AP week one

• 4 types of tissue in the body: Epithelial tissue, Connective tissue, Muscle tissue, Nervous tissue
• Functions of the Systems:

  • Respiratory System: provides O2 needed for oxidation
  • Cardiovascular system: pumps blood around the body, delivers O2/nutrients, removes CO2/waste
  • Gastrointestinal tract: breaks down nutrients, passes to liver via portal vein
  • Renal system: controls the contents of the extracellular fluid
  • Musculoskeletal system: involved in locomotion, maintenance of posture, breathing, and protection
  • Endocrine and Nervous System: co-ordinates organ system activity by hormones or electrical signals
• Prefixes in anatomical terminology:

  • Sub-: under, beneath, smaller
  • Hypo-: under, beneath
  • Infra-: under, within, below
  • Super- or Supra-: above, on top of
  • Epi-: above, upon, on top of
  • Fossa-: depression, hollow
  • Inter-: between
  • Ad-: towards
  • Ab-: away from
  • Contra-: opposite
  • Ipsi-: same
  • Bi-: two
  • Uni-: one
• Anatomical Terminology for Quadrupeds / fish:

  • Frontal or dorsal plane
  • Ventral-dorsal
  • Transverse plane
  • Anterior-posterior (cranial-caudal)
  • Median or sagittal plane
  • Medial-lateral
  • Proximal-distal
• Anatomical Terminology for Bipeds (Human):

  • Frontal plane
  • Ventral-dorsal = Anterior-posterior
  • Transverse plane
  • Cranial-caudal = Superior-inferior
  • Median or sagittal plane
  • Medial-lateral
  • Proximal-distal
• Cavities in the body:

  • Cranial Cavity: contains the brain
  • Thoracic Cavity: contains trachea, lungs, heart, oesophagus, and more
  • Abdominal Cavity: contains stomach, liver, pancreas, kidneys, and more
  • Pelvic Cavity: contains reproductive system, sigmoid colon, urinary bladder
• Main Skeletal Muscles:

  • Scapula
  • 4th Metatarsal
  • Mandible
  • Humerus
  • Femur
• Body water


  Accounts for about 60% of the total body weight
• For a 70 kg man, body water is ~42 litres
• Fluid compartments


  • Intracellular fluid (ICF) - fluid within cells (cytosol) (67%)
  • Extracellular fluid (ECF) - represents the internal environment (33%)
  • Transcellular fluid – 'other' fluid (eg. CSF, joints, ocular)
  • Plasma - fluid component of blood
  • Interstitial fluid (ISF) - fluid surrounding cells
• Homeostasis


  The control or stabilisation of the internal environment
• Fluid intake and output are balanced
• Fluid Balance


  Homeostasis is "the control or stabilisation of the internal environment"
• 67% ICF, 33% ECF
• Daily water intake/output (mL/day)

  • Intake: Ingested food and drink (2100)
  • Intake: Metabolism (200)
  • Total intake (2300)
  • Output: Insensible-skin (350)
  • Output: Insensible- lungs (350)
  • Output: Sweat (100)
  • Output: Faeces (100)
  • Output: Urine (1400)
  • Total output (2300)
• Evaporative loss that we are not consciously aware of
• Biochemistry


  The chemistry of life
• Components of matter


  • Atoms
  • Molecules (e.g. H2O, O2, C6H12O6, NaCl)
• Types of bonds


  • Covalent bonds - sharing of electrons, strong stable bond
  • Hydrogen bonds - attractive force between hydrogen and electronegative atom, often forms between water molecules
  • Ionic bonds - donated or received electrons, weaker more unstable bond
• Electrolytes


  Ionic compounds dissolved in water
• Importance of electrolytes


  • Conduct electricity (muscle and nerve function)
  • Osmotic pressure (keeping fluids in their own compartment)
  • Buffers (resist pH changes in body fluids)
• Functions of water


  • Temperature regulation: evaporation from skin and lungs
  • Protective cushion: amniotic fluid, CSF
  • Lubricant: synovial fluid
  • Reactant: hydrolysis reactions (e.g. starch breakdown)
  • Solvent: dissolves solutes, salts (ions) and nutrients
  • Transport: medium for nutrient delivery/waste removal via plasma
• Properties of water


  • Water is a charged dipole (great for dissolving things)
  • Ability to form H-bonds accounts for exceptional properties of water: high latent heat of evaporation (cools body efficiently), high heat capacity (body temp changes slowly)
• Constituents of body fluids


  • Electrolytes (charged ions dissolved in water): Na+, K+, Ca2+, Cl-, proteins
  • Non-electrolytes (uncharged): e.g. glucose
• Blood cells do not dissolve and therefore are not considered as part of body fluid
• Plasma and interstitial fluid very similar (free movement)
• Interstitial fluid and intracellular fluid very different (regulated movement)
• Despite different compositions, the osmolarity of intracellular and interstitial fluid is about the same (iso-osmotic), therefore the push/pull of water is balanced
• Within a fluid compartment the ionic charge balance is equal, even though the number of ions may differ
• Functions of electrolytes


  • Co-factors: Ca2+, Mg2+ and Zn2+ act as co-factors for enzyme reactions
  • Contribute to action potential generation (Na+ and K+)
  • Secretion and action of neurotransmitters (Ca2+)
  • Muscle contraction (Ca2+)
  • Acid-base balance (HCO3-, phosphate, protein)
  • Primary and secondary active transport (e.g. Na+/K+ ATPase, glucose co-transport)
  • Osmosis: electrolytes and protein promote water movement between fluid compartments across semi-permeable membranes
• Movement of substances within and between body fluids, sometimes across a barrier, is essential in normal physiology
• Types of transport


  • Passive: Simple diffusion, Facilitated diffusion, Osmosis
  • Active: Sodium-potassium pump, Bulk transport
• Electrochemical gradient


  The balance between the electrical and chemical gradients
• Chemical gradient


  Movement from high concentration to low concentration
• Electrical gradient


  Movement from positive to negative charge (or -ve to +ve)
• Inside cells is generally -ve due to proteins
• Diffusion


  • A physical process which operates at all times throughout the body
  • Driven by a concentration gradient, or in the case of charged particles/solutes by an electrochemical gradient
  • Very rapid over short distances (μm), but slow over distances > mm. Thus, diffusion is very rapid for distances on the cellular scale (typical mammalian cells are 5-100 μm diameter)
• Active Transport


  Transport of substances up their concentration gradient, requires energy (ATP), uses specific carrier proteins
• Sodium-potassium pump


  Present on all cells, maintains unequal concentrations of sodium and potassium across the membrane, uses up to 30% of cellular ATP requirement
• Cells contain lots of solutes, therefore water will move into the cell by osmosis