biosphere: Global ecosystem; where life is possible.

Organization of Animal Bodies

  • Hierarchical structure: Cell → Tissue → Organ → Organ System → Organism.

  • Anatomy: Study of structure and form.

  • Physiology: Study of function of body parts.

Characteristics of Animals (Kingdom Animalia)

  • Eukaryotic, multicellular, heterotrophic, no cell walls or chloroplasts, motile.

Essential Needs of Animals

  1. Sense and respond to environment.

  2. Acquire and digest food.

  3. Exchange respiratory gases (O2, CO2).

  4. Eliminate waste.

  5. Protect against injury and disease.

  6. Reproduce.

Four Tissue Types

  • Epithelial Tissue: Functions in protection, secretion, absorption; tightly packed cells.

  • Connective Tissue: Supports, connects, and protects; characterized by extensive extracellular matrix.

  • Muscle Tissue: Specialized for contraction and movement (Skeletal, Cardiac, Smooth).

  • Nervous Tissue: Transmits signals via neurons; supports functions of communication.

Organ Systems and Homeostasis

  • Organ systems (e.g., nervous, skeletal, muscular) work together to maintain homeostasis and support life functions.

  • Feedback loops (negative and positive) regulate physiological responses and homeostasis.

Thermoregulation

  • Endotherms: Internal temperature regulation; maintain temperature regardless of environment.

  • Ectotherms: Body temperature determined by external conditions; utilize behavioral adaptations for thermoregulation.

Learning Outcomes

  • Understand organization from cellular to organismal levels.

  • Compare anatomy vs. physiology and tissue types.