Excretory System Structures PDF

Outcome D3 Explain the role of the excretory system in maintaining an internal equilibrium in humans through the exchange of energy and matter with the environment. Excretory System Structures Outcome D3, Lesson 1 Functions of the Excretory System Main functions: Remove metabolic wa...

Outcome D3 Explain the role of the excretory system in maintaining an internal equilibrium in humans through the exchange of energy and matter with the environment. Excretory System Structures Outcome D3, Lesson 1 Functions of the Excretory System Main functions: Remove metabolic waste from the blood Excrete that waste (in solution) from the body Removal of Waste Products A variety of organs excrete (remove) waste products Lungs Removes carbon dioxide (from cellular respiration) Skin Releases water, salts, and some urea as perspiration Liver Removes bile pigment (breakdown of hemoglobin) Removes lactic acid (anerobic cellular respiration) Eliminated toxins (such as alcohol and heavy metals) Removal of Waste Products Kidneys Remove ammonia, urea, and uric acid Where do these compounds come from? Ammonia is produced when excess protein you eat turns into sugar by undergoing the process of deamination in the liver Removal of the amino group (-NH2) Urea is made in the liver when ammonia is immediately combined with carbon dioxide (100 000x less toxic) Uric acid is a product of the breakdown of nucleic acids (DNA and RNA) Water Balance in Blood Kidneys also maintain water balance in the blood Average adult loses 2 L of water each day to sweat, urine, and exhalation To compensate for this loss, we just drink at least 2 L of water a day Drop in fluid levels is dangerous 1% drop – thirst 5% drop – extreme pain and collapse 10% drop – death The kidneys process 180 L of fluid a day! (Body has ~5 L of blood) Parts of the Excretory System Parts of the Excretory System Kidneys Humans have two kidneys Can function with one If one stops working or is removed due to disease or donation, the remaining kidney will increase in size to handle to increased workload Fist-sized organs located in your lower back on either side of your spine Surrounded by fatty tissue and the lower portion of the rib cage to provide protection Filter blood to produce urine Kidney Parts of the Excretory System Renal artery Provides blood to the kidneys to be filtered Provides oxygen and nutrients to the kidneys Branches off the aorta Renal vein Returns deoxygenated, filtered blood from the kidneys to the heart Joins with inferior vena cava  Aorta Inferior vena cava Renal Renal vein artery Parts of the Excretory System Ureters 28 cm long tubes that connect the kidneys to the bladder Urine is moved by peristalsis Ureter Parts of the Excretory System Bladder Hollow, muscular organ that stores urine until it is ready to be excreted Drainage from the bladder is controlled by two sphincters Both must relax for drainage to take place Internal sphincter is involuntarily controlled by the brain External sphincter is under voluntary control During childhood, you learn to control this Bladde r Parts of the Excretory System Urethra Tube connecting the bladder to the external environment Males: Urethra is approximately 20 cm in length Merges with the vas deferens (reproductive tract) to form a single passageway to the external environment Females: Urethra is approximately 4 cm in length This is why females are more likely to have urinary tract infections Bacteria needs to travel a shorter distance to reach the bladder Reproductive and excretory tracts have different openings Urethr a Kidney Structure 3 layers Renal pelvis Inner layer of kidney Mouth of ureter flares open to form a funnel-like structure Renal pelvis has cup-like extension that receive urine from the renal tissue Funnels urine into the ureter Renal pelvis Kidney Structure 3 layers Renal medulla Middle layer of kidney Contains most of the nephrons Functional unit of the kidney  Renal Renal medulla medulla Kidney Structure 3 layers Renal cortex Outer layer of kidney Gives kidney shape and protects inner parts Has some of the nephrons  Renal Renal cortex cortex Kidney Structure Nephron Microscopic tubules that filter blood and process urine Closely associated with a network of blood vessels Each kidney contains about 1 million nephrons Nephro n Parts of the Nephron Glomerulus High-pressure capillary bed Small branches from the renal artery that supply the nephrons with blood Afferent (going to) and efferent (going away) arterioles Surrounded by Bowman’s capsule  Glomerulus Efferent arteriole Afferent arteriole Parts of the Nephron Bowman’s Capsule Cup-like sac that surrounds the glomerulus Catches substances that leave the blood in the glomerulus Bowman’s capsule Parts of the Nephron Proximal Tubule Portion of duct system which leads from the Bowman’s capsule to the loop of Henle Proximal tubule Parts of the Nephron Loop of Henle Long U-shaped portion of the tube Loop of Henle Parts of the Nephron Peritubular Capillaries Surround nephron, allowing substances to move back and forth between blood and solution in the nephron Peritubular capillaries Parts of the Nephron Distal Tubule Portion between the loop of Henle and the collecting duct Distal tubule Parts of the Nephron Collecting Duct Collects urine made by nephron and moves it towards the renal pelvis and ureters Collecting duct Renal Cortex Renal Medulla  https://www.youtube.com/watch?v=sRZ7VOeIr6g