12. (a) What is meant by the term excretion? (b) Mention one method of excretion in flowering plants - Leaving Cert Biology - Question 12 - 2011

One method of excretion in flowering plants is through diffusion or leaf fall, where waste products can be eliminated through stomata or lenticels.

To draw the diagram, ensure you clearly label the cortex, medulla, and pelvis. Indicate the areas of reabsorption by marking the proximal convoluted tubule and the loop of Henle.

Reabsorption takes place primarily in the proximal convoluted tubule and the loop of Henle, where essential substances and water are reabsorbed back into the bloodstream.

The blood vessel that supplies blood to a kidney is the renal artery.

The renal artery arises from the aorta, which is the main artery in the body that carries oxygenated blood from the heart.

The kidneys are located in the abdominal cavity, specifically in the retroperitoneal space.

Urea is one substance, other than water, that is commonly excreted in the urine.

A feature of the kidney that indicates it is an exocrine gland is that it has ducts that lead to the renal pelvis, allowing for the excretion of urine.

1 = Bowman's capsule; 2 = glomerulus; 3 = afferent arteriole; 4 = efferent arteriole; 5 = proximal convoluted tubule; 6 = distal convoluted tubule.

Filtration occurs at the glomerulus, where blood pressure forces water, ions, and small molecules through the porous walls of the glomerular capsule, allowing them to enter the nephron and form filtrate.

The hormone associated with changing the permeability of the nephron, particularly in the collecting duct, is the anti-diuretic hormone (ADH), also known as vasopressin.

The presence of protein in the urine suggests a malfunction in the filtration process, as protein molecules are typically too large to pass through the glomerular filter.

No, the presence of protein in urine is not normal and may indicate a condition such as proteinuria, which can result from kidney disease or other health issues.

The presence of protein in urine signifies that the filtration barrier in the kidneys is compromised. Normally, only small molecules such as glucose and salts are filtered into the urine, while larger proteins remain in the bloodstream.