Biology - Coordination and response: HORMONES

Spring term 2025 Biology

How is an increase in blood glucose controlled?

1. The increase is detected by the pancreas

2. pancreas produces insulin

3. travels through the blood to the liver where the liver converts glucose to glycogen where it is stored

How is a decrease in blood glucose controlled?

1. The decrease is detected by the pancreas

2. pancreas produces glucagon that travels through the blood to the liver

3. triggers the liver to break down glycogen into glucose

How is glycogen different from glucagon?

Glucagon is the hormone that is produced in the liver that stimulates the breakdown of glycogen. Glycogen is the body’s method of storage for glucose

What are exocrine glands

Glands that secrete products down a duct (e.g salivary and tear glands)

What are endocrine glands

Glands that secrete products directly into the bloodstream (e.g pancreas)

Where is adrenaline produced?

In the adrenal glands (kidney)

What does adrenaline do and the effects of it?

prepares your body for movement - increases heartrate, dilates airways, raises blood glucose levels, diverts blood to muscles instead of the digestive system

Where is insulin produced?

beta cells in the pancreas

What does insulin do?

Controls blood glucose levels, lovers blood glucose by helping cells reabsorb glucose

What does testosterone do?

Controls/stimulates secondary sexual characteristics, deepens voice, produces sperm, increases muscle mass

Where is testosterone produced?

In the testes

Where is progesterone produced?

In the ovaries

What does progesterone do?

Maintains uterus lining, preventing further ovulation during pregnancy

Where is oestrogen produced?

in the ovaries

What does oestrogen do?

Stimulates/controls female secondary sexual characteristics, regulates the menstrual cycle, growth of uterus lining, breast development and ovulation

What does Benedicts test for?

Glucose

Results of benedicts tests?

Blue = none, green = traces, orange = moderate, brick red = large amount

What does Buriets test for?

Peptide bonds/protein

Results of Buriets tests?

blue = negative, purple = positive

Where is urea excreted?

in the kidneys when proteins are broken down into amino acids and the nitrogen is removed through the process of deamination

What is the kidney’s main role?

To remove toxic urea from the body and osmoregulation of water potential levels

What is the renal vein?

The renal vein carries filtered and deoxygenated blood away from the kidney into the heart

What is the renal artery?

Supply of oxygenated blood to the kidneys for filtration

What is ultrafiltration?

When blood is filtered before the key substances are reabsorbed back into the blood again

What is the afferent arteriole?

small blood vessels that carry oxygenated blood from the renal artery to the glomerulus for filtration.

What is the pressure of the afferent arterioles?

It is wider and higher in pressure for more efficient filtration

What is the efferent arteriole?

small blood vessel that carries blood away from the glomerulus/away from the nephron.

What is the pressure of the efferent arteriole?

It is narrower and lower in pressure which resists blood flow, so more blood builds up in the glomerulus so pressure is raised for filtration

Where does selective reabsorption occur?

in the proximal convoluted tubule

What is selective reabsorption?

Reabsorbs glucose into the bloodstream through active transport which requires energy/ATP

What is the Loop of Henle?

Salts are reabsorbed through diffusion and water is reabsorbed through osmosis or from the collecting duct, depending on how much water the body needs

Name the process of the kidney tubule

1. Glomerulus - pushes blood under high pressure so SMALL molecules are forced out of blood into nephron

2. Bowman’s capsule - filters out SMALL molecules (urea, salts, glucose) and prevents large molecules from entering/leaving the blood

3. Proximal convoluted tubule - reabsorption of all glucose and selective reabsorption of salts and water back into the blood

4. Loop of Henle - further water reabsorption, so excess water is not lost in urine

5. Collecting duct - urine is collected, which can be further concentrated and is passed to the bladder via the ureter

How is blood water content regulated?

Through osmoregulation, where changes in the blood water content is detected by the hypothalamus

Process when normal blood water content incerases

1. Increase is detected by the hypothalamus

2. less ADH is produced

3. travels in the blood to the collecting duct

4. collecting duct becomes less permeable to water

5. less water reabsorbed by collecting duct

6. higher volume of dilute urine is produced so more water is excreted

Process when normal blood water content decreases

1. Decrease is detected by hypothalamus

2. more ADH is produced

3. travels in the blood to the collecting duct

4. collecting duct becomes more permeable

5. more water reabsorbed by collecting duct

6. smaller volume of concentrated urine is produced so more water is retained