Topic 1: Intro to Physiology

Question 1

What is physiology?

Answer 1

• study of how the body functions

Question 2

What is homeostasis?

Answer 2

• the ability to maintain relatively stable conditions in the internal environment (despite changes in external environment)

Question 3

Cells can only survive within a narrow range of conditions, so body conditions must be maintained within physiological limits. What conditions must be controlled? (6)

Answer 3

1. pH
2. temperature
3. Blood gases (O2 and CO2)
4. Blood pressure (b.p.)
5. ICF and ECF volumes
6. etc.

Question 4

What function together to maintain homeostasis?

Answer 4

organ system functions

Question 5

What is disease?

Answer 5

• failure to maintain homeostasis

Question 6

Which systems control all other systems? In other words, which systems are control centers? (2)

Answer 6

nervous and/or endocrine system

Question 7

What is the function of the control center systems? (2)

Answer 7

1. maintain homeostasis
2. Permit departures from homeostasis in a CONTROLLED manner
   ex. pregnancy, growth, sudden fright

Question 8

What is homeostasis regulation?

Answer 8

• change in internal environment must be detected or anticipated

Question 9

What occurs in homeostasis regulation?

Answer 9

NS and/or endocrine system respond, altering system(s) responsible for that condition

Question 10

What are the 2 types of NS/endocrine responses in homeostasis regulation?

Answer 10

1. Anticipatory responses
2. Feedback mechanisms

Question 11

What is an example of an anticipatory response? What occurs here?

Answer 11

• increased respiratory rate at start of exercise
• proprioceptors (NS sensory receptors) signal movement before a change in internal conditions (gases in blood)

Question 12

Anticipatory responses can be ____ or behavioral

Answer 12

• learned
  ex. putting on a coat

Question 13

What are feedback mechanisms?

Answer 13

• mechanisms that respond to change in system

Question 14

What are the three basic components of feedback mechanisms?

Answer 14

• receptors
• control areas
• effectors

Question 15

What is the function of a receptor?

Answer 15

• monitors variables/conditions

Question 16

What is the function of control centers?

Answer 16

• integrate info and maintain setpoints by signalling to effectors

Question 17

What are setpoints?

Answer 17

• range of values of a variable (ex. body temp) that do not bring about a response (ie. normal range)

Question 18

What is the function of an effector?

Answer 18

• create a response that will alter the variable/condition

Question 19

Describe the general feedback mechanism pathway (3)

Answer 19

1. variable/condition is monitored by receptors
2. info (input) is fed back to control area (NS/endocrine gland)
3. Controls the effector (output)

Question 20

Which type of feedback is the most common homeostatic control mechanism?

Answer 20

negative

Question 21

What occurs to the result of “output” for negative feedback? (2)

Answer 21

• variable moves back toward the set point
• in opposite (negative) direction to the change that triggered the response (input)
  ex. body temp

Question 22

What occurs when you increase body temp?

Answer 22

• set point is 36-37.8 C
• result is core blood goes to skin surface, and sweat evaporates
• heat loss and decrease body temp (opposite direction of input)

Question 23

What occurs when you decrease body temp?

Answer 23

• decrease temp causes shivering, then increases body temperature
• set point can change (ie. fever)

Question 24

Is positive feedback homeostatic?

Answer 24

no
- less common feedback

Question 25

What occurs in positive feedback? (2)

Answer 25

• output intensifies the input
• variable moves further away from set point

Question 26

What is an example of positive feedback?

Answer 26

childbirth - labour

Question 27

Childbirth positive feedback diagram

Answer 27

add later after lecture

Question 28

Diagram of increased temperature negative feedback

Answer 28