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.