Principles of physiology Flashcards
What is physiology?
the study of the function of living things
- describes how processes occur
-mechanism of action
Define a cell?
a basic unit of life
Define Tissue?
groups of cells with similar specialisation
What are the 4 types of tissue and function?
Epithelial - absorption, protection, secretion
Connective - structural support
Muscle - movement, support
Nervous - communication, coordination, control
Recall the 10 body systems?
-nervous
-immune
-reproductive
-circulatory
-respiratory
-musculoskeletal
-integumentary = skin
-urinary
-endocrine
-digestive
Define homeostasis?
maintenance of a stable internal environment
In the foundation of physiology, cells make up body systems and functions contribute to homeostasis
Define pathophysiology?
abnormal functioning of the body associated with disease
Define Intrinsic?
means within/ local, inherent in an organ
e.g. exercising a skeletal muscle - vasodilation of blood vessels
Define Extrinsic?
means outside of/ systemic initiated outside an organ to alter its activity
e.g. blood pressure - NS acts on heart and blood vessels
Explain Negative Feedback?
- detects a change away from set point
- initiates mechanisms to correct situations
- shuts itself off
What’s the purpose of Negative Feedback?
A change in controlled variables triggers a response to oppose it
-> maintains a level of a specific range
Explain Positive Feedback?
- rare within the body - opposes homeostasis
- control variable continues to move in the direction of the initial change
-reinforce the change in the same direction > away from the set point
What is the first law of thermodynamics?
- energy can neither be created or destroyed
- energy input = output
What’s external work and give an example
-> energy expended by skeletal muscles
skeletal muscle activity - shivering, posture
What’s internal work and give an example
-> all other forms of biological energy expenditure
energy - expending activities required to sustain life - pumping blood
What’s metabolic Rate (MR)
-> rate at which energy expended by the body per unit of time
- bodies expenditure eventually appears as heat
- rate of heat production /hr (Kcal/hr)
What are the factors that influence MR
- muscular activity
- shivering
- food intake
- anxiety
- fasting
- fever
- hormones - catecholamines, thyroid
What is Basal Metabolic Rate (BMR)
-> index of metabolism under standardised conditions
-> minimal waking rate of internal energy expenditure
What are standardised BMR conditions?
- awake
- relaxed and rested (>30min)
- supine
- warm (20-25)
- fasting (8hr-12hr)
What factors influence BMR?
- Age (increases in children, decreases with age)
- Gender (increases in males)
- Genetic determinants
- Body weight (increase with obesity)
- Body surface area (taller people it’s higher)
- Environmental temp
- Sleep (decreases 10-15%)
- Hormones -thyroid, catecholamines
