u4- reproductive system

What are gametes?

Specialized reproductive cells that contain half the normal chromosome number (haploid). They combine during fertilization to form a zygote.

What are examples of gametes?

Sperm (male gamete) and oocyte/egg (female gamete).

What is the function of the testes?

Produce sperm (spermatogenesis) and secrete testosterone.

Where are the testes located?

In the scrotum outside the pelvic cavity.

Why are testes located in the scrotum?

Sperm production requires a temperature about 2–3°C lower than body temperature

What structures make up the testes?

Seminiferous tubules, interstitial cells (Leydig cells), and sustentacular cells (Sertoli cells).

What are the male accessory reproductive organs?

Epididymis, ductus deferens, ejaculatory duct, urethra, seminal glands, prostate gland, and bulbourethral glands.

What is the function of the epididymis?

Site where sperm mature and are stored.

What is the function of the ductus deferens?

Transports sperm from epididymis to ejaculatory duct.

What is the function of seminal glands?

Produce fructose-rich fluid that nourishes sperm and makes up most of semen.

What is the function of the prostate gland?

Produces alkaline fluid that helps activate sperm and neutralize acidity.

What is the function of bulbourethral glands?

Produce mucus that lubricates and neutralizes the urethra.

What is semen?

Mixture of sperm cells and fluids from accessory glands.

What are the sources of semen?

Sperm from testes + secretions from seminal glands, prostate, and bulbourethral glands.

Describe the structure of a sperm cell.

Head, middle piece, and tail.

What is located in the sperm head?

Nucleus containing DNA and acrosome containing enzymes to penetrate the egg.

What is the function of the sperm middle piece?

Contains mitochondria that produce ATP for movement.

What is the function of the sperm tail?

Allows movement.

What is spermatogenesis?

Production of sperm cells

Where does spermatogenesis occur?

Seminiferous tubules of the testes.

What are the steps of spermatogenesis?

Spermatogonia → primary spermatocytes → secondary spermatocytes → spermatids → spermatozoa.

What do Sertoli (sustentacular) cells do?

Support developing sperm cells and secrete inhibin.

What do Leydig (interstitial) cells do?

Produce testosterone

*What hormone begins male reproductive regulation?

GnRH from hypothalamus.

*What does GnRH stimulate?

Anterior pituitary release of LH and FSH.

*What does LH do in males?

Stimulates Leydig cells to produce testosterone.

*What does FSH do in males?

Stimulates Sertoli cells and sperm production.

*What does testosterone do?

Supports sperm production and male reproductive characteristics.

What are the functions of the ovaries?

Produce oocytes and secrete estrogen and progesterone.

Where are ovaries located?

Lateral to the uterus in the pelvic cavity.

What is the function of the uterine tubes (fallopian tubes)?

Transport oocyte; site of fertilization

What is the function of the uterus?

Site of implantation and fetal development.

What is the function of the vagina?

Receives sperm, birth canal, and exit for menstrual flow.

What are the external female genital structures?

Mons pubis, labia majora, labia minora, clitoris, vestibule.

What is the function of mammary glands?

Produce milk for infant nourishment.

What hormone stimulates milk production?

Prolactin

What hormone causes milk ejection?

Oxytocin

What is oogenesis?

Production of female gametes (oocytes).

Where does oogenesis occur?

Ovaries

What is the role of the follicle?

Supports and nourishes developing oocyte and produces hormones.

*What are the three phases of the ovarian cycle?

Follicular phase, ovulation, luteal phase.

*What happens during the follicular phase?

Follicles develop and estrogen levels rise.

*What causes ovulation?

LH surge.

*What happens during the luteal phase?

Corpus luteum forms and produces progesterone.

What are the three phases of the uterine cycle?

Menstrual phase, proliferative phase, secretory phase.

What happens during the proliferative phase?

Estrogen causes endometrium to rebuild.

What happens during the secretory phase?

Progesterone prepares uterus for implantation.

**What starts female reproductive hormone regulation?

GnRH from hypothalamus.

**What does GnRH stimulate?

Anterior pituitary release of FSH and LH.

**What does FSH do in females?

Stimulates follicle development.

**What does LH do in females?

Causes ovulation and formation of corpus luteum.

**What does estrogen do?

Develops female characteristics and rebuilds uterine lining.

**What does progesterone do?

Maintains uterine lining for pregnancy.

What is fertilization?

Fusion of sperm and egg nuclei to form a zygote.

Define zygote.

Fertilized egg cell.

Define embryo.

Developing organism from implantation through week 8.

Define fetus.

Developing organism from week 9 until birth.

Define gestation.

Length of pregnancy (~38 weeks from fertilization).

What is the corpus luteum?

Structure formed after ovulation that produces progesterone.

Why is progesterone important after ovulation?

Maintains uterine lining for implantation.

What is hCG?

Human chorionic gonadotropin produced by embryo.

Why is hCG important?

Maintains corpus luteum so progesterone production continues.

What is cleavage?

Rapid cell division of the zygote.

What is a morula?

Solid ball of cells after cleavage.

What is a blastocyst?

Hollow structure that implants into uterus.

What is implantation?

Attachment of blastocyst to uterine wall.

What are placenta functions?

Nutrient exchange, gas exchange, waste removal, hormone production.

What is the chorion?

Outer membrane involved in placenta formation.

What is the amnion?

Membrane surrounding embryo filled with amniotic fluid.

What is amniotic fluid's function?

Protects fetus and allows movement.

What is the yolk sac?

Early blood cell formation.

What is the allantois?

Contributes to umbilical cord and blood vessel formation.

What is gastrula?

Embryonic stage where germ layers form.

What are the three germ layers?

Ectoderm, mesoderm, endoderm.

What are the three stages of labor?

1. Cervical dilation

2. Delivery of baby

3. Delivery of placenta

What is true labor?

Regular contractions causing cervical dilation.

What is false labor?

Irregular contractions without cervical changes.

What is colostrum?

First milk produced after birth rich in antibodies and nutrients.

Why is colostrum important?

Provides immune protection for newborn

What are the main classes of birth control?

• Hormonal methods

• Barrier methods

• Intrauterine devices

• Surgical methods

• Natural methods

Which birth control methods are most effective?

Sterilization and IUDs.

Which prevents STDs?

Condoms

**Trace sperm from production to fertilization.

Seminiferous tubules
→ Epididymis
→ Ductus deferens
→ Ejaculatory duct
→ Urethra
→ Penis
→ Vagina
→ Cervix
→ Uterus
→ Fallopian tube
→ Ovum