hubs

• Levels of organisation


  • Chemical
  • Cellular
  • Tissue
  • Organ
  • Organ system
  • Organism
• Anatomical Terminology

  • Left and right - left and right of person in anatomical position
  • Anterior (ventral)- front of the body
  • Posterior (dorsal) - back of the body
  • Superior - above or towards head
  • Inferior - below or towards feet
  • Proximal and distal - only use when describing two points on same limb, Proximal - closer to where arm or leg inserts into body, Distal - further away from where arm or leg insert into body
  • Medial - closer to midline
  • Lateral - further from midline
• Anatomical planes

  • sagittal
  • frontal
  • transverse
  • oblique
• Frontal plane


  When body is divided into anterior and posterior planes
• Body cavities

  • cranial
  • thoracic
  • verterbral
  • pleural
  • pericardial
  • abdominal
  • Pelvic
  • Diaphragm
• Anabolic

  Bonds are formed (results in the absorption of energy)
• Catabolic

  Bonds are broken (results in release of energy)
• Rearrangements

  Bonds are rearranged between molecules (there is no net change in energy as bonds are both broken and formed)
• Covalent bond


  When 2 or more atoms share electrons
• Ionic bond


  When atoms give/take electrons from each other. Are charged due to the loss/gain of electrons.
• Major elements in the human body

  • Hydrogen
  • Carbon
  • Nitrogen
  • Oxygen
• Minor elements in the human body

  • Calcium
  • Phosphorus
  • Potassium
  • Sulfur
  • Sodium
  • Chlorine
  • Magnesium
  • Iodine
  • Iron
  • Chromium
  • Cobalt
  • Copper
  • Fluorine
  • Manganese
  • Molybdenum
  • Selenium
  • Silicone
  • Tin
  • Vanadium
  • Zinc
• Chemicals in the human body

  • Water
  • Electrolytes
  • Acids & bases
  • Carbohydrates
  • Lipids
  • Proteins
  • ATP
  • Nucleic acids
• Water

  Most important and abundant chemical in the body, body solvent which regulates heat, provides cushioning, and is highly reactive with other chemicals
• Electrolytes

  Ions that dissolve in water, forming solutes that conduct electrical currents
• Acids & bases


  Specific electrolytes that release hydrogen or hydroxide ions in water
• Carbohydrates


  Composed of saccharides (sugars) which provide an important source of energy for body cells
• Lipids


  Water insoluble cellular energy source composed of fatty acids
• Proteins


  Composed of chains of amino acids creating important structural components of the body and forming enzymes
• ATP


  Energy in the bonds of this chemical is immediately available to cells to drive cellular activity
• Nucleic acids


  Chains of nucleotides making up the genetic makeup of the body
• Homeostasis


  The process of maintaining a stable internal environment
• Variables


  Parameters that are monitored and controlled by the feedback systems
• Stimulus


  Change in variable value
• Set point range


  The physiological value around which the normal range fluctuates
• Positive feedback loop


  Aim to enhance change in variable, e.g. stretching cervix in labour
• Negative feedback loop


  Aim to get back to set point range, e.g. releasing sweat to cool down
• Variables homeostasis regulates


  • Temperature
  • Blood pressure
  • Blood sugar
  • Heart rate
  • O2 levels
  • H2O levels
• Negative feedback loop

  • sensors detect change in variable
  • send afferent signals to hypothalamus
  • hypothalamus compares variable to set point range
  • sends efferent signals to effectors
  • Effectors work to bring variable back to SPR
  • effectors are blood vessels constrict, muscles contract, thyriod gland increases BMR
• Cell (plasma) membrane


  Forms the external boundary of the cell, separates the cell from its external environment, regulates the transportation of substances into or out of the cell
• Cytoplasm


  Consists of gel-like substance in which numerous organelles are suspended, provides structure and carries out various functions of the cell

  
• Nucleus


  Control centre of the cell, contains DNA which directs protein synthesis and regulates the cell life cycle and cell division
• Cell membrane


  Flexible structure that defines the extent of the cell by separating two fluid compartments: intracellular fluid (within the cell) and extracellular fluid (outside the cell)

  
• Components of the cell membrane

  • Phospholipid bilayer
  • Proteins
  • Carbohydrates
  • Glycolipids
  • Glycoproteins
  • Cholesterols

  
• Intracellular fluid (ICF)


  The fluid within the cell

  makes up 2/3 of body water

  main electrolyte is potassium
• Extracellular fluid (ECF)


  The fluid outside the cell

  makes up 1/3 of body water

  divided into plasma (8%) and interstitial fluid (22%)
• Passive cell transport


  Occurs without the use of cellular energy and occurs via diffusion or filtration
• Diffusion


  Solutes move from high concentration to low concentration

  simple diffusion requires no protein transport, diffuses lipid soluble solutes

  filtrated diffusion requires protein channels and carriers as they move lipid insoluble solutes.
• Osmosis


  The diffusion of water, occurs via special protein channels called aquaporins, water moves from low osmolarity to high osmolarity

  Osmolarity is the total concentration of all solutes in fluid compartments. if ICF osmolarity is low, ECF will enter the cell. this is called a fluid shift.
• Filtration


  Movement of water and permeable substances across cell membranes due to the force of pressure