5.1.4 - Hormonal Communication✅

Question 1

Define endocrine glands?

Answer 1

Glands that release hormones directly into the blood - hormones produced in cells and secreted directly into blood capillaries

Question 2

Define exocrine glands?

Answer 2

Glands that secrete chemicals into ducts which carry them to another place

Question 3

Define hormones?

Answer 3

Molecules released by endocrine glands and acts as chemical messengers - carried in the blood

Question 4

Define protein and peptide hormones?

Answer 4

Hormones made up of amino acids (eg adrenaline, insulin and glucagon) they cannot pass through the phospholipid bilayer

Question 5

Define steroid hormones?

Answer 5

Hormones that are lipid-based (eg sex hormones) they pass through membrane and have direct impact on DNA

• binding to receptor proteins to form hormone-receptor complex (HRC)
• HRC acts as transcription factor which facilitates or inhibits specific gene

Eg oestrogen

Question 6

define target cells and target tissue?

Answer 6

Cells that posses specific receptors that a specific hormone will bind to in order to have an effect on the cell

• tissues which contains a number of target cells grouped together are target tissue

Question 7

Explain how non-steroid hormones work?

Answer 7

Bind to specific receptors on cell surface membrane - triggers a cascade reaction mediated by ‘second messengers’

• complementary shape
• eg adrenaline

Question 8

Compare the hormonal system with the nervous system - give 6?

Answer 8

1) communication is by chemicals (hormones) instead of nerve impulses

2) transmission by blood system instead of by neruons

3) transmission relatively slow - where as transmission is very rapid

4) hormones travel to all parts of body (only target organs respond) nerve impulses travel to specific part of body

5) response is widespread where as response is localised

6) effect may be permanent and irreversible where as effect is temporary and reversible

Question 9

What is the structure of the adrenal glands - what are the 2 parts and what is their function?

Answer 9

Two small glands located on top of each kidney - consist of 2 parts surrounded by capsule

• adrenal cortex (outer region) produces hormones like cortisol and aldosterone (vital for life)
• adrenal medial (inner region of gland) produces non-essential hormones - like adrenaline

Question 10

What are the 3 main hormones produced by the adrenal cortex?

Answer 10

• glucocorticoids
• mineralocorticoids
• androgens

production of these hormones controlled by hormones released from pituitary gland

Question 11

What are the hormones glucocorticoids produced by the adrenal cortex?

Answer 11

• include cortisol
• help regulate metabolism - controls how body converts fats, proteins and carbs to energy
• involved in regulation of BP and cardiovascular function

Question 12

What are the hormones mineralocoricoids produced by the adrenal cortex?

Answer 12

• main one produced is aldosterone - controls BP by maintaining balance between salt and water conc in blood

Question 13

What are the hormones androgen produced by the adrenal cortex?

Answer 13

• small amounts of M and F sex hormones released
• impact relatively small compared to that of sex organs (testes/ovaries)

Question 14

Outline the structure of the pancreas?

Answer 14

• made up of exocrine glandular tissue - acini - responsible for producing digestive enzymes in pancreatic juice
• enzymes in juice secrete into ducts which lead to pancreatic duct where its released in duodenum
• islets of langerhans produces insulin and glucagon

Question 15

What are the 2 functions of the pancreas?

Answer 15

• exocrine gland - to produce enzymes and release then via a duct in the duodenum
• endocrine gland - to produce hormones and release them into blood §

Question 16

How are hormones from adrenal medulla released - what w hormones does it release?

Answer 16

Released due to sympathetic nervous system stimulation when body is stressed (secretes adrenaline and noradrenaline)

• adrenaline - increases heart rate increases blood flow to muscles and brain (raises blood glucose conc levels)
• noradrenaline - produces effects like increased heart rate, widened pupils and widening of air passages in lungs - increases BP

Question 17

What 3 hormones does the pancreas produce?

Answer 17

• amylase - breaks starch down into simple sugars
• protease - breaks proteins down into amino acids (eg trypsin)
• lipases - breaks lipids down into fatty acids + glycerol

Question 18

What is the function of the islets of langerhans?

Answer 18

Smalls regions of endocrine tissue called islets of langerhans - the cells are responsible for producing insulin and glucagon

• secrete hormones directly into blood stream

Question 19

Outline the structure of the islets of langerhans?

Answer 19

Are different cells
- alpha cells procure and secrete glucagon (larger cells and more of them)
- beta cells produce and secrete insulin

difficult to distinguish between using standard staining techniques

Question 20

Explain why blood glucose concentration can increase - give 3 ways and explain them?

Answer 20

• diet - carbohydrates broken down to release glucose which is absorbed by blood stream
• glycogenolysis - glucose stored in liver and muscle cells is broken down into glucose
• glyconeogenesis - production of glucose from non-carbohydrate sources (liver able to make glucose form lipids (glycerol) and amino acids

Question 21

Define glycogenolysis and glyconegenesis as methods of increasing glucose concentration?

Answer 21

• glycogenolysis - glucose stored in liver and muscle cells is broken down into glucose
• glyconeogenesis - production of glucose from non-carbohydrate sources (liver able to make glucose form lipids (glycerol) and amino acids

Question 22

Explain glycogenesis and respiration as methods of decreasing glucose concentration?

Answer 22

• Respiration - glucose used by cells to release energy - increases with exercise due to more muscle contractions
• Glycogenesis - production of glycogen - excess glucose taken and converted into glycogen and stored in liver

Question 23

Pancreas Finnish notes

Question 24

Explain how insulin causes an increase in the uptake of glucose - outline the steps

Answer 24

• insulin binds to a receptor in the plasma membrane
• receptors signals to the cell and makes vesicles carrying glucose transporter proteins merge with the plasma membrane
• glucose can now diffuse into the cell down conc gradient

GLUT 4 transporters