Human Reproduction Human Reproduction The REPRODUCTIVE SYSTEM is

Human Reproduction

Human Reproduction • The REPRODUCTIVE SYSTEM is the ONLY system in the body that isn’t necessary for the SURVIVAL of an individual. • However, the REPRODUCTIVE SYSTEM is necessary for an entire SPECIES’ survival! • It allows us to not go EXTINCT.

VOCABULARY • Gonad: MALE and FEMALE SEX GLANDS • Ex: OVARIES and TESTES • Gamete: MALE and FEMALE SEX CELLS • Ex: EGG and SPERM • Meiosis: Type of cell division that PRODUCES and MATURES gametes.

MALE REPRODUCTIVE SYSTEM • FUNCTION: PRODUCE and RELEASE of sperm

PARTS OF THE MALE REPRODUCTIVE SYSTEM Testes: also known as the male GONAD --testes are glands and therefore they secrete a HORMONE called TESTOSTERONE --where SPERM are produced and developed by the process of MEIOSIS Scrotum: holds the TESTES outside the body --provides optimum TEMPERATURE for sperm PRODUCTION and STORAGE ** 1 to 2 degrees cooler

PARTS OF THE MALE REPRODUCTIVE SYSTEM • Epididymus: stores SPERM • Vas deferens: TUBE that carries SPERM from each testicle to the URETHRA • Urethra: tube that carries URINE and SPERM through the penis to the OUTSIDE of the body • Seminal vesicle and the prostate gland: ▫ --secretes nourishing FLUID into the URETHRA ▫ --mixes with SPERM to make SEMEN ▫ --allows SPERM to survive their JOURNEY through the female reproductive system

SIDE VIEW OF THE MALE REPRODUCTIVE SYSTEM 5. BLADDER 6. SEMINAL VESICLE 7. PROSTATE 10. RECTUM 8. URETHRA 9. PENIS 22 2. TESTES 1. SCROTUM 3. EPIDIDYMUS 4. VAS DEFERENS

FRONT VIEW OF THE • MALE REPRODUCTIVE • SYSTEM • • • 1. sperm & testosterone are developed in the TESTES 2. sperm are collected in the EPIDIDYMUS 3. sperm travel through the VAS DEFERENS 4. SEMINAL VESICLE provides fructose for the sperm 5. the BLADDER holds urine until discharge 6. the URETHRA releases urine & semen 7. the PROSTATE GLAND produces a protective, nutritive secretion for the sperm

FRONT VIEW OF THE MALE REPRODUCTIVE SYSTEM • In the body of the prostate, ducts from the seminal vesicles and the prostate unite with the urethra.

PARTS OF THE FEMALE REPRODUCTIVE SYSTEM • Ovaries: also known as the female GONAD ▫ ovaries are glands and therefore secrete HORMONES called ESTROGEN and PROGESTERONE ▫ Where EGGS are produced and developed by the process of MEIOSIS

PARTS OF THE FEMALE REPRODUCTIVE SYSTEM • Follicles: egg SACS found in the OVARIES ▫ 1 EGG is formed and MATURED in each follicle ▫ Females are BORN with an IMMATURE egg in each follicle ▫ Eggs begin to mature at PUBERTY ▫ The process that produces and matures an egg is called MEIOSIS

PARTS OF THE FEMALE REPRODUCTIVE SYSTEM 1. OVARY 2. FOLLICLE 3. EGG being released

PARTS OF THE FEMALE REPRODUCTIVE SYSTEM • Oviduct (Fallopian tube): has CILIA to draw EGG into the tube • *** Where FERTILIZATION takes place

PARTS OF THE FEMALE REPRODUCTIVE SYSTEM FERTILIZATION OVIDUCT CILIA Follicle releasing an egg OVARY

PARTS OF THE FEMALE REPRODUCTIVE SYSTEM • Uterus: thick-walled MUSCULAR organ where IMPLANTATION occurs (if fertilization occurred) ▫ If no fertilization occurs, the uterine lining SHEDS ▫ This is known as MENSTRUATION

PARTS OF THE FEMALE REPRODUCTIVE SYSTEM FOLLICLE

PARTS OF THE FEMALE REPRODUCTIVE SYSTEM • Cervix: NARROW neck of the UTERUS • Vagina: where MENSTRUAL fluid EXITS the body ▫ Where SPERM is deposited ▫ Also known as the BIRTH canal

FRONT VIEW OF THE FEMALE REPRODUCTIVE SYSTEM FOLLICLE Aka OVIDUCT Aka UTERINE LINING

SIDE VIEW OF THE FEMALE REPRODUCTIVE SYSTEM OVARY OVIDUCT UTERUS BLADDER URETHRA CERVIX VAGINA

THE MENSTRUAL CYCLE • • Begins at PUBERTY Ends at MENOPAUSE Takes about 28 days Regulated by 4 hormones: ▫ 1) LH (LUTEINIZING HORMONE) secreted by pituitary ▫ 2) FSH (FOLLICLE-STIMULATING HORMONE) secreted by pituitary ▫ 3) ESTROGEN secreted by ovaries ▫ 4) PROGESTERONE secreted by ovaries

HORMONES & THEIR TARGET CELLS Pituitary Gland secretes: 1. LH (Luteinizing Hormone) 2. FSH (Follicle Stimulating Hormone) Target Cells: OVARIES Ovaries Secrete: 1. ESTROGEN 2. PROGESTERONE Target Cells: UTERUS

THE MENSTRUAL CYCLE

THE STAGES OF THE MENSTRUAL CYCLE • Follicle Stage (10 – 14 days long) • FSH causes egg to mature • ESTROGEN increases, thus shutting down the FSH (negative feedback)

STAGES OF THE MENSTRUAL CYCLE • Ovulation (1 day long) • EGG bursts from the follicle due to high amounts of LH

STAGES OF THE MENSTRUAL CYCLE • Corpus Luteum Stage: (10 – 14 days long) • PROGESTERONE increases, thus shutting down LH (negative feedback) • Uterus THICKENS with blood and mucus in anticipation of fertilized egg

STAGES OF THE MENSTRUAL CYCLE • Menstruation: (3 – 5 days long) • Uterine lining is SHED along with unfertilized egg because all the hormones are low • THEN…. the whole cycle starts over again!

TWINS • Fraternal twins: ▫ More than one EGG is fertilized ▫ Either the same OVARY releases 2 mature eggs or both OVARIES release a MATURE egg ▫ Each egg reaches the OVIDUCT where they are FERTILIZED by 2 DIFFERENT sperm ▫ GENETIC: runs in families because ovulation is regulated by hormones and hormones are produced genetically

TWINS • Identical twins: ▫ ONE early stage EMBRYO splits in TWO ▫ Not GENETIC = random ▫ **An embryo splitting occurs by chance

TWINS