Reproduction

Importance: Managing population size for all species

Female Reproduction

Estrous Cycle: endocrine/physical events that prepare the reproductive tract for pregnancy

Estrus: Period of receptivity to be bred by male (being in heat)

Menstrual Cycle: endocrine/physical events that prepare the reprocuvitve tract for pregnancy *HUMANS AND PRIMATES*

OVARIES (2 functions)

Exocrine - Gamete Production

  • ovum

    • Female Gamete

    • not an egg, only the genetic material

  • Follicle

    • ovum + cells that aid in development

    • follicle grows & grows until ovulation

  • Ovulation = release of ovum from follicle of ovary

Endocrine - Hormone Production

  • Chemical signals or messages transported via blood to target tissue

  • need testosterone & estrogen

    • excess production of estrogen causes the animal to enter estrus

    • produced by follicle

  • Corpus Luteum

    • Produces progesterone (P4) “hormone of pregnancy”

    • Temporary structure formed in ovaries after ovulation


OVIDUCT (Fallopian Tube)

Functions: *captures ovum at ovulation & moves towards uterus*

  • transports sperm & ovum

  • site of fertilization

  • nutrition for embryo during transportation

UTERUS

Functions:

  • site of gestation

    • placental attachment

  • nourishment for growing fetus

CERVIX

  • protection of the uterine environment

    • usually closed except during estrus & parturition

VAGINA

  • semen deposition

EMBRYO

  • ovum = haploid

    • ½ chromosome material

  • Sperm = haploid

    • ½ chromosome material

  • zygote = diploid

    • sperm + ovum

zona pellucida: cover around the embryo

PLACENTA

  • fetal origin

  • out pocketing of the small intestine

  • attaches to uterine wall of fam

  • exchange of products

    • nutrients & waste, 02 & C02

  • Hydraulic dampener: shock absorption

    • supports a stable environment for baby

    • cushions from impact & sudden movements

    • designed to handle changes in blood flow/pressure from mother

  • during parturition helps to dilate cervix & provide fluid lubrication

Parturition Process

Stage I

  • final preparation

    • seeks solitude

    • contractions

    • cervical dilation

    • stage ends w/ the rupture of chorioallantoic sac (water breaks)

Stage II

  • fetal expulsion

Stage III

  • removal of placenta from uterus

    • separation of placental uterine attachment points

Dystocia: When there is any problem during the pregnancy “difficult birth”

Common causes:

  • ratio of birth weight in relation to size of dam

  • conditions of dam

  • malpresentation (fetal position/orientation in the uterus)

Avian Female

LEFT OVARY

(they don’t have a right one)

  • follicle (ovum + yolk)

  • branched lobes(follicles) allow for production of multiple eggs

  • ensures steady supply of eggs for laying

MODIFIED LEFT OVIDUCT

Infundibulum

  • captures follicle

  • fertilization site

  • sperm nests (where sperm stores)

Magnum

  • protein source

  • thick and thin layers

  • chalazae (holds yolk in center of eggs)

Isthmus

  • packaging area

  • creates inner and outer shell membrane (paper looking thing on inside of the shell)

  • semi-permeable (keeps bacteria out while letting 02 and C02 in and out)

Uterus aka Shell Gland

  • polar salts

  • pigmentation comes from cells in the shell gland

    • color of egg has nothing to do w nutrition/quality

Ovulation

  • every 25-28 hrs

  • Infundibulum → magnum → isthmus → shell gland → cloaca

Incubation

ground nesting

  • 25-27 hrs between oviposition

  • 8-10 eggs per clutch

  • all eggs hatch within 12hr period

    • embryonic communication (so that they can all sync and hatch within 12 hours)

      • fast clicks = decrease neighbors development

      • slow clicks = increase neighbors development

Tree nesting

  • no embryonic communication to sync hatching

    • hatch according to schedule in which they were laid

  • smaller clutches (2-4)

Male Reproduction

Organs:

  • 2 testes

  • 2 epididymis

  • 2 vas deferens

    • urethra → accessory fluids → penis

TESTES

Exocrine - gamete (sperm)

  • seminiferous table: sperm production

  • sperm goes through mitosis & meiosis (multiple stages and changes)

    • lots of sperm variation

      • 3 components

        • head: DNA

        • Mid piece: mitochondrial helix

          • ATP → motility

          • “engine” or “motor”

        • Principle piece (not a tail)

          • spins like a propeller

Endocrine

  • 2 main hormone

    • testosterone (T) and estrogen (E2)

Cooling System

*purpose is to regulate optimal temp for spermatogenesis(sperm production)

  • keep testes 2-5F below body temp

    • pampiniform plexus: vein network

    • scrotum: more swear glands on testes than any other surface

    • panting

EPIDIDYMUS

  • collects sperm from testes

    • transports/maturation

    • storage/ejaculation

    • nutrition

VAS DEFERENS

The long tube!

One function: rapid transport from epididymus to urethra

ACCESSORY GLANDS

produce accessory fluids

semen= sperm + accessory fluids

  • 3 glands *not all species have all 3

    • seminal vesicles (vesicular glands)

      • produce thick alkaline fluids

    • prostate (acidic af)

      • liquifies semen after ejaculation

    • bulbourethral (cowper’s gland)

      • PRECUM

  • Functions:

    • adds nurtients

    • adds volume

    • in some species stimulates contractions in the uterus

PENIS

delivery of semen from urethra into the female reproductive tract

vascular (stallions and humans)

  • more vascular tissue = blood influx

  • increase in length & diameter

  • increase in stiffness (BONER)

Fibrous (boar, ram, bull)

  • less vascular tissue

  • no change in length/diameter during erection

  • increase in stiffness

Avian Male

TESTES

  • endocrine and exocrine

  • located internally as opposed to externally

VAS DEFERENS

  • transports sperm from testes to cloaca

EPIDIDYMUS

  • stores and matures sperm after being produced in the testes