Sexual Reproduction in Humans - finished Flashcards
What are the testes?
Site of sperm rouction inside SEMINIFEROUS TUBULES
Site of testosterone production
What is the scrotum?
Sac like pouch that holds the testes outside the body so that it is at optimal temperature for sperm production
What is the epididymis?
Tube like structures alongside the testes
Site of sperm maturation
What is the fuction of the Vas deferens?
transport sperm
Peristaltic movements to move sperm from the epididymis upto the seminal vesicle and prostate gland/ top of the urethra
What is the function of the seminal vesicle?
Add fluid -> slightly alkaline (to neutralise acidity in the vagina) Add fructose (Source of energy for sperm)
What is the function of the prostate gland?
Adds more fluid to the semen
What is the function of the penis?
Intromitent organ -> inserted into the female vagina to deliver the sperm/semen
urination
What is the function of the urethra?
Allows sperm/urine to leave the body
What is the function of the ovary?
site of production of female gametes
Site of female sex hormone production
What is the function of the fallopian tubes?
Allow passage of the “egg”/gamete (peristaltic movements/cilia)
Site of fertilisation
What is the function of the uterus?
Site of development of the foetus.
What is the function of the Endometrium?
Starts as a single layer of cells -> becomes thinker and vascularised (blood vessels) also becomes glandular (secretes hormones)
Layers lost in menstruation
What is the fuction of the Vagina?
Muscular tube into which the males penis is inserted during copulation/intercourse
Tube along which the baby is pushed during birth
What is the process of Spermatogenesis?
The production of sperm
What is the process of oogenesis?
The production of female gametes
Where does Spermatogenesis take place?
The seminiferous tubules of the testis
How long does the process of spermatogenesis take?
75 days
What cell is used in the production of sperm?
Sertoli Cell
How many stages are there in Spermatogenesis?
Germinal epithelium (mitosis) Spermatigonium (mitosis) Primary Spermatocyte (meiosis 1) Secondary Spermatocyte (meiosis 2) Spermatid (loose cytoplasm and grow tail) Spermatozoa
Why do sperm need Mitochondia?
To provide ATP for movement
What is in the acrosome in the head of the sperm?
hydrolitic enzyme - used to digest a way for the sperm through the egg
What is the sperms tail called?
Flagellum
What happens during Oogenisis?
When the female is still a foetus: the oogonia undergoes mitosis to become primary oocytes. The primary oocyte undergoes meiosis 1 but stops at prophase 1. During Birth and Childhood nothing happens but once the female enters puberty ONe primary oocyte continues its development once a month. The primary oocyte finishes meiosis 1 and leaves the ovary during ovulation. If there is no sperm present, nothing happens (no secondary division) if there is sperm present Meiosis 2 occurs and an ovum (female gamete) is formed.
Where does the sperm meet the secondary oocyte?
Fallopian tube
How many layers are there in a secondary oocyte
Corona Radiata (Cells)
Zona Pellucida (Glycoprotein)
Vitelline Mebrane
Secondary Oocyte
What happens in an acrosome reaction?
Hydrolytic enzymes are released from the sperms head and they digest a pathway through the corona Radiata and the Zona Pellucida to the Secondary Oocyte
How many sperm make it through to the secondary oocyte?
1
What happens after the makes it to the secondary oocyte?
changes occur the othe cell membrane of the oocyte to prevent the entry of any more sperm
THe entry of the head into the oocyte triggers Meiosis 2 which forms an ovum 9female gamete) and 2nd polar body
What is fertilization?
The fusing of the Male and Female gametes
What does fertilization form?
A zygote
What happens to the zygote?
The zygote divides by cleavage (no increase in size) and travels down the fallopiaan tubes untill it forms a hollow balls of cells called a blastocyst.
What does a Blastocyst do?
Givs of hormones which maintain the corpus luteum
Embeds into the endometrium by IMPLANTATION and them forms a foetus.
What does the corpus luteum do?
Produces the hormone Human Chorionic Gonadrophin (HCG) which maintains the endometrium (no periods) and it is also the hormone that pregnancy tests look for.
What do pregnancy tests do?
Use monoconal antibodies to test for HCG
What happens to the endometrium when the blastocyst becomes embedded?
It becomes thicker and develops blood vessels which provide nutrients to the baby
What is the most common cause of infertility?
Blocked fallopian tubes
How can people get round the problem of Blocked Fallopian tubes?
In Vitro Fertilization (IVF) - Fertilization takes place outsize the females body in a petri dish
Then is placed in the uterus in the blastocyst stage.
