Lecture 01

• What is homeostasis?

  Maintenance of stable internal conditions
• Why is homeostasis significant to the body?

  It keeps organs healthy and body functions stable
• What are the four major types of cells in the body?

  Epithelial, connective, muscle, and nerve cells
• What are the levels of organisation in the body?

  • Cells form tissues
  • Tissues form organs
  • Organs form organ systems
• What is an organ system?

  Collections of organs working together
• What does the respiratory system consist of?

  Nasal passages, mouth, pharynx, larynx, trachea
• What are the organ systems in the body?

  • Endocrine
  • Nervous
  • Musculoskeletal
  • Cardiovascular
  • Respiratory
  • Urinary
  • Gastrointestinal
  • Reproductive
  • Immune
  • Integumentary
• How do organ systems work together?

  They maintain body functions collectively
• What is the role of the nervous and endocrine systems?

  They regulate other organ systems
• What does homeostasis maintain in the body?

  Balance of internal conditions
• What separates the internal and external environments of the body?

  Epithelial tissue barrier
• What is the internal environment of the body?

  Immediate environment of most body cells
• How does the external environment differ from the internal environment?

  The external environment is constantly changing
• What are the methods of material exchange between environments?

  • Lungs: diffusion of gases
  • Gastrointestinal tract: absorption and secretion
  • Kidneys: filtration and excretion

  
• What is the total body water (TBW) volume?

  42L excluding lumen
• What is the volume of intracellular fluid (ICF)?

  28L including blood cells
• What is the volume of extracellular fluid (ECF)?

  14L including plasma

  
• What is the volume of plasma?

  3L excluding blood cells
• What is the volume of interstitial fluid (ISF)?

  11L excluding plasma

  
• What happens when the body gets cold?

  Shivering generates heat and restricts blood flow

  
• What happens when the body gets too hot?

  Body sweats and increases blood flow to skin
• What are the methods of cooling down the body?

  • Radiation: without contact
  • Conduction: direct contact
  • Evaporation: loss of heat through water
  • Convection: moving air or liquid
• What is the ideal body temperature for cellular reactions?

  37°C
• What happens if body temperature regulation fails?

  Can lead to heat exhaustion or hypothermia

  
• What is heat exhaustion?

  Inability of the body to cool itself
• What is hypothermia?

  Body temperature drops too low
• What are symptoms of heat exhaustion?

  Dizziness, headaches, and heat rash
• What are symptoms of hypothermia?

  Shivering, slurred speech, and cramps
• What happens if body temperature drops to 29°C?

  Loss of consciousness
• What happens if body temperature drops to 26°C?

  Death
• What is the role of homeostasis in the body?

  • Maintains balance of internal environment
  • Involves self-regulation of internal conditions
  • Requires endocrine and nervous systems
  • Utilises feedback loops for regulation
• What is negative feedback regulation?

  Opposes change to maintain balance
• What is an example of negative feedback regulation?

  Body temperature regulation

  
• What is an example of positive feedback regulation?

  Increasing uterine contractions in childbirth
• How does the body maintain balance in temperature?

  Through negative feedback systems

  
• What is the role of the hypothalamus in thermoregulation?

  Acts as a thermostat with a set point

  
• What questions should be asked about homeostasis in organ systems?

  • What is regulated?
  • Why is it needed?
  • How is it achieved?
  • What are the components?
  • What are the limitations?