Lecture 1 and 2 Flashcards
What is physiology?
The study of the function of living things (how processes occur)
Define tissue
Groups of cells with similar specialization
Name the 4 types of tissue
Epithelial
Connective
Muscle
Nervous
What are the three functions of epithelial tissue?
Protection, secretion, absorption
What is the function of connective tissue?
Structural support
What is the function of muscle tissue?
Movement
What are three functions of nervous tissue?
Communication, coordination, control
Name the body systems.
Nervous Immune Reproductive Circulatory Respiratory Muscular Skeletal Integumentary Urinary Endocrine Digestive
What two components make up the extracellular fluid?
Plasma (fluid portion of blood) Interstital fluid (surrounds and bathes the cells)
Define homeostasis
Maintenance of a stable internal environment
Which body systems contribute to homeostasis?
All body systems
Homeostatic control mechianisms may be _____ (local) or ______ (systemic)
Intrinsic
Extrinsic
What is an intrinsic control system?
A control mechanism that is inherent in an organ
Give an example of an intrinsic control system
Exercising skeletal muscle- vasodilation of blood vessels
Give an example of an extrinsic control system
Blood pressure: nervous system acts on heart and blood vessels
What is an extrinsic control system?
A control system initiated outside an organ to alter its activity
What mediates extrinsic control systems?
Nervous and endocrine systems
In negative feedback systems, changes in controlled variables triggers what?
A response to oppose that change, in opposite direction of initial change
What is the result of negative feedback systems?
Maintain level of a specific variable within a given range/set point
Negative feedback systems can do what?
Shut itself off
A sensor detects deviation in a controlled variable and informs an….
Integrator
What do integrators do in negative feedback systems?
Send instructions to effectors which then bring about compensatory responses
Why is positive feedback rare within the body?
It opposes homeostasis
What is positive feedback?
Control variable continues to move in the same direction of initial change, away from set point
Give an example of positive feedback.
Release of oxytocin during end stages of pregnancy
During parturition, what happens when the fetus changes position?
Pressure on the cervix causes stimulation of stretch-sensitive cells
What happens when stretch-sensitive cells in the cervix are stimulated?
They send nerve impulses to the brain which releases oxytocin
What does oxytocin cause?
Uterus contraction, increasing pressure on cervix
What is the first law of thermodynamics?
Energy can neither be created or destroyed
What are two types of energy output?
External work and internal work
What is external work?
Energy expended by skeletal muscles to move external objects
What is internal work?
Other forms of biological energy expenditure such as skeletal muscle activity and energy expending activities required to sustain life
What uses the most ATP in the body?
The heart
How much ATP does the heart use a day?
6KG, 20-30x its own weight
How many times does the heart beat per day?
100,000 beats
How many tons of blood does the heart pump per day?
10 tons
What is metabolic substrate utilization?
Fuel from food
Define metabolic rate.
Rate at which energy expended by the body per unit of time
How does most of the body’s energy expenditure appear?
As heart
How is metabolic rate expressed?
Rate of heart production per hour (Kcal/hr)
What factors influence metabolic rate?
Muscular activity, food intake, shivering, anxiety, fasting/malnutrition, fever, hormones
What hormones influence metabolic rate?
Catecholamines, growth hormone, thyroid hormone
Define basal metabolic rate (BMR).
Index of metabolism under standardised conditions, minimal waking rate of internal energy expenditure
What are the standardised basal conditions?
Awake, relaxed and rested (>30 mins), supine, warm (20-25 degrees), fasting (8-12 hr)
What is the average BMR?
20-25 kcal/kg body weight/day
How is BMR measured?
Direct or indirect calorimetry
What is indirect calorimetry?
Practical, less constly, O2 uptake per unit of time is measured
Why is O2 uptake measured to measure BMR?
Direct relationship between O2 consumed and heat produced
Food+O2–> CO2 + H2O + energy (mostly heat)
How does age effect BMR?
Higher BMR in children, age decreases BMR
How does gender effect BMR?
BMR lower in females
How does body weight effect BMR?
Higher BMR in obesity
How does sleep effect BMR?
Can decrease BMR by 10-15%
What other factors influence BMR?
Genetic determinants, lean body mass, body surface area. environmental temp, hormones
