Kidney Structure Lesson NM PDF

Sunday 8 December 2024 The Kidney & Excretion Lesson Objectives: Starter: Know the function of the urinary system, to 1.Name the two main waste products made by include: the human body. o ureter o bladder...

Sunday 8 December 2024 The Kidney & Excretion Lesson Objectives: Starter: Know the function of the urinary system, to 1.Name the two main waste products made by include: the human body. o ureter o bladder 2.Describe how each of these is removed from o renal artery and vein. the body. Understand the structure and function of a Answers: kidney nephron, to include: o glomerulus and its role in ultrafiltration 1.Carbon dioxide and urea. o Bowman’s capsule o proximal convoluted tubule and its role in 2.Carbon dioxide diffuses from the blood into the selective reabsorption of glucose alveoli in the lungs, where it is then exhaled out. Urea diffuses from the blood into the kidneys, where it becomes part of the urine. Urine is then removed by the bladder. Task Green Pens out: Answers:  Filter 180 litres of blood a day, producing 1.5 litres of urine. Homeostatic organs: Regulate blood pressure through maintaining water levels in the blood. Regulate mineral ion levels in the blood by removing excess ions. Remove Urea – a nitrogenous waste product. The Location of the Human Kidneys Humans have two kidneys located at the back of the abdominal cavity. They connected to the bladder via the ureters – a long white tube, carrying urine from the kidneys to the bladder  Why is the kidney needed? Water - cells only function in isotonic solution; required for metabolic reactions Ions - required for cellular processes and osmotic balance Urea - toxic product of amino acid breakdown so could damage cells Urea is made by the breakdown of excess amino acids in the liver. This process is called deamination. Amino acids → ammonia → urea  Vena Aorta cava To the eye the kidney appears a dark red structure on its surface. Kidney The inner appears to be made Ureter Renal up with the cortex, and a inner artery paler medulla. Renal The whitish area, the pelvis, lies vein in the centre of one edge. Bladder Sphincter muscles (2 sets) Urethra Location of the Kidneys  A single nephron (up to 1 000 000 Renal per artery kidney) Renal Cortex vein Medulla Pelvis Pyramids Urete r Cortex - contains glomeruli and convoluted tubules - ultrafiltration and some reabsorption takes place Renal artery and vein - brings blood to Pelvis – collects urine kidney and takes it away Medulla - contains loops of Henle - most Ureter - takes urine reabsorption takes place from kidney to bladder Label the diagram Answers: Mark with green pen http://www.youtube.com/watch?v=6RezlDy65w o&NR=1 © Pearson Education Ltd 2009 This document may have been altered from the original The Kidneys and Urine Production Kidneys produce urine in a two-stage process 1. Ultrafiltration - small molecules and ions are filtered out of the blood into the renal capsule - this process is called ultrafiltration because it filters out molecules which are much smaller than the particles separated by filters such as filter paper - ultrafiltration takes place under pressure 2. Reabsorption - molecules and ions which are required by the body are taken back from the nephron 3. Collection - Waste products are collected and form urine.  Blood Supply to the kidneys The kidneys are supplied with blood from the renal artery branching off the aorta Blood is taken away via the renal vein connecting to the inferior vena cava https://www.youtube.com/watch?v=oOz3c kmAfqk&pbjreload=101 Each kidney contains about 1-2 million microscopic units called nephrons. Each nephron contains the following structures: Renal/ Bowman’s capsule First (proximal) convoluted tubule Loop of Henle Second (distal) convoluted tubule Collecting duct  The Nephron The kidney is made of thousand of tiny subunits called nephrons A nephron begins in the cortex and the loop of Henle moved down into the medulla https://www.youtube.com/watch?v=tx9hYFeEd1E  Glomerulu Distal s convoluted Proximal tubule convoluted tubule Bowman’s capsule Collecting duct. Loop of Henlé. To the tip of the pyrami Diagram of the nephron and associated blood capillaries © Pearson Education Ltd 2009 This document may have been altered from the original  Task: Attempt the card sort! Pl don’t stick until it is checked by me Nephron region Function How are the tissues adapted? Bowman’s Selective reabsorption The descending limb is permeable to water. capsule (glucose, amino acids, and However, the ascending limb is impermeable to water, but most Na ions, Cl− ions, and Na and Cl ions are actively transported from the filtrate into water molecules are the medulla, which raises the water potential of the filtrate. reabsorbed into the blood). Proximal Establishing a water potential Three filtering systems help to prevent cells and large convoluted gradient (i.e. the water molecules from leaving the blood: tubule (PCT) potential in the nephron filtrate Narrow gaps (fenestrations) between endothelium cells in becomes higher than it is in capillaries. the medulla; additional water can then be reabsorbed from Podocytes (epithelial cells of the capsule that have finger- the collecting duct). like projections, which form filtration slits). Basement membrane (a mesh of collagen and glycoprotein around the glomerulus). Loop of Henle Ultrafiltration (i.e. filtering small PCT cells are adapted for reabsorption in the following ways: molecules and ions out of the Microvilli to increase surface area for reabsorption. blood, but keeping large Plasma membranes have many pumps and transporter molecules and cells in the blood). proteins for active transport and facilitated diffusion. Many mitochondria to produce ATP for active transport. Distal Determination of urine The cells of the collecting duct wall contain aquaporin convoluted concentration and volume (i.e. proteins, which can be placed in the plasma membranes of tubule (DCT) additional reabsorption of these cells to enable additional water reabsorption. water into the blood). Collecting duct Additional ion reabsorption. Plasma membranes of DCT cells have many pumps and transporter proteins for active transport and facilitated diffusion. (Next slide)Review: Nephron Function How are the tissues adapted? region Bowman’s Ultrafiltration (i.e. filtering small Three filtering systems help to prevent cells and large capsule molecules and ions out of the blood, molecules from leaving the blood: but keeping large molecules and cells Narrow gaps (fenestrations) between endothelium cells in in the blood). capillaries. Podocytes (epithelial cells of the capsule that have finger- like projections, which form filtration slits). Basement membrane (a mesh of collagen and glycoprotein around the glomerulus). Proximal Selective reabsorption (glucose, PCT cells are adapted for reabsorption in the following convoluted amino acids, and most Na ions, Cl− ways: tubule (PCT) ions, and water molecules are Microvilli to increase surface area for reabsorption. reabsorbed into the blood). Plasma membranes have many pumps and transporter proteins for active transport and facilitated diffusion. Many mitochondria to produce ATP for active transport. Loop of Establishing a water potential gradient The descending limb is permeable to water. Henle (i.e. the water potential in the nephron However, the ascending limb is impermeable to water, but filtrate becomes higher than it is in the Na and Cl ions are actively transported from the filtrate medulla; additional water can then be into the medulla, which raises the water potential of the reabsorbed from the collecting duct). filtrate. Distal Additional ion reabsorption. Plasma membranes of DCT cells have many pumps and convoluted transporter proteins for active transport and facilitated tubule (DCT) diffusion. Collecting Determination of urine concentration The cells of the collecting duct wall contain aquaporin duct and volume (i.e. additional proteins, which can be placed in the plasma membranes reabsorption of water into the blood). of these cells to enable additional water reabsorption. Task Green Pens out: Answers:  Task Osmoreceptors are specialized cells that respond to changes in the water potential of the blood. (a) Give the location of osmoreceptors in the body of a mammal. (1) (b) Stimulation of osmoreceptors can lead to secretion of the hormone ADH. Describe and explain how the secretion of ADH affects urine produced by the kidneys. (4) Extension  Green Pens out: Answer (4 marks) (a) Hypothalamus. (b) 1. Permeability of membrane / cells (to water) is increased; (1) 2. More water absorbed from / leaves distal tubule / collecting duct; (1) 3. Smaller volume of urine; (1) 4. Urine becomes more concentrated. (1)  Extension Task Answer: If you have not attempted the extension task you have two minutes to do so. If you have completed it, self reflect and come up with a specific target for yourself to help you understand this topic Green Pens out: Answer: 1. Blood pressure / hydrostatic pressure; 2. Small molecules / named example; 3. Pass through basement membrane / basement membrane acts as filter; 4. Protein too large to go through / large so stays behind; 5. Presence of pores in capillaries / presence of podocytes;