chapter 14 - hormonal comunication

Question 1

what is the endocrine system

Answer 1

made up of endocrine glands to secrete chemicals called hormones

Question 2

where are hormones secreted to

Answer 2

bloodstream

Question 3

what does pituitary gland do

Answer 3

produces growth hormone, ADH

Question 4

what does thyroid gland do

Answer 4

produces thyroxine which controls rate of metabolism

Question 5

what does adrenal gland do

Answer 5

produces adrenaline

Question 6

what does pancreas do

Answer 6

produces insulin which converts excess glucose to glycogen in liver and glucagon which converts glycogen back to liver

Question 7

what are target cells

Answer 7

cells in target organs containing receptors for hormone

Question 8

what are steroid hormones

Answer 8

lipid soluble
pass through lipid component of cell membrane and bind to steroid hormone receptors
hormone receptor complex acts as transcription factor which facilitates or inhibits transcription of a specific gene, e.g oestrogen

Question 9

what are non steroid hormones

Answer 9

hydrophilic so cannot pass directly through cell membrane
bind to specific receptors on cell surface membrane of target cell
triggers cascade reaction e.g adrenaline

Question 10

what is difference between hormonal and nervous system

Answer 10

hormonal system uses hormones whereas nervous system used nerve impulses
hormonal system transmits by blood system whereas nervous system is transmited by neurones
hormonal system is slow but long laster whereas nervous system is fast but short-lived

Question 11

what is adrenal gland

Answer 11

2 glands located on top of kidney
adrenal cortex
adrenal medulla

Question 12

what does adrenal cortex do

Answer 12

outer region of glands that produces hormones vital to life such as cortisol and aldosterone

Question 13

what does adrenal medulla do

Answer 13

inner regions of glands that produce non-essential hormones such as adrenaline

Question 14

what hormones do adrenal cortex produce

Answer 14

glucocorticoids
mineralocorticoids
androgens

Question 15

what do glucocorticoids do

Answer 15

-regulate metabolism by controlling how body converts fats,proteins and carbohydrates to energy.
Regulate blood pressure
corticosterone which works with cortisol to regulate immune response
controlled by hypothalamus

Question 16

what do mineralocorticoids do

Answer 16

e.g aldesterone
controls blood pressure by maintaining balance between salt and water concentrations in blood and body fluids
controlled by signals triggers by kidney

Question 17

what do androgens do

Answer 17

release male and female sex hormones

Question 18

what do adrenal medulla produce

Answer 18

adrenaline
noradrenaline

Question 19

what does adrenaline do

Answer 19

increases heart rate sending blood quickly to muscles and brain
raises blood glucose concentration by converting glycogen to glucose in the liver

Question 20

what does noradrenaline do

Answer 20

works with adrenaline in response to stress increasing heart rate, widening of pupils, widening of air passages in lungs, and narrowing of blood vessels

Question 21

where is pancreas found

Answer 21

upper abdomen behind stomach

Question 22

what is function of pancrease

Answer 22

exocrine gland - produce enzymes released via duct into duodenum
endocrine gland - produces hormones and release them into blood

Question 23

what 3 enzymes are produced in exocrine gland in pancreas

Answer 23

amylase - breaks down starch into simple sugars e.g pancreatic amylase
proteases - breaks down proteins into amino acids e.g trypsin
lipases- breaks down lipids into fatty acids and glycerol e.g pancreatic lipase

Question 24

what hormone is produced in endocrine gland in pancreas

Answer 24

insulin and glucagon to control blood glucose concentration

Question 25

what is islets of langerhans

Answer 25

endocrine tissue within exocrine tissue producing insulin and glucagon secreted directly into bloodstream

Question 26

what does islet of langerhans look under micrscope

Answer 26

large spherical clusters, lightly stained

Question 27

what cells are in islet of langerhans

Answer 27

alpha cells - produce and secret glucagon
beta cells - produce and secrete insulin

Question 28

what colour stain are alpha and beta cells

Answer 28

alpha cells are stained blue
beta cells are stained pink

Question 29

what increases blood glucose concentration

Answer 29

diet-eating carbohydrate rich food
glycogenolysis - glycogen broken down to glucose
gluconeogenesis - glucose produced from non carbohydrate sources such as glycerol and amino acids

Question 30

what decreases blood glucose concentration

Answer 30

respiration
glycogenesis - production of glycogen

Question 31

how does insulin increase absorption of glucose from cells

Answer 31

binds to glycoprotein recpetors causing change in tertiary structure of glucose protein channels causing them to open and allow glucose into cells

Question 32

how does insulin lower blood glucose concentration

Answer 32

increase rate of absorption of glucose by cells
increase respiratory rate of cells
increase rate of glycogenesis
increase rate of glucose to fat conversion
inhibit release of glucagon from alpha cells in islet of langerhans

Question 33

which cells have glucagon receptors

Answer 33

liver cells
fat cells

Question 34

how does glucagon increase blood concentration

Answer 34

increase rate of glycogenolysis
increase gluconeogenesis
reduce amount of glucose absorbed by liver cells

Question 35

how is insulin secreted

Answer 35

1) at normal blood glucose concentrations, potassium ion channels in plasma membrane of b-cells are open so potassium diffuse out. Inside cell has -70MV
2) when blood glucose concentration rises, glucose enters cell by glucose transporter
3) glucose is metabolised inside mitochondria forming ATP
4) ATP binds to ATP sensitive potassium channels closing them so potassium ions no longer diffuse out causing depolarisation, -30Mv
5) depolaroisaton causes voltage gated calcium ion channels to open so calcium ions enter cell and cause secretory vesicles to release insulin by exocytosis

Question 36

what is type 1 diabetes

Answer 36

unable to product insulin as b cells in islet of langerhans do not work
may be caused by autoimmune response

Question 37

what is type 2 diabetes

Answer 37

cannot effectively use insulin because b cells dont produce enough insulin or body doenst respond to it becuase insulin glycoprotein dont work
caused by overweight, physical inactivity

Question 38

how is type 1 diabetes controlled

Answer 38

insulin injections

Question 39

how is type 2 diabetes controlled

Answer 39

regulate intake of carbohydrates , increase exercise

Question 40

what is hypoglycaemia

Answer 40

very low blood glucose concentration

Question 41

how is stem cells used in diabetes

Answer 41

replace faulty b-cells

Question 42

advantages of stem cells

Answer 42

donor availability is not an issue as stem cells could produce unlimited sources
reduced likelihood of rejection
no longer need insulin rejection

Question 43

how does adrenaline work

Answer 43

1) adrenaline is hydrophilic so cant pass cell membrane therefore binds to receptor activating enzyme adenylyl cyclase
2) Adenylyl cyclase converts ATP to cyclic AMP which acts as second messenger and activates other enzymes ( protein kinases) to convert glycogen to glucagon

Question 44

how does adrenal medulla control heart rate

Answer 44

has 2 centres linked to SAN in heart by motor neurones
one centre increases heart rate by sending impulses through sympathetic nervous system transmitted by accelerator nerve
one centre decreases heart rate by sending impulses through parasympathetic nervous system transmitted by vagus nerve

Question 45

what receptors affect heart rate

Answer 45

baroreceptors - detect changes in blood pressure. Found in aorta, vena cava and carotid artery
chemoreceptors - detect change in level of chemicals in blood such as co2. Located in aorta, carotid artery and medulla