Beijing normal university printing plate seventh grade biology teaching plan
Skin and sweat secretion
[Teaching objectives]
1. Knowledge:
(1) Say the structure of skin and use these terms correctly in life;
(2) Understand the excretory function of skin.
2. Ability:
(1) Observe the skin structure with a microscope, and cultivate the ability of hands-on operation and observation and discrimination;
(2) Cultivate innovative consciousness and divergent thinking ability in the situation created by teaching;
(3) Through learning, we can truly understand the relationship between skin and daily life, increase common sense and skills in life, learn to apply what we have learned to real life, initially cultivate self-care ability and develop good living habits;
(4) Develop the ability to process information quickly and express and communicate flexibly through activities in the classroom.
3. Emotional attitudes and values:
(1) Understanding the skin structure through a microscope is helpful for students to look at and analyze problems from the perspective of dialectical materialism.
(2) Through the study of skin structure and health care knowledge, pay attention to life, love life, fully understand the importance of biology in actual production and life, and carry out aesthetic education for students.
(3) Educate students in patriotism by introducing relevant scientific and technological achievements in China.
Skin and sweat secretion.
Class hours: one class hour.
Skin is the largest organ of human body, which has many functions and is closely related to our daily life. But because the textbook will arrange this section in? The discharge of human excrement? This chapter is introductory, so the structure and function of skin should be introduced with excretory function as the main line in teaching design.
What is the focus of this class? The structure of skin? Although it is easier to observe under a microscope, it may be difficult for students to distinguish epidermis, dermis and subcutaneous tissue, which requires the guidance of teachers. ? The excretory function of the skin? Partly because the students are right? The formation and secretion of sweat? Lack of perceptual knowledge, so it is the difficulty of this class, you can use Cai.
This lesson begins with the macro world that students are familiar with. Clean-up of urban garbage? For example, let students understand the importance of discharging human metabolic waste in time. Ask questions at the same time? What channels can the human body excrete metabolic waste?
[Student's answer] ① It is excreted in the form of gas through the respiratory system;
② Excretion in the form of urine through the urinary system;
③ excreted through the skin in the form of sweat.
Take the opportunity to review the two ways of excretion I learned before and introduce today? Skin? The content of.
New course introducer: Some people say: I am familiar with skin! One for each person? (Starting from a light topic) So, can students list some words to describe skin? (Please list)
Students compete to speak: white and black; Skin as thick as a wall; Glossy; Sweating; ? White inside and red inside, different from others? ; ? Stay young and not get acne? ; ? On this day last year, in this door, people's faces and peaches set each other off.
The teacher said with a smile: The words listed by the students just now are very lively and interesting (give affirmation), but when you think about it carefully, these words also imply a series of problems about the skin (the topic turns sharply), such as the skin is exposed all the year round and exposed to a lot of bacteria, why doesn't it rot and deteriorate? Some people's skin is whiter than snow, while others are as black as charcoal. Why is the skin color of human body different? Dragon? Acne? What is the reason? Why do people sweat? (A series of questions make students think) These are undoubtedly related to the skin structure!
First, the structure of the skin
[Activity] Observe the structure of the skin.
(1) Students observe skin sections under a microscope to gain perceptual knowledge of skin structure;
(2) By comparing the skin structure map on the big screen, identify the various components of the skin;
(3) Show three simple questions to guide students to consciously observe and explore:
What is the structure of the skin?
② What are the characteristics of skin structure?
③ Infer the structure and function of each part.
【 Precautions 】 ① Teachers' patrol guidance;
② Please pay attention to the distance between the objective lens and the glass slide to prevent extrusion;
(3) After the observation, put it back into the sectioning microscope to complete the experiment.
Ask the students to compare the schematic diagram of skin structure on the screen, say the characteristics of skin structure and cell arrangement, and guess what function it has. Show courseware, summarize the structure of skin and guide students to understand the function from the structure.
Structure of skin: epidermis-stratum corneum, mucosa.
corium
Skin appendages: fur, sweat glands, sebaceous glands, nails, etc.
(1) epidermis
When introducing the division and growth ability of mucus layer, we can quote a set of data to confirm:? Generally, the whole epidermis of human body should be completely replaced every 3 ~ 4 weeks, and about 18kg of skin debris will be lost in a person's life? ; Introduction? Why is the skin of people who often bask in the sun darker? Pay attention to guide students to observe melanocytes in mucus layer.
(2) skin
Teacher: The dermis is composed of dense connective tissue (see figure). Is it thinner or thicker than the epidermis in thickness?
Health: thick!
Teacher: There are a lot of elastic fibers and collagen fibers in the dermis. What's the role? (The flash flashes two parts of the structure at the same time)
Teacher's demonstration: everyone hugs their faces together, then gently twists and releases their hands to see if there is any big change in the skin. (Or experiment with a fresh thick pigskin, tear, pull, pull)
The student smiled and said, No!
The teacher continued to demonstrate: this is a blank sheet of paper. I grabbed it, gave it a little twist and let go. Let's see what's wrong with this paper.
Health: It's wrinkled!
Teacher: What does this mean? (Tell me about the skin difference between Jia Baoyu and Granny Liu in a Dream of Red Mansions.)
Health: elastic fibers and collagen fibers in dermis give skin certain elasticity and toughness.
Teacher: In the dermis, we can also see sensory nerve endings and very rich capillaries (flashing flashes respectively). What are their functions? (Show the changes of capillaries in winter and summer through Flash to help students intuitively perceive and deeply understand this knowledge point)
Health: sensory nerve endings can make us feel external stimuli; Capillary can pass through its own? Contraction? With what? Diastolic pressure? To regulate body temperature to adapt to different environments.
(3) the accessory structure of the skin
Ask the students to observe their skin, tell which appendages are left on the skin, and then show the structural photos on the big screen.
In the introduction of sebaceous glands, we should pay attention to supplement the methods of preventing acne in adolescence and do a good job in psychological and physical health education in adolescence.
Second, the formation and secretion of sweat.
(1) Sweat gland composition
Secretory part: it is composed of thin tubes bent into a group, surrounded by capillaries.
Catheter: a slender tube with an opening on the skin surface.
Teacher: I'm sure all the students have had this experience, and staying in the hot summer sun for a while will make them feel sweaty. Sweating is a normal physiological phenomenon. But people didn't know how the sweat came before. Modern medicine and physiology tell us that there are 2.5 million small glands hidden in human dermis, from which sweat is transported to the skin surface. Flash the composition of sweat glands, pay attention to guide students to observe the capillaries around the secretory part of sweat glands and think about their functions.
(2) Composition of sweat
Teacher's demonstration: press your finger on the mirror, remove it after 5 seconds, and find water vapor on the mirror, which proves that there is water in sweat. Then let the students think and tell the evidence, and judge the other components of sweat from their daily experience.
Health: White salt is left on clothes and hats during military training, and the smell of sweat is salty! Which means there are inorganic salts.
Health: When sweating, there should be a bad smell, indicating that the components of sweat contain urea.
(3) the formation and secretion of sweat
This is the difficulty of this lesson, which can be demonstrated by Flash animation combined with information technology. The whole process avoids the pallor of simple language description, which makes the teacher's story vivid and the students' understanding intuitive and clear. )
The teacher explained with multimedia: when the environment temperature is high or the human body is exercising vigorously, the capillaries around sweat glands dilate and the blood flow increases. The cells in the secretory part of sweat gland absorb water, inorganic salts, urea and other substances from capillaries to form sweat, and then reach the body surface through the catheter to be discharged.
(4) advantages and disadvantages of sweating
Discussion: Let the students discuss the advantages and disadvantages of sweating in groups, so as to lead to the discussion on its function and cultivate students' oral expression ability and divergent thinking ability (time 4 minutes).
Health: it can be excreted!
Health: the role of regulating body temperature!
The teacher conveniently asked: how to achieve it? (in-depth question)
Health: The evaporation of sweat will take away some heat, so you can regulate your body temperature.
Teacher: (nod your head in agreement and play Flash at the same time? Sweat evaporates to take away heat? In addition to the skin can regulate body temperature through the contraction and relaxation of capillaries, the evaporation of sweat can also regulate body temperature. Especially during strenuous exercise, the heat released by muscle activity is equivalent to 65,438+00 ~ 65,438+05 times that at rest. At this time, it is too late to rely solely on the heat dissipation of the skin, and if these heats are not released in time, it will be enough to make the whole body excited. At this time, it is necessary to urgently start the 2.5 million of the whole body skin.
Teacher: Dialectical materialism tells us that everything has two sides, so what's wrong with sweating? (change the subject and educate the world outlook by the way)
Health: A lot of sweating will make people lose salt and cause heat spasm, so people should replenish water and salt in time in hot weather.
Health: Dirty clothes require us to do personal hygiene and develop good living habits.
Junior high school biology teaching thesis
The key point of implementing quality education is to promote the development of students. Therefore, in the implementation of quality education in biology teaching, we must establish students' dominant position, let students become the masters of learning, and let them develop their interest and emotion in learning while gaining knowledge development ability.
So, how to establish students' dominant position in biology teaching?
First, establish the concept of students' dominant position.
Family quality is the deep connotation of people's personality characteristics, and its basic feature is people's internal subjectivity. According to the basic principle of materialist dialectics, the formation of students' quality can only be realized by mobilizing their inner enthusiasm and internalizing their personality. The difference between initiative and passivity is the water ridge of quality education.
Adhering to the principle of subjectivity in quality education is to regard students as living beings who can have equal dialogue and communication with teachers. In education, we should regard students as the center of the classroom and the main body of learning, and give full play to their subjective initiative in the learning process? At the same time, the teacher's role should also be changed from the lecturer of knowledge to the student's learning guide, the student's activity guide and the student's ability coach.
In teaching, it is necessary to stimulate students' motivation for autonomous learning, cultivate students' autonomous learning ability, develop students' autonomous learning habits and awaken students' autonomous consciousness. Want me to learn? Develop into? I want to learn? So as to establish students' dominant position in biology teaching.
Second, explore? Autonomous learning? Mode, highlighting students' dominant position.
1. Create a problem environment to guide students to learn actively.
According to the development characteristics of middle school teachers and students? Strong curiosity, like to explore this feature, actively create problem situations in the teaching process, so that students can actively participate in learning. Such as: let students find problems and ask questions through self-study textbooks; According to the problems found by students in discussion and operation; Students can also ask related questions in extracurricular activities. So as to guide students to study independently, think positively and explore deeply, and realize students' initiative in learning.
2. Let students choose their own exercises to cultivate their own development in many aspects.
On the basis of fully mastering the basic knowledge of the classroom, teachers can arrange more kinds of homework and let students choose their own exercises. This will enable students with different learning abilities to successfully complete their difficult learning. Secondly, students with spare capacity can get opportunities for independent promotion and development, and further develop their own specialties. Such as: class a homework? For homework with unlimited methods and contents, you can find out the questions by reading other related books and answer them according to your own fff. Class b homework? Selected assignments refer to those exploratory or research assignments. Class c homework? There is a routine written assignment, but? Less but better? .
Such as: after learning? Root absorption? After the festival, I assigned the following kinds of homework: Class A homework: read the existing "Growing Flowers" and "Dancing Grass" in the school reading room, find out the questions and answer them by yourself. Class b homework: cultivate plants that are easy to survive, such as radish and spinach, and observe and study them? How do the roots of plants absorb and transport water? And then what? What's the difference between them in absorbing inorganic salts? Class C homework: What is the principle and process of root water absorption and inorganic salts? What is the connection? Department? . In this way, it not only stimulates students' interest in learning biology, cultivates students' practical ability, but also mobilizes students' enthusiasm, and has developed independently in many aspects.
Third, create a relaxed and harmonious classroom atmosphere and establish students' confidence in participating in learning.
The key to establishing a relaxed and harmonious classroom atmosphere is that teachers use their sincerity to arouse students' self-esteem, so that they can experience that teachers respect them and have confidence in their potential and problem-solving ability, so that students will get rid of their timidity, make a positive response, try their best to live up to teachers' trust and actively answer questions. This feeling of mutual trust and respect between teachers and students will naturally make the classroom atmosphere relaxed and harmonious, build confidence and create conditions for students to participate in learning.
Fourth, make use of the psychological effects of expectation and encouragement to promote students to actively seek development.
As we all know, what a student is regarded as, described as and treated as will become the reality of students in a short time. Rosenthal effect? . I have had such teaching experience. For example, in the teaching process, some students with average intelligence are often praised and encouraged when answering questions or correcting homework in class. In this way, these students not only make rapid progress in their studies, but also strive for perfection in their homework, and soon become advanced in their classes, and often rush to answer questions and actively think about solving problems: for some who belong to? Stubborn? When some students find their bright spots, they often give timely care and praise. As a result, there is no bad habit of skipping classes and not handing in homework in biology class. I was deeply moved by these experiences? Let every student experience success and let students study happily? . If students want to seek new development independently and give full play to their potential, talent and aura, they should constantly encourage, build up their self-confidence, raise the sails of competition and curiosity, and embark on the exploration road of independent learning.
In short, in biology teaching, only when teachers respect students, truly establish a people-oriented educational concept, and consciously use students' subjective concept to improve their teaching concept can they fully mobilize students' autonomy in learning and open the way for students' active learning and self-development.