BASIC BUILDING BLOCKS#

• Anatomy


  The study of body structure and its organisation
• Physiology


  The study of the processes or functions of living systems
• Anatomy and Physiology


  Inter-related in the human body
• Structural levels of organisation within the body

  • Cells
  • Tissues
  • Organs
  • Systems
• Cells


  • All living creatures are made of cells
  • A cell is the smallest irreducible unit of life
  • Approx. 100 trillion cells in the human body, with over 200 different types which differ in function and appearance
• Four tissue types


  • Nervous Tissue
  • Epithelial Tissue
  • Muscle Tissue
  • Connective Tissue
• Cell function

  DNA to mRNA to Proteins to Functions
• DNA (DeoxyriboNucleic Acid)


  DNA is made up of individual nucleotides with three components: Adenine, Thymine, Guanine, Cytosine
• Chromosomes


  • DNA is condensed into chromosomes within the nucleus
  • Humans have 46 (2 x 23) chromosomes in most cells, sperm/egg only have 23

  
• Proteins


  • Over 20,000 proteins needed to make the human body function properly
  • Expression pattern determines cell type/function
  • Enables normal function of systems
  • Determines physical & chemical characteristics
• Roles of proteins


  • Enzymes - catalyse chemical reactions
  • Structural - hold cells together and provide shape
  • Signal and send messages - allow cells and tissues to communicate
  • Transport - move substances in and out of the cell
• Proteins are polypeptides composed of amino acids (20 available)
• Mutation


  • Change to the DNA sequence
  • Base pair change
  • Codon change
  • Change in amino acid
  • Alters protein function
• Sources of mutation


  • Chance (Spontaneous or error prone)
  • Mutagen exposure
  • Inherited
• Potential effects of mutation

  • No change
  • No impactful change (e.g. Albinism)
  • Harmful effect (e.g. cancer)
  • Beneficial effect (e.g. Sickle Cell, Apolipoprotein AI–Milano, lactose persistence, Infection resistance)
• Environmental mutagens

  • Chemicals (good and bad)
  • Diet (good and bad)
  • Smoking
  • Hormones
  • Radiation
  • Infections (Virus - e.g. HIV, HPV; Bacteria - e.g. H. pylori)
  • Random damage
  • Alcohol
• Elements


  Simplest examples of matter
• Biomolecules


  Molecules that carry out specific functions in the body
• Types of biomolecules


  • Structure (Phospholipids)
  • Signalling (Hormones)
  • Energy, storage (Glycogen) and structure
  • Structure, Enzymes, signalling, transport
  • Information storage
• Water


  • Vital for life - 50-60% of body, 92% of blood
  • Serves as a mixing medium
  • Properties: Cohesion and adhesion (Solvent), High specific heat, Protection, Lubricant, cushion, Participates in chemical reactions, Dehydration and hydrolysis
• Acid

  Any substance that releases hydrogen (H+, Proton) atoms into water

  
• Base (Alkali)


  A proton acceptor or any substance that binds to or accepts hydrogen ions. Hydroxide Ions (OH-)
• pH Scale


  • Measure of Hydrogen (H+) or hydroxide (OH-) ion concentration in a solution
  • Neutral: pH of 7 or equal hydrogen and hydroxide ions
  • Acidic: a greater concentration of hydrogen ions
  • Alkaline or basic: a greater concentration of hydroxide ions
  • Physiologic pH is 7.4
  • Deviations impact on physiological functions
• Buffer


  • Chemicals that resist pH Change!
  • Composed of a weak acid and conjugate base
  • Neutralises small amounts of acids and bases to maintain pH
• Important biological buffers


  • Bicarbonate
  • Phosphates
  • Protein
• Body systems jointly regulate pH such as respiratory and urinary system
• Salt


  • A compound composed of oppositely charged ions i.e. salt (NaCl)
  • Salts are abundant in tissues and fluids
  • They dissociated in water to provide many necessary ions such as Sodium (Na+), Potassium (K+), Magnesium, Phosphate, bicarbonate, chloride, Iron
  • Important for many physiological functions
• Characteristics of Life


  • Organization
  • Metabolism
  • Responsiveness
  • Growth and Development
  • Homeostasis
  • Reproduction
  • Adaptation
• No easy way to show all the organ systems in one image
• All organ systems INTERACT together i.e. Blood interacts with the respiratory system and many others
• Organs are collected in the central part of our body for protection and ease of coordination
• Systems have evolved to give primacy to our organs
• System Characteristics


  • Use the simplest approach to undertake their function
  • Try to maintain a constant state – homeostasis
  • Need to sense their state
  • Need different levels of organisation and regulation
  • Need to adapt to change - local, external, rapid or chronic
  • Are intertwined – dysregulation / failure impacts other systems
  • Have redundancy / extra capacity
• Homeostasis

  • Existence and maintenance of a relatively constant environment within the body
  • Values of variables fluctuate around the set point to establish a normal range of values
  • Set point: the ideal normal value of a variable
• Body temperature is maintained through processes such as shivering or sweating
• Body temperature can't be kept at a constant temperature, but has small fluctuations around set point
• Maintaining normal body temperature is essential for normal chemical reactions
• Feedback Systems


  • Two types: negative and positive
  • Components: Receptor, Control center, Effector
• Negative Feedback System


  • Deviation from set point resisted or made smaller
  • The effector (output) reduces the effect of the stimulus – reduces deviation
• Positive Feedback System


  Enhances the original effect / stimulus