homeostasis

Question 1

what is homeostasis

Answer 1

Homeostasis: the process by which an organism maintains a stable internal environment, despite fluctuating external environment conditions

Question 2

2 reasons WHY MUST ORGANISMS KEEP CONSISTENT INTERNAL CONDITIONS (temperature, pH, water levels)

Answer 2

• Maintain their enzymes functioning at their optimal conditions
• Cells survive best in an isotonic (same concentration) solution-> needs to be maintained so that cells don’t shrink or expand and can efficiently carry out their individual function

Question 3

2 stages of homeostasis

Answer 3

HOMEOSTASIS STAGES

1. Body detects changes from the stable state (body at optimal conditions). Th nerves 
2. Body counteracts changes

Question 4

NEGATIVE FEEDBACK LOOPS define and explain

Answer 4

• Show how the body detects, processes, and counteracts changes in the external environment eg. temp glucose
• When some variable triggers a counteracting response

Question 5

explain the glucose negative feedback loop

Answer 5

to lower glucose:
- high glucose levels are detected by insulin-secreting pancreas cells -> liver takes up the glucose and stores it as glycogen-> blood glucose levels decline to a set period-> stimulus for insulin release decreases and homeostasis returns

to increase glucose
- low glucose levels are detected by glucagon-releasing pancreas cells-> liver breaks down glycogen stores and releases glucose into the blood-> blood glucose levels rise to a set point-> stimulus for glucagon release diminishes and homeostasis returns

Question 6

explain temperature homeostasis

Answer 6

to lower temperature:
-> temperature increase is detected by thermo-receptor sensors in the skin-> message is sent to hypothalamus by nervous system-> message is sent to effectors, causing body to sweat and blood vessels to dilate

• to increase temperature
• > decrease in temp detected by thermo-receptor sensors in the skin-> message is sent to hypothalamus by nervous system-> message is sent to effectors, causing body to shiver and blood vessels to constrict