Lecture 1 Terms/Questions/Outline

Question 1

What is physiology?

Answer 1

comes from the Greek word PHUSIOLOGIA

- means knowledge of nature

Question 2

Definition of physiology

Answer 2

is the study of the normal functioning of a LIVING ORGANISM and its component parts

Question 3

Definition of “living”, or “alive” (minimum of 4 conditions)

Answer 3

1. Made of one or more cells (cell is basic unit of life)
2. Regulate its internal environment
3. Respond to stimuli (“sensory systems” to detect stimuli)
4. Capable of reproduction (self-replication)

Question 4

Levels of organization of life sciences, where physiology fits in (Fig 1.1)

Answer 4

Chemistry
- atoms
- molecules
Molecular Biology
- cells
Cell Biology
- tissues
Physiology
- organs
- organ systems
- organisms (behaviour)
- populations of one species
Ecology
- ecosystem of different species
- biosphere (behaviour)

Question 5

Why is physiology important?

Answer 5

1. leads to treatment of diseases in humans & other organisms (pathophysiology)
2. helps us understand how organisms cope with environmental stressors
3. foundation of understanding of the philosophical question “What is life?”
4. required credit for some academic programs, requirement for MCAT, PCAT…

Question 6

What is homeostasis?/Definition

Answer 6

the ability to maintain a RELATIVELY constant internal environment even when the external environment is variable

• in the 1800’s Claude Bernard called this “la fixite du MILLIEU INTERIEUR”
• word was coined by Walter Canon, 1929

internal environmental parameters of an animal must be regulated to within certain levels to support life
- temp, pH, salinity (concentration of ions & other solutes), oxygen, carbon dioxide, nutrients

Question 7

What is a control system?

Answer 7

monitors & adjusts regulated variables (internal temp, pH, salt balance, etc)

Question 8

Internal vs external environments

Answer 8

homeostasis does NOT mean “equilibrium”
- we observe a dynamic steady state inside vs outside cells

homeostasis does NOT mean “never changing”
- internal parameters change often, in response to environmental challenges

Question 9

A general scheme of homeostasis

Answer 9

• organisms in homeostasis (external change or internal change)
• internal change results in loss of homeostasis
• organism attempts to compensate (compensation fails or compensation succeeds)
• illness or disease or wellness

Question 10

What is a control system?

Answer 10

• homeostasis requires control systems

- monitors & adjusts regulated variables (internal temp, pH, salt balance, etc)