Anatomy and Physiology: Week 1

• Course: MC102 nur - Human Anatomy and Physiology
• Lecture: Week 1
• Date: February 10 – 15, 2025
• School: St. Paul University Philippines

Objectives

• Define anatomy and physiology
• Describe the relationship between anatomy and physiology
• Explain the structural organization of the human body
• Discuss the characteristics of life
• Relate the characteristics of life to the survival needs of the body
• Discuss homeostasis
• Discuss the importance of studying anatomy and physiology in nursing.

Anatomy Defined

• Anatomy studies the structure of body parts and their relationships.

Physiology Defined

• Physiology studies the function of body parts.

Complementarity of Structure & Function

• What a structure can do depends on its specific form.
• Structure dictates function.

Subdivisions of Anatomy

• Gross or Macroscopic anatomy involves parts visible to the naked eye, such as regional, surface, and systemic anatomy
• Microscopic anatomy includes:
  • Cytology: study of cells
  • Histology: study of tissues
• Developmental anatomy includes:
  • Embryology: study of changes that occur before birth

Physiology Levels

• Cell physiology examines processes in cells
• Systemic physiology considers the functions of organ systems
• Neurophysiology focuses on the nervous system
• Cardiovascular physiology deals with the heart and blood vessels
• Exercise physiology focuses on changes in function and structure caused by exercise

Relationship Between Anatomy and Physiology

• They are always related.
• Structure determines what functions can take place.
  • Example: Lungs have thin walls that facilitate gas exchange, unlike the muscular heart.

Levels of Structural Organization

• The levels of structural organization are chemical, cellular, tissue, organ, organ system, and organism.

Chemical Level

• The chemical level involves interactions between atoms; these tiny building blocks of matter combine to form more complex molecules such as water, sugar, fats, and proteins.

Cell Level

• Cells, the basic structural and functional units of plants and animals, are formed when molecules combine into organelles.

Tissue Level

• A tissue is a group of similar cells and surrounding materials, with the characteristics of these determining the tissue's function.

Organ Level

• An organ is composed of two or more tissue types performing common functions.

Organ System Level

• An organ system is a group of organs performing a common function, viewed as a unit.

Organism Level

• An organism is any living thing considered as a whole, whether composed of one cell (like a bacterium) or trillions of cells (like a human being).

Overview Of Organ Systems

• Integumentary System:
  • Forms the external body covering, protecting deeper tissues from injury.
  • Synthesizes vitamin D.
  • Houses cutaneous (pain, pressure, etc.) receptors and sweat and oil glands.
• Skeletal System:
  • Protects and supports body organs.
  • Provides a framework for muscles to cause movement.
  • Forms blood cells within bones.
  • Stores minerals.
• Muscular System:
  • Allows manipulation of the environment, locomotion, and facial expression.
  • Maintains posture.
  • Produces heat.
• Nervous System:
  • A fast-acting control system
  • Responds to internal and external changes by activating appropriate muscles and glands.
• Endocrine System:
  • Glands secrete hormones that regulate processes such as growth, reproduction, and nutrient use (metabolism).
• Cardiovascular System:
  • Blood vessels transport blood, carrying oxygen, carbon dioxide, nutrients, and wastes.
  • The heart pumps blood.
• Lymphatic System/Immunity:
  • Picks up fluid leaked from blood vessels and returns it to blood.
  • Disposes of debris in the lymphatic stream.
  • Houses white blood cells (lymphocytes) involved in immunity.
  • The immune response attacks foreign substances within the body.
• Respiratory System:
  • Keeps blood constantly supplied with oxygen.
  • Removes carbon dioxide.
  • Gaseous exchanges occur through the walls of the air sacs of the lungs.
• Digestive System:
  • Breaks down food into absorbable units that enter the blood for distribution to body cells.
  • Indigestible foodstuffs are eliminated as feces.
• Urinary System:
  • Eliminates nitrogenous wastes from the body.
  • Regulates water, electrolyte, and acid-base balance of the blood.
• Male and Female Reproductive Systems:
  • Overall function is production of offspring
  • Testes produce sperm and male sex hormone; male ducts and glands aid in delivery of sperm to the female reproductive tract
  • Ovaries produce eggs and female sex hormones; remaining female structures serve as sites for fertilization and development of the fetus.
  • Mammary glands of female breasts produce milk to nourish the newborn.

Characteristics of Life

• Organization refers to the specific interrelationships among the parts of an organism and how those parts interact to perform specific functions.
• Metabolism refers to all of the chemical reactions taking place in an organism.
• Responsiveness is an organism's ability to sense changes in its external or internal environment and adjust to those changes.
• Growth refers to an increase in the size or number of cells, which produces an overall enlargement of all or part of an organism.
• Development includes the changes an organism undergoes through time, beginning with fertilization and ending at death.
• Reproduction is the formation of new cells or new organisms.

Survival Needs

• Nutrients
• Oxygen
• Water
• Normal Body Temperature (98.6°F or 37°C)
• Atmospheric Pressure.

Homeostasis

• Homeostasis is the maintenance of relatively stable internal conditions.
• Negative Feedback: Reduces the effect of the stimulus.
  • Examples: body temperature, breathing rate, blood sugar levels
• Positive Feedback: Increases the response.
  • Examples: labor contractions, blood clotting
• Diseases = homeostatic imbalance.

Negative Feedback

• Most systems of the body are regulated by negative-feedback mechanisms, which maintain homeostasis (EQUILIBRIUM)
• Negative means that any deviation from the set point is made smaller or is resisted
• Often it causes the output of a system to be lessened so that the feedback will stabilize the system

3 Components of Negative Feedback Mechanism

These work towards maintaining variables near a normal value (set point), and is crucial for maintaining homeostasis:

• A receptor monitors the value of a variable.
• A control center receives information about the variable from the receptor and establishes the set point.
• An effector produces responses that change the value of the variable.

Positive Feedback

• Positive-feedback mechanisms occur when a response to the original stimulus results in the deviation from the set point becoming even greater, required to re-achieve homeostasis.