Homeostasis Flashcards
What are the 10 different organ systems?
Endocrine, Nervous, Muscoskeletal, Cardiovascular, Respiratiry, Urinary, Digestive (GI), Reproduction, Immune, Integumentary
Dr Urinemic
How is the body’s internal and external environment separated?
By a barrier of epithelial tissue
Describe the exchange between internal/external env of the lungs, GI tract and kidneys
Lungs: Simple diffusion of CO2 and O2
GI tract: Absorbs water, nutrients, secretes acid
Kidneys: Filtration, Reabsorption, Excretion
What is the total body water made up of?
Intracellular + Extracellular fluid
What percentage makes up the ECF?
60%
Of the 60% of ECF, what does it divide into?
Plasma + Interstitual fluid
Give numerical values for TBW, ICF, ECF, Plasma, ISF
TBW = 42L ICF = 28L ECF = 14L Plasma = 3L ISF = 11L
Define homeostasis
Maintanence of constant conditions (temp/vol) of ECF in the internal environment despite changes in external environment
What is the importance of homeostasis?
Consistent internal environment
Body continually faced with disrupting changes
Central organising principle
Describe the similarity between positive/negative feedback
Output of system depends on input
Describe the difference between positive/negative feedback (give example)
Negative - Opposite to initial change eg blood sugar level
Positive - Same as initial change eg childbirth oxytocin levels
Describe the 4 ways heat transfers between the body to external environments
Radiation (no contact)
Conduction
Evaporation
Convection
Describe how radiation transfers heat to the body
Via electromagnetic waves
Describe how conduction transfers heat to the body
Between objects in contact
Describe how evaporation transfer heat to the body
Heat loss from objects via evaporation of water from surface (eg sweat)
Describe how convection transfers heat to the body
Via air/liquid movement
What are the 3 components of the system?
Sensors, Integrating centre, Effectors
Describe the sensors
Thermoreceptors
Central (spinal cord) - Core temp
Peripheral (skin) - Env temp
Describe the integrating centre
Thermoregulatory centre (eg hypothalamus)
Describe the effectors
Sweat glands - Evap heat loss
Blood vessels in skin - Conduct/radiate heat loss
Skeletal muscles - Heat loss via shivers // Raising thickness in skin layer to reduce heat loss
Describe the limitations of the system
Inconsistent - Fluctuations
Fevers - Raises set point
Long exposure to extreme env temp - Body losses regulatory ability
