homeostasis, exercise and adaptation (control of internal environment)

Question 1

list behavioural responses

Answer 1

• drink water regularly from bottle
• eating when not hungry
• holding breath
• wearing hat in sunshine

Question 2

list physiological responses

Answer 2

• increased urination after drinking
• increase body temp when sick
• increasing HR during exercise

Question 3

what happens when exposed to cold temps

Answer 3

• body keeps higher temps in the core where all the core organs and systems are

Question 4

what is a negative feedback loop?

Answer 4

• signal results in a return to a set condition
• acts to reduce an effect
• when change occurs it opposes this change and restores controlled variable back to usual value

Question 5

what is a positive feedback loop

Answer 5

• acts to increase effect - when change occurs in system change becomes amplified

Question 6

what is a feedforward control loop

Answer 6

• results in physiological responses in anticipation of a change in a variable

Question 7

define homeostasis

Answer 7

• fundamental principle of body function
• physiological mechanisms operate within narrow range of values so needs to be balanced between different variables
• variable not indecent of other variables
• maintenance of a constant and normal internal environment

Question 8

define steady state

Answer 8

• physiological variable unchanging, but not necessarily normal
• balance between demands placed on body and body’s response to those demands
• HR, temp, arterial BP
  reaching a plateau it is at steady state

Question 9

what are biological control systems of the body?

Answer 9

• series of interconnected components maintaining a physical or chemical parameter at near constant value

Question 10

examples of components of biological control systems

Answer 10

1. sensor or receptor (detects changes in variable)
2. control centre (assesses input and initiates response)
3. effector (changes internal env. back to normal)

Question 11

what do intracellular control systems do?

Answer 11

• protein breakdown and synthesis
• energy production
• maintain stored nutrients

Question 12

what do organ systems do?

Answer 12

• pulmonary and circulatory systems
• replenish O2 and remove Co2

Question 13

what is gain (sensitivity of the response)?

Answer 13

• degree to which a control system maintains homeostasis
• pulmonary and cardiovascular systems have large gains more capable of maintaining homeostasis

Question 14

examples of homeostatic control

Answer 14

1. regulation of body temp
2. regulation of blood glucose
3. regulation of cellular homeostasis
4. stress proteins

Question 15

what is a major test for homeostatic control?

Answer 15

• exercise
• it disrupts homeostasis by changing PH,PO2 . temp and pCO2 in cells
• if steady state sent maintained it causes fatigue and cessation

Question 16

define adaptation

Answer 16

• change in structure and function of cell or organ system
• improved ability to maintain homeostasis
• many adaptive changes occur within cells

Question 17

define acclimation

Answer 17

• adaptation to environmental stresses (heat or hypoxic stress) means improved function of existing homeostatic system

Question 18

what is exercise-induced hormesis

Answer 18

• process which a low-moderate dose of potentially harm stress results in a beneficial adaptive response on cell or organ system
• change in structure and function of cells or organ system
• improved ability to maintain homeostasis

Question 19

5 cells signalling pathways promoting cellular adaptation

Answer 19

1. intracrine signalling
2. juxtracrine signalling
3. autocrine signalling
4. paracrine signalling
5. endocrine signalling