Levels of Structural Organization and Organ Systems

Levels of Structural Organization

• Atoms combine to form molecules, which are the basic units of chemical compounds
• Molecules combine to form cells, the basic structural and functional units of life
• Cells with similar functions form tissues.
• Tissues combine to form organs.
• Organs working together form organ systems.
• Organ systems make up an organism.

Organ Systems

• Integumentary: Protection, temperature regulation, sensation (skin, hair, nails)
• Skeletal: Support, movement, blood cell production (bones, cartilage, ligaments)
• Muscular: Movement, posture, heat production (skeletal muscles, tendons)
• Nervous: Rapid communication, sensory input, motor control (brain, spinal cord, nerves)
• Endocrine: Hormone production, growth regulation, reproduction (thyroid, adrenal glands, pancreas)
• Cardiovascular: Transport of nutrients, gases, wastes (heart, blood vessels, blood)
• Lymphatic/Immune: Defense against infection, fluid balance (lymph nodes, spleen, lymphatic vessels)
• Respiratory: Gas exchange (O2 in, CO2 out) (lungs, trachea, bronchi)
• Digestive: Nutrient breakdown and absorption (stomach, intestines, liver)
• Urinary: Excretion of waste, fluid/electrolyte balance (kidneys, bladder, urethra)
• Reproductive (Male/Female): Production of offspring (male: testes, penis; female: ovaries, uterus, mammary glands)

Body Planes, Directions, and Cavities

• Planes:
  • Sagittal: Divides body into left and right
  • Transverse: Divides body into superior and inferior
  • Frontal: Divides body into anterior and posterior
• Directional Terms:
  • Superior/Inferior: Above/below
  • Anterior/Posterior: Front/back
  • Medial/Lateral: Toward/away from midline
  • Proximal/Distal: Closer to/farther from point of attachment
• Body Cavities:
  • Dorsal: Cranial (brain) and spinal (spinal cord)
  • Ventral: Thoracic (heart, lungs) and abdominopelvic (digestive, urinary, reproductive organs)

Tissues

• Epithelial Tissue: Covers surfaces, lines cavities (simple squamous, transitional)
• Connective Tissue: Supports, connects, and protects (bone, cartilage, blood)
• Muscle Tissue: Movement (skeletal, cardiac, smooth)
• Nervous Tissue: Conducts electrical impulses

Cell Structure and Function

• Nucleus: DNA storage, cell control
• Mitochondria: ATP production (abundant in muscle cells)
• Rough ER: Protein synthesis
• Smooth ER: Lipid synthesis
• Golgi Apparatus: Packaging proteins
• Lysosomes: Digesting waste
• Membrane Transport:
  • Diffusion: Passive movement (high to low concentration)
  • Osmosis: Water diffusion
  • Endocytosis: Ingestion of substances (pinocytosis for liquids, phagocytosis for solids)

Homeostasis and Feedback Mechanisms

• Negative Feedback: Maintains stability (e.g., blood glucose regulation)
• Positive Feedback: Amplifies changes (e.g., childbirth)
  • High blood pressure triggers responses to lower it (negative feedback)
  • Uterine contractions intensify until delivery (positive feedback)

Chemistry in Physiology

• pH Scale: 0-14, neutral is 7. Enzymes function optimally at specific pHs
• Biomolecules:
  • Proteins: Amino acids
  • Carbohydrates: Monosaccharides
  • Lipids: Fats, cholesterol

Membranes

• Cutaneous: Skin
• Mucous: Lines open cavities (digestive, respiratory)
• Synovial: Lines joints, produces synovial fluid

Anatomical Position and Regions

• Anatomical Position: Body erect, arms at sides, palms forward
• Key Regions: Axillary (armpit), brachial (arm), crural (leg), coxal (hip)

Blood Flow from Right Atrium to Left Hand

• Right Atrium receives deoxygenated blood
• Tricuspid Valve: Directs blood to the Right Ventricle
• Right Ventricle pumps blood to the lungs
• Pulmonary Semilunar Valve: Allows blood to enter the Pulmonary Trunk then Pulmonary Arteries
• Lungs: Blood becomes oxygenated
• Pulmonary Veins: Carry oxygenated blood back to the Left Atrium
• Mitral (Bicuspid) Valve: Directs blood to the Left Ventricle
• Left Ventricle pumps blood to the body
• Aortic Semilunar Valve blood enters the Aorta then Aortic Arch
• Subclavian Artery: blood to the arm, which branches the Axillary Artery -> Brachial -> Radial or Ulnar Artery sending blood to the left hand.

Tips for Mastery

• Visual Aids: Use diagrams and models.
• Interactive Tools: Engage with online quizzes and flashcards.
• Study Groups: Collaborate and test each other.
• Practice Matching: Link systems to functions and organs.