Lecture 11 Flashcards
What bodily functions does physiology affect?
Metabolism, homeostasis, growth, reproduction.
How does physics affect physiology?
Larger animals experience greater gravitational forces and have a smaller S.A:Volume ratio.
What are some effects of large size?
Slower movement, digestion, respiration and water and heat loss to the environment.
What is allometry?
The study of differential growth. How physiological processes scale with body size.
Define ontogenic allometry.
During the growth of a single organism.
E.g. Isometric scaling.
Define static allometry.
Between different individuals at the same developmental stage within a species.
E.g. differences in sexes.
Define evolutionary allometry.
Between different individuals at the same developmental stage within a species.
What is the equation used to describe allometric relationships.
Size of body part = initial growth index times measure of whole body size to the power of the scaling exponent (proportional change in size of body part per unit measure of whole body size).
If the scaling exponent is zero?
Size of body part is unrelated to the whole body size.
If the scaling exponent is 1?
Size of body part grows at the same rate of the whole body (Isometric scaling).
What if the scaling exponent is less than 1?
Size of the body part increases slowly relative to body size (Negative allometry).
E.g. Human head.
What if the scaling exponent is greater than 1?
Size of the body part increases faster relative to the body size (positive allometry).
E.g. Human legs.
What is the issue with isometry?
Cubed law: Limb area increases disproportionately to weight on it, Volume increases more rapidly than S.A.
Therefore larger organisms need more robust skeletons relative to their body size.
What is metabolic rate?
Amount of energy per unit used in an organism, the speed at which chemical reactions take place in the body.
How does body mass affect metabollic rate?
There is a positive correlation.
