Characteristics of Living Things Quiz

Characteristics of Living Things

• Energy Production & Consumption:
  • Living things produce energy and use it for various functions.
  • Metabolism encompasses all chemical reactions driving life functions.
  • Anabolism builds large molecules from small ones, while catabolism breaks large molecules into smaller ones.
• Growth & Repair:
  • Organisms increase in size and cells specialize based on function.
  • Mechanisms exist to fix malfunctioning cells.
• Adaptation:
  • Responsiveness allows organisms to sense and react to environmental stimuli.
  • Homeostasis maintains a constant internal environment.
• Reproduction:
  • Cell replication supports growth and repair (cellular level).
  • Reproduction creates new organisms (organismal level).

Levels of Organization in the Body

• Chemical Level:
  • Atoms and molecules make up cells.
• Cellular Level:
  • Cells are the basic building blocks of tissues, with specialized functions.
• Tissue Level:
  • Tissues are composed of similar cells performing a common function. There are four main types: epithelial, muscle, connective, and nervous.
• Organ Level:
  • Organs are composed of two or more tissue types, collectively working toward a specific function.
• System Level:
  • Systems consist of multiple organs working together toward a common goal.
• Organismal Level:
  • The organismal level encompasses all structural levels working harmoniously to maintain life.

Cell Theory

• All living organisms are composed of one or more cells.
• Cells are the fundamental unit of life.
• Cells carry out metabolic activities enabling biological processes.
• Cells originate only from preexisting cells.
• Hereditary information (DNA) is used to create biomolecules, aiding in reproduction.

Cells as Living Units of Life

• Cells are the building blocks of tissues.
• Cells are equipped to maintain homeostasis.
• All cells share basic components: a membrane, genetic material, and cytosolic fluid.
• Specialized organelles in human cells lead to compartmentalization and complexity.
• Gene expression dictates cell specialization.

Cell Differentiation

• Cells develop specific features and functions during their life cycle that typically cannot be reversed.
• Early in development, cells are totipotent (stem cells).
• As tissues and organs develop, cells differentiate to perform specialized functions.

Tissues

• Tissues are groups of similar cells with a common structure or function.
• There are four basic tissue types: epithelial, connective, muscle, and nervous.
• Epithelial tissues cover surfaces; connective tissues support and connect; muscle tissues facilitate movement; and nervous tissues control communication.
• Organs integrate all four tissue types to produce specific structures and functions.

Integrating Tissues: Organs

• Organs are structures comprised of at least two or more tissues to perform functions.
• Different tissues within an organ need to cooperate to achieve the specific function of the organ.

Intro to the Organ Systems

• Integumentary System: Skin, hair, nails, glands—protects, regulates temperature.
• Nervous System: Brain, spinal cord, nerves—detects signals and coordinates physiological responses.
• Musculoskeletal System: Bones, muscles, cartilage, ligaments—movement, support, protection, blood cell production.
• Respiratory System: Nasal passage, trachea, lungs—brings in air and regulates gas exchange in blood.
• Cardiovascular System: Heart, blood vessels, blood—circulates blood carrying materials throughout body.
• Immune & Lymphatic System: Lymph nodes, tissues, spleen—defends against pathogens.
• Endocrine System: Hormones—regulates growth, metabolism, reproduction.
• Urinary System: Kidneys, ureters, bladder, urethra—filters blood, regulates volume, and excretes waste.
• Digestive System: Mouth, esophagus, stomach, intestines, liver, gallbladder—digests food, absorbs nutrients.
• Reproductive System: Testes/Ovaries, associated ducts and glands—production of gametes and embryo development.

Regional Anatomical Terms

• Axial region encompasses the head, neck, and trunk.
• Appendicular region includes the limbs and their girdles.
• Specific regions exist within the main regions (e.g., cephalic, cervical, thoracic, abdominal).

Body Cavities

• Cavities are hollow areas within the body where organs are contained.
• Posterior (Dorsal) cavity: Cranial (brain) and vertebral (spinal cord).
• Ventral cavity: larger and positioned anteriorly; Thoracic (lungs, heart) and Abdominopelvic (digestive, reproductive glands).
• Serous membranes line the ventral cavity, reducing friction as organs move.

Serosa

• Serosa is a two-layered membrane that surrounds organs in the ventral cavities.
• Parietal layer lines the cavity wall; visceral layer directly covers the organ, allowing for minimal friction. Fluid sits between the two layers.

The Thoracic Cavity

• Thoracic cavity: located within the chest, surrounded by the ribs and chest muscles.
• Contains the pleural cavities (enclosing lungs) and the pericardial cavity (housing the heart).
• Mediastinum is the central region of the thoracic cavity containing the heart, major blood vessels, esophagus, and trachea.

The Abdominopelvic Cavity

• The abdominopelvic cavity is inferior to the diaphragm.
• It's subdivided into an abdominal cavity (superior region) and a pelvic cavity (inferior region). Organs of the digestive, urinary, and reproductive systems are housed within the cavity.

Abdominopelvic Regions

• The abdominopelvic cavity is further divided into nine regions (or four quadrants) to aid in describing organ location.

Directional Terms

• Terms describe positions of structures in relation to each other or to the body's midline. Examples: anterior, posterior, medial, lateral, superior, inferior, proximal, distal, superficial, deep. Understanding these terms is essential to anatomical study.

Body Planes and Sections

• Anatomical position: body upright, arms at the sides, palms forward.
• Coronal (Frontal) plane divides the body into anterior and posterior sections; Midsagittal (Median) plane divides the body into right and left halves; Transverse (Horizontal) plane divides the body into superior and inferior sections.

Homeostasis

• Homeostasis is the dynamic state of balance within the body to maintain stable internal conditions despite external changes.
• The components of homeostasis include variables, stimuli, receptors, control center, and effectors.
• Negative feedback loops maintain homeostasis; positive feedback enhances an initial deviation from homeostasis.

Negative vs. Positive Feedback

• Negative feedback: commonly used mechanism of regulation to maintain homeostasis (example: thermoregulation).
• Positive feedback: mechanisms amplify an initial deviation (example: childbirth).