Human Body Systems: Parts and Functions

Human Body Systems, Parts and Function

• Circulatory System: Consists of the heart, blood, and blood vessels. Transports gases, fluids, waste products, nutrients, and hormones throughout the body.
• Digestive System: Includes the mouth, pharynx, esophagus, stomach, small and large intestines, rectum, and anus. Breaks down food into absorbable particles using enzymes.
• Endocrine System: Composed of the hypothalamus, pituitary, thyroid, parathyroid, adrenal glands, pineal body, and reproductive organs. Produces hormones, controlling growth, development, and metabolism.
• Excretory/Urinary System: Includes the kidneys, ureter, urinary bladder, and urethra. Eliminates waste products from the body.
• Integumentary System: Consists of skin, hair, nails, sweat glands, and oil glands. Provides a barrier against injury, regulates body temperature, protects against dehydration, and secretes sweat and gases.
• Lymphatic/Immune System: Involves white blood cells, tonsils, adenoids, thymus, spleen, and lymph nodes. Protects the body against disease and infection.
• Muscular System: Includes skeletal, smooth, and cardiac muscles. Enables body movement, digestion, and circulation.
• Nervous System: Comprised of the brain, spinal cord, and nerves. Monitors internal organ function, responds to external environment changes, and coordinates actions.
• Respiratory System: Includes the nose, mouth, pharynx, larynx, lungs, trachea, bronchi, bronchioles, and alveoli. Facilitates gas exchange (carbon dioxide and oxygen) between blood and air.
• Reproductive System: Composed of testes, penis, prostate, seminal vesicles, ovaries, vagina, uterus, and fallopian tubes. Produces reproductive cells, produces hormones, and supports the development of embryos.
• Skeletal System: Includes bones, cartilages, ligaments, and tendons. Provides structure, support, enables movement, and produces blood cells.

Fundamental Properties of Life

• Cellular Organization: All organisms consist of one or more cells, complex assemblies of molecules enclosed by membranes.
• Sensitivity: Organisms respond to stimuli, although not always in the same ways.
• Growth: Assimilate energy to grow (metabolize), a crucial process for all life. Plants, algae, etc use sunlight to produce covalent bonds, essential to life on Earth.
• Development: Multicellular organisms undergo systematic gene-directed changes while growing and maturing.

How to Determine if Something is Alive

• Movement: Although not all living things move, it's not a definitive criterion.
• Sensitivity: Most living things respond to stimuli, but not always to the same degree.
• Death: The loss of life, a concept inadequate for determining life.
• Complexity: Living things are complex, but so are some non-living things.

Theories on How Life Began

• Extraterrestrial Origin: Life originated on another planet and was brought to Earth.
• Panspermia: The "seeds" of life exist throughout the universe and can propagate across space.
• Divine Creation: Many believe life was created by a divine force.
• Origin from Non-living Matter: Life arose from non-living matter after Earth cooled.

Ecology, Biological Systems, and Levels of Organization

• Ecology: The study of living organisms and their relationships with each other and the environment.
• Biological Systems: Consists of interrelated parts, and each part plays a significant role in its function.
• Levels of Organization: Life's organization goes from cells to tissues, organs, organ systems, and ultimately organisms.

Forms and Functions

• Forms and Structure: The function of an organism, or part, depends on its form and structure.
• Reproduction: Ensures species survival (asexual or sexual).
• Energy and Life: Organisms obtain and use energy from food (photosynthesis or consumption).
• Thermal Regulation: Maintaining internal conditions (homeostasis).
• Adaptation and Evolution: Organisms change over time to adapt and survive.

Cell Discovery and Theory

• Cell Discovery: Microscopes allowed the observation of cells.
• The Cell Theory:
  • All living things are made of cells;
  • The cell is the smallest living unit of structure and function;
  • All cells arise from pre-existing cells.