Introduction to Anatomy and Physiology

Introduction to Anatomy and Physiology

• Biology is the study of living organisms.
• It encompasses various specialized fields, including morphology, physiology, anatomy, behavior, origin, and distribution.

Anatomy and Physiology

• Anatomy is the study of body structures (morphology) and their relationships.
• Physiology is the study of body functions, what they do, and how they do it.
• Anatomy examines form, while physiology examines function.

Gross Anatomy & Microscopic Anatomy

• Gross Anatomy studies anatomy at the macroscopic level, typically through dissection.
• Microscopic Anatomy explores anatomy not visible to the naked eye, requiring the use of a microscope.
• Microscopic anatomy includes:

  Histology

    - Examines tissues, groups of specialized cells.
  

  Cytology

    - Analyzes the structure of individual cells, the simplest units of life.
  

Body Systems

• The human body comprises 11 organ systems:

  Integumentary System

    - **Organs:** Skin
    - **Functions:** Waterproofs, cushions, protects deeper tissue; excretes salts and urea; provides pain and pressure sensation; regulates body temperature; synthesizes vitamin D.
  

  Skeletal System

    - **Organs:** Bones, cartilages, ligaments, joints
    - **Functions:** Protects and supports body organs; provides a framework for muscles and movement; hematopoiesis (blood cell production); stores minerals.
  

  Muscular System

    - **Organs:** Skeletal muscle (attached to bone)
    - **Functions:** Contraction and mobility (locomotion); facial expression; posture; produces body heat.
  

  Nervous System

    - **Organs:** Brain, spinal cord, nerves, and sensory receptors
    - **Functions:** Acts as a fast-acting central control system; responds to external and internal stimuli via nerve impulses (electrical messages).
  

  Endocrine System

    - **Organs:** Pituitary, thyroid, parathyroids, adrenals, thymus, pancreas, pineal, ovaries, testes... etc.
    - **Functions:** Slow-acting control system; glands produce hormones that regulate growth, reproduction, metabolism, etc.
  

  Circulatory System

    - **Organs:** Heart, blood vessels, capillaries, and blood
    - **Functions:** Transports O2, nutrients, hormones, and other substances to and from tissue cells; white blood cells protect against bacteria, toxins, and tumors.
  

  Lymphatic System

    - **Organs:** Lymphatic vessels, lymph nodes, spleen, tonsils
    - **Functions:** Complements circulatory system by returning leaked fluid back to blood vessels; cleanses the blood; involved in immunity.
  

  Respiratory System

    - **Organs:** Nasal cavity, pharynx, larynx, trachea, bronchi, and lungs
    - **Functions:** Keeps blood supplied with O2 and removes CO2; carries out gas exchange through air sacs in lungs. 
  

  Digestive System

    - **Organs:** Oral cavity, esophagus, stomach, small intestine, large intestine, rectum, anus (liver and pancreas)
    - **Functions:** Breaks down food into absorbable units that enter the blood; indigestible food is eliminated as feces. 
  

  Urinary (Excretory) System

    - **Organs:** Kidney, ureter, urinary bladder, urethra
    - **Functions:** Eliminates nitrogenous waste from the body (urea and uric acid); regulates water, electrolytes, and acid-base balance of the blood.
  

  Reproductive System

    - **Organs:** 
        - **Male:** Seminal vesicles, prostate, penis, vas deferens, testis, scrotum
        - **Female:** Ovaries, mammary glands, uterus, vagina, uterine tube
    - **Functions:** Primary function for both sexes is to produce offspring; Male – testes produce sperm and male sex hormones; Female – ovaries produce eggs and female sex hormones; mammary glands produce milk.
  

Characteristics of Living Matter

• Organization: Made up of one or more cells; possess a genetic code/DNA.
• Metabolism: Requires energy to survive.
• Growth: Increases in size or number of cells.
• Reproduction: The ability to produce offspring.
• Adaptation: The ability to change over time in response to environmental changes.

Chemical Level of Organization

• Matter exists in three states: solid, liquid, and gas.
• All forms of matter are made up of chemical elements.
• An element is a substance that cannot be broken down into a simpler substance by ordinary chemical means.
• There are 118 recognized elements.
• Each element is composed of atoms, the smallest units of matter that retain the properties and characteristics of the element.
• Atoms consist of subatomic particles: neutrons, protons, and electrons.
• The nucleus is the dense central core of an atom, containing protons and neutrons.

Atomic Structure and Bonding

• Each atom carries an electric charge:
  • Electrons have a negative charge (-1).
  • Protons have a positive charge (+1).
  • Neutrons have no charge (0).
• Like charges repel each other, while opposites attract.
• Electrons occupy specific regions around the nucleus called electron shells.
• The atomic number represents the number of protons in an atom.
• The atomic mass (atomic weight) is determined by the total number of protons and neutrons.
• Isotopes are atoms of the same element that differ in the number of neutrons in their nucleus.
• Atoms interact with each other by gaining, losing, or sharing electrons to achieve stability.
• Atoms can gain or lose electrons to become ions:
  • Cations are positively charged ions (e.g., Na+).
  • Anions are negatively charged ions (e.g., Cl-).
• Atoms can join with other atoms to form molecules (e.g., O2) or compounds (e.g., NaCl).

Chemical Bonds

• Ionic Bonds: Formed by the attraction between oppositely charged ions.
• Covalent Bonds: Formed by the sharing of electron pairs between atoms.
  • Polar Covalent Bonds: Involve uneven sharing of electrons, resulting in one end of the molecule being slightly positive and the other slightly negative.

Molecular Ions, Acids, and Bases

• Molecular Ions: Charged molecules that can participate in ionic bonds with oppositely charged ions.
• Acids: Donate protons (H+ ions) when dissolved in water.
• Bases: Accept protons (H+ ions) when dissolved in water.
• pH Scale: A measure of the acidity or alkalinity of a solution.
  • Values range from 0 to 14, with lower values indicating acidity and higher values indicating alkalinity.
  • Pure water has a pH of 7, considered neutral.