Organisms Respond to Change - Blood Glucose

Question 1

define homeostasis

Answer 1

maintenance of a constant internal environment within a living organism

Question 2

what is maintained in homeostasis?

Answer 2

blood pH

core termperature

blood glucose concentration

water potential of blood

Question 3

why is it important to regulate blood pH?

Answer 3

so enzymes can work at optimum activity

maintaining the shape of proteins

Question 4

why is it important to regulate the water potential of blood?

Answer 4

so body cells don’t shrink or burst due to osmosis

Question 5

why is it important to regulate blood glucose concentration?

Answer 5

to regulate water potential

provide a steady source of energy for respiration

Question 6

why is it important to maintain a core temperature?

Answer 6

for optimum enzyne activity

Question 7

which systems carry out homeostasis?

Answer 7

nervous system

endocrine system

Question 8

what is the optimum point?

Answer 8

point at which the system operates best

Question 9

what is a stimulus?

Answer 9

deviation from the optimum

Question 10

what is a feedback mechanism?

Answer 10

mechanism where a receptor responds to a stimulus created by a change to the system from the effector

Question 11

what is negative feedback?

Answer 11

change in conditions are reversed and returned to a set point to maintain optimum conditions

Question 12

what is positive feedback?

Answer 12

change detected is further increased away from optimum conditions

Question 13

what are the 3 ways hormones interact with cells?

Answer 13

affects permeability of cell membranes

causes release of second messenger inside cells

diffuse into cell and promote/inhibit transcription

Question 14

what detects changes in blood glucose?

Answer 14

cells in the islets of langerhans

Question 15

why is it important to regulate blood glucose?

Answer 15

hypo/hyperglycaemia can kill cells due to affecting water potential

glucose required for respiration

Question 16

what detects low blood glucose?

Answer 16

alpha cells in islets of langerhans

Question 17

what detects high blood glucose?

Answer 17

beta cells in islets of langerhans

Question 18

what happens when high blood glucose is detected?

Answer 18

beta cells secrete insulin

insulin binds to receptors on surface of muscle and liver cells

in liver - glycogenesis

in muscle - increases uptake of glucose into the cells

excess converted into fat

Question 19

what happens when low blood glucose is detected?

Answer 19

alpha cells secrete glucagon

glucagon binds to receptors on muscle + liver cells

in liver - glycogenolysis and gluconeogenesis

in muscle - gluconeogenesis

Question 20

what is glycogenesis?

Answer 20

synthesis of glycogen from glucose

Question 21

what is glycogenolysis?

Answer 21

breakdown of glycogen into glucose

Question 22

what is gluconeogenesis?

Answer 22

synthesis of glucose from lipids and amino acids

Question 23

what factors can affect blood glucose concentration?

Answer 23

glucose directly gained through diet

glycogenolysis/gluconeogenesis

Question 24

what are the types of diabetes?

Answer 24

type 1 - insulin dependent

type 2 - insulin independent

Question 25

what is type 1 diabetes?

Answer 25

where the body is unable to produce insulin

usually develops in childhood

Question 26

what causes type 1 diabetes?

Answer 26

usually due to an autoummine response

immune system attacks beta cells of islets of langerhans

Question 27

what are the signs of type 1 diabetes?

Answer 27

frequent urination

glucose in urine

weight loss

tiredness

Question 28

what is type 2 diabetes?

Answer 28

insulin receptors lose receptiveness or are lost completely

usually older people, but increased in obese adolescents

Question 29

what are the signs of type 2 diabetes?

Answer 29

same as type 1 but less severe

Question 30

how is type 2 diabetes treated?

Answer 30

injections of insulin that are matched to glucose intake

regulation of glucose intake

Question 31

how is type 1 diabetes treated?

Answer 31

insulin injections matched to glucose intake

Question 32

why can’t insulin be ingested in treatment of diabetes?

Answer 32

it would be digested

Question 33

describe the second messenger model

Answer 33

adrenaline binds to transmembrane protein receptor on liver cell

protein changes shape and activates adenyl cyclase to form cyclic AMP from ATP

cAMP binds to protein kinase, changing its shape and activating it

protein kinase catalyses conversion of glycogen to glucose which leaves the cell