Biol5 12

Front 1

What is meant by homoestasis?

Back 1

The maintenance of a constant internal environment

Front 2

What is the normal range for pH, and blood glucose?

Back 2

7.3-7.45

4-11 mmol/L

Front 3

Why is it important to maintain a constant blood-glucose conc?

Back 3

Change water potential and cause cells to shrink or expand or burst;

constant source of respiration

Front 4

What is the difference between endotherms and ectotherms?

Back 4

Endotherms maintain constant bodytemp (regluate body temp through behavioural and physiological means)

Ectotherms only regulate body temp using behavioural means + obtain heat from external sources

Front 5

What monitors the temperature of the blood?

Back 5

The hypothalamus

Front 6

What behavioural mechanisms do ectotherms use to regulate body temp?

Back 6

expose themselves to the sun;

taking shelter (overheating);

press against ground;

colour variation

Front 7

How are mammals and birds adapted to living in cold environments?

Back 7

low surface area to volume ratio

Fat

thick hair

small extremities

Front 8

How do endotherms increase body temp?

Back 8

vasoconstriction;

shivering (involuntary rhythmic contractions, heat distributed by blood);

raising of hair (hair erector muscles contract, layer of air to insulate, less lost by convection/conduction);

release of adrenaline to increase metabolic rate (adrenaline, more resp_;

(decrease in sweating);

(shelter/sun basking/huddling

Front 9

Describe how vasoconstriction increases body temp

Back 9

Diameter of arterioles near surface of skin decrease (muscle contracts)

Less blood to skin surface, less heat lost by radiation (more blood through shunt vssel

Front 10

Describe how endotherms decrease their body temp

Back 10

Vasodilation (shunt closes, arterioles dilate)

Sweating (from sudorific gland)

Decrease BMR

Hairs lowered

Front 11

Where is insulin produced?

Back 11

beta cells in islets of Langerhans

Front 12

Where is glucagon produced?

Back 12

alpha cells of islets of Langerhans

Front 13

What are the symptoms of hyperglyceamia and why?

Back 13

Thirst and urinating, lower water potential of blood

Front 14

What are the symptoms of hypoglycaemia and why?

Back 14

Dizziness and tiredness, brain cells can only respire glucose

Front 15

Why is the control of blood glucose?

Back 15

CNS not involved, levels monitored by alpha and beta cells

Front 16

What is meant by glycogenesis?

Back 16

The production of glycogen by polymerisation of glucose

Front 17

What is meant by glycogenlysis?

Back 17

Breakdown of glycogen into glucose

Front 18

What is meant by gluconeogenesis?

Back 18

Production of glucose from non-carb sources (amino aicds, lipid)

Front 19

What is the role of adrenaline in controlling blood glucose?

Back 19

Increase blood glucose levels

Activates enzyme to breakdown glycogen

Inhibits enzyme to form glycogen

Front 20

What happens if blood glucose levels are too high?

Back 20

beta cells detect rise and secrete insulin

insulin binds to glycoprotein receptors

more glucose absorbed (protein channels change shape/more in membrane)

increase respiratory rate

increase conversion into glycogen and fat

increase glycogenesis

by activating enzyme pathways

Front 21

What happens if blood glucose is too low?

Back 21

alpha cells detect change

glucagon secreted

cause glycogenolysis

cause gluconeogenesis

decrease resp

Front 22

What are the advantages of endothermy?

Back 22

enzymes at optimum;

metabolic reactions quickly;

independent of environment

Front 23

What are the advantages of ectothermy?

Back 23

Don't need constant food/can endure without food

need less food

Front 24

What are the 2 types of diabetes mellitus and their differences?

Back 24

Type 1; insulin dependent, cant produce insulin due to autoimmune response - hyperglycaemia

thirst, glucose in urine, ketosis, weight loss

Type 2; not enough insulin , glycoprotein receptors less receptive

Front 25

How are Type 1 diabetes and Type 2 managed?

Back 25

Type 1: injections (oral would be digested)Blood levels monitored, balanced diet and exerciseType 2: regulate carb intake and exercise and weight loss

Front 26

Describe the stages in a self-regulating system?

Back 26

set point

receptor

controller

effector

feedback loop

Front 27

Why is it important that control mechanisms are co-ordinated?

Back 27

Ensure action of effectors work harmonously - sweating and vasodilation

ensure information from all receptors used to provide greater control

Front 28

How are changes in temp detected by endotherms?

Back 28

Thermoreceptors (cold and warm) in sking

Receptors in hypothalamus monitors temp of blood

send impulses by autonomic nervous system

Front 29

What is hte main source of blood glucose?

Back 29

Carbohydrates in food

Front 30

Why does temp decrease more slowly in humid conditions?

Back 30

Smaller water potential gradient

evaporation of sweat slower

Front 31

Describe the difference between positive and negative feedback?

Back 31

Negative keeps conditions constant

positive brings about further change

Front 32

Describe how hormones could have diff effects on males and females?

Back 32

Diff membrane receptro proteins

diff pathway of second messengers

diff enzymes activated

Front 33

Describe the mode of action of steroid hormones

Back 33

Diffuse through phosphlipid bilayer

bind to nuclear receptors

transcription factors activated/inhibitor molecule released + passes into nucleus

genes transcribed

Front 34

Describe the mode of action of glucagon?

Back 34

Glucagon acts by second messenger

binds to specific glycoprotein receptors in membrane of LIVER cells

the hormone-receptor complex activates adenyl cyclase which converts ATP into cyclic AMP

cyclic AMP is second messenger which activates enzyme pathways

to convert glycogen into glucose

Front 35

Describe the hormone-producing cells in the pancreas

Back 35

larger alpha cells - glucagon

smaller beta cells - insulin

Front 36

Why do glucose levels fluctuate?

Back 36

Dont eat continously and eat diff things

used at diff rates due to physical and mental activity

Front 37

How can you tell if someone is diabetic?

Back 37

Can't control glucose within normal limits

Front 38

Which cells have insulin receptors?

Back 38

Most aside from red blood cells

Front 39

Which cells have glycogen receptors?

Back 39

Liver cels

Front 40

Where is adrenaline produced?

Back 40

Adrenal glands above the kdineys

Front 41

What is the role of adrenaline?

Back 41

Activates enzymes that convert glycogen into glucose

Front 42

Why does insluin have to be injected?

Back 42

It is a protein that would otherwise be digested