Tissues and structures

• Cells


  Smallest independent units of living matter
• Cells

  • Enclosed by a plasma membrane with selective permeability
  • Enclose organelles within a watery fluid called cytosol
• Organelles


  • Nucleus
  • Mitochondria
  • Ribosomes
  • Endoplasmic reticulum
  • Golgi apparatus
  • Lysosomes
  • Cytoskeleton
• External environment

  Source of oxygen, nutrients
• Waste products of cellular activity

  Excreted into the external environment
• Cells

  Bathed in interstitial fluid or tissue fluid
• Total body water

  40L (60%)
• Extracellular fluid (ECF)


  30% (12L)
• Intracellular fluid (ICF)

  70% (28L)
• ECF

  Blood, plasma, lymph, CSF, interstitial fluid, and other fluids such as synovial, pleural and pericardial fluid
• Interstitial fluid


  Medium for diffusion of substances across cells to the blood and vice versa
• Intracellular fluid

  Fluid within the cell
• Tissue

  A group of similar cells, usually having similar embryonic origin and specialized function
• General types of tissue


  • Epithelial
  • Connective
  • Muscle
  • Nervous
• Covering and lining epithelium

  Epithelial tissue that covers and lines surfaces

  
• Glandular epithelium


  Epithelial tissue adapted for secretion into ducts, onto a surface or into blood

  
• Types of glandular epithelium


  • Endocrine (ductless) - secretory products released to extracellular space
  • Exocrine - secrete products directly into ducts

  
• Connective tissue

  • Binds together, supports and strengthens other tissues, protects & insulates internal organs and compartmentalizes structures
  • Blood & lymph responsible for transport
  • Adipose tissue stores energy and insulates
• Types of connective tissue

  • Loose connective tissue: Areolar, Adipose, Reticular
  • Dense connective tissue
  • Cartilage
  • Bone, blood & lymph

  
• Muscle tissue


  • Provides motion, maintenance of posture, and heat production
• Types of muscle tissue


  • Skeletal: attached to bones, striated, voluntary
  • Cardiac: heart wall, striated, involuntary
  • Smooth: walls of hollow structures, not striated, involuntary
• Nervous tissue

  • Quickly communicate between parts of the body, sensitive to stimuli, interpret information, coordinate action
• Types of nervous tissue


  • Neurons: generate and conduct electrical impulses
  • Neuroglia: provide protection and support for neurons
• Organ systems

  • Integumentary
  • Skeletal
  • Articular
  • Muscular
  • Nervous
  • Circulatory
  • Digestive/Alimentary
  • Respiratory
  • Urinary
  • Reproductive
  • Endocrine
• Integumentary system


  • Provides protection, containment, heat regulation, sensation, synthesis and storage of Vitamin D
• Skin

  • Body's largest organ, consists of dermis and epidermis, contains specialized structures like hair follicles, sebaceous glands, sweat glands, and erector pili muscle
• Superficial fascia


  Loose connective tissue between dermis and deep fascia, contains fat, blood vessels, lymphatics and nerves, provides most of the body's fat storage
• Deep fascia


  Dense connective tissue covering muscles, may form fascial compartments and intermuscular septa
• Body cavities


  Cranial, thoracic, abdominal, pelvic
• Membranes

  Epithelial or connective tissue that lines cavities, main types are mucous, serous, and cutaneous (skin)

  
• Mitosis


  Replication of body cells
• Meiosis


  Production of gametes
• Apoptosis

  Aging cell at end of life cycle shrinks and remaining fragments are phagotosed
• Necrosis


  Cell death due to injury or pathological process, cell membrane ruptures and intracellular structures trigger an inflammatory response leading to tissue repair and healing
• Hypertrophy


  Cells may enlarge
• Atrophy

  Cells may decrease in size or number
• Hyperplasia


  Cells may increase in number at a rapid rate
• Most body organs mature by puberty, most organs able to repair and replace tissue except brain and heart
• Tumors

  Abnormal hyperplasia where cells develop at a rapid rate and show abnormal characteristics, classified as malignant or benign and by tissue origin
• Tissue regeneration


  Epithelial tissues have continuous replication, some tissues can retain ability to replicate but do so infrequently, some tissues unable to replicate