Answer:
Spermatogonia , Primary Spermatocyte, Secondary Spermatocyte, Spermatids and Spermatozoa.
Explanation:
Seminiferous tubules are the main site for spermiogenesis. The two main cells included in the seminiferous tubules are germ cells which produce sperms another one is the Sertoli cells which nurture the germ cells throughout the developement process.
There are 3different phases described below:
1. Proliferative Phase: Spermatogonia i the basal region of the tubular epithelium undergo mitosis. Spermatogonia divide to give rise to primary spermatocytes. All descendants of a B spermatogonium remain connected by cytoplasmic bridges, forming a syncytium - like cell clone which undergoes synchronous development.
2. Meiotic Phase:Each primary spermatocyte divides to give rise to two short-lived secondary spermatocytes, which in turn give rise to two spermatids each. The spermatids contain a haploid number of chromosomes (half the number of a somatic cell). Primary spermatocytes are the largest cells in the spermatogenic series and are located approximately midway within the seminiferous epithelium.The process of meiosis occurs over a long period, with prophase of the first meiotic division taking up to three weeks
3. Differentiation phase
This phase is also known as spermiogenesis.
Spermatids undergo transformation into spermatozoa. Many changes occur within the cells, the three major ones being:
i) formation of the acrosome, which covers the cranial part of the head. The acrosome will contain hydrolytic enzymes to allow fusion of sperm and egg for fertilisation.
ii) condensation of nuclear chromatin in the head to form a dark-staining structure
iii) growth of the tail opposite the acrosome, and loss of excess cytoplasmic material which is shed as a residual body. The body is phagoctosed by the Sertoli cells..
Answer:
Amniocentesis is a process in which amniotic fluid is taken out from the uterus for the treatment or testing. It is a fluid which surrounds and protects the baby during pregnancy. This fluid contains different fetal cells & proteins.
Person may need an amniocentesis if doctor doubts that an unborn child has an anaemia or other infection. They may also suggest this in case of uterine infection. Its very much important, this procedure can also be performed to decrease the amount of amniotic fluid in mother's womb. Amniocentesis distinguish chromosomal abnormalities, defects of neural tubes & genetic defects. The most common chromosomal disorder is down syndrome or trisomy 21. Genetic disorders include cystic fibrosis. The most common neural tube defect is spina bifida.
Explanation:
Answer:
Physical and Chemical Barriers (Innate Immunity) Physical and chemical barriers form the first line of defense when the body is invaded. Physical Barriers. The skin has thick layer of dead cells in the epidermis which provides a physical barrier. Periodic shedding of the epidermis removes microbes.
Explanation
Physical and chemical barriers form the first line of defense when the body is invaded. The skin has thick layer of dead cells in the epidermis which provides a physical barrier. Periodic shedding of the epidermis removes microbes. The mucous membranes produce mucus that trap microbes.
Computer
A computer is a device or equipment that follows instructions from a hardware or software program to carry out tasks, computations, and activities. It has the capacity to receive input data, process that data, and then generate outputs.
In the right storage media, computers may also store data for later use and retrieve it as needed. Modern computers are electrical devices that may be used for a wide range of activities, such as web surfing, document authoring, video editing, application creation, video game playing, etc.
They combine integrated hardware and software components to perform programs and offer a range of solutions.
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