BIOL 2210 – Lab Module 1B: Organ Systems

Structural Hierarchy of the Human Body (Section 1.5a, Fig. 1.5)

• Successively larger, more complex levels of organization
  • Chemical level – atoms → molecules → macromolecules (e.g.
    DNA, proteins, lipids, carbohydrates)
  • Organelle – functional structures inside a cell (mitochondria,
    Golgi apparatus, ribosomes)
  • Cell – the smallest living unit; contains all organelles; basic
    unit of structure & function
  • Tissue – group of similar cells & extracellular matrix working
    together (epithelial, connective, muscle, nervous)
  • Organ – two or more tissue types combined to perform a specific
    function (heart, liver, skin)
  • Organ system – group of organs that cooperate to accomplish
    related functions (cardiovascular, urinary, etc.)
  • Organism – the complete living individual; sum of all systems
• Remember the simple mnemonic: “C O C T O O O” → Chemical, Organelle,
  Cell, Tissue, Organ, Organ System, Organism.
• Video review link: https://training.seer.cancer.gov/anatomy/body/

Key Definitions (Book-Based)

• Organ – a discrete anatomical structure composed of at least two
  tissue types that performs a specific, recognizable physiological
  function within the body.
• Organ system – a cooperative group of organs that perform closely
  related or complementary functions to maintain homeostasis of the
  organism as a whole.

The Eleven Organ Systems: Organs & Primary Functions (Sections 1.5a, Fig. A.9)

(The following lists merge textbook content with common anatomical
examples; bold = hallmark organs.)

1. Integumentary System

• Organs: skin (epidermis & dermis), hair, nails, sweat glands,
  sebaceous (oil) glands, sensory receptors.
• Functions:
  • Protects against environmental hazards (physical, chemical,
    microbial, UV)
  • Regulates body temperature (sweating, vasodilation/vasoconstriction)
  • Provides sensory information (touch, pain, temperature)
  • Synthesizes vitamin D

2. Skeletal System

• Organs: bones, cartilages, ligaments, bone marrow.
• Functions:
  • Structural support & protection for soft tissues
  • Leverage for movement (with muscles)
  • Blood cell production in marrow (hematopoiesis)
  • Mineral storage – \text{Ca}^{2+}, \text{PO}_4^{3-}

3. Muscular System

• Organs: skeletal muscles (~700 in the body), associated tendons &
  aponeuroses.
• Functions:
  • Movement, posture, facial expression
  • Generates heat (thermogenesis)
  • Guards entrances/exits of digestive & urinary tracts

4. Nervous System

• Organs: brain, spinal cord, peripheral nerves, sense organs
  (eye, ear, etc.).
• Functions:
  • Rapid coordination of body activities via electrical impulses
  • Interprets sensory input; initiates motor output
  • Higher mental functions (consciousness, memory, learning)

5. Endocrine System

• Organs: pituitary gland, thyroid, parathyroids, adrenal glands,
  pancreas (islets), gonads (testes/ovaries), pineal gland, thymus.
• Functions:
  • Long-term regulation via hormones in the bloodstream
  • Controls metabolism, growth, reproduction, electrolyte balance

6. Cardiovascular (Circulatory) System

• Organs: heart, blood vessels (arteries, veins, capillaries), blood
  itself.
• Functions:
  • Transport of O2/CO2, nutrients, hormones, wastes
  • Thermoregulation via blood redistribution
  • Immune cell & antibody circulation; pH/stabilization of interstitial
    fluids

7. Lymphatic / Immune System

• Organs: spleen, thymus, lymph nodes, lymphatic vessels, tonsils,
  lymph, MALT/Peyer’s patches.
• Functions:
  • Returns interstitial fluid to bloodstream
  • Filters lymph; removes pathogens & debris
  • Houses & matures immune cells (B & T lymphocytes)

8. Respiratory System

• Organs: nasal cavities, sinuses, pharynx, larynx, trachea, bronchi, lungs, alveoli.
• Functions:
  • Gas exchange (O2 uptake, CO2 removal)
  • Acid-base balance (via CO_2 exhalation)
  • Airflow for vocalization (phonation)

9. Digestive System

• Organs: oral cavity (teeth, tongue), pharynx, esophagus, stomach,
  small intestine, large intestine, liver, gallbladder, pancreas.
• Functions:
  • Ingestion, mechanical/chemical breakdown of food
  • Absorption of nutrients, water, ions
  • Eliminates indigestible residues as feces
  • Liver: detoxification & bile production; pancreas: digestive
    enzymes/bicarbonate

10. Urinary System

• Organs: kidneys, ureters, urinary bladder, urethra.
• Functions:
  • Removes nitrogenous wastes (urea, creatinine)
  • Regulates water, electrolytes, and acid-base balance
  • Blood volume/pressure control via renin, erythropoietin secretion

11. Reproductive System

• Male Organs: testes, epididymides, ductus deferens, seminal
  vesicles, prostate gland, penis, scrotum.
• Female Organs: ovaries, uterine (fallopian) tubes, uterus, vagina,
  labia, clitoris, mammary glands.
• Functions:
  • Production of gametes (sperm & oocytes) and sex hormones
  • Fertilization, development, nourishment of offspring
  • Secondary sexual characteristic development

Identifying an Organ System from Its Component Organs (Objective 5)

• Kidney + urinary bladder → Urinary System.
• Bones alone → Skeletal System.
• Heart alone → Cardiovascular System.
• Brain & spinal cord → Nervous System.

Torso Model / Atlas Figures (Objective 6)

• Study points: Fig. A.9 (composite of 11 systems atop a torso), Fig. 1.8
  (regional anatomy overlay), instructor’s D2L video.
• Recommendation: practice pointing out organs in three views:
  anterior, posterior, midsagittal.

Body Cavities & Abdominopelvic Regions (Objective 7, review from Lab 1A)

• Major cavities: cranial, vertebral, thoracic (pleural + mediastinum),
  abdominopelvic (abdominal + pelvic).
• Nine abdominopelvic regions & example organs:
  1. Right hypochondriac – liver, gallbladder
  2. Epigastric – stomach, pancreas, part of liver
  3. Left hypochondriac – spleen, part of stomach
  4. Right lumbar – ascending colon, right kidney
  5. Umbilical – small intestine, transverse colon
  6. Left lumbar – descending colon, left kidney
  7. Right iliac (inguinal) – cecum, appendix
  8. Hypogastric (pubic) – urinary bladder, uterus (when gravid)
  9. Left iliac (inguinal) – sigmoid colon
• Example asked: “The liver is located in which abdominopelvic
  regions?” → primarily right hypochondriac & epigastric, with minor
  extension to left hypochondriac.

Practice Lab Questions (Not Graded, but Suggested Answers)

1. Which organ system contains bones? → Skeletal System.
2. (Create additional self-quizzes e.g.) “The pancreas belongs to which
   two systems?” → Digestive & Endocrine.

Concept Connections & Relevance

• Foundational principle: Homeostasis relies on organ systems acting in
  concert; disorder in one level (e.g.
  molecular mutation \rightarrow dysfunctional protein) cascades up
  the hierarchy.
• Clinical link: Understanding cavities & regions guides physical exams,
  imaging interpretation, and emergency diagnosis (e.g. RUQ pain →
  gallbladder/liver differential).
• Ethical note: Manipulation of endocrine or reproductive systems has
  bioethical implications (hormone therapy, fertility treatments).

Quick Reference Equations / Numbers (Few in this unit)

• \text{pH} = -\log_{10}[\text{H}^+] – acid-base balance affected by
  respiratory & urinary systems.
• Bone mineral composition ≈ \mathbf{65\%} inorganic (hydroxyapatite), \mathbf{35\%} organic matrix.
  (Useful when considering skeletal function.)

End of comprehensive notes for BIOL 2210 Lab Module 1B – Organ Systems.