BIO 202: Reproductive System, Pregnancy & Human Development, and Endocrine System Study Guide

Reproductive System (Chapter 27)

Anatomy of the Male Reproductive System

The male reproductive system is specialized for the production, nourishment, and transport of sperm. It also produces male sex hormones.

• Testes: Primary male gonads; produce sperm and testosterone.

• Epididymis: Site of sperm maturation and storage.

• Vas deferens: Transports sperm from the epididymis to the ejaculatory duct.

• Seminal vesicles, prostate gland, bulbourethral glands: Accessory glands that produce seminal fluid to nourish and transport sperm.

• Penis: Organ for copulation and delivery of sperm into the female reproductive tract.

Example: The prostate gland secretes a fluid that activates sperm and is a component of semen.

Anatomy of the Female Reproductive System

The female reproductive system is designed for the production of ova, reception of sperm, and support of fetal development.

• Ovaries: Primary female gonads; produce ova (eggs) and female sex hormones (estrogen and progesterone).

• Uterine (fallopian) tubes: Transport ova from the ovaries to the uterus; site of fertilization.

• Uterus: Muscular organ where implantation and fetal development occur.

• Vagina: Muscular canal for copulation and childbirth.

• External genitalia (vulva): Includes labia, clitoris, and vestibular glands.

Example: The endometrium is the inner lining of the uterus that thickens in preparation for implantation.

Physiology of Male and Female Reproductive Systems

• Male: Spermatogenesis occurs in the seminiferous tubules; testosterone regulates development and maintenance of male secondary sex characteristics.

• Female: Oogenesis occurs in the ovaries; estrogen and progesterone regulate the menstrual cycle and secondary sex characteristics.

Spermatogenesis and Oogenesis

• Spermatogenesis: The process of sperm production in males. Occurs in the seminiferous tubules and involves meiosis to produce haploid sperm cells.

• Oogenesis: The process of egg (ovum) production in females. Occurs in the ovaries and involves meiosis, but only one functional ovum is produced from each primary oocyte.

Key Equation:

$\text{Meiosis:} \\ 2n \rightarrow n$

Hormones Involved in Male and Female Reproduction

• Male: Testosterone (from testes), Luteinizing hormone (LH), Follicle-stimulating hormone (FSH) (from anterior pituitary).

• Female: Estrogen and progesterone (from ovaries), LH and FSH (from anterior pituitary).

Example: LH stimulates ovulation in females and testosterone production in males.

Sexually Transmitted Diseases (STDs)

• Bacterial: Chlamydia, gonorrhea, syphilis.

• Viral: Human immunodeficiency virus (HIV), herpes simplex virus (HSV), human papillomavirus (HPV).

• Fungal/Parasitic: Trichomoniasis, candidiasis.

Example: HPV infection can lead to cervical cancer in females.

Pregnancy and Human Development (Chapter 28)

Fertilization

Fertilization is the union of a sperm and an ovum, usually occurring in the ampulla of the uterine tube.

• Acrosomal reaction: Sperm releases enzymes to penetrate the egg's protective layers.

• Fusion of membranes: Sperm and egg membranes fuse, allowing the sperm nucleus to enter the egg.

Six Steps of Penetration and Their Importance

1. Approach: Sperm approaches the oocyte.

2. Acrosomal reaction: Enzymes digest the zona pellucida.

3. Binding: Sperm binds to oocyte membrane receptors.

4. Fusion: Sperm and oocyte membranes fuse.

5. Blocks to polyspermy: Prevents entry of additional sperm.

6. Completion of meiosis II: Oocyte completes meiosis, forming the ovum and second polar body.

Importance: Ensures only one sperm fertilizes the egg, maintaining correct chromosome number.

The Three Germ Layers and Their Derivatives

• Ectoderm: Forms nervous system and skin.

• Mesoderm: Forms muscles, bones, cardiovascular system.

• Endoderm: Forms lining of digestive and respiratory tracts, and associated organs.

Primitive Organs Formed by Endodermal Differentiation

• Digestive tract lining

• Respiratory tract lining

• Liver and pancreas

Fetal vs. Newborn Circulation

Feature	Fetus	Newborn
Foramen ovale	Open (shunts blood from right to left atrium)	Closes after birth
Ductus arteriosus	Connects pulmonary artery to aorta	Closes after birth
Umbilical vessels	Present (exchange with placenta)	Closes and becomes ligaments

Developmental Events of the Fetal Period

• Weeks 9 to birth: Growth and maturation of tissues and organs.

• Organ systems become functional.

• Rapid weight gain in last trimester.

Effects of Pregnancy on the Mother

• Increased blood volume and cardiac output

• Weight gain and changes in posture

• Hormonal changes (e.g., increased progesterone and estrogen)

• Possible gestational diabetes or hypertension

Endocrine System and Hormones (Chapter 16)

Organs Involved in the Endocrine System

• Pituitary gland

• Thyroid gland

• Parathyroid glands

• Adrenal glands

• Pineal gland

• Pancreas

• Gonads (ovaries and testes)

Hormones Produced by the Anterior Pituitary and Their Functions

• Growth hormone (GH): Stimulates growth of tissues.

• Thyroid-stimulating hormone (TSH): Stimulates thyroid hormone release.

• Adrenocorticotropic hormone (ACTH): Stimulates adrenal cortex.

• Follicle-stimulating hormone (FSH): Stimulates gamete production.

• Luteinizing hormone (LH): Stimulates hormone production in gonads.

• Prolactin (PRL): Stimulates milk production.

Hormones Produced by the Posterior Pituitary and Their Functions

• Antidiuretic hormone (ADH): Promotes water reabsorption in kidneys.

• Oxytocin: Stimulates uterine contractions and milk ejection.

Hormones Produced in the Adrenal Gland and Their Functions

• Adrenal cortex:

  • Cortisol: Regulates metabolism and stress response.

  • Aldosterone: Regulates sodium and potassium balance.

  • Androgens: Contribute to secondary sex characteristics.

• Adrenal medulla:

  • Epinephrine and norepinephrine: Mediate fight-or-flight response.

Example: Cortisol increases blood glucose during stress.

Additional info: The endocrine system works via hormones, which are chemical messengers secreted into the bloodstream to regulate various physiological processes.