5.1.4 Hormonal communication

Question 1

What is Thermoregulation?

Answer 1

The control and maintenance of body temperature

Question 2

What is Osmoregulation?

Answer 2

The control of water potential of bodily fluids

Question 3

What are the 3 homeostatic mechanisms that are used to keep the conditions within the body near to constant?

Answer 3

• Thermoregulation
• Osmoregulation
• Control of blood glucose concentration

Question 4

What is the endocrine system?

Answer 4

A chemical messenger system, where chemicals are secreted from glands into ducts or the bloodstream

Question 5

What is a hormone?

Answer 5

A hormone is a chemical messenger produced by an endocrine gland and carried by the blood

Question 6

What are the differences between Exocrine and Endocrine glands?

Answer 6

Endocrine Exocrine

• secretes into bloodstream -secretes into ducts
• has no ducts -has ducts
• releases hormones -releases saliva/enzymes/sweat

Question 7

What are some key features of hormones

Answer 7

-They are small molecules that can either be polypeptide/proteins/amino-acid
derivatives OR steroid based hormones
-released from ductless exocrine glands straight into the blood plasma
-affect only target cells with the receptor for that specific hormone
-they have a short lifespan (hydrolised by enzymes or excreted via urine) to turn off
the effects quickly

Question 8

how does a protein based hormone act on a cell?

Answer 8

It attaches to a receptor on the outside of the cell, releasing a second messenger on the inside

Question 9

How does a steroid based hormone act on a target cell?

Answer 9

A steroid based hormone can pass through the plasma membrane and will attach to an intracellular receptor and make direct changes to the DNA

Question 10

Give some examples of important protein based hormones and how the act on a cell

Answer 10

• Adrenaline
• Insulin
• Glucagon

These attach to receptors on the outside of a cell and cause a secondary messenger molecule to be released on the inside of a cell

Question 11

Give some examples of steroid hormones and how they act on a cell

Answer 11

• Testosterone
• Oestrogen

Passes straight through plasma membrane and binds to an intracellular receptor, having an effect on the DNA in the nucleus

Question 12

where are the Adrenal glands situated and what is their structure?

Answer 12

The adrenal glands are situated above the kidneys, they are separated into the cortex (outer) and medulla (inner)

releases adrenaline

Question 13

what hormones are secreted by the Cortex of the Medulla of the Adrenal glands?

Answer 13

• GLUCOCORTICOIDS
  
  • Cortisol: regulates glucose and protein metabolism as well as blood pressure
  • Corticosterone: supresses inflammatory response

MINERALOCORTICOIDS
-Aldosterone: maintains salt conc to regulate blood pressure

ANDROGENS
-sex hormones with little effect

Question 14

what hormones are released by the medulla of the adrenal glands

Answer 14

PROTEIN HORMONES (controlled by stress/fight or flight)
-Adrenaline: increases heart rate and blood glucose concentration
-noradrenaline: dilates pupils and allows vasoconstriction of blood vessels to non
essential organs

Question 15

what are the 3 layers of the cortex of the Adrenal glands?

Answer 15

• Zona glomerulosa
• Zona Fasciculata
• Zona Reticularis

Question 16

what is the Zona Glomerulosa?

Answer 16

• the outer layer of the cortex of the kidney. secretes mineralocorticoids
  e. g aldosterone

Question 17

What is the function of the Zona fasciculata?

Answer 17

Secretes glucocorticoids and is the middle layer of the cortex of the adrenal glands

Question 18

What is the function of the Zona Reticularis?

Answer 18

It is the inner layer of the cortex of the adrenal glands and secretes cortisol and precursor molecules for sex hormones (androgens)

Question 19

How does Adrenaline work on on the liver specifically?

Answer 19

Adrenaline in the bloodstream binds to a receptor on the target tissue, this will causes a secondary messenger to be produced (via the activation of adenyl cyclase with ATP) which is [cyclic AMP] which causes glycogenolysis in the liver converting glycogen to glucose

Question 20

what are the effects of adrenaline on the Sino atrial node?

Answer 20

increased heart rate

Question 21

what are the effects of adrenaline on ventricular cardiac muscle tissue

Answer 21

increased stroke volume

Question 22

what are the effects of adrenaline on the muscles in the iris?

Answer 22

Dilates the pupils, the radial muscles contract and the circular muscles relax

Question 23

what are the effects of adrenaline on the cerebrum of the brain

Answer 23

elevates mental awareness

Question 24

what are the effects of adrenaline on the erector pili muscles of the skin

Answer 24

erects body hair (may scare predators/be more intimidating)

Question 25

what are the effects of adrenaline on the smooth muscle on the gut wall?

Answer 25

inhibits peristalsis (the constriction of the intestines to move food along the gut)

Question 26

what are the effects of adrenaline on the smooth muscle of arterioles

Answer 26

Means that less blood goes to the capillaries in the skin and gut and so it vasoconstricts

Question 27

what is the histology (labelling parts of pancreas) of a pancreas under the microscope?

https://docs.google.com/document/d/1EQ2MKbjG-CcL6_XuwW4lnk8J4cHRp4GcVVxxBR_MvR4/edit?usp=sharing

try labelling this diagram ^^^^^^^^

Answer 27

answers to diagram:

https://docs.google.com/document/d/1ciPKV5ahjH8xf31HpQaPuVNnLPxOR-Cni2v6KKN9h5I/edit?usp=sharing

Question 28

what is the function of the pancreas?

Answer 28

An organ just below the stomach that has both endocrine and exocrine glands which mostly secretes pancreatic juice containing enzymes AND has special cells that produce hormones Glucagon and Insulin

Question 29

what are the islets of Langerhan?

Answer 29

these are areas of cells in the pancreas that contains both alpha and beta cells
a-cells produce Glucagon
b-cells produce insulin

Question 30

what are the exocrine function of the pancreas?

Answer 30

-contains pancreatic juice filed with enzymes
-juice contains sodium hydrogen carbonate, making it alkaline and able to
neutralise stomach acid
-

Question 31

what are the endocrine functions of the pancreas?

Answer 31

-α-cells produce and secrete glucagon, a hormone that raises blood glucose levels
via stimulating glycogenolysis and lipolysis
-β-cells produce insulin, a hormone that lowers blood glucose levels via stimulating glycogenesis

Insulin and glucagon are antagonistic to each-other as they both have opposite effects on the body

Question 32

what happens if blood glucose levels go too high (hyperglycaemia)?

Answer 32

β-cells will detect the change in blood glucose levels and decrease the levels of glucagon being produced while increasing insulin levels, this inhibits glycogenolysis and gluconeogenesis and promotes glycogenesis and lipogenesis in tissues with insulin receptors e.g. the liver or skeletal muscle cells

Question 33

how does insulin affect cells?

Answer 33

• increases permeability of cell plasma membranes to glucose via increasing the no of glucose channels
• increases aerobic respiration so more glucose is used and promotes glycogenesis and lipogenesis

Question 34

what happens if blood glucose levels fall (Hypoglycaemia)?

Answer 34

α-cells detect change in blood glucose levels in blood and secrete glucagon. Main target cells like hepatocytes in the liver have the specific glucagon receptor, resulting in gluconeogenesis and glycogenolysis to happen releasing glucose into the blood

Question 35

what are the effects of glucagon on the body?

Answer 35

causes glycogen to be converted into glucose via glycogenolysis, usually at the hepatocytes in the liver as they have glucagon receptors

also promotes the use of fatty acids in respiration

Question 36

what are the 2 main types of hormones?

Answer 36

steroid hormones

peptide hormones

Question 37

where in the adrenal gland is adrenaline produced?

Answer 37

adrenal medulla

Question 38

How does adrenaline act on a target tissue?

Answer 38

• Adrenaline is released form the adrenal medulla into the bloodstream
• it binds to a complementary receptor on the outside of the target tissue, being the primary messenger
• this activates the enzyme adenyl cyclase, tht converts ATP into cyclic-AMP (cAMP), which is the secondary messenger
• cAMP starts a cascade of enzyme reactions within the cell

Question 39

what is the structure of the adrenal gland

Answer 39

https://docs.google.com/document/d/1dIu7uRJXOVJy92lyX94EOUha6nME9_2be5sBSPCnEFY/edit?usp=sharing