RT 211 | LECTURE 2

• Divisions of the Body:

  • The head
  • The neck
  • The trunk
  • Thorax
  • Abdomen
  • Pelvis
  • The limbs or members
  • Superior or upper limb or member
  • Inferior or lower limb or member
• Body Cavities:

  • Ventral Cavity
  • Thoracic Cavity
  • Abdominopelvic Cavity
  • Dorsal Cavity
  • Cranial Cavity
  • Spinal Canal
• Openings in diaphragm:

  • Esophagus
  • Aorta
  • Superior Vena Cava
• Regional Surface Areas Defined:

  • Axilla: the armpit, the space between the medial surface of the upper arm and the adjacent lateral chest wall
  • Groin: the area of the oblique crease on the front of the body where the lower limb joint the trunk in front of the hip
  • Loin: the lateral side of the abdomen between the lowest rib and the upper margin of the ilium
  • Lumbar Region: one of the nine regions into which the abdomen is divided, sometimes refers to the posterior abdominal wall adjacent to the lumbar vertebrae
• • The buttock: the prominent area of the rump on either side lying lateral to and behind the hip
  • Perineum: the space between the upper medial surfaces of the thighs, and extending from the anus behind to the pubic arch in front, becomes visible when the thighs are separated
• Organization of Body Structures:

  • Cells: the unit of structure and function of the body
  • Tissues: group of similar cells
  • Organs: groups of tissues organized into a unit and concerned with some specific function
  • Systems: groups of tissues and organs arranged to perform some function
• Composition of Cells:

  • Protoplasm: living matter
  • DNA or Deoxyribose Nucleic Acid
  • Consists of complex molecules located in the chromosomes of the nuclei of body cells
  • Responsible for multiple genes and the transmission of hereditary traits
  • RNA or Ribose Nucleic Acid
  • A compound molecule located in the nucleoli of cell nuclei, or in the cytoplasm
  • Contains nitrogen, ribose, a sugar with 5 carbon atoms and a phosphate
• Units of Microscopic Measurements:

  • 1 micron = 1/1000 mm (1/25,000 of an inch)
  • 1 millimicron = 1/1000 micron (1/25,000,000 of an inch)
  • 1 angstrom = 1/10 millimicron (1/250,000,000 of an inch)
• Cells consist of three parts:

  • Cell membrane
  • Nucleus
  • Cytoplasm
• Epithelial Tissue or epithelium:

  • Thin sheet of tissue composed of cells cemented together to form a covering or lining membrane
  • Contains nerve endings (receptors) but no blood vessels
  • Gives protection, manufactures secretions, and allows absorption and excretion
• Connective Tissues:

  • Are supporting and binding tissues of the body
  • Functions to support, connect or bind other important tissues and to fill in spaces within and about organs
  • Types include:
  • Loose (Areolar) Connective Tissue
  • Adipose (Fatty) Tissue
  • Fibrous Tissue
  • Elastic Tissue, Elastic Connective Tissue
  • Reticular Tissue
  • Cartilage or Gristle
  • Bone or Osseous Tissue
• Loose (Areolar) Connective Tissue:

  • Consists of semiliquid or jellylike matrix surrounding well separated cells
  • Network of loosely arranged fibers containing collagen and elastic fibers
• Adipose (Fatty) Tissue:

  • Modified connective tissue where fat is deposited in the cytoplasm, pushing the nucleus to one side
  • Resembles a signet ring
• Fibrous Tissue:

  • Consists of bundles of collagen fibers that form strong cords or sheets of tissue
  • Found in tendons, ligaments, and aponeuroses
• Elastic Connective Tissue:

  • Composed of elastic fibers that are contractile and stretchable
  • Found in structures that must expand and contract like the walls of large blood vessels and lungs
• Reticular Tissue:

  • Composed of a fine network of fibers
  • Found in lymph nodes, spleen, thymus, and bone marrow
• Cartilage or Gristle:

  • Oval shaped tissue
• Cartilage or Gristle:

  • Oval shaped nucleated cells surrounded by a matrix that cements the cells into a firm but flexible structure
  • Types of cartilage include hyaline, fibrocartilage, and elastic cartilage
• Bone or Osseous Tissue:

  • Modified connective tissue
  • Hardest tissue with nucleated cells and calcium phosphate forming a rigid matrix
• Muscular Tissue:

  • Elongated, cylindrical or spindle-shaped cells forming bundles or sheets
  • Types of muscle tissue include skeletal muscle (voluntary, striated), visceral muscle (involuntary, non-striated), and cardiac muscle (involuntary, striated)
• Nervous Tissue:

  • Neurons have a central nucleus, axon, and dendrites
  • Axons conduct impulses away from the cell body, while dendrites carry impulses toward the cell body
• Organs:

  • Group of tissues organized into units concerned with specific bodily functions
  • Examples include lungs, heart, kidney, spleen, liver, and brain
• System:

  • Group of tissues and organs arranged to perform a specific function
  • Examples include skeletal system, muscular system, circulatory system, respiratory system, digestive system, urinary system, reproductive system, endocrine glands, and nervous system
• Physiochemical Processes in Cells and Tissues:

  • Includes filtration, diffusion, osmosis, and homeostasis
• Cell Division:

  • Mitosis: cell division resulting in 2 identical daughter cells; occurs in somatic cells
  • Meiosis: cell division in genetic or reproductive cells, reducing the number of chromosomes; occurs in ova and spermatozoa
• Phases of Cell Division:

  • Interphase
  • Prophase
  • Metaphase
  • Anaphase
  • Telophase
• Some Definitions Restated:

  • Chromosomes: fine filaments containing DNA molecules, participate in cell division
  • Centromere: point of contact of paired daughter chromatids during cell division
  • Miosis: process reducing the number of chromosomes, occurs in oogenesis and spermatogenesis
  • Genes: fractions of DNA molecules of chromosomes, in various combinations