第十八章第十八章 男性生殖系统男性生殖系统 (male reproductive system) l一一 睾丸睾丸 testis 被膜被膜 浆膜浆膜 白膜白膜l一般结构一般结构 实质实质 生精小管生精小管 间质间质 睾丸间质细胞睾丸间质细胞 l（一）生精小管一）生精小管 seminiferous tubule 精原细胞精原细胞生精上皮生精上皮 生精细胞生精细胞 初级精母细胞初级精母细胞 次级精母细胞次级精母细胞 精子细胞精子细胞 精子精子 支持细胞支持细胞基膜基膜胶原纤维胶原纤维 、肌样细胞、肌样细胞 l1 1 生精细胞生精细胞 spermatogenic celll 精子发生精子发生 spermatogenesis 精原细胞发育形成精子的过程精原细胞发育形成精子的过程l 1 1）精原细胞）精原细胞 spermatogenous celll 2 2）初级精母细胞）初级精母细胞 primary spermatocytel 3 3）次级精母细胞）次级精母细胞 secondary spermatocytel 4 4）精子细胞）精子细胞 spermatidl 5 5）精子）精子 sperm l 1 1）精原细胞）精原细胞 spermatogenous cell 形态：紧靠基膜，圆形，核圆染色深形态：紧靠基膜，圆形，核圆染色深 A A型（干细胞）型（干细胞） A A型型 干细胞干细胞 B B型型 分化初级精母细胞分化初级精母细胞 spermatogenous cell l 2)2)初级精母细胞初级精母细胞 primary spermatocytel形态：胞体大，核大而圆形态：胞体大，核大而圆（（46，，xy））l第一次成熟分裂第一次成熟分裂 次级精母细胞次级精母细胞（（ 23x）） 次级精母细胞次级精母细胞（（23y））primary spermatocyte l 3 3）次级精母细胞）次级精母细胞 secondary spermatocytel形态：体积较小，存在时间短不易见到形态：体积较小，存在时间短不易见到 第二次成熟分裂第二次成熟分裂 精子细胞精子细胞（（23x）） 精子细胞精子细胞（（23y））secondary spermatocyte maturation division4n DNA2n DNA1n DNA l 4 4）精子细胞）精子细胞 spermatidl形态：靠近管腔，小而圆，核圆染色深，形态：靠近管腔，小而圆，核圆染色深， 无分裂能力无分裂能力 spermatid 精子精子形形成成：：精子细胞由圆形分化为蝌蚪形精子精子细胞由圆形分化为蝌蚪形精子 主要变化：主要变化：( (1 1）核浓缩：构成精子头部）核浓缩：构成精子头部 (2 2）顶体形成）顶体形成 ( (3 3）中心粒产生轴丝）中心粒产生轴丝 (4 (4）线粒体鞘形成）线粒体鞘形成 (5 (5）多余胞质脱落）多余胞质脱落 精子发生与精子形成精子发生与精子形成 § 精原细胞：精原细胞： § 初级精母细胞：初级精母细胞：46，，XY§ 次级精母细胞次级精母细胞: 23, X 23, Y§ 精子细胞精子细胞: 23, X 23, Y§ 精子精子: 23, X 23, Y精精子子发发生生精子形成精子形成 精母细胞二次成熟分裂精母细胞二次成熟分裂 l 5 5）精子）精子 sperm 呈蝌蚪形呈蝌蚪形l 头：浓缩的细胞核，头：浓缩的细胞核， 核前核前2/32/3覆盖有覆盖有顶体顶体 acrosome 内含顶体酶内含顶体酶l 尾尾( (鞭毛鞭毛) )：精子的运动装置：精子的运动装置 颈段：中心粒颈段：中心粒 中段：轴丝中段：轴丝+Mi +Mi 鞘鞘 主段：轴丝主段：轴丝+ +纤维鞘纤维鞘 末段：轴丝末段：轴丝 LM: sperm EM: sperm l2 2 支持细胞支持细胞 Sertoli's cell;supporting cell l1 1））LMLM：细胞轮廓不清，：细胞轮廓不清， 核不规则，着色浅，核仁清楚核不规则，着色浅，核仁清楚 Sertoli's cell l2））EM：：( (1 1）不规则锥体形）不规则锥体形(2(2）顶部和侧面嵌有生精细胞）顶部和侧面嵌有生精细胞 (3(3））Go.RER.SER.MiGo.RER.SER.Mi丰富丰富(4(4）细胞基部有紧密连接）细胞基部有紧密连接 Sertoli's cell l3 3）功能）功能：：l(1(1）支持、营养生精细胞）支持、营养生精细胞l ( 2 2）分泌）分泌 雄激素结合蛋白雄激素结合蛋白 等等 l ( 3 3）吞噬功能）吞噬功能l (4 4）） 参与构成参与构成 血血- -睾屏障睾屏障l 毛细血管内皮及基膜毛细血管内皮及基膜 结缔组织结缔组织 生精上皮基膜生精上皮基膜l 支持细胞间紧密连接支持细胞间紧密连接blood-testis barrier l（二）睾丸间质（二）睾丸间质 interstitial tissue of testis 疏松结缔组织疏松结缔组织 睾丸间质细胞睾丸间质细胞 Leydig cellLeydig cell l睾丸间质细胞睾丸间质细胞l 1 1））LMLM：胞体大，圆或多边形，胞质嗜酸性：胞体大，圆或多边形，胞质嗜酸性l 2 2））EMEM：分泌类固醇激素细胞超微结构特点：分泌类固醇激素细胞超微结构特点 （（ SERSER、、MiMi、脂滴丰富、脂滴丰富））l 3 3）功能：分泌雄激素）功能：分泌雄激素 androgenLMEM 二二 附睾附睾 epididymidis l1 1 组织结构组织结构l 输出小管：上皮为高柱状纤毛细胞、低柱输出小管：上皮为高柱状纤毛细胞、低柱 状细胞相间排列，腔面不规则。
状细胞相间排列，腔面不规则l 附睾管：上皮为假复层柱状上皮，附睾管：上皮为假复层柱状上皮， 有静纤毛，腔面规则有静纤毛，腔面规则l2 2 功能功能 分泌分泌 精子功能成熟，获得运动能力，精子功能成熟，获得运动能力， l输出小管输出小管efferent ductl副睾管副睾管epididymal duct l三三 前列腺前列腺 prostatel1 1 组织结构组织结构 分泌部分泌部: : 1 1）上皮细胞形态多样）上皮细胞形态多样 2 2）腺腔不规则）腺腔不规则 3 3）腺腔内有）腺腔内有前列腺凝固体前列腺凝固体 导管：开口于尿道精阜两侧导管：开口于尿道精阜两侧 间质：弹性纤维、平滑肌丰富间质：弹性纤维、平滑肌丰富l2 2 功能功能 分泌分泌 prostate 重点重点l1 1 生精上皮组成，生精上皮组成， 生精细胞组成生精细胞组成 l2 2 支持细胞光镜结构和功能支持细胞光镜结构和功能 间质细胞光镜结构和功能间质细胞光镜结构和功能l3 3 血血- -睾屏障睾屏障 CHAPTE 18 MALE REPRODUCTIVE SYSTEM OUTLINE The male reproductive system is composed of the testes , genital ducts, accessory glands , and penis. The dual function of the testis is to produce androgen , the testosterone and spermatozoa. The genital ducts and accessory glands produce secretions that, aided by smooth muscle contraction, propel spermatozoa toward the exterior. These secretions also provide nutrients for spermatozoa while they are confined to the male reproductive tract. Spermatozoa and the secretions of the genital ducts and accessory glands make up the semen, which is introduced into the female reproductive tract through the penis. Each testis is composed of about 250 pyramidal compartments called the testicular lobules. Each lobule is occupied by 1-4 seminiferous tubules enmeshed in a web of loose connective tissue that is rich in blood and lymphatic vessels, nerves, and interstitial (Leydig) cells. The seminiferous tubule consists of a fibrous tunica propria , a well- defined basal lamina , and a complex germinal , or seminiferous epithelium. The seminiferous epithelium consists of 2 types of cells; Sertoli, or supporting cells and spermatogenic cells, which regularly replicate and differentiate into mature sperms. The production of spermatozoa is called spermatogenesis, a process that includes cell division through mitosis and meiosis and the final differentiation of spermatozoids , called spermiogenesis. The spermatogenesis begins with a primitive germ cell, the spermatogonium. At sexual maturity, spermatogonia begin dividing by mitosis, producing successive generations of cells . The newly formed cells can follow one of 2 paths: they can continue dividing as stem cells, also called type A spermatogonia, or they can differentiate during progressive mitotic cycles to become type B spermatogonia. Type B spermatogonia will differentiate into primary spermatocytes. They replicate their DNA shortly after they form. So that each primary spermatocyte contains 4N amount of DNA before meiosis begins. The primary spermatocytes enter the first meiotic division, from which arise smaller cells called secondary spermatocytes with only 23 chromosomes (22 + X or 22 + Y ) and 2N of DNA. Then the cells quickly enter into the second meiotic division. Division of each secondary spermatocyte results in 2 cells that contain 23 chromosomes , the spermatids. Because no S phase (DNA synthesis ) occurs between the first and second meiotic division of the spermatocytes, each spermatid has 1N of DNA. The meiotic process therefore results in the formation of cells with a haploid number of chromosomes. With fertilization , they return to the normal diploid number. The spermatids undergo spermiogenesis , by which spermatids transform into spermatozoa with a series of morphologic changes. The Sertoli cells are elongated pyramidal cells that partially envelop cells of the spermatogenic lineage. The bases of the Sertoli cells adhere to the basal lamina, and their apical ends frequently extend into the lumen of the seminiferous tubule. In the light microscope , the outline of Sertoli cells appear poorly defined because of the numerous lateral processes that surround spermatogenic cells. Studies with electron microscope reveal that these cells contain abundant smooth endoplasmic reticulum , some rough endoplasmic reticulum. a well-developed Golgi complex, and numerous mitochondria and lysosome. The elongated nucleus, which is often triangular in outline, possesses numerous infoldings and a prominent nucleolus, it exhibits little heterochromatin. Adjacent Sertoli cells are bound together by occluding junctions at the basal lateral part of the cell, forming a blood-testis barrier. The functions of the Sertoli cells include: (1) the support, protection, and release of the spermatogenic cells; (2) the nou-rishment of the spermatocytes, spermatids, and spermatozoa; (3) the phagocytosis of the residual bodies derived from the sper-matids; (4) the secretion of fluid into the lumen of the seminiferous tubule for the transport of spermatozoa; and (5) the secretion of an androgen-binding protein for concentrating testosterone in the seminiferous tubule. The Leydig cells have the chara-cteristics of steroid-secreting cells. These cells produce the male hormone testosterone, which is responsible for the proliferation and differentiation of the spermatogenic cells, and for the develo-pment of the secondary male sex chara-cteristics. 。