BIO 3347 Lecture 1: Reproduction
Document Summary
Sexual reproduction produces new individuals gametes (sperm and egg) formed by testes and ovaries. Fertilization produces one cell (a zygote) with one set of chromosomes from each parent. Urology is study of urinary and male reproductive system. Sac of loose skin, fascia and smooth muscle divided into two pouches by a septum. Sperm survival requires 2-3 degrees lower temperature than core body temperature. Muscle in scrotum - elevates testes on exposure to cold and during arousal and warmth reverses the process. Paired oval glands measuring 2 in. by 1 in. Each is lled with 2 or 3 seminiferous tubules where sperm are formed. Sertoli cells extend from basement membrane to lumen. Produce uid and control release of sperm into lumen. Second meiosis division give four spermatids, each with 23 single stranded chromosomes. First meiosis division give two secondary spermatocytes, each with 23 chromosomes that become double stranded. Head contains dna and the acrosome with enzymes for penetrating the egg.
