Human Reproduction and Development

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Human Reproductionand Development

• Starr/Taggarts
• Biology
• The Unity and Diversity of Life, 9e
• Chapter 45

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Male Reproductive Structures and Glands
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Spermatogenesis

• In testis
• Seminiferous tubules
• Spermatogenesis occurs here
• Other structures
• Vas deferens
• Glands
• Prostate
• Seminal vesicles

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Spermatogenesis
Fig. 10.8 p. 169
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part of the lumen of a seminiferous tubule
MITOSIS
MEIOSIS I
MEIOSIS II
Sertoli cell
spermatogonium (diploid)
primary spermatocyte
immature sperm (haploid)
late spermatid
secondary spermatocyte
early spermatids
tail (with core of microtubules)
head (DNA in enzyme-rich cap)
midpiece with mitochondria
Fig. 45.4, p. 787
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Hormonal ControlNegative Feedback Loop

• Hypothalamus
• GnRH
• Anterior pituitary
• LH, FSH
• Leydig cells in testes
• Testosterone

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Male Negative Feedback
FSH and LH (pituitary)
GnRH (hypothalamus)
Testosterone and sperm levels (testes)
HIGH
Testosterone/Sperm Levels
LOW
Testosterone and sperm levels (testes)
GnRH (hypothalamus)
FSH and LH (pituitary)
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Female Reproductive Structures
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Oogenesis

• Regulated by the menstrual cycle
• Ovary
• Oogenesis occurs here
• Other structures
• Fallopian tubes or oviducts
• Uterus
• Vagina

Fig. 10.2, p. 162
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Oogenesis
Fig. 10.9 p. 169
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Hormonal Control in the Menstrual Cycle

• Hypothalamus
• GnRH
• Anterior Pituitary
• FSH
• LH
• Ovaries
• Estrogen
• Progesterone

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Changes in the Ovary and Uterus
Hormonal changes
Ovarian and Uterine changes
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hypothalamus
GnRH
anterioir pituitary
FSH
LH
midcycle peak of LH (triggers ovulation)
hypothalamus
Blood levels of FSH (purple) and LH (lavender)
anterior lobe of pituitary gland
FSH
LH
LH
growth of follicle
ovulation
corpus luteum
estrogens
progesterone, estrogen
Blood levels of estrogens (light blue) and
progesterone (dark blue)
estrogens
progesterone, estrogen
endometrium of uterus
menstruation
Fig. 45.9, p. 792
Days of one menstrual cycle (using 28 days as the
average duration)
FOLLICULAR PHASE OF MENSTRUAL CYCLE
LUTEAL PHASE OF MENSTRUAL CYCLE
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Female Flowchart
GnRH (hypothalamus)
FSH and LH (pituitary)
Follicle and oocyte maturation
Uterine lining and ovulation
Estrogen (ovary)
LH spike (pituitary)
Sustaining a pregnancy
Progesterone (corpus luteum)
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Menstrual Cycle Overview

• Follicular Phase
• Menstruation
• Endometrium breakdown and buildup
• Maturation of oocyte
• Ovulation
• Release of oocyte from ovary
• Luteal Phase
• Corpus luteum
• Endometrium gets ready for pregnancy

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Fertilization

• Sperm surround ovum
• Cap releases acrosomal enzyme
• One sperm penetrates
• Oocyte completes meiosis II
• Sperm and egg nuclei fuse
• Zygote

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Formation of the Early Embryo
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Early Embryo and Implantation
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Embryonic Period of Vertebrate

• Primitive streak
• Notochord
• Brain and spinal cord

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Maternal and Fetal Blood Circulation

• Diffusion of O2, CO2 and other solutes

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Placental Development
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Embryo at 4 Weeks
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Fetus at 16 Weeks

• Reflex actions
• Limb differentiation

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What Can Affect Development?

• Nutrition
• Diet
• Extra vitamins
• Increased calories
• Infections
• Bacteria
• Rubella virus

• Prescription drugs
• Tranquilizers
• Barbiturates
• Anti-acne medication
• Antibiotics
• Alcohol
• Cocaine
• Cigarettes

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Birth

• Labor
• Oxytocin
• Uterine contractions

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Control of Human Fertility