T14 - HOW CAN AN ORGANISM SURVIVE WITHOUT CONSTANTLY FEEDING?

Question 1

homeostasis 1

Answer 1

ability of living systems to maintain a steady state - optimal normal conditions with a constant internal environment

Question 2

homeostasis 2

Answer 2

negative feedback maintains this range whcih is very important for enzymes so they have the correct ph temp for process to occur
- works by detecting changes caused by stimuli and then respondingh

Question 3

how does the body do this

Answer 3

uses:
- nervous system
- endocrine sysyem

as forms of communication

Question 4

insulin

Answer 4

hormone that converts glucose to glycogen
lowering the glucose levels in blood when they are too high

Question 5

glucagon

Answer 5

hormone that converts stored glycogen to glucose to increase the BGC when it is too low

Question 6

when BGC are too high

Answer 6

1. this increase is detected and insulin is secreted by beta cells in pancreas into blood
2. insulin increases the uptake of glucose and rate of respiration in cells, as well are converting glucose to glycogen in the liver for storage
3. this lowers the BGC back to normal ranges

Question 7

when BGC are too low

Answer 7

1. detected and alpha cells secrete glucagon into blood
2. glucagon promotes break down of glycogen in liver to release glucose back into blood
3. BGC rises back to normal ranges

Question 8

negative feedback

Answer 8

maintains body parameters in the normal range, centred around a set point

Question 9

positive feedback

Answer 9

once there is a stimulus, this is amplified and goes away from the starting state
- eg. platelets being activated

Question 10

diabetes

Answer 10

When BGC are too high and cannot be controlled
- type 1
- type 2

Question 11

without diabetes…

Answer 11

insulin will bind to insulin receptors and that triggers glucose transports in cell membrane to open so glucose can enter and be removed from blood, lowering BGC

Question 12

in type 1 diabetes…

Answer 12

insulin is not produced by beta cells, so no insulin to bind to receptors, therefore glucose transporters are not opened so no glucose can enter and no decrease in BGC, remaining high

Question 13

type 1 occurs ..

Answer 13

in childhood due to an autoimmune disease
- regulated by insulin injections and monitorting

Question 14

in type 2 diabetes …

Answer 14

insulin still produced but the insulin receptors are unresponsive so no glucose uptake so BGC remains high

Question 15

type 2 occurs…

Answer 15

in adult hood due to obesity and diet
most common form of diabetes
regulated by diet and exercise

Question 16

because glucose cannot enter cells…

Answer 16

fat becomes main substrate for cellular respiration

as such high BGC, glucose remains in urine so can test for diabetes that way

Question 17

appeptite regulation

Answer 17

these are controlled by homeostatic regulation mechanisms

Question 18

Ghrelin

Answer 18

secreted by stomach walls to target the satiety centre to trigger hunger before a meal

Question 19

insulin and PYY

Answer 19

secreted by small intestine after meals to supress hunger

Question 20

leptin

Answer 20

hormone produced by fat tissue to suppress hunger and therefore regulates levels of fat

Question 21

regulator

Answer 21

an animal that uses homeostasis to moderate internal changes when faced with external flucations
e.g. - if temp in external increases, temp internally stays constant and is moderates

Question 22

conformer

Answer 22

an animal that allows its internal conditions to change in accordance with external conditions
e.g. if temp in water increases, body temp increases