Anatomy and Physiology Notes

Chapter 1 - Introduction to Anatomy and Physiology

Prokaryotes vs. Eukaryotes

  • Prokaryotes: Bacteria (lack a nucleus).
  • Eukaryotes: Humans (have a nucleus).

Anatomy

  • Describes the structures of the body.
  • Includes 11 organ systems and associated structures.
  • Example: Integumentary system (skin, hair, nails, oil, sweat glands).

Physiology

  • Study of the functions of anatomical structures.
  • Focuses on individual and cooperative functions.

Human Anatomy

Gross Anatomy (Macroscopic Anatomy)

  • Examines large, visible structures (outside).

Microscopic Anatomy

  • Examines cells and molecules.
  • Cytology: Study of cells (Cyt/o = cells, ology = the study of).
    • Microscope/microscopy created by Robert Hooke (17th century).
  • Histology: Study of tissues (Hist/o = tissues).

Human Physiology

  • Cell physiology: Functions of cells (smallest living unit).
  • Organ physiology: Function of specific organs (e.g., cardiocytes - heart cells).

Pathology

  • Study of disease (patho = disease).
  • Patients may present with:
    • Signs (e.g., fever).
    • Symptoms (e.g., tiredness).
  • Physicians use the scientific method for diagnosis:
    • Evaluate observations.
    • Form hypothesis.
    • Test hypothesis.
  • Steps:
    • 1. Make an observation.
    • 2. Ask a question.
    • 3. Form a hypothesis.

Levels of Organization

  • Chemical level: Atoms are the smallest stable units; molecules are groups of atoms.
  • Cellular level: Cells are the smallest living units in the body (prokaryotes and eukaryotes).
  • Tissue level: A tissue is a group of cells working together (e.g., epithelial and connective tissues).
  • Organ level: Organs are made of two or more tissues (e.g., skin, bones, muscles, brain, spinal cord).
  • Organ system level: A group of interacting organs.
  • Organism level: An individual life form.

Organ Systems Overview

  • Integumentary
  • Skeletal
  • Muscular
  • Nervous

Integumentary System

  • Major organs:
    • Skin (epidermis, dermis, hypodermis)
    • Hair (terminal and vellus)
    • Sweat glands/oil glands (sudoriferous/sebaceous glands)
    • Nails
  • Functions:
    • Protects against environmental hazards (pathogens).
    • Regulates body temperature (thermoregulation, 98.6^\circ F).
    • Provides sensory information.

Skeletal System

  • Major organs:
    • Bones (206 in adults, 300+ in fetus)
      • Axial (80 bones)
      • Appendicular (126 bones)
    • Cartilages (elastic, hyaline, fibrocartilage)
    • Associated ligaments (bone to bone)
  • Functions:
    • Provides support and protection.
    • Stores calcium (calcification/ossification) and other minerals.
    • Forms blood cells.
    • Stores fat (adipose tissue).

Muscular System

  • Important concepts for the exam:
    • Shape
    • Uninucleate/multinucleate
    • Intercalated discs
    • Striated (stripes)
  • Major organs:
    • Skeletal muscles and associated tendons.
  • Functions:
    • Provides movement (locomotion/kinesis).
    • Provides protection and support.
    • Generates heat to maintain body temperature.
  • Types:
    • Smooth
    • Cardiac
    • Skeletal

Nervous System

  • Major organs:
    • Brain and spinal cord (Central Nervous System - CNS).
    • Peripheral nerves (Peripheral Nervous System - PNS).
    • Sense organs (eyes, ears, skin, nose).
  • Tissues: Neurons/neuroglia (supporting cells).
  • Functions:
    • Directs immediate response to stimuli.
    • Coordinates other organ systems.

Anatomical Landmarks

  • Anatomical position: Hands at sides, palms forward (supine).
  • Supine: Lying face up.
  • Prone: Lying face down.

Medical Imaging

  • X-ray
  • Ultrasound
  • CT (Computerized Tomography)
  • MRI (Magnetic Resonance Imaging)
  • PET (Positron Emission Tomography)

Anatomical Regions

Abdominopelvic Quadrants

  • Right Upper Quadrant (RUQ)
  • Left Upper Quadrant (LUQ)
  • Left Lower Quadrant (LLQ)
  • Right Lower Quadrant (RLQ)
  • Appendicitis affects the right lower quadrant (RLQ).

Abdominopelvic Regions

  • Hypochondriac (below the ribs)
  • Lumbar (lower back)
  • Inguinal (pelvic area/groin)
  • Epigastric (above the stomach)
  • Umbilical (navel)
  • Hypogastric (below the stomach)

Anatomical Directions

  • Medial: Toward the body’s longitudinal axis; toward the midsagittal plane.
  • Lateral: Away from the body's longitudinal axis.
  • Proximal: Closer to the point of attachment (joints).
  • Distal: Farther from the point of attachment (joints).

Quadrant-Related Diseases

  • RUQ: Gallstones, hepatitis.
  • LUQ: Pancreatitis, gastric ulcers.
  • RLQ: Appendicitis.
  • LLQ: Hernias.

Directional Terms

  • Coronal: Sectional.
  • Cephalic: Directional.

Sectional Anatomy

  • A section is a slice through a three-dimensional object.
  • Used to visualize internal organization.
  • Important in radiological techniques.
  • MRI: Brain, spinal cord, joints.
  • PET: Oncology (cancer).
  • CT: Emergency medicine (stroke, fractures, tumors, trauma, internal bleeding).

Body Cavities

Sectional Planes

  • Frontal (coronal) plane: Divides body into anterior (front) and posterior (back) portions.
  • Sagittal plane: Divides body into left and right portions.
    • Midsagittal plane: Divides body perfectly down the middle.
    • Parasagittal plane: Offset from the middle.
  • Transverse plane: Divides body into superior (top) and inferior (bottom) portions.

Essential Functions of Body Cavities

  • Protects organs from shocks and impacts.
  • Permits changes in size and shape of internal organs.

Ventral Cavity

  • Divided by diaphragm.
  • Thoracic cavity: Pleural cavity, pericardial cavity, mediastinum.
  • Abdominopelvic cavity: Peritoneal cavity, abdominal cavity, pelvic cavity.
  • Body cavities contain viscera (internal organs).

Serous Membrane (Serosa)

  • Lines body cavities and covers organs.
  • Consists of parietal and visceral layers.
    • Parietal serosa: Lines cavity.
    • Visceral serosa: Covers organ.
  • Serous cavity: Space between parietal and visceral layers containing serous fluid.
  • Serous fluid: Reduces friction between body cavities and organs.

Abdominopelvic Cavity

  • Abdominal cavity: Superior portion (diaphragm to pelvic bones) containing digestive organs.
  • Retroperitoneal space: Posterior to peritoneum, anterior to muscular body wall (pancreas, kidneys, ureters, digestive tract).
  • Pelvic cavity: Inferior portion (medial to pelvic bones) containing reproductive organs, rectum, bladder.
  • Pelvic girdle: Ilium, ischium, pubis (pelvic bones); sacrum and coccyx.

Thoracic Cavity

  • Right and left pleural cavities: Contains right and left lungs.
  • Mediastinum: Middle cavity.
    • Upper portion: Blood vessels, trachea, esophagus, thymus.
    • Lower portion: Pericardial cavity (heart).

Pericardium

  • Fibrous pericardium
  • Serous pericardium

Abdominopelvic Cavity - Peritoneal cavity

  • Parietal peritoneum lines the internal body wall.
  • Visceral peritoneum covers the organs.

Clinical Conditions

  • Peritonitis: Inflammation of the peritoneum (infection, injury, organ rupture).
  • Ascites: Excess fluid in the peritoneal cavity (heart failure, cancers).

Homeostasis

  • Balance or equilibrium (reaching a set point).
  • Body systems maintain a stable internal environment.
  • Responses to external and internal changes.
  • Thermoregulation: Maintain internal temperature (98.6^\circ F).
  • Blood is connective tissue (pH 7.35 - 7.45).

Homeostatic Regulation

  • Autoregulation: Automatic response within a specific area (e.g., oxygen regulation, blood flow).
  • Extrinsic regulation: Responses controlled by nervous and endocrine systems (e.g., sweating, shivering).

Glands

  • Endocrine glands: Affect the bloodstream.
  • Exocrine glands: Affect outside the bloodstream.

Feedback Mechanisms

  • Negative feedback (most common):
    • Response negates the stimulus.
    • Brings body back into homeostasis.
    • Examples: Thermoregulation, blood sugar regulation (insulin lowers glucose levels).
  • Positive feedback (less common):
    • Examples: Fever, blood clotting, childbirth (contractions), lactation.