Unit 1 A&P Study Notes

Anatomy vs Physiology

• Anatomy = structure (what the body parts are)
  • Example: Identification of the biceps muscle
• Physiology = function (what the body parts do)
  • Example: Stages of a muscle contraction
• Tip: If the question asks what it looks like → Anatomy. If it asks what it does → Physiology.

Levels of Organization

• $1$. Chemical (atoms, molecules)
• $2$. Cellular (cells, organelles)
• $3$. Tissue (groups of similar cells)
• $4$. Organ (two or more tissues working together)
• $5$. Organ system (organs working together for a function)
• $6$. Organism (all systems working together → human body)

Necessary Life Functions

• Maintain boundaries (skin separates internal/external)
• Movement (muscles, bones, internal movement)
• Responsiveness (nervous system detects/responds to stimuli)
• Digestion (breakdown and absorption of nutrients)
• Metabolism (chemical reactions in the body)
• Excretion (removing wastes: urine, sweat, feces)
• Reproduction (cell division, producing offspring)
• Growth (increase in size and number of cells)

Survival Needs

• Nutrients (food, vitamins, minerals)
• Oxygen (needed for ATP energy)
• Water (most abundant substance in body)
• Normal body temperature ($37^\circ\mathrm{C} / 98.6^\circ\mathrm{F}$)
• Appropriate atmospheric pressure (for breathing and gas exchange)

Homeostasis & Feedback Loops

• Homeostasis = body’s ability to maintain stable internal conditions.
• Controlled by: receptor → control center → effector
• Feedback Types:
  • Negative feedback = reverses a change, keeps stable. Example: Body temperature regulation, blood glucose control
  • Positive feedback = enhances a change, pushes further. Example: Childbirth contractions, blood clotting

Anatomical Position and Directional Terms

• Anatomical Position - Standard reference: standing upright, feet slightly apart, arms at sides, palms facing forward, thumbs out.
• Directional Terms:
  • Superior / Inferior = above / below
  • Anterior / Posterior = front / back
  • Medial / Lateral = toward midline / away from midline
  • Proximal / Distal = closer to / farther from point of attachment
  • Superficial / Deep = toward surface / away from surface

Body Planes

• Sagittal plane = divides body left/right
• Midsagittal = equal left/right halves
• Frontal (coronal) = divides anterior/posterior (front/back)
• Transverse (horizontal) = divides superior/inferior (top/bottom)

Body Regions

• Cephalic = head
• Thoracic = chest
• Abdominal = abdomen
• Pelvic = pelvis
• Upper limb = arm
• Lower limb = leg
• Lumbar = lower back
• Gluteal = buttocks

Body System Functions

• Integumentary: skin, protection, regulate temp
• Skeletal: support, protection, blood cell production
• Muscular: movement, posture, heat
• Nervous: fast control, communication
• Endocrine: hormones, long-term regulation
• Cardiovascular: transport blood, oxygen, nutrients
• Lymphatic/Immune: defense, fluid return
• Respiratory: gas exchange
• Digestive: breakdown and absorption of food
• Urinary: removes waste, regulates water and electrolytes
• Reproductive: produce offspring

Medical Terminology

• Prefixes, suffixes, root words give meaning
• Examples:
  • Hypo- = below (hypoglycemia = low blood sugar)
  • Hyper- = above (hypertension = high blood pressure)
  • Cardio- = heart
  • Gastro- = stomach
  • -itis = inflammation (arthritis)
  • -ectomy = removal (appendectomy)