NPB 101: Reproductive Physiology Overview

Reproductive system & homeostasis

- Controlled through the hormones of the endocrine system

- homeostatic for species, not individual

- Reproductive processes may impact glucose levels and cardiovascular aspects

reproductive patterns

- can be internal (in the body) or external (outside of the body, like an egg) fertilization

OVIPAROUS - egg laying (invertebrates and some vertebrates); fertilization can be external or internal

VIVIPAROUS - development in oviduct/ uterus, nourished by mother (mammal, fishes, scropions, etc)

Anisogamy

Refers to a difference in gamete size in males and females. Eggs large and costly, sperm small and cheap

Role of male reproductive system

1. Sperm production

2. Deliver sperm to female to fertilize egg

Sperm pathway

"SEVEN UP"

Seminiferous tubules

Epididymis

Vas deferens

Ejaculatory duct

(Nothing)

Urethra

Penis

Male differentiation

Testes develop from a common pair of undifferentiated gonads (which can grow to become testes or ovaries). If the embryo has XY sex chromosomes, the Y chromosome has a gene (SRY gene) on it that directs the differentiation of the testes

• Testosterone secreted from the fetal testes cause differentiation of the internal male reproductive ducts and accessory glands as well as external structures

• The Anti-Mullerian Hormone causes loss of female reproductive ducts

Female reproductive functions

• production of eggs (ova from oogenesis)

• Reception of sperm

• Transport of sperm and ovum to common site for union (fertilization)

• The maintenance of the developing fetus until it can survive in the outside world (gestation or pregnancy). Usage/Formation of placenta for nourishment

• Birth of a baby

• Nourishment after birth by lactation

Development of ovaries

Ovaries develop from a common pair of undifferentiated gonads (which can grow to become testes or ovaries). If the embryo has XX sex chromosomes, there are no hormones secreted from the female ovaries, which leads to the loss of the male reproductive ducts and accessory glands. Additonally, this leads to the further differentitation of internal female reproductive ducts.