The Reproductive System Flashcards

1
Q

What are the three cylindrical columns of erectile tissue in the penis?

A
  • Corpora cavernosa
    • 2 columns
    • deep artery embedded
  • Corpus spongiosum
    • erectile tissue
    • around urethra
    • more elastic fibres
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2
Q

What are the three cells contained in each testis?

A
  • Leydig cells
    • produce sex hormones
  • Spermatogenic cells
    • make sperm
  • Sertoli cells
    • mechanical and nutritional support
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3
Q

What are the steps in spermatogenesis starting from germ cells (spermatogonia)?

A
  1. Spermatogonia divide by mitosis
  2. Differentiate into primary spermatocytes
  3. Undergo meiosis I to form secondary spermatocytes
  4. Undergo meiosis II to form spermatids
  5. Differentiates into spermatozoa/sperm
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4
Q

Describe the properties of mature sperm

A
  • Lacks intracellular structures
    • Reduces sperm size and mass
  • Absorbs nutrients (fructose) from surrounding fluid
  • Mitochondrial spiral provides ATP
    • Energy to move flagellum
    • Movement (swim)
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5
Q

Describe the functions of the fluid secreted by Sertoli cells

A
  • Secretes fluid rich in PENBIA
    • P: Proteins
    • E: Enzymes
    • N: Nutrients
    • B: Bicarbonate ions
    • I: Ions
    • A: Androgens
  • Fluid enters lumen
    • Nourish developing sperm
    • Flushes sperm into epididymis
    • Damaged spermatogonia engulfed by sertoli cells
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6
Q

Describe the functions of the proteins synthesized by Sertoli cells

A
  • Androgen-binding protein
    • Binds to testosterone to increase its concentration
  • Inhibin
    • Stimulates pituitary gland to inhibit FSH secretion
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7
Q

Describe the hormonal control of spermatogenesis

A
  • Testosterone
    • Stimulated by LH
    • Secreted by Leydid cells
    • Promotes meiosis and early spermatid maturation
  • FSH
    • Promotes spermatogenesis
    • Direct: Acts on Sertoli cells to influence no. of germ cells
    • Indirect: More ABP to concentrate testosterone levels
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8
Q

Why is the incidence of bladder infections in males lower than in females?

A
  • Longer urethra in males
    • Lower chance of bacteria reaching bladder
  • Male urinary tract has natural defenses to infection
    • Seminalplasmin, an antibiotic
  • Male urethra separated from rectum
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9
Q

Describe the overall effects of testosterone

A
  • Maintains spermatogenesis
  • Enlarges penis and testes
  • Wrinkles and pigments scrotal skin
  • Grows facial, pubic, and body hair
  • Enlarges vocal cords and larynx
  • Increases body growth
  • Increases muscle mass
  • Grows long bones
  • Forms red blood cells
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10
Q

Describe the pathway of sperm from production to ejaculation

A
  1. Seminiferous tubules
  2. Rete testis
  3. Efferent ductules
  4. Epididymis
  5. Ductus deferents
  6. Ejaculatory duct
  7. Urethra
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11
Q

Describe the features and functions of the epididymis

A
  • Lined with smooth muscle
  • Secretes fluid with nutrients, enzymes, hormones
  • Site of sperm maturation and storage
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12
Q

Describe the functions of the seminal vesicle, a male accessory sex organ

A
  • Produces 60% of semen volume
  • Contains fructose
  • Prostaglandins (fatty acids) to stimulate smooth muscle contractions
  • Fluid is alkaline to neutralize vaginal acids
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13
Q

Describe the functions of the prostate gland, a male accessory sex organ

A
  • Produces ~20% of semen volume
  • Acidic
  • Contains seminalplasmin, a protein with antibiotic properties
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14
Q

Describe the functions of Cowpers gland, a male accessory sex organ

A
  • Secretes thick mucus
  • Alkaline to neutralize urinary acids in the urethra
  • Lubricates penis tip
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15
Q

Describe the functions of Cowpers gland, a male accessory sex organ

A
  • Secretes thick mucus
  • Alkaline to neutralize urinary acids in the urethra
  • Lubricates penis tip
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16
Q

Describe what triggers an erection

A
  • Parasympathetic (POINT)
  • Nitric oxide released
  • Arteries dilate
  • Increased blood flow
17
Q

Describe what triggers ejaculation

A
  • Emission prior
    • movement of semen into urethra
  • Sympathetic (SHOOT)
  • Contraction of smooth muscle
    • Seminal vesicle, prostate, muscles at penis base
  • Semen expelled
18
Q

Describe the four main functions of the uterus

A
  • Mechanical protection
  • Nutritional support
  • Removes waste for developing embryo
  • Uterus wall contracts during labor
19
Q

What is capacitation of sperm?

A
  • Maturation process
  • Sperm stays in female tract for hours
  • Sterols and glycoproteins removed
  • Increased membrane permeability to calcium ions
  • Increased intracellular cAMP levels
  • Increased motility
  • Ability to penetrate ovum
20
Q

Why do only 0.1% of sperm reach the uterine tubes?

A
  • 50% is lost due to abnormal shape or reduced motility
  • Destroyed by acidic vaginal secretions
  • Blocked by cervix mucus
21
Q

Describe the process of fertilization

A
  • In fallopian tubes
  • Acrosome reaction: for sperm to enter oocyte
  • Calcium ions released
    • Prevents other sperm from entering
    • Activates oocyte to complete meiosis
  • Diploid zygote forms 12 hours later
22
Q

Describe the process of implantation

A
  • Blastocyst releases chorionic gonadotropin
    • Keeps corpus luteum alive
    • Continued release of estrogen and progesterone
    • Maintains thick endometrium
    • Increased vascularization
23
Q

Describe molecule exchange between the fetus and the mother

A
  • Umbilical cord connects fetus and placenta
  • Umbilical arteries deliver fetal blood to placental vessels
  • Umbilical veins return fetal blood
  • Molecules diffuse across placental tissue
    • From maternal to fetal: Oxygen and nutrients
    • From fetal to maternal: Carbon dioxide and wastes
24
Q

Describe the process of parturition (delivery)

A
  • Dilation
    • > 8 hours
    • Labor contractions every 10-30 minutes
    • Amniochorionic membrane ruptures
  • Expulsion
    • <2 hours
    • Cervix dilates (hormonal) with pressure (physiological)
    • Labor contractions every 2-3 minutes
  • Placental
    • Muscle tension
    • Tears connection between endometrium and placenta
    • Afterbirth: Placenta expelled
    • Contraction of uterine vessels restrict blood loss