1.2: Levels of Structural Organization and Body Systems

Levels of structural organization

chemical level, cellular level, tissue level, organ level, organ system level, organismal level

Atoms

Fundamental unit of matter that retains properties of an element

Essential elements for life

Carbon, Oxygen, Nitrogen, Hydrogen, Phosphorus, Calcium, Sulfur

Molecules

Chemically combined atoms that form building blocks of body structures

Biomolecules

Carbohydrates, lipids, proteins, and nucleic acids essential for growth and development

Cellular Level

Organelles and cells

Organelles

Specialized subcellular structures that perform specific life functions

Cells

Fundamental structural and biological unit of life

Prokaryotes

Unicellular organisms that lack a nucleus and membrane-bound organelles

Eukaryotes

Organisms with a nucleus and complex membrane-bound organelles

Tissue

A specialized group of cells and cell products that work together to perform one or more specific functions.

Tissue Types

Muscle tissue, nerve tissue, connective tissue, and epithelial tissues.

Organ

A group of different types of tissues carries out a common function

Organ System

A set of related organs carrying out a major function

Integumentary System

• Components: skin, hair, nails, oil, and sweat glands

• Functions: protects the body, receive sensory input, regulate temperature, produces vitamin D

Skeletal System

• Components: bones, joints, cartilage

• Functions: provide an internal and flexible framework, protects internal organs, forms, blood cells, stores minerals

Muscular System

• Components: muscles attached to the skeleton, such as smooth, cardiac, skeletal muscles

• Functions: provides movement, maintain posture, produce insulation

Nervous System

• Components: brain, spinal cord, nerve cells, eyes, ears

• Functions: stores and transmit century input, coordinate organ systems, maintain homeostasis

Endocrine System

• Components: hormone secreting glands, such as pineal gland, hypothalamus, pituitary gland, thymus, thyroid gland, parathyroid gland, adrenal gland, pancreas, ovaries, testes, etc.

• Functions: secretion of hormones, direct long-term changes in the activities of other organ systems

Cardiovascular System

• Components: heart, blood vessels (veins, arteries, capillaries), blood

• Functions: transport, blood, nutrients, gases; defends from disease diseases; maintain temperature, fluid, PH balance

Lymphatic System

• Components: lymph nodes, spleen, thymus gland, bone marrow, tonsils, lymph plasma

• Functions: houses the immune system, defense from affect and diseases, transport, tissue fluid and absorb fat

Respiratory System

• Components: lungs, trachea, larynx, nasal passages

• Functions: regulate breathing, exchange, gas, maintain pH balance

Digestive System

• Components: mouth, salivary glands, esophagus, stomach, intestines, liver, gallbladder, pancreas

• Functions: chemical and physical breakdown of food, absorb nutrients, elimination of feces

Urinary System

• Components: kidneys, ureters, urinary bladder, urethra

• Functions: stores and excretes waste, maintain pH and electrolyte balance, filters blood from nitrogenous waste

Reproductive System

• Components (Male): testes, epididymis, ductus deferens, seminal glands, prostate, penis

• Components (Female): ovaries, uterine tubes, uterus, vagina, clitoris, mammary glands

• Functions: production of sperm and eggs, secretion of sex, hormones, produce gametes

Organisms

A living being