The role of the kidney Dissecting the kidney

Aim and Objectives We are learning to……… Understand the function of the kidney What I’m looking for……….. You must be able to recall and label the parts of the kidney You should be able to explain the functions of the kidney You could be able to explain the kidney’s role in homeostasis

Where are the kidneys? Humans have two kidneys. They are bean-shaped organs, approximately 11.5 cm long, situated in the abdominal cavity, just below the ribcage, one on either side of the spine. They are embedded in fatty tissue for protection.

A closer look at the kidney This is a human kidney. You have 2, but can survive with only 1.

The function of the kidney The kidneys are essentially blood filters. Blood is brought to the kidneys to be filtered by the renal artery. After filtering, the blood is taken away again by the renal vein. The kidneys have four functions: Regulation of blood water levels Reabsorption of useful substances into the blood Adjustment of the levels of salts and ions in the blood Excretion of urea and other metabolic wastes Write this in the front of your books

Excretion of Urea Urea is a waste product from the breakdown of proteins. If more protein is eaten than is needed the body will have an excess of amino acids, which cannot be stored by the body. The excess amino acids are broken down by the liver, with urea as a by-product. Urea is toxic, and must be excreted from the body, so it is passed into the blood to be filtered out by the kidneys. It is then passed to the bladder for storage as urine, before leaving the body. Write this in the front of your books

Diagram of the Kidney A longitudinal section through a kidney shows three distinct areas: an outer region called the cortex a middle region called the medulla, and an inner region leading to the ureter, called the pelvis.

Dissecting a Kidney: Instructions Carefully laterally bisect your kidney using the scalpel Using the pins and card, identify and label 1. the Ureter 2. Medula (renal pyramids) 3. renal Cortex 4. Renal Artery 5. Renal Vein 6. Pelvis 7. Nephron (only if you are very lucky!!!) Write these in the back of your books

Dissecting a Kidney: What to look for

Dissecting a Kidney: Safety Scalpels are sharp! Wear gloves and goggles at all times. You are NOT a butcher – take care, small cuts only. Label your kidney sections Pins are sharp! Do not dispose of kidney down the sinks, use the bin! Wash desk tops down with disinfectant when you have finished.

And Finally…… Homework; 1. Revise for module test 2. Visit http://www.bbc.co.uk/schools/gcsebitesize/biology/humansasorganisms/6homeostasisrev5.shtml. work your way through the section on kidneys and try the higher tier test.