Hormonal communication 5.4

Question 1

describe what is the endocrine system

Answer 1

made up of endocrine glands and hormones and made up of non-steroid and steroid hormones

Question 2

what are hormones

Answer 2

released into blood directly and travel around the whole body and bind to specific receptors on target cells to produce a response

Question 3

what are non-steroid hormones

Answer 3

proteins like insulin that cant pass through the cell membrane so bind to receptors on the cell surface of target cells

Question 4

what are steroid hormones

Answer 4

lipids that can pass through cell membrane of target cells
produced by adrenal cortex

Question 5

describe the secretion and detection of hormones

Answer 5

hormone is the first messenger and binds to specific receptors on cell surface

membrane of target cells

activates adenyl cyclase an enzyme

cAMP activates a cascade of enzyme controlled reactions

Question 6

what are the two parts of the adrenal gland

Answer 6

adrenal cortex

adrenal medulla

Question 7

describe the adrenal cortex

Answer 7

secretes steroid hormones - like cortisol when stressed

stimulates the breakdown of proteins into glucose - inc the amount of energy for brain bcs of stressful situation

inc blood volume and pressure - inc the uptake of Na+ and H2O by kidneys

suppress immune system

Question 8

describe the adrenal medulla

Answer 8

secretes adrenaline- when stressed

inc. heart rate and breathing rate

breaks down glycogen into glucose

vasoconstriction so blood is diverted from brain and muscles

Question 9

describe the pancreas

Answer 9

made of Islets of Langerhans

B-cells: secrete insulin

a-cell: secrete glucagon

Question 10

what are acinar cells

Answer 10

produce digestive enzymes into the small intestine

Question 11

what does sodium hydrogencarbonate do

Answer 11

neutralise stomach acid in the pancreas

Question 12

when does blood glucose conc. increase

Answer 12

when eating food containing carbohydrates

Question 13

when does blood glucose conc. fall

Answer 13

after exercise , more glucose used in respiration during exercise to release energy

Question 14

when glucose conc. is too high what happens

Answer 14

insulin binds to specific receptors on liver and muscle cells

inc. permeability –> cells take up more glucose

glycogenesis - glucose to glycogen

glycogen stored as an energy source

inc. rate of respiration

Question 15

when glucose conc. is too low what happens

Answer 15

glucagon binds to receptors on liver cells only

glycogenolysis - glycogen to glucose

gluconeogenesis - glycerol and AA to glucose

decreases rate of respiration

Question 16

how is insulin regulated

Answer 16

B-cells contain insulin in vesicles

when blood glucose conc. is high, more glucose enters the B-cells by facilitated diffusion

more ATP made, triggers K+ channels in plasma membrane to close

inside is more -ve than outside

depolarisation triggers Ca2+ channels to open, Ca2+ diffuse into B-cell

causes vesicles to fuse with B-cell plasma membrane releasing insulin via exocytosis

Question 17

what is Type 1 diabetes and who can get it

Answer 17

autoimmune disease where body cells attack B-cells
insulin not produced

young adults or children
higher risk with family history

Question 18

with type 1 diabetes what happens after you eat

Answer 18

blood glucose conc. stays high

Question 19

with type 1 diabetes what happens to the kidneys

Answer 19

cant reabsorb all glucose
excreted as urine

Question 20

symptoms of type 1 diabetes

Answer 20

thirsty

frequent urination

weight loss

Question 21

treatments for type 1 diabetes

Answer 21

insulin injections regularly

islet cells transplant

insulin pump

Question 22

what is type 2 diabetes and who can get it

Answer 22

B-cells dont produce enough insulin or body cells dont respond to insulin because insulin receptors dont work properly
blood glucose conc. is higher than normal

obesity or from african/asian ethnic groups or family history

Question 23

symptoms of type 2 diabetes

Answer 23

hypoglycemia - low blood sugar

hyperglycemia - high blood sugar

weight gain

frequent thirst and urination

Question 24

treatments for type 2 diabetes

Answer 24

low sugar and salt diet

exercise

medication like metformin

Question 25

what other ways can you obtain insulin from to cure diabetes

Answer 25

genetically modified bacteria or stem cells

Question 26

benefits of using GM bacteria to cure diabetes

Answer 26

cheaper
make large amounts
make human insulin instead of animals which for vegans/vegetarians or religious ppl they prefer this

Question 27

why is it beneficial that GM bacteria can produce human insulin

Answer 27

less likely to be rejected rather than animal insulin

vegetarians and vegans prefer using human insulin

religious reasons

Question 28

what are the benefits of using stem cells to cure diabetes

Answer 28

can grow into B-cells then implanted into pancreas of a type 1 diabetic so they can make insulin like normal

Question 29

describe the structure of the adrenal glands

Answer 29

1. adrenal medulla :
   . secretes adrenaline
2. adrenal cortex:
   . zona glomerulosa: Secretes aldosterone

.zona fasciculata and zona reticularis: Secrete glucocorticoids e.g cortisol

Question 30

what does aldosterone help regulate

Answer 30

helps the kidneys regulate blood pressure