Homeostasis

Question 1

Homeostasis definition

Answer 1

maintenance of a constant and normal internal environment

Question 2

Homeostatis principles

Answer 2

variables operate within a narrow range

balance between demands on body and body’s response

Question 3

Dynamic constancy

Answer 3

MAP remains constant
due to baroreflex response/kidney function

Question 4

Changes in body core temp during submaximal exercise

Answer 4

reaches a plateau
steady state = variable unchanging

Question 5

Intracellular control systems

Answer 5

protein breakdown and synthesis
energy production
maintenance of stored nutrients

Question 6

Organ systems

Answer 6

pulmonary and circulatory systems
replenish oxygen and remove carbon dioxide

Question 7

Biological control system definition

Answer 7

series of interconnected components that maintain a physical or chemical parameter at a near constant value

Question 8

Sensor/receptor

Answer 8

detects changes in variable

data to control centre

Question 9

Control centre

Answer 9

assess input and initiates response

Question 10

Effector

Answer 10

changes internal environment back to normal

negative feedback –> homeostatis

Question 11

Stimulus

Answer 11

change of internal conditions

Question 12

Cell signaling definition

Answer 12

communication between cells using chemical messengers

coordinates cellular activities

important for maintaining homeostasis

Question 13

5 cell signaling pathways in cells:

Answer 13

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

Question 14

Intracrine signalling

Answer 14

CM inside cell triggers response

Question 15

Juxtracrine signaling

Answer 15

CM passed between 2 connected cells

Question 16

Autocrine signaling

Answer 16

CM acts on that same cell

Question 17

Paracrine signaling

Answer 17

CM act on nearby cells

Question 18

Endocrine signaling

Answer 18

CM (hormones) released into blood (affects cells with specific receptor to the hormone)

Question 19

Negative feedback definition

Answer 19

response reverses the initial disturbance in homeostatsis

reduce effect
back to normal

Question 20

Example - control of CO2 conc in extraceullar fluid

Answer 20

1. increase in extracellular CO2 triggers a receptor
2. sends info to respiratory control centre
3. respiratory muscle activated to increase breathing
4. CO2 conc returns to normal

Question 21

Positive feedback definition

Answer 21

biological response increases the original stimulus

Question 22

Example - childbirth

Answer 22

1. initiation of childbirth stimulates receptors in cervix and sends message to brain to release oxytocin from pituitary gland
2. oxytocin promotes increased uterine contractions

Question 23

Gain (or sensitivity of the response) definition

Answer 23

degree to which control system maintains homeostasis

example - pulmonary and cardiovascular systems
= more capable of maintaining homeostasis

Question 24

Regulation of body temp

Answer 24

thermal receptors send message to brain

response by skin blood vessels and sweat glands regulates temp

Question 25

Exercise disrupts homeostatsis

Answer 25

changes in pH, PO2, PCO2 and temp in cells inability to maintain steady state = fatigue/end exercise

Question 26

Set point

Answer 26

37 degree celsius

Question 27

Adaptation

Answer 27

change in structure and function of cell or organ system = improved ability to maintain homeostasis

Question 28

Acclimation

Answer 28

adaptation to environ stresses (heat) = improved function of existing homeostatic system

Question 29

Hormesis definition

Answer 29

process in which a low-to-moderate dose of potentially harmful stress resuslts in a beneficial adaptive response on the cell or organ system

Question 30

Exercise-induced hormesis

Answer 30

optimal training

Question 31

Positive feedback loop

Answer 31

acts to increase an effect when a change occurs in a system, that change becomes amplified example - menstrual cycle

Question 32

Feedforward loop

Answer 32

results in physiological responses in anticipation of a change in a variable example - increase HR before race

Question 33

Submax exercise

Answer 33

exercise generate heat from working muscles = increase body temp detected by thermoreceptors relayed to hypothalamus increase vasodilation/sweating negative feedback loop = limit increase heat loss/gain = balanced = temp constant = steady state

Question 34

When does HR reach steady state at submax exercise?

Answer 34

5 mins

Question 35

Hormesis applied to exercise

Answer 35

training adaptations initiated after exercise - cessation, recovery, repair = return to baseline/trigger adaptive mechanism load/recovery period suboptimal = overtraining/undertraining