The liver is the most large gland person. It is the main "laboratory" for the breakdown and synthesis of large quantities organic matter, entering hepatocytes from the hepatic artery and portal vein.
The weight of the liver in an adult is 1200-1500 g. It is covered with peritoneum on all sides, with the exception of a small area on the posterior surface adjacent to the diaphragm. Select the right and left lobe liver. The interlobar border passes through the gall bladder bed, the portal of the liver and ends at the confluence of the right hepatic vein into the inferior vena cava. Based on general principles intrahepatic branching bile ducts, hepatic arteries and portal veins in the liver are divided into 8 segments (Fig. 12.1). The entire surface of the liver is covered with a thin fibrous membrane (Glissonian capsule), which thickens in the area of the portal of the liver and is called the “portal plate”.
Blood supply The liver is carried out by its own hepatic artery, located as part of the hepatoduodenal ligament. In the area of the portal of the liver, it is divided into the right and left hepatic arteries, going to the corresponding lobes of the organ. The hepatic artery carries about 25% of the blood to the liver, while the portal vein carries 75%.
Intrahepatic bile ducts begin with bile canaliculi located between hepatocytes; gradually increasing in diameter and merging with each other, they form interlobular, segmental and lobar ducts. The right and left hepatic ducts, merging together in the area of the porta hepatis, form a common hepatic duct, which after flowing into it cystic duct is called the common bile duct. The latter flows into duodenum in the area of its vertical branch.
Venous drainage from the liver is carried out through the hepatic veins. They begin with the central lobular veins, with the fusion of which sublobular and segmental veins are formed. The latter, merging, form 2-3 large trunks, flowing into the inferior vena cava immediately below the diaphragm.
Lymphatic drainage occurs through lymphatic vessels located along the intrahepatic biliary tract and hepatic veins. Of these, lymph enters lymph nodes hepatoduodenal ligament, para-aortic nodes and from there into the thoracic duct. From upper sections liver lymphatic vessels, perforating the diaphragm, they also flow into the thoracic duct.
Innervation liver is carried out by sympathetic nerves from the right celiac nerve and parasympathetic from the hepatic branch of the left vagus nerve.
Liver functions. Liver plays important role in the metabolism of carbohydrates (accumulation and metabolism), fats (utilization of exogenous fats, synthesis of phospholipids, cholesterol, fatty acids, etc.), proteins (albumin, protein factors of the blood coagulation system - fibrinogen, prothrombin, etc.), pigments (regulation bilirubin metabolism), fat-soluble vitamins (A, D, E, K), B vitamins, many hormones and biologically active substances, as well as in bile formation. In the capillaries of the liver, i.e. in the sinusoids, along with endothelial cells, Kupffer cells occupy a significant place. They perform the function of resident macrophages. It should be emphasized that Kupffer cells make up more than 70% of all macrophages in the body. They own main role in the removal of microorganisms, endotoxin, protein breakdown products, xenogenic substances. Liver cells play a key role in the production of pro-inflammatory and anti-inflammatory interleukins, other cytokines and important inflammatory mediators, on which the course of the disease depends. inflammatory process, maintaining the regulatory role of the immune system and favorable outcome inflammation, trauma and other damaging factors. Reticuloendotheliocytes of the liver (Kupffer cells), performing a protective function, fix immune complexes, carry out phagocytosis of bacteria, destroy old red blood cells, etc. In addition, they produce proteins of the early phase of inflammation (C-reactive protein), gamma globulin and others substances involved in immune defense body.
In many diseases of the liver and biliary tract, one of the first to suffer is its pigment function, which is clinically manifested by jaundice. Therefore, it is very important for a practicing physician to know the physiological cycle of bilirubin metabolism in the body.
IN normal conditions“old” red blood cells are destroyed in the spleen and in small quantities in some other organs of the reticuloendothelial system (bone marrow, liver, lymph nodes). From the hemoglobin of erythrocytes, during their breakdown, the protein globin, hemosiderin and hematoidin are formed. Globin breaks down into amino acids, which subsequently participate in general protein metabolism. Hemosiderin is oxidized to ferritin, which further participates in iron metabolism and is again utilized by the body. Hematoidin, through the biliverdin stage, is converted into indirect (free) bilirubin (insoluble in water), which in turn enters into a loose bond with blood proteins. With the blood flow through the portal vein system, indirect bilirubin enters the liver, where, under the influence of liver enzymes, it binds with glucuronic acid, forming water-soluble direct bilirubin (bilirubin glucuronide), which is subsequently released into the intestines by bile. Here, stercobilin is formed from direct (bound) bilirubin, which gives the stool a brown color, as well as urobilinogen and urobilin, which are partially excreted in the feces and partially absorbed through intestinal wall into the blood through the portal vein system. Most of the urobilinogen and urobilin enter the liver, where they are converted back into bilirubin and only a small amount is excreted in the urine. Indirect bilirubin is not filtered by the kidneys and is not excreted in the urine, while direct water-soluble bilirubin has this ability.
2) spleen
3) pancreas
4) adrenal gland
Answer: 1
43. What role does bile play in digestion?
1) breaks down fats into glycerol and fatty acids
2) activates enzymes, emulsifies fats
3) breaks down carbohydrates into carbon dioxide and water
4) accelerates the process of water absorption
Answer: 2
44. In which part of the human intestine does the breakdown of plants occur?
Noah fiber
1) duodenum
2) colon
4) cecum
Answer: 2
45.V digestive system human basic chemical transformations
Niya food ends in
1) cecum
2) stomach
3) small intestine
Answer: 3
The enzymatic breakdown of proteins into amino acids in the human digestive system begins in
Answer: 1
47. Toxic substances, which enter the human body with food, neutralize
Huddle in
3) large intestine
4) pancreas
Answer: 2
48. Digestion of starch and others complex carbohydrates starts at:
1) large intestine;
2) small intestine;
3) oral cavity;
4) in the stomach.
Answer: 3
49. What vitamin should be included in the diet of a person suffering from scurvy?
Answer: 3
The conversion of glucose to glycogen occurs in
1) stomach
4) intestines
Answer: 3
51. Enzymatic breakdown of proteins to amino acids in the digestive tract
The human system begins in
1) stomach, and ends in small intestine
2) the oral cavity, and ends in the small intestine
3) the oral cavity, and ends in the esophagus
4) the cecum, and ends in the rectum
Answer: 1
52. Bile and pancreatic juice enter through the ducts into:
1) stomach
2) duodenum
3) sections of the large intestine
4) rectum
Answer: 2
In the human small intestine, it is absorbed into the bloodstream
1) starch
2) amino acids
3) glycogen
Answer: 2
Suction function nutrients in the human digestive system perform
1) muscle cells
3) stomach glands
4) blood vessels
Answer: 2
Lack of vitamin A in the human body leads to disease
4) rickets
Answer: 1
56. In the human digestive system, the main chemical transformations
Niya food ends in
1) cecum
2) stomach
3) small intestine
Answer: 3
57. Conversion of glucose into storage carbohydrate - glycogen is the most intense
Option 1
A1. What is the name of the science of the structure of man and his organs?
1) anatomy 3) biology
2) physiology 4) hygiene
A2. What part of the brain is called the small brain?
1) midbrain 3) medulla oblongata
2) spinal cord 4) cerebellum
A3. What muscle group do the temporal muscles belong to?
1) to facial expressions 3) to respiratory ones
2) to chewing 4) to motor
A4. What is the process of destroying microbes by eater cells called?
1) immunity 3) phagocytosis
2) brucellosis 4) immunodeficiency
A5. What is the name of the enzyme? gastric juice, capable of acting only in acidic environment and breaking down protein into simpler compounds?
1) hemoglobin 3) cerebellum
2) pituitary gland 4) pepsin
A6. What are the names of the nerve structures that convert perceived stimuli into nerve impulses?
1) sensory neurons 3) interneurons
2) receptors 4) synapses
A7. What is excessive elevation called? blood pressure?
1) hypertension 3) hypotension
2) allergy 4) arrhythmia
B1. What functions do the nervous and nervous organs perform? endocrine system?
B2. What is the constant composition of the liquids that make up the internal
B3. What is a liquid containing weakened microbes or their poisons called?
Q4. Who discovered central braking?
B5. What are the rhythmic vibrations of arterial walls called?
C1. What secretory gland does the pancreas belong to? Explain why?
C2. What are the consequences of impaired kidney function in humans?
Biology test for 8th grade course
Option 2
A1. What is the name of the warm salty liquid that connects all human organs with each other, providing them with oxygen and nutrition?
1) tissue fluid 3) lymph
2) blood 4) intercellular fluid
A2. What is the name of the part of the brain that provides coordination and consistency of movements, as well as body balance?
1) medulla oblongata 3) cerebellum
2) hypothalamus 4) midbrain
A3. What type of fabric is it? bone tissue?
1) connective 3) muscular
2) epithelial 4) nervous
A4. What makes up the bulk of plasma?
1) lymph 3) red blood cells
2) water 4) shaped elements
A5. What is the name of the most large gland our body, located in the abdominal cavity under the diaphragm?
1) thyroid 3) pancreas
2) spleen 4) liver
A6. What is the means of contact between neurons and cells of working organs?
1) with the help of synapses 3) with the help of the vagus nerve
2) with the help of alveoli 4) with the help of receptors
A7. What is lymph formed from?
1) from blood 3) from tissue fluid
2) from the intercellular substance 4) from gastric juice
B1. What is the name of the transparent semi-liquid mass that fills the internal space? eyeball?
B2. What does the gray matter of the brain consist of?
B3. What is the lack of vitamins in the body called?
Q4. Where does gas exchange occur?
B5. What is the ability of an organ to be rhythmically excited under the influence of impulses arising in it without external stimuli?
C1. Name at least 3 criteria that allow us to classify a person as a mammal.
C2. Is it possible for a person with blood group II to be transfused with blood group III and why? Why can blood of group I be transfused to all four groups?
Answers
Option 1
A3 - 2
A4 - 3
A5 - 4
A6 - 2
B1 - regulatory
B2 - homeostasis
B3 - vaccine
B4 – I.M.Sechenov
B5 – pulse
C1 – Mixed secretion. Some pancreatic cells secrete hormones (insulin) directly into the blood, while the other part releases pancreatic juice, which enters the duodenum through the ducts.
C2 – Kidneys – organ excretory system. Disruption of their work can lead to disruption of homeostasis (changes in the composition of the internal environment) and to poisoning of the body with metabolic products
Option 2
A3 - 1
A4 - 2
A5 - 4
A6 - 1
B1 – vitreous body
B2 – from neuron cell bodies
B3 - hypovitaminosis
B4 - in the alveoli of the lungs and tissues
B5 – automaticity
C1 – the presence of a uterus and mammary glands, lungs of the alveolar type, the heart includes 4 chambers, constant temperature body, chest and abdominal cavity separated by a diaphragm.
C2 – it is impossible, because the meeting of β agglutinins contained in the blood of group II with agglutinogens B contained in the blood of group III will lead to agglutination. Group blood does not contain agglutinogens A and B, so it can be transfused to all blood groups.
Response evaluation criteria
For each correctly completed task under the letter A, 1 point is awarded, a total of 7 points.
For each correctly completed task under the letter B, 2 points are awarded, for a total of 10 points.
For each correctly completed task under the letter C, 3 points are awarded, for a total of 6 points.
Total – 23 points
80-100% - score “5”
60-80% - score “4”
40-60% - score “3”
0-40% - estimate "2".
To carry out intermediate certification a set has been compiled for biology in the 8th grade test tasks(2 options). They are compiled taking into account the state educational standard. Content educational material correlated with the amount of time allocated to studying biology in the 8th grade by the basic curriculum(2 hours per week/68 hours per year).
All questions and tasks are divided into three difficulty levels (A, B, C).
Level A - basic (A1-A7). For each task there are 4 possible answers, only one of which is correct.
Level B – contains 5 tasks (B1-B5). Each task at this level requires a short answer (in the form of one or two words).
Level C – increased complexity contains 2 tasks (C1-C2). This task requires you to write a detailed answer.
For execution test work 45 minutes are allotted (1 lesson).
Of all the organs human body the liver is the largest gland and is second in size only to the skin, being the largest internal organ. The liver is formed in the embryo in the fourth week of pregnancy. During fetal development, the liver is divided into two parts called the right and left lobes. At the end of intrauterine development right lobe the liver will be six times larger than the left. By the time a baby is born, the liver weighs about 5 percent of the baby's total body weight. A baby's liver grows and weighs three to four pounds (3 to 4 kg) in an adult. If you feel the right bottom corner under chest, you will find a dense mass that, when tapped, makes a dull sound. This is your liver. Healthy liver has the consistency of a sponge. In a child with liver disease, the liver is often denser.
The liver is located under the diaphragm and ribs, it is stretched along top edge stomach to the left side of the body. Under the right edge of the liver are green gallbladder and its ducts. The blood supply system of the liver is unique: through the large blood vessel, called the portal vein, blood comes from both the heart and digestive tract. Each of the two large lobes is made up of smaller compartments called lobules. Typically, the liver has 50,000 to 100,000 lobules, consisting of a vein surrounded by tiny liver cells called hepatocytes. These cells cleanse the blood, remove waste, toxins and poisons, and store nutrients for use by the body when needed. The liver has a variety of functions: it converts sugar (glucose) into glycogen and stores it until the body needs it.
The liver also stores vitamins, minerals and iron until they are needed. Liver cells produce proteins and lipids, or fats, which include triglycerides, cholesterol and lipoproteins. The liver produces bile acids that break down dietary fats. Bile acids allow the body to absorb fat soluble vitamins A, D and E. The liver removes from the blood chemicals, alcohol, toxins and drugs and sends them either as urea to the kidneys, which excrete them from the body in the form of urine, or to gastrointestinal tract, from where they are excreted in the form of feces.
When a person consumes food, nutrients pass through the throat into the stomach and then into the intestines. In these organs, food is broken down into small particles, thanks to enzymes produced by the pancreas, which are absorbed into the blood. Most of these small particles pass from the intestines to the liver, which filters food and turns it into nutrients that the blood delivers to the cells that need them. The liver stores these nutrients, releasing them throughout the day when the body needs them. Proteins, fats, enzymes and others chemical compounds, which the liver synthesizes from nutrients, determine human health
The liver produces proteins necessary for blood clotting. If the liver is unable to produce these substances, death may occur due to blood loss. The liver also produces bilirubin, a red-yellow pigment formed when hemoglobin breaks down in dying red blood cells. The blood carries it to the liver, where it mixes with bile, and then enters the duodenum for excretion from the body. If the liver is damaged and is unable to remove reddish-yellow bilirubin from the body, jaundice occurs - the sclera of the eyes and skin acquire a yellowish tint. The liver produces the blood protein albumin, as well as cholesterol, which is necessary for the formation of external cell membranes. When liver cells are damaged and cannot perform these functions, they release certain enzymes into the blood. To determine liver damage or disease, doctors test the presence of all these enzymes in the blood, as well as other liver-related substances. The liver is a very complex organ, so it is subject to many influences. negative factors, including excess alcohol or medications, infections such as viral hepatitis, cancer and other metabolic disorders. However, at the same time, the liver is a resilient organ, since it is capable of recovering from damage or inflammation; In addition, the liver contains reserves of nutrients that it can resort to when damaged. When the liver is infected with the hepatitis virus, its cells are damaged or destroyed. The liver can survive this type of damage due to its ability to regenerate and compensate for the damage caused. This stage of the disease is called compensated liver disease because the liver is able to continue performing all its functions. When the liver begins to succumb to disease, it can no longer regenerate its tissues, and the growth of scar tissue impairs its ability to filter and store nutrients. This final stage of the disease is called decompensated because the liver cannot compensate for the damage caused.
