Chapter 7 Sexual Reproduction In Humans Flashcards
What does the male reproductive system consist of?
Pair of testes
Penis
Ducts connecting the penis and testes
Accessory glands e.g - prostate gland
What are seminiferous tubules?
Coiled tubes located in the testis. The cells that line the seminiferous tubules are germ cells that undergo sperm formation.
What are seminal vesicles?
Pair of glands below the bladder which secrete fluid that partly composes semen
What is the epididymis?
A highly convoluted duct behind the testis along which sperm passes to the vas deferens.
What is the vas deferens?
A tube that carries sperm from the epididymis towards the penis into the ejaculatory duct
What are the functions of secretions of accessory glands?
Maintains sperm mobility
Provide nutrients for sperm including fructose from the seminal vesicles mucus and zinc ions from prostate fluid
Alkaline to neutralise the acidity of any urine remaining in the urethra
Neutralise acidity of the vaginal tract
What are the functions of Sertoli cells?
Secrete fluid which nourishes the spermatids and protect them from the male immune system
What are interstitial cells?
Cells between seminiferous tubules which secrete testosterone needed for the formation and maturation of sperm
What is the structure of the uterus?
The uterus consists of 3 layers:
The perimetrium is a thin layer on the outside
The Myometrium is the muscle layer
The endometrium is the inner most layer. It’s a mucous membrane, supplied with blood.
What is the structure of the ovaries?
Consists of a matrix called the stroma, containing follicles. Follicles can be primary, secondary or Graafian. Follicles contain oocytes surrounded by cells called the corona radiata and zone pellucida.
Describe spermatogenesis
Germ line Cells divide by mitosis multiple times to form spermatogonium, followed by spermatogonia and then primary spermatocytes. Primary spermatocytes undergo meiosis 1 to form secondary spermatocytes. Secondary spermatocytes undergo meiosis 2 so that they become haploid spermatids. Sertoli cells nourish the spermatids allowing cell differentiation into spermatozoa.
Describe oogenesis
Before birth, Germ line cells divide by mitosis to form an oogonium, followed by oogonia. A primary oocyte develops within the primary follicles and undergoes meiosis stopping at prophase 1. FSH stimulates meiosis during puberty so that the primary oocyte divides by meiosis to form a secondary oocyte and first polar body and stops at metaphase 2. The secondary oocyte undergoes the rest of meiosis 2 but does not complete it until fertilisation takes place.
How are sperm adapted to their function?
Acrosome contains vesicles that hold digestive enzymes required to breakdown the ovum wall.
Haploid nuclei to ensure correct number of chromosomes.
Mid-section contains many mitochondria to synthesis ATP providing energy for movement.
How are ova adapted to its function?
Haploid nuclei
Corona radiata provides proteins/nutrients
Cortical granules are secretory organelles preventing polyspermy (the entry of more than one sperm)
