Physiology

Question 1

6 themes of physiology

Answer 1

Structure/function relationships
Homeostasis
Cell to Cell Communication
Crossing the membrane
Compartments
Steady State vs Equilibrium

Question 2

Hometostasis

Answer 2

internal limits within the body

Question 3

Negative Feedback

Answer 3

maintain homeostasis

1. Sensory receptor: detects when a parameter deviates from its set point
2. Afferent pathway: relies information from the sensor to the integration center; usually neural
3. Integration/control center: where the amount of deviation is processed, sends signal to return parameter towards set point
   In some cases, the sensory receptor and integration center are in the same cell/tissue and an afferent pathway is not needed
4. Efferent pathway: the exit path from the integration center to the effector; may be neural or hormonal
5. Effector: the specific physiological response that returns the parameter back towards its set point

Question 4

Positive feedback

Answer 4

moves away from set point

o Positive feedback systems are relatively rare in physiological systems; all positive feedback systems require some type of “external” stop mechanism

Question 5

Positive feedback examples

Answer 5

uterine contractions in birth, action potentials, blood clot cascade

Question 6

Canon’s postulates

Answer 6

1. The nervous system works to preserve conditions that are compatible with normal organismal function
2. Many systems maintain a tonic level of activity basal level of activity at all times that can then be modulated either up or down, ex blood vessels maintain some shape but can contract/dilate
3. Systems that are not under tonic control are usually under antagonistic control, either by hormones or the nervous system
   Example: Increase in parasympathetic ACh- decrease HR, increase in sympathetic Nor- increase HR
4. The same chemical signal can have different effects in different tissues in the body depending on the type of receptor present

Question 7

Extracellular Fluid (ECF)

Answer 7

refers to all the fluid inside the body but outside of the cells, divided into interstitial fluid compartment and vascular compartment (plasma)

Question 8

intracellular fluid

Answer 8

includes blood cells