Lecture 1: Principles of Physiology Flashcards
study the structure and function of the
various parts of animals and plants; how these
parts work together to allow organisms to
perform their normal behaviours and respond
to their environment.
Physiologist
Unifying themes of physiological processes
• obey physical and chemicals laws
• regulated to maintain internal conditions and
trigger an appropriate response
• physiological state of an animal is part of its
phenotype, which arises as the product of
the genetic make-up, or genotype, and its
interaction with the environment.
Subdisciplines of Physiology
- Comparative Physiology
- Environmental Physiology
- Evolutionary Physiology
- Developmental Physiology
- Cell Physiology
species are compared in order to
discern physiological and
environmental patterns
Comparative Physiology
examines organisms in the
context of the environments they
inhabit (evolutionary adaptations)
Environmental Physiology
techniques of evolutionary biology and
systematics are used to understand the
evolution of organisms from physiological
viewpoint, focusing on physiological markers
rather than anatomic markers
Evolutionary Physiology
how physiological processes unfold
during the course of organism development
from embryo through larva or fetus to
adulthood
Developmental Physiology
vital information on the
physiology of the cells
themselves, which can be used to
understand the physiological
responses of tissues, organs, and
organ systems
Cell Physiology
Central Themes in Physiology
- Structure/Function Relationships
- Adaptation, Acclimatization, and Acclimation
- Homeostasis
- Function is based on structure
- Form fits function at all the levels of life, from
molecules to organisms
Structure/Function Relationships
structure-function relationship is clear in the _____
aerodynamic efficiency of birds
Physiology of an organism is very well
matched to the environment it occupies,
thereby ensuring its survival
Adaptation, Acclimatization, and
Acclimation
evolution through natural selection
leading to an organism whose
physiology, anatomy, and behavior are
matched to the demands of its
environment
Adaptation
- a physiological, biochemical, or anatomic change within an individual animal during its
life that results from an animal’s chronic
exposure in its native habitat to new,
naturally occurring environmental condition - animal in migrate to high altitude
- Reversible
Acclimatization
- refers to the same process as
acclimatization when the changes are
induced experimentally in the laboratory or
in the wild by an investigator - animal placed in hypobaric chamber
- Reversible
Acclimation
The tendency of organisms to regulate and maintain
relative internal stability
Homeostasis
The milieu interieur
◦“Constancy of the internal
environment is the condition of
free life”
Clauded Bernard
the ability of animals to survive in
often stressful and varying
environments directly reflects their
ability to maintain a stable internal
environment.
Claude Bernard
extended notion of internal
consistency to the organization and
function of cells, tissues and organs
Walter B. Cannon
1929 – Nobel
Price
“Homeostasis” – tendency towards
internal stability
- The evolution of homeostasis and the physiological
systems that maintain it were essential factors in
allowing animals to venture from relatively
“physiologically friendly” environments and invade
habitats more hostile to life processes.
Walter B. Cannon
antagonistic
hormones that help maintain glucose
homeostasis
Insulin and glucagon
clusters of endocrine cells of pancreas
Islets of Langerhans
Alpha cells
produce glucagon
Beta cells
produce insulin
Hypoinsulinism
Diabetes mellitus
- hereditary factors and obesity play a role in its
development
-high blood sugar levels – sugar excreted in the
urine
- symptoms: excessive urination and excessive
thirst - if severe: fat substitutes for glucose as major
fuel source ® production of acidic metabolites
® life threatening lowering of blood pH
Hypoinsulinism
Type I diabetes mellitus
insulin-dependent
diabetes
- autoimmune disorder
- usually appears in childhood
- treatment: insulin injections
Type I diabetes mellitus (insulin-dependent diabetes)
Type II diabetes mellitus
non-insulin-dependent diabetes
- usually due to target cells having a decreased
responsiveness to insulin - usually occurs after age 40 – risk increases
with age - accounts for over 90% of diabetes cases
Type II diabetes mellitus (non-insulin-dependent
diabetes)
animals can survive large fluctuations in
external osmolarity
Euryhaline
Adaptation of some aquatic
invertebrates in
temporary ponds
lose almost all their
body water and
survive in a dormant
state
anhydrobiosis
2 ways an organism can respond if confronted with changes in its environment
Conformity or Regulation
environmental challenges induce
internal body changes that simply parallel the
external conditions (unable to maintain
homeostasis)
conformers
osmoconformers
shark, starfish
Oxyconformers
annelid worms
biochemical, physiological, behavioral,
and other mechanisms to regulate their internal
environment over a broad range of external
environmental changes (maintain homeostasis)
regulators
maintain ion
concentrations of
body fluids above
environmental
levels when placed
in dilute water vice
versa
Osmoregulators
Ion movements away from the fish
Water movement towards the fish
Freshwater Fish
Marine Fish
direction of ion is towards the fish, direction of water is away
based largely on controlled
movement of solutes between internal fluids and the
external environment
Osmoregulation
