11 Organ Systems

Human body structural organization hierarchy from simplest to most complex

Atom $\rightarrow$ molecule $\rightarrow$ macromolecule $\rightarrow$ organelle $\rightarrow$ cell $\rightarrow$ tissue $\rightarrow$ organ $\rightarrow$ organ system $\rightarrow$ organism

Organ system responsible for protection, temperature regulation, and sensation (Memory word: PROTECT)

Integumentary system (key organ: skin)

Organ system responsible for structural support, organ protection, mineral storage, and blood cell production (Memory word: SUPPORT)

Skeletal system (key organ: femur / bone)

Organ system responsible for movement, maintaining posture, and heat generation (Memory word: MOVE)

Muscular system (key organ: biceps brachii)

Organ system responsible for rapid control, communication, and detecting and responding to stimuli (Memory word: FAST CONTROL)

Nervous system (key organ: brain)

Organ system responsible for chemical regulation of growth, metabolism, and long-term body processes (Memory word: HORMONES)

Endocrine system (key organ: thyroid gland)

Organ system responsible for pumping and circulating blood, gases, nutrients, and wastes throughout the body (Memory word: TRANSPORT)

Cardiovascular system (key organ: heart)

Organ system responsible for returning excess tissue fluid to circulation and supporting immune defense (Memory phrase: FLUID RETURN + DEFENSE)

Lymphatic system (key organ: spleen)

Organ system responsible for gas exchange ($O_2$ in, $CO_2$ out) and regulating blood pH (Memory phrase: GAS EXCHANGE)

Respiratory system (key organ: lung)

Organ system responsible for breaking down food, absorbing nutrients and water, and eliminating undigested material (Memory phrase: BREAK DOWN + ABSORB)

Digestive system (key organ: stomach)

Organ system responsible for filtering blood, removing metabolic wastes, and regulating fluid and electrolyte balance (Memory phrase: FILTER + WASTE)

Urinary system (key organ: kidney)

Sequential anatomical pathway of urine travel through the body

Kidney $\rightarrow$ ureter $\rightarrow$ urinary bladder $\rightarrow$ urethra

Organ system responsible for producing gametes and sex hormones to make reproduction possible (Memory word: REPRODUCE)

Reproductive system (key organs: ovary