Biology 207 - Anatomy and Physiology 1

Introduction to Anatomy and Physiology

  • Welcome to Bio 207 - Anatomy & Physiology 1!
  • Course Instructor: Dr. Kaleena Veit

What is Anatomy and Physiology?

  • Anatomy and Physiology (A&P) is the biology of the human body, focusing on composition and function.
  • A&P serves as a foundation for careers in healthcare, pathophysiology, exercise physiology, and various health-related fields.

Definitions

  • Anatomy: Study of structure.
  • Physiology: Study of function.
  • The two fields are complementary and inseparable.

Anatomy—The Study of Form

  • Gross Anatomy: Study of structures visible to the naked eye.
  • Histology (Microscopic Anatomy): Examination of tissues using a microscope.
  • Histopathology: Microscopic examination of tissues for disease signs.
  • Cytology: Study of the structure and function of cells.
  • Ultrastructure: View molecular details under an electron microscope.

Methods to Study Gross Anatomy

  • Inspection: Visual examination of appearance.
  • Palpation: Feeling structures with hands.
  • Auscultation: Listening to sounds produced by the body.
  • Percussion: Tapping the body and listening for abnormalities.
  • Dissection: Cutting and separating tissues to reveal relationships.
  • Comparative Anatomy: Comparing structures across different species.
  • Exploratory Surgery: Direct opening of the body to investigate health issues—now largely replaced by medical imaging.
  • Radiology: Medical discipline focused on imaging techniques.

Physiology

  • Physiology employs experimental science methods to understand function.
  • Comparative Physiology: Limits on human experimentation; includes studies of various species to inform bodily functions.
  • Example: Development of drugs tested on animals before human trials.

History of Anatomy and Physiology

  • Early knowledge was limited due to cadaver dissection bans and disease explanations involving supernatural beliefs.
  • Key milestones include:
    • Challenging traditional beliefs.
    • Development of the scientific method.
    • Conducting dissections.
    • Invention of the microscope.
    • Advances leading to modern biomedical science, including:
    • Completion of the human genome project.
    • Application of gene therapy.
    • Enhanced medical imaging techniques.
    • Developments like surgery, immunization, chemotherapy, and organ transplants.

The Body’s Structural Hierarchy

  • Anatomy studied at several levels of detail:
    • Organism: Complete individual.
    • Organ System: Group of organs working together for a common function.
    • Organ: Structure composed of two or more tissue types working collectively.
    • Tissue: Group of similar cells performing a specific function.
    • Cell: Smallest unit capable of performing all life functions.
    • Organelle: Structural component within a cell carrying out specific tasks.
    • Molecule: Particles made of two or more atoms, with largest molecules (macromolecules such as proteins, fats, DNA).
    • Atom: Smallest unit with a unique chemical identity.

Principal Organs and Functions per Organ System

  1. Integumentary System: Organs - Skin, hair, nails, glands. Functions - Protection, thermoregulation, sensation, vitamin D synthesis.
  2. Skeletal System: Organs - Bones, cartilages, ligaments. Functions - Support, movement, blood formation, mineral storage.
  3. Muscular System: Organs - Skeletal muscles. Functions - Movement, stability, heat production.
  4. Lymphoid System: Organs - Lymph nodes, vessels, thymus, spleen. Functions - Fluid recovery, defense against disease.
  5. Respiratory System: Organs - Nose, pharynx, trachea, lungs. Functions - Gas exchange, acid-base balance.
  6. Urinary System: Organs - Kidneys, bladder. Functions - Waste elimination, blood pressure regulation.
  7. Nervous System: Organs - Brain, spinal cord, nerves. Functions - Internal communication, sensation.
  8. Endocrine System: Organs - Glands (e.g., thyroid, pancreas). Functions - Hormone production.
  9. Circulatory System: Organs - Heart, blood vessels. Functions - Distribution of nutrients and waste.
  10. Digestive System: Organs - Stomach, intestines, liver. Functions - Nutrient absorption, metabolism.
  11. Male Reproductive System: Organs - Testes, ducts, glands. Functions - Sperm production, hormone secretion.
  12. Female Reproductive System: Organs - Ovaries, uterus. Functions - Egg production, fetal development.

Anatomical Variation

  • Common structural variations include:
    • Extra/missing vertebrae.
    • Missing muscles or organs.
    • Situs inversus: condition where organs are reversed or mirrored from normal positions.

Physiological Variation

  • Physiological differences can arise from:
    • Sex, age, diet, genetics, physical activity, weight, and environment.
  • Typical physiological values:
    • Reference man: 22 years, 154 lbs., 2800 kcal/day.
    • Reference woman: 22 years, 128 lbs., 2000 kcal/day.
  • Neglecting variation may lead to overmedication, particularly among elderly or women.

Characteristics of Life

  1. Organization: Higher complexity than non-living things.
  2. Cellular Composition: Living matter consists of cells.
  3. Metabolism: Sum of chemical changes.
  4. Responsiveness: Ability to react to environmental changes.
  5. Movement: Motion of the organism and substances within.
  6. Homeostasis: Stability of internal conditions.
  7. Development: Changes in form/function over time.
  8. Differentiation: Transformation of unspecialized cells into specialized roles.
  9. Growth: Increase in size via chemical changes.
  10. Reproduction: Organisms create copies, passing genes to offspring.
  11. Evolution: Genetic changes over generations due to mutations.

Homeostasis and Negative Feedback

  • Homeostasis: The ability to detect changes, activate corrective mechanisms, maintaining stability.
  • Components of Homeostasis System:
    • Receptor: Senses change.
    • Integrating (Control) Center: Processes information and determines action.
    • Effector: Executes the response.
  • Negative Feedback:
    • Mechanism that senses a deviation and activates processes to revert it.
    • Loss of homeostatic control can lead to illness or death.

Example of Negative Feedback in Thermoregulation

  1. Room cools down to 19°C.
  2. Thermostat activates the furnace.
  3. Heat output increases until room temperature rises to 20°C.
  4. Thermostat shuts off once desired temperature achieved.
  5. Fluctuations occur within a range (dynamic equilibrium).

Positive Feedback

  • Positive Feedback: A self-amplifying cycle leading to greater change in the same direction.
    • Typical for rapid changes, such as during childbirth or blood clotting.
    • Can be dangerous; for example, high fevers can be harmful past a threshold (e.g., 104°F).

Example of Positive Feedback in Childbirth

  1. Fetal head pushes against the cervix.
  2. Signals sent from cervix to the brain.
  3. Brain stimulates the pituitary gland to release oxytocin.
  4. Oxytocin increases uterine contractions, pushing fetus downward.

Gradients and Flow

  • Gradient: Difference in concentration, charge, or temperature between two points.
  • Matter and energy flow down gradients from higher to lower values, requiring no energy.
    • Example: Blood flows from high to low pressure areas.
  • Movement against the gradient requires metabolic energy.

Types of Gradients

  1. Concentration Gradients: Chemicals flow from high to low concentrations.
  2. Electrical Gradients: Charged particles flow down differences in charge.
  3. Thermal Gradients: Heat flows from high to low temperatures.

Anatomical Position

  • Anatomical Position: Standard reference posture to describe anatomical relations.
    • Standing upright, facing forward, feet flat, arms at sides, palms facing forward.

Anatomical Planes

  • Anatomical Planes: Imaginary lines that help describe body orientation:
    1. Sagittal Plane: Divides body into right and left.
    2. Frontal (Coronal) Plane: Divides body into anterior and posterior.
    3. Transverse (Horizontal) Plane: Divides body into superior and inferior.

Directional Terms in Human Anatomy

  • Ventral: Toward the front or belly.
  • Dorsal: Toward the back or spine.
  • Anterior: Toward the ventral side.
  • Posterior: Toward the dorsal side.
  • Cephalic: Toward the head.
  • Rostral: Toward the forehead or nose.
  • Caudal: Toward the tail.
  • Superior: Above.
  • Inferior: Below.
  • Medial: Toward the median plane.
  • Lateral: Away from the median plane.
  • Proximal: Closer to the point of attachment.
  • Distal: Farther from the point of attachment.
  • Ipsilateral: Same side of the body.
  • Contralateral: Opposite sides of the body.
  • Superficial: Closer to the body surface.
  • Deep: Farther from the body surface.

Major Body Regions

  1. Axial Region: Head, neck, trunk.
    • Trunk divided into: Thoracic region (above diaphragm) and Abdominal region (below diaphragm).
  2. Abdominal Region divided into two schemes:
    • Abdominal Quadrants:
      • RUQ: liver, gallbladder, parts of stomach, right kidney, pancreas.
      • LUQ: spleen, pancreas, most of stomach, left kidney.
      • RLQ: appendix, right reproductive organs.
      • LLQ: left reproductive organs.
    • Abdominopelvic Regions (9 regions structured like a tic-tac-toe grid).

Body Cavities

  • The body encompasses multiple cavities to protect organs:
    • Cranial Cavity: Encloses the brain.
    • Vertebral Canal: Encloses the spinal cord.
    • Thoracic Cavity: Encloses the heart and lungs.
    • Abdominopelvic Cavity: Encloses digestive, urinary, and reproductive organs.