6.2.2. Urine formation

Urine formation

The blood carries waste products to the kidney. The urine is a liquid obtained from the blood, composed mainly of water, minerals and excretion products, such as urea and uric acid.

The urine formation process follows the following stages:

Filtration

Blood vessels leading to the nephron form the glomerulus of Malpighi, a microscopic, ball-shaped capillary system surrounded by Bowman's capsule. The blood that reaches the nephrons is under great pressure, and water, glucose, vitamins, amino acids, sodium, potassium, chlorides, urea and other salts leave these capillaries, which pass into Bowman's capsule. 20% of the blood plasma that reaches the nephron is filtered, about 150 liters of primary urine per day. Logically, an organism that loses so much water would dehydrate very quickly, so it cannot afford it.

Reabsorption

In the filtration, waste substances, but also a lot of water and other useful substances, have passed into the Bowman capsule, which are reabsorbed and returned to the blood.

In the proximal convoluted tubule it reabsorbs glucose, amino acids, sodium, chloride, potassium and other substances. Here, approximately 65% of the filtrate is reabsorbed. The remainder is reabsorbed in the loop of Henle and the distal convoluted tubule. The toxic urea cannot escape from the tubules.

With reabsorption, a large part of the water and the filtered useful substances are recovered, leaving only 1.5 liters of urine per day to be reabsorbed, which is directed towards the renal pelvis.

Secretion

It consists of the passage of some substances that have not been filtered, or have been erroneously reabsorbed, from the capillaries that surround the distal convoluted tubule towards its interior. Here some substances such as penicillin, potassium and hydrogen are secreted, which are added to the urine that is being formed.

Thus, this final liquid, urine, will be made up of water, some salts, and urea, and will pass through the collecting tubules to the renal pelvis, and from there, through the ureters, to the urinary bladder.

Activity: Tour of waste substances.

Activity: Location of excretory processes.

Activity: We specify some concepts.

Activity: Parts of the nephron.

Song: Urine is formed here (Julinky).

Answer in your notebook

6.5.- Name all the parts through which a urea molecule passes from when it reaches the kidney until it goes outside.

Answer in your notebook

6.6.- If urine comes from blood, why is it not red or does it have blood cells?

Answer in your notebook

6.7.- How is the blood that goes through the renal artery different from that which goes through the renal vein?

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Skip navigation Biology and Geology 3rd compulsory secondary education Biology and Geology 3rd ESO 01. General organization of the human body 1.1. Levels of organization of the human body 1.2. The cell 1.2.1. The prokaryotic cell 1.2.2. The eukaryotic cell 1.2.2.1. The eukaryotic animal cell 1.2.2.2. The eukaryotic plant cell 1.3. Tissues 1.4. Organs, systems and apparatus 1.5. Bibliography and student work 02. Food and health 2.1. Feeding and nutrition 2.2. Nutrients 2.2.1. Types of nutrients 2.2.2. The energy of nutrients 2.3. The food 2.4. Diets 2.5. Food consumption 2.5.1. Labelled 2.5.2. How to shop and cook 2.6. Food preservation and hygiene 2.7. Food production 2.7.1. Intensive agriculture 2.7.2. Intensive livestock 2.7.3. Aquaculture 2.7.4. Transgenic foods 2.7.5. Organic food 2.8. Eating-related illnesses 2.9. Bibliography and student work 03. The digestive system and digestion 3.1. Nutrition function 3.2. Digestive system 3.2.1. Ingestion 3.2.1.1. Chewing 3.2.1.2. 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Healthy habits for the circulatory system 5.11. Bibliography and student work 06. The excretory system and excretion 6.1. Excretion 6.2. Urinary system 6.2.1. Kidneys 6.2.2. Urine formation 6.2.3. Urinary tract 6.3. Kidney disease 6.4. Healthy habits for the excretory system 6.5. Bibliography and student work 07. The nervous system 7.1. Relationship function and the nervous system 7.2. Cells of the nervous system 7.2.1. Neuron 7.2.2. Glia 7.3. Nerve impulse 7.4. Organization of the nervous system 7.4.1. The Central Nervous System 7.4.1.1. Encephalon 7.4.1.2. Spinal cord 7.4.2. The Peripheral Nervous System 7.4.2.1. Somatic Nervous System 7.4.2.2. Autonomic nervous system 7.5. Nervous acts 7.6. Nervous system diseases 7.6.1. Brain injuries 7.6.2. Spinal cord injuries 7.6.3. Neuropsychological diseases 7.6.4. Pathologies related to lifestyle 7.7. Healthy habits and mental health 7.8. Drug addiction 7.8.1. Common characteristics of drugs 7.8.2. Classification of drugs 7.9. Bibliography and student work 08. The endocrine system 8.1. The types of responses 8.2. The endocrine system 8.2.1. Endocrine glands 8.2.2. Hormonal control 8.3. Endocrine system diseases 8.4. Bibliography and student work 09. Sensory receptors. The sense organs 9.1. Perception: sensory receptors 9.1.1. The touch and the pain 9.1.2. The sense of smell 9.1.3. Taste 9.1.4. The eye and vision 9.1.5. The ear: hearing and balance 9.2. Healthy habits for the sense organs 9.3. Bibliography and student work 10. Effector organs. The locomotor system 10.1. The skeleton 10.1.1. The bones 10.1.1.1. Bones of the human body 10.1.2. Joints 10.2. Musculature 10.2.1. Muscles of the human body 10.3. Healthy habits of the locomotor system 10.4. Musculoskeletal disorders 10.5. Bibliography and student work 11. Human sexuality and reproduction 11.1. Human reproduction 11.1.1. The male reproductive system 11.1.2. Spermatozoon 11.1.3. The female reproductive system 11.1.4. The ovule 11.1.5. The menstrual cycle 11.1.6. Fertilization, pregnancy and childbirth 11.1.6.1. Fertilization 11.1.6.2. Pregnancy 11.1.6.3. Birth 11.2. Natality control 11.2.1. Contraceptive methods 11.2.2. Reproduction techniques 11.2.2.1. Exploratory techniques 11.2.2.2. Assistance techniques in childbirth 11.2.2.3. Assisted reproductive techniques 11.3. Adolescence and sexuality 11.4. Main sexually transmitted diseases and prevention 11.5. Prevention and sexual hygiene 11.6. Bibliography and student work 12. Health and disease 12.1. What is health? 12.1.1. Health indicators 12.1.2. Health determinants 12.2. The disease and types of diseases 12.3. Infectious diseases 12.3.1. Types of infectious diseases 12.3.2. Immunity and immune system 12.3.3. Prevention and cure of infectious diseases 12.4. Non-infectious diseases 12.5. First aid 12.6. Transplants and donation of cells, blood and organs 12.7. Bibliography and student work 13. Ecosystems 13.1. Ecosystem components 13.2. Types of ecosystems 13.3. Factors influencing the ecosystem 13.4. Balance in ecosystems 13.5. The soil as an ecosystem 13.6. Bibliography and student work 14. The external geological activity of the Earth 14.1. Solar energy on Earth 14.2. External geological processes 14.2.1. Weathering 14.2.2. Erosion, transport and sedimentation 14.3. Factors that condition the modeling of the relief 14.4. Forms of relief modeling 14.4.1. Wild or stream waters 14.4.2. Torrential modeling 14.4.3. River modeling 14.4.4. Karst modeling. Groundwater 14.4.5. Littoral modeling 14.4.6. Glacier modeling 14.4.7. Wind or desert modeling 14.5. Geological action of living beings 14.6. Geological action of the human being 14.7. Bibliography and student work 15. The internal geological activity of the Earth 15.1. The internal energy of the Earth 15.2. Volcanoes 15.2.1. Types of volcanoes 15.2.2. Volcanic risk 15.3. Earthquakes 15.3.1. Seismic risk 15.4. Bibliography and student work « Previous \| Next » 6.2.2. Urine formation Urine formation The blood carries waste products to the kidney. The urine is a liquid obtained from the blood, composed mainly of water, minerals and excretion products, such as urea and uric acid. The urine formation process follows the following stages: Filtration Blood vessels leading to the nephron form the glomerulus of Malpighi, a microscopic, ball-shaped capillary system surrounded by Bowman's capsule. The blood that reaches the nephrons is under great pressure, and water, glucose, vitamins, amino acids, sodium, potassium, chlorides, urea and other salts leave these capillaries, which pass into Bowman's capsule. 20% of the blood plasma that reaches the nephron is filtered, about 150 liters of primary urine per day. Logically, an organism that loses so much water would dehydrate very quickly, so it cannot afford it. Reabsorption In the filtration, waste substances, but also a lot of water and other useful substances, have passed into the Bowman capsule, which are reabsorbed and returned to the blood. In the proximal convoluted tubule it reabsorbs glucose, amino acids, sodium, chloride, potassium and other substances. Here, approximately 65% of the filtrate is reabsorbed. The remainder is reabsorbed in the loop of Henle and the distal convoluted tubule. The toxic urea cannot escape from the tubules. With reabsorption, a large part of the water and the filtered useful substances are recovered, leaving only 1.5 liters of urine per day to be reabsorbed, which is directed towards the renal pelvis. Secretion It consists of the passage of some substances that have not been filtered, or have been erroneously reabsorbed, from the capillaries that surround the distal convoluted tubule towards its interior. Here some substances such as penicillin, potassium and hydrogen are secreted, which are added to the urine that is being formed. Thus, this final liquid, urine, will be made up of water, some salts, and urea, and will pass through the collecting tubules to the renal pelvis, and from there, through the ureters, to the urinary bladder. Activity: Tour of waste substances. Activity: Location of excretory processes. Activity: We specify some concepts. Activity: Parts of the nephron. Song: Urine is formed here (Julinky). Answer in your notebook 6.5.- Name all the parts through which a urea molecule passes from when it reaches the kidney until it goes outside. Answer in your notebook 6.6.- If urine comes from blood, why is it not red or does it have blood cells? Answer in your notebook 6.7.- How is the blood that goes through the renal artery different from that which goes through the renal vein? Licensed under the Creative Commons Attribution Share Alike License 4.0 « Previous \| Next » You can ask, comment, contribute, get in touch with other users in the forum of this course. This course is translated from https://biologia-geologia.com/BG3/
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Urine formation

Filtration

Reabsorption

Secretion