Human Anatomy & Physiology I Study Notes

Human Anatomy & Physiology I

Course Overview

  • Course Code: BIO:168
  • Instructor: Dr. Marie Ripslinger-Atwater

Content Outline

  • Orientation to the Human Body
  • Cells & Membrane Transport
  • Tissues
  • Integumentary System
  • Skeletal System
  • Muscular System
  • Nervous System
  • Special Senses
  • Endocrine System

Orientation to the Human Body

  • ANATOMY: The study of the structure of the body, divided into several categories:
    • Gross Anatomy: Study of body structures visible to the naked eye
    • Regional Anatomy: Study based on regions of the body
    • Systemic Anatomy: Study of organ systems
    • Surface Anatomy: Identification of superficial anatomical features
    • Microscopic Anatomy: Study that requires magnification, includes:
    • Cytology: Study of cells
    • Histology: Study of tissues
  • Physiology: The study of the function of the body and its parts.
    • Focuses on cellular and molecular events and processes.
    • Emphasizes the need to understand anatomy (structure) to fully grasp physiology (function).

Principle of Complementarity

  • States that structure and function are interdependent in the human body.

Biological Hierarchy of Organization

  • Levels of Organization:
    • Atoms: The smallest units of matter.
    • Definition: Indivisible by chemical means and form the basic building blocks of matter.
    • Molecules: Combinations of two or more atoms.
    • Atoms combine to form molecules, e.g., water, proteins.
    • Organelles: Functional components of cells, e.g., mitochondria, nucleus.
    • Cells: The basic unit of life, made up of molecules.
    • Tissues: Groups of similar cells working together to perform a specific function.
    • Example: Smooth muscle tissue consists of similar types of cells.
    • Organs: Structures made up of different types of tissues working together.
    • Example: Blood vessels (organs) include smooth muscle tissue, connective tissue, and epithelial tissue.
    • Organ Systems: Groups of organs that work closely together.
    • Example: The cardiovascular system, which consists of the heart and blood vessels.
    • Organismal Level: The human organism is a collection of organ systems that works together to maintain life.

Major Organ Systems of the Human Body

  1. Integumentary System:

    • Components: Skin, hair, nails
    • Functions: Protects deeper tissues from injury, synthesizes vitamin D, houses pain/pressure receptors, sweat and oil glands.

  2. Skeletal System:

    • Components: Bones, joints
    • Functions: Protects and supports body organs, framework for muscles, blood cell formation in bones, mineral storage.

  3. Muscular System:

    • Components: Skeletal muscles
    • Functions: Manipulation of the environment, locomotion, facial expression, maintenance of posture, heat production.

  4. Nervous System:

    • Components: Brain, nerves, spinal cord
    • Functions: Fast-acting control system responding to internal/external stimuli, activating appropriate muscles and glands.

  5. Endocrine System:

    • Components: Glands (e.g., thyroid, adrenal, pancreas, reproductive glands)
    • Functions: Glands secrete hormones regulating growth, reproduction, and nutrient use, impacting metabolism.

  6. Cardiovascular System:

    • Components: Heart, blood vessels
    • Functions: Transports blood, carrying oxygen, carbon dioxide, and nutrients; pumps blood via the heart.

  7. Lymphatic System/Immunity:

    • Components: Lymphatic vessels, lymph nodes, spleen
    • Functions: Picks up fluid leaked from blood vessels; disposes debris, houses white blood cells for immunity.

  8. Respiratory System:

    • Components: Lungs, airways (trachea, bronchi)
    • Functions: Supplies blood with oxygen and removes carbon dioxide through air sacs in lungs.

  9. Digestive System:

    • Components: Oral cavity, esophagus, stomach, intestines, liver
    • Functions: Breaks down food into absorbable units; eliminates indigestible foodstuffs as feces.

  10. Urinary System:

    • Components: Kidneys, ureters, bladder, urethra
    • Functions: Eliminates waste, regulates water and electrolyte balance, regulates blood pH.

  11. Male Reproductive System:

    • Components: Testes, penis, ducts
    • Functions: Production of sperm and male hormones, aids in sperm delivery.

  12. Female Reproductive System:

    • Components: Ovaries, uterus, vagina
    • Functions: Produces eggs and hormones, sites for fertilization and fetus development, mammary glands for lactation.

Maintaining Life

  • Maintaining Boundaries:
    • At the cellular level, plasma membranes provide boundaries.
    • At the organismal level, skin maintains boundaries.
  • Movement:
    • Locomotion (e.g., walking), smooth muscle contraction (e.g., organs).
  • Responsiveness:
    • The ability to sense and react to stimuli, facilitated by the nervous system (e.g., withdrawal reflex).
  • Digestion:
    • Breakdown of food for metabolism.
  • Metabolism:
    • Sum of all chemical reactions in the body, including catabolism and anabolism.
  • Excretion:
    • Removal of waste products from the body.
  • Reproduction:
    • Occurs at both cellular (mitosis) and organismal levels.
  • Growth:
    • Involves hypertrophy (increase in cell size) and hyperplasia (increase in cell number).

Homeostasis

  • Definition: The body's ability to maintain stable internal conditions despite external changes.
  • Key Systems: The Nervous and Endocrine systems regulate homeostasis.
  • Importance: Adaptation to environmental changes is crucial for survival; deviations can lead to disease or death.

Homeostatic Regulation

  • Physiological Adjustments: The body makes adjustments to restore internal balance.
  • Hundreds of physiological variables (e.g., temperature, pH) are controlled within narrow ranges.
  • Control Mechanisms: Feedback loops play a crucial role in homeostatic regulation, which can be:
    • Extrinsic: External control via nervous or endocrine system.
    • Intrinsic: Local or inherent controls.

Basic Homeostatic Feedback Loop Components

  1. Stimulus: Initial change that disrupts homeostasis.
  2. Receptor: Senses the change and sends information to the control center.
  3. Control Center: Processes the information and determines the response needed.
  4. Effector: Carries out the response to restore balance.
  5. Response: The reaction to the initial stimulus.

Example of Sweating as a Feedback Loop

  • Stimulus: Increased body temperature.
  • Receptors: Temperature-sensitive cells in the skin and brain.
  • Control Center: Thermoregulatory center in the hypothalamus.
  • Effectors: Sweat glands activated to produce sweat.
  • Response: Evaporation of sweat cools the skin, reducing body temperature and ending the stimulus.

Differences in Feedback Loops

  • Feedback loops are classified into two types:
    • Negative Feedback Loops: Oppose the stimulus, more common in homeostatic control. An example includes sweating.
    • Positive Feedback Loops: Enhance the stimulus, less common due to risk of extreme conditions. An example includes blood clotting, where a break in blood vessel walls attracts more platelets, forming a plug.