Summary of biological knowledge points in the second volume of grade seven 1
Chapter IV Transportation of Substances in Human Body
The blood circulation system consists of heart (organ), blood vessels (organ) and blood (connective tissue).
Section 1 Flowing Tissue-Blood
1. Blood composition and function
Hb components in plasma: water (about 90%), protein, glucose, inorganic salts, etc.
Function: Carrying blood cells, transporting nutrients and wastes.
Blood cells:
red blood cell
white blood cell
blood platelet
Functions of blood: transportation, defense and protection, and temperature regulation.
2. Comparison of three kinds of blood cells
3. Hemoglobin: A kind of hemoglobin contained in red blood cells. Hemoglobin is red because it contains iron.
Characteristics: It combines with oxygen in places with high oxygen content and separates from oxygen in places with low oxygen content.
4. Gas poisoning, that is, carbon monoxide CO poisoning, because the binding ability of carbon monoxide and hemoglobin is stronger than that of oxygen and hemoglobin, leading to hypoxia in patients.
5. Altitude sickness, referred to as "altitude sickness", is a natural physiological reaction to adapt to the changes of low pressure, low oxygen content and dry air caused by altitude after people reach a certain altitude.
Symptoms of altitude sickness generally include headache, shortness of breath, chest tightness, anorexia, low fever, dizziness and fatigue. Some people appear because of low oxygen content: purple lips and fingertips, lethargy, hyperactivity, insomnia and other different manifestations. However, red blood cells in human blood will gradually increase to improve the efficiency of oxygen transportation.
6. Athletes in plain areas go to plateau for training before the competition, which is beneficial to produce more red blood cells in human blood. When they return to low altitude areas to compete, the oxygen transport efficiency of blood is higher, which is beneficial to the human body to get enough energy.
7. Stem cells: They can differentiate into various cells and then form different tissues and organs. It mainly exists in umbilical cord blood and bone marrow of newborns.
Section 2 Blood Flow Pipeline-Blood Vessel
1. When observing the blood flow in the tail fin of a small fish with a microscope, use a low-power microscope to wrap the head and trunk of the small fish with moist cotton wool, and keep dripping water on the cotton wool to keep it moist during the observation to ensure the normal breathing of the small fish.
2. Types, structures and functions of blood vessels
3. Chinese medicine uses the radial artery at the wrist to "feel the pulse". Veins are commonly known as "veins" and are used for blood drawing, blood transfusion and intravenous drip.
4. The capillary tube wall is very thin and consists of only one layer of epithelial cells, and the blood flow velocity in the tube is the slowest, which is beneficial to the material exchange between blood and tissue cells. Oxygen and nutrients in capillaries enter tissue cells, and carbon dioxide and other wastes produced by tissue cells enter blood in capillaries.
The third quarter-the heart-the pump that transports blood
1. Structure and function of the heart: It is located in the middle of the chest, at the lower left, about the size of my fist.
It is mainly composed of muscle tissue and has the functions of contraction and relaxation. The heart is the dynamic organ of blood circulation.
There are four cavities:
Left ventricle (aorta) left atrium (pulmonary vein)
Right ventricle (pulmonary artery) and right atrium (superior and inferior vena cava)
★ Memory instruction: Left and right are opposite (when looking at the anatomical map, the left side of the map is actually the right side of the body organ)
Upper atrium and lower ventricle (two atria above and two ventricles below)
Atrial static ventricular artery (atrial connecting vein, ventricular connecting artery)
Left main right lung (left ventricle is connected with aorta and right ventricle is connected with pulmonary artery)
Connected up and down, left and right are not connected (the atrium and ventricle on the same side are connected, but the left and right are separated by muscle wall). )
2. Valve
Atrioventricular valve (located between atrium and ventricle, only open to ventricle)
Arterial valve (located between the ventricle and the artery, only open to the artery)
Valves ensure that blood flows in a certain direction and prevent blood from flowing backwards.
3. Blood circulation: divided into systemic circulation and pulmonary circulation.
Comparison of two ways of blood circulation;
The two blood circulation paths * * * have the same point (blood flow direction):
Ventricular artery capillary network vein on the other side of atrium
4. Arterial blood has high oxygen content and bright red color, while venous blood has low oxygen content and deep red color. There is venous blood in pulmonary artery and arterial blood in pulmonary vein. There is arterial blood in other arteries and venous blood in veins. (explanation: the definition of artery refers to the blood vessels that transport blood from the heart to all parts of the body, not what blood flows in it. The pulmonary artery is a blood vessel that transports venous blood from the right ventricle of the heart to the lungs, so it is venous blood in the pulmonary artery. )
5. Coronary circulation: delivering oxygen and nutrients to the heart itself and transporting waste. If the coronary artery is diseased, it will cause coronary heart disease.
6. Heart rate, pulse and blood pressure
Heart rate refers to the number of heartbeats per minute. Pulse is caused by the beating of the heart, and blood impacts the arterial wall, resulting in obvious pulsation of the artery. The number of pulses in one minute is consistent with the heart rate. Blood pressure refers to the lateral pressure of blood on blood vessel wall, which can be measured at brachial artery with sphygmomanometer. Too high or too low blood pressure will endanger human health.
7. Discovery of blood circulation:17th century, British doctor Harvey pointed out that blood circulates in the body.
The fourth quarter blood transfusion and blood type
1. Blood volume: 7%-8% of body weight.
With a small amount of blood loss (below 400ml), the lost plasma components and blood cells can be replenished and returned to normal in a short time. If the blood loss exceeds 800- 1000ml at a time, symptoms such as dizziness, heartbeat, black eyes and cold sweat will appear. If the blood loss exceeds 1200- 1500ml at a time, it will be life-threatening, and blood transfusion is needed in time.
2. Blood type: 1900, Austrian scientist Karl Landsteiner divided blood types into A, B, AB, O, that is, ABO blood type. Humans also have other blood group classification systems, such as Rh blood group system. In the Han population, 99% were Rh positive and 1% were Rh negative (panda blood).
3. Blood transfusion: Blood transfusion is based on the same type of blood. In an emergency, people of any blood type can accept (input) a small amount of O blood. (Component transfusion: For patients with thrombocytopenia, only platelets are needed; Plasma infusion for burn patients. That is to say, the patient lost what he lacked)
4. Advocating voluntary blood donation: Since 1998, China has implemented a voluntary blood donation system and advocated voluntary blood donation by healthy citizens aged 18-55. Healthy adults donate 200-300ml blood each time, which will not affect their health. June 14 is World Blood Donor Day (Karl Landsteiner's birthday).
Induction of biological knowledge points in the second volume of the seventh grade
Chapter V Discharge of Wastes in Human Body
1. excretion
(1) Concept: The process that wastes such as carbon dioxide, urea, excess water and inorganic salts produced when the human body decomposes substances in the body are discharged from the body is called excretion.
(2) Ways:
① Skin: excrete water, inorganic salts, urea, etc. In the form of sweat.
② Respiratory system: discharging carbon dioxide and water. In the form of gas.
③ Urinary system: Water, inorganic salts and urea are discharged in the form of urine.
(3) Different from:
Excretion: the process of excreting feces formed by the residue after digestion of food.
2. Composition of urinary system
Kidney: the place where urine forms.
Ureter: transport urine
Bladder: temporary storage of urine
Urethra: excretion of urine
The kidneys are located on both sides of the spinal column in the posterior abdominal wall, one on the left and the other on the right. Each kidney consists of more than 654.38+00000 nephrons, which are the basic units of urine formation. The structure and function of nephron are as follows:
Glomerulus: dozens of capillaries branched from input arterioles are bent and coiled, and the other ends converge into output arterioles.
Renal capsule: the blind end of renal tubule is swollen, and the capsule wall is divided into two layers, the inner layer is close to glomerulus and the outer layer is connected with renal tubule.
Renal tubule: the cavity between the inner and outer layers of the renal capsule is connected with the renal tubule.
3. The formation of urine
(1) filtration function of glomerulus and renal capsule wall: The glomerulus and renal capsule wall filter blood, and all plasma components except protein of blood cells and macromolecules can be filtered to form protourine in the renal capsule.
(2) Renal tubular reabsorption: Substances that are useful to human body, including most water, all glucose and some inorganic salts, are reabsorbed into capillaries around renal tubules (into blood circulation), and the rest form urine.
(3) Urinary tract and blood route:
Blood path: renal artery → input arteriole (arterial blood) → glomerular capillary (arterial blood) → output arteriole (arterial blood) → capillary outside renal tubule (arterial blood venous blood) → renal vein (venous blood).
Urinary tract: renal capsule (urine) → renal tubule (reabsorption) → collecting tube → ureter → bladder → urethra.
4. Urine excretion
Kidney → ureter → bladder → urethra
5. The significance of urination:
(1) Discharge metabolic waste.
(2) Adjust the balance of water and inorganic salts in the body and maintain the normal physiological functions of tissues and cells.
(3) regulating body temperature.
6. Transdermal excretion: Sweat glands (exocrine glands with ducts) secrete sweat, the main component of which is water, and a small amount of urea and inorganic salts. Sweat evaporation can take away some heat, so sweat glands also have the function of regulating body temperature.
Difference: Blood (including blood cells and plasma).
Plasma (containing various nutrients and metabolic wastes).
Raw urine (no blood cells, no protein, a lot of water, inorganic salts, urea, etc.). ).
Urine (no blood cells, no protein and glucose, mainly water, inorganic salts, urea, etc. ).
Summary of biological knowledge points in the second volume of the seventh grade 3
Chapter VI Adjustment of Human Life Activities
Section 1 Human Body's Perception of the External Environment
1. Most of the information the human body gets from the outside world comes from vision.
Structure and function of eyeball;
Cornea: colorless and transparent, transparent.
Scleral: white and tough, protecting the inside of eyeball (white part of eyeball).
Iris: Pigment (determines the color of human eyes, such as black, brown, blue, etc. ), and the central hole is the pupil.
Choroid: There are blood vessels (providing nutrition for the eyeball) and pigment cells (shading, forming a "dark room" inside the eyeball).
Pupil: the passage through which light enters, the size of which can be adjusted. Pupils shrink in strong light and expand in dark light.
Retina: There are a large number of photosensitive cells on the surface, which can feel the stimulation of light and form an object image.
Lens: A biconvex lens with adjustable curvature, which refracts light and enables the eyes to see objects at different distances.
Ciliary body: adjust the curvature of the lens.
Vitreous body: a transparent colloidal substance that supports the wall of the eye and refracts light.
2. Formation of vision:
(1) imaging:
(2) Form a vision:
External light → imaging on retina, photoreceptor cells generate excitement and nerve impulse → visual nerve → visual center of cerebral cortex, forming vision.
3. Eye care:
(1) Myopia: Because the anterior-posterior diameter of eyeball is too long or the curvature of lens is too large, the object image falls in front of retina.
Correction: wear concave lenses
(2) Hyperopia: Because the anterior-posterior diameter of eyeball is too short or the curvature of lens is too small, the object image falls behind retina.
Correction: wear convex lens (reading glasses)
(3) To protect eyesight and prevent myopia, we should achieve "three musts" and "four don 'ts".
4. The structure and function of the ear:
(2) the formation of auditory conduction along the ossicles
5. When encountering a lot of noise, or quickly open your mouth to open the eustachian tube; Or shut up and plug your ears. These two methods are to keep the air pressure balance inside and outside the eardrum and avoid damaging the eardrum. Treat pharyngeal inflammation in time to avoid otitis media (eustachian tube connects pharynx and middle ear).
6. nose: sense of smell. Tongue: Taste. Skin: touch.
The composition of the nervous system in the second quarter
1. The nervous system consists of brain, spinal cord and its nerves.
2. Neurons are the basic units of the structure and function of the nervous system.
Section 3 Basic ways of nerve regulation
1. reflex is the basic way of neuromodulation.
Concept of reflex: Animals (including people) respond regularly to various external or internal stimuli through the nervous system.
Different from: stress (the characteristic that all living things must respond to stimuli)
2. The structural basis of reflection-reflex arc
Composition: receptor → afferent nerve → nerve center → efferent nerve → effector.
The completion of reflection activity must have a complete reflex arc.
3. Knee bounce reflex: ligament below the knee.
Phenomenon: The calf suddenly bounces on the knee and is out of control of the brain.
When you shrink your hand, you shrink your hand first, and then you feel pain or burning. The nerve center of hand retraction is in the spinal cord; The nerve center of sensation (pain, burning sensation) is in the cerebral cortex.
4. Types of reflection
Simple reflex: the nerve center is located in the spinal cord.
Complex reflex: The nerve center is located in the cerebral cortex.
(1) Simple reflexes, such as hand retraction reflex, blink reflex, micturition reflex and knee jerk reflex, are all natural reflexes. This kind of reflex, as long as there is stimulation, the normal human body will respond accordingly, without the need for the brain to analyze and judge first.
(2) Complex reflection: hearing the bell ringing into the classroom, hearing the car horn quickly avoiding, etc. , is the accumulation of long-term life experience.
(3) Reflection related to language and writing is the most complex and unique for human beings. Such as: looking at plums to quench thirst, talking about a tiger turning pale, painting cakes to satisfy hunger, drinking a glass of bow and snake shadow, etc.
Eating plums and drooling is a simple reflection; People who have eaten plums drool at the sight of plums, which is a complicated reflection; People who have eaten plums will drool when they talk about plums, which is the most complicated reflection related to language and writing, and only human beings have it. )
The fourth quarter hormone regulation
1. Main endocrine glands of human body:
Pituitary gland: secretes growth hormone, etc.
Thyroid gland: secretes thyroid hormone.
Islet: Located in the pancreas, it secretes insulin.
Adrenal gland: Secretes adrenal hormones.
Thymus: Secretes thymic hormone.
Gonadas: Testicles (male): secrete male hormones.
Ovary (female): secretes estrogen.
2. Hormone: a chemical substance secreted by glandular cells of endocrine glands that has a special effect on the body.
Endocrine glands have no ducts, and secretions-hormones-directly enter the capillaries in the glands and are transported to the whole body with blood circulation.
(Exocrine glands have ducts, and secretions can be excreted or stored in structures other than exocrine glands, such as sweat secreted by sweat glands, milk secreted by mammary glands, bile secreted by liver, pancreatic juice secreted by pancreas, etc. Note: The pancreas is both an exocrine gland and an endocrine gland)
3. Symptoms of abnormal secretion of growth hormone, thyroid hormone and insulin:
4. Relationship between nerve regulation and hormone regulation: The regulation of human life activities is mainly regulated by the nervous system, but also by hormones.
Summary of biological knowledge points in the second volume of the seventh grade 4
Chapter VII Influence of Human Activities on Biosphere
The first section analyzes the impact of human activities on the ecological environment
1. China implements the family planning policy, encouraging late marriage and childbearing, and having fewer and healthier children.
The purpose is to control population, improve population quality, relieve biosphere pressure and realize sustainable development.
2. Human activities destroy the ecological environment
Deforestation and destruction of vegetation
Grassland overgrazing, serious sandstorm.
Kill many wild animals
A large number of pesticides and fertilizers are used to pollute the environment.
3. Biological invasion: Scientists refer to the phenomenon that organisms migrate to new environments with commodity trade and personnel exchanges, and cause serious harm to the environment as biological invasion. Such as Mikania micrantha, Spartina, Eichhornia crassipes, Eupatorium adenophorum, Ampullaria gigas and so on.
The second part discusses the influence of environmental pollution on biology.
1. Acid rain: Also known as "death in the air", it is caused by artificially releasing a large number of acidic substances into the atmosphere. Acid rain in China is mainly caused by burning a lot of coal with high sulfur content.
Hazards of acid rain:
Acidify the soil so that it cannot be absorbed and utilized by plants;
Acidizing water quality, thus affecting the growth and development of aquatic organisms, and even death;
Acidified water sources threaten people's health and affect drinking;
Acid rain directly harms the buds and leaves of plants, and in severe cases, it will kill many plants.
The fundamental measures to control acid rain: reducing the emission of pollutants in fuels such as coal and oil through purification devices; Reduce the use of fuels such as coal and oil and develop new energy sources.
2. Toxic substances discharged into water may increase the probability of gene mutation and induce cancer. Many heavy metal pollutants in water and soil, such as mercury, cadmium and arsenic, will accumulate through the food chain and eventually endanger human health.
3. Formation of the greenhouse effect: It is caused by the increasing global emissions of carbon dioxide and other gases. Harm: Global warming, accelerated melting of glaciers, rising sea level, more frequent typhoons and more arid land have caused worldwide crop reduction and survival crisis of various organisms.
Section III Formulation of Eco-environmental Protection Planning
1. To protect the ecological environment, we should do the following:
Protect forests and vegetation
Control acid rain and reduce environmental pollution
Improve people's awareness of environmental protection.
2. In order to prevent soil erosion, land desertification, sandstorm, etc. The main measures taken are: planting trees, protecting vegetation, returning farmland to forests and returning grass to lakes.
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