Question

1. Trace a sperm from formation to fertilization. Name all of the structures through which it passes. Include all additional structures that contribute to semen volume. Identify the products each produces.  
   
2. Once fertilized, describe all of the steps and sub-steps discussed in the lectures, from zygote to delivery. Include the physiological changes that occur and the hormones that are involved.  
   
3. Explain Incomplete Dominance and give an example.   

Answer 1

The sperm is formed in the testicles which contains a tiny tubes called as seminiferous tubules that have testosterone hormone. and germ cells.The germ cells will divide and change into a tadpole with a head and tail which is short is formed.The short tail make a push of the sperm to the epididymis locates behind the testes. It takes about 5 weeks to complete the full development of sperm in the epididymis and the sperm pass to the vas deferens .So when a man is a with a stimulus the sperm with seminal fluid which is a liquid white that is produced by the seminal vesicles and the prostate gland is released via the male reproductive organ with the mixture of semen and sperm. The normal volume of semen is 2-6 mL that contains 10% of sperms and fluid, 60% seminal fluid, 30% of prostatic fluid and also a fructose for the nutrition of sperm.

sperm production with chromosomal division:

The released sperm enter into female reproductive system and travels via vagina,uterus and at last to fallopian tube where the sperm meets the ovum an egg from the ovulation and penetrates into the egg and get fertilized.The survival rate of sperm in the genital tract is more than the ovum because ovum has 24 hours of survival and sperm has 72 hours. After fertilization there is a formation of zygote which contains 46 chromosomes that forms an embryo and continues to divide and form morula that moves via fallopian tube and implanted in the uterus and the process of implantation end by 11 day.

Fertilization process:

During the pregnancy, hCG hormone named as human chorionic gonadotrophin hormone produced at the 7 days of fertlization and reaches its peak at 60 days of fertilization that results in nausea,vomiting and fatigue. Relaxin is the hormone that is secreted in the pregnancy that relaxes the joints and even the cervix for the purpose of delivery. Oxytocin hormone helps in uterine contraction at the delivery.The physiological changes of pregnancy include the nausea,vomiting.fatigue, joint pain, joint laxity,increased blood circulation over uterus ,stretching of uterus and abdominal muscles,increased cardiac output, increased heart rate,frequent urination,food carvings,mood swings etc..

Incomplete dominance is where the one allele from the parent does not completely expressed over its paired allele that results in the production of another third phenotype by the combination of both the alleles from the parents. For an example the father has a curly hair and the mother has a straight hair but their child results into having a wavy hair by the combination of two alleles from the parents and Tay-Sach disease is also an example of incomplete dominance that affects the nervous system which is accumulated by lipids by the increased break down of lipids.