Who knows the key point of embryo formation?

Haha, it seems that we are all studying medicine. I graduated last year. When we finished the embryo assembly, I summarized the relevant points. You can refer to them: 1. What is histology? Many students will find this title too simple. The first sentence in the book is: histology is a science that studies the fine structure of the body and its related functions. Let me explain the meaning of this sentence: 1, the body can be animals, people, etc. We study medicine, of course, referring to the human body. 2, microstructure, human anatomy is about the structure that can be directly seen by the naked eye, which we generally call the gross structure. Of course, the microstructure here can't be directly seen by the naked eye, and it can only be seen with the help of a microscope, so it is called microstructure. Histology used to be called microanatomy. Generally speaking, there are two kinds of microscopes, optical microscope and electron microscope. So in the exam, if you are asked about the structure of a cell, you have to answer it from an optical microscope and an electron microscope. For example: the structure of the main cells of the gastric fundus gland? Answer: (1) Light microscope: the cell is columnar, with a round nucleus, near the base of the cell, with basophilic cytoplasm, and the cytoplasm at the top is filled with zymogen particles. Because these particles are not easy to preserve, they are often vacuolated in common fixed staining specimens. (2 points) Electron microscope: It can be seen that there are a large number of round zymogen particles at the top of cytoplasm, and there are abundant rough endoplasmic reticulum and developed Golgi complex around the nucleus. Generally, the structure of optical microscope is described by describing the shape of cells, such as columns or ellipses, just like describing a person. We will first say whether he is tall or short, fat or thin, that is, the overall image of the cell. Then the details are described, starting from the core, including the shape, quantity and location of the core. If it is a nucleus, there is no need to describe the number, but like skeletal muscle, there are nearly a hundred nuclei, so it is necessary to say its number. The nucleus of the main cell is round (shape) and located at the bottom (position) of the cell base. Okay, it's time to describe the cytoplasm. The first is the color, which is actually eosinophilic (red) or basophilic (blue), and then the substance contained in it. Just say what it mainly contains. There are many zymogen particles here, so describe them. So far, the optical microscope structure of cells has been described. To sum up briefly: the structure of optical microscope, first talk about the overall image of cells (column, circle, etc. ), and then talk about the number, shape and position of the nucleus. Finally, the acidophilic, alkalophilic and main substances in cytoplasm are described. The electron microscope only needs to describe the main organelles. It should also be noted that the structure of electron microscope is ultrastructure. For example, asking you about the ultrastructure of myocardial fibers is actually asking you about the electron microscope structure. One of the questions is about the cell structure of gastric fundus gland wall. Many of them only talked about one "cell endocrine tubule" and forgot another "microtubule vesicle system". If the electron microscope structure is 2 points, you can only get 1 point. 3, function, this is also a question that is often asked in the exam. In class, every time we talk about a structure, we should talk about its functions, such as what functions microvilli and cilia use. Similarly, when you ask about the structure of cells, you will also ask about the functions of cells. Take the main cell as an example, its function is to secrete pepsinogen. The point of this sentence is actually the point of histology and the focus of the exam. Generally speaking, this sentence is: histology is the study of structures that can not be directly seen by the naked eye, that is, tiny things, through optical microscope and electron microscope. When talking about these things, it will simply tell you what they do. 2. Histological content framework: From the book catalogue, there are four basic tissues: epithelial tissue, connective tissue, muscle tissue and nerve tissue. Connective tissue in a broad sense also includes liquid blood, solid cartilage and bones. Then there are eight systems, nerve, circulation, immunity, endocrine, digestion, respiration, urine and reproduction, plus two: senses (eyes and ears) and skin. What is said in each system is actually the structure of an organ. Points of each chapter: 1. Introduction: Some basic concepts, such as eosinophils and basophils, electron density and PAS reaction, can be seen in every chapter. Two dyes dyed by h.e.2. Epithelial tissue: Page 9, Table 2- 1. Its distribution is also often tested. For example, ask you: where are there no single-layer flat epithelial cells below: A. the outer surface of the heart B. the inner surface of the heart C. the outer surface of the stomach D. the renal tubules E. the alveoli. (answer d). There are two basic concepts in this table: endothelium and mesothelium. The first chapter focuses on the specialized structure of cell surface. 3. Connective tissue: The focus is loose connective tissue, and the key cells are fibroblasts, macrophages, plasma cells and mast cells. 4. Blood: Red blood cells are the key points, as shown in Table 4- 1 on page 3 of the book. 5. Cartilage and bone: some basic concepts of cartilage segment: cartilage cavity, homologous cell group and cartilage capsule. Types and distribution of main fibers in three kinds of cartilage. Some concepts of osteophyte: osteoid, bone plate, osteon, lacuna and tubule. Cells are mainly osteoblasts, osteoclasts and osteoclasts. The focus is on the structure of long bones. 6. Muscle tissue: the focus is on the light and electron microscopic structure of skeletal muscle, and one of the concepts is very important: sarcomere. Light and electron microscopic structure of myocardium. 7. Nerve tissue: Nerve tissue consists of two kinds of cells, one is neurons and the other is glial cells. So the focus is on neurons, and the key concepts are Nissl bodies and neurofibrils. The electron microstructure of chemical synapses is also very important. Nerve fibers are mainly myelinated nerve fibers, and the key concepts are Lang Feijie and myelin sheath. Nerve endings pay attention to its name, location and main function, as well as the key concept: motor endplate. 8. Nervous system: blood-brain barrier 9. Eyes and ears: the three layers of the eyeball wall, focusing on the cornea and retina. The ear focuses on the inner ear, especially the position and function of sensory receptors (sensory points and ampulla crista) and auditory receptors (spiral organs). 10, circulatory system: the structure of the heart wall, the respective structural characteristics and functions of the fourth grade arteries, the difference between the middle artery and the middle vein, and the structure, classification and function of capillaries. 1 1. skin: five-layer structure of epidermis, with hair and sebaceous glands as appendages. 12, immune system: two main lymphocytes T and B, key concept: lymphocyte recycling. Two forms of lymphoid tissue and their respective characteristics, key concepts: retrocapillary venules and lymphoid nodules. As we know, the circulatory system includes blood circulation and lymphatic circulation, so lymph nodes (filtering lymph) and spleen (filtering blood) are the key organs in lymphatic organs. The key concepts are: thymus corpuscle, blood-thymus barrier and thymus-dependent region. 13. Endocrine system: key concepts: hormones, target organs and cells, ultrastructure of cells secreting nitrogen-containing hormones and steroid hormones. This chapter focuses on: which cell secretes which hormone and the role of this hormone, for example, the main cell of parathyroid gland secretes parathyroid hormone, which increases blood calcium. Structure and function of adrenal cortex, structure and function of distal pituitary. Key concept: Pituitary portal vein system. 14. Digestive tube: four-layer structure of digestive tube wall, structure and function of gastric fundus gland, structure and function of small intestine villi and small intestine gland. Key concepts: wrinkled wall, taste buds, endocrine tubules, Paneth cell, intestinal villi. Key cells: main cells and parietal cells of gastric fundus gland, absorptive cells of small intestine. 15. Digestive gland: the structure and function of serous and mucinous cells (page 12- 14 of the book), the structure and function of exocrine part of pancreas, the structure and function of islets, and the structural characteristics of hepatic lobules. 16, respiratory system: nasal cavity, olfactory cells. Three-layer structure of trachea wall. This chapter focuses on the lung, one is the change law of bronchial tree wall, and the other is the structure and function of alveoli. Key concepts: pulmonary lobule and qi-blood barrier. 17, urinary system: nephron is the key, in the book 170 page table 17- 1. Key concepts: filter barrier, paravesicular complex, paravesicular cells, dense spots. 18, male reproductive system: key organ: testis, which has two main structures, one is seminiferous tubule and the other is leydig. Especially the five stages of spermatogenic cells in seminiferous tubules and the structure and function of supporting cells. Note that sperm cells and sperm are two different concepts. When some students answered sperm cells, they said tadpoles in the first sentence, which is obviously the shape of sperm, and the shape of sperm cells is round. There are also two confusing concepts: spermatogenesis (five stages) and spermatogenesis (the process in which sperm cells form sperm). 19. Female reproductive system: key organs: ovary and uterus. Ovary has two main structures, one is follicle and the other is corpus luteum. Therefore, the focus is on the four stages of follicles, especially the structural characteristics of growing follicles (primary follicles and secondary follicles), the formation, structure and function of corpus luteum. The uterus focuses on the three-layer structure of the uterine wall, especially the relationship between the structural changes of the endometrium and the ovary (i.e. menstrual cycle). 20, embryology: general part, pay attention to key concepts, two of which are easy to confuse, embryo and fetus, such as asking the structure of the blastoderm (second embryo and third embryo blastoderm), you should not answer placenta. Blastoderm and placenta, embryo and fetus. Select several main concepts: capacitation, fertilization, acrosome reaction, zona pellucida reaction, cleavage, implantation, morula, blastocyst, body pedicle (actually composed of ectoderm), primordia, fetal membrane, chorion and teratogenic sensitive period. Key topic: 1, specialized structure of cell surface. 2. Loose connective tissue structure. 3. Structure and function of red blood cells. 4. The structure of long bones. 5. Structure of skeletal muscle and myocardium. 6. Structure and function of neurons. 7. Structure of chemical synapse 8. The structure of peripheral myelinated nerve fibers. 9, the structure of the heart wall. 10, structure and function of arteries at all levels 1 1, structure and function of lymph nodes and spleen 12, structure and function of thyroid follicles 13, structure and function of adrenal cortex 14, and structure and function of the distal part of adenohypophysis. Structure and function of gastric fundus gland 17, structure and function of small intestinal villi and small intestinal glands 18, structure and function of exocrine and endocrine parts of pancreas 19, structure and function of hepatic lobule 20, structure and function of alveoli 2 1, and the changing law of the wall structure of pulmonary airway 22, structure and function of nephron. The development process of spermatogenic cells supports the structure and function of cells, the development process of follicles (especially the structural characteristics of growing follicles), the formation, structure and function of corpus luteum, and the structure and function of uterine wall (especially the relationship between endometrium and ovary).