Ch 2 Male Reproductive System Flashcards
Accessory sex glands
Seminal Vesicles
Prostate
Bulbourethral glands
Produce sperm and secrete hormones
Testes
Dense white fibrous capsule that extends inward and divides each testis into internal compartments
Lobules
Produce sperm by a process called spermatogenesis. Lined with spermatogenic cells
Seminiferous tubules
Located between the developing sperm cells in the seminiferous tubules
Support, protect, and nourish spermatogenic cells
Phagocytize degenerating spermatogenic cells
Secrete fluid for sperm transport
Release inhibin - which regulate sperm production
Sertoli Cells
Located between the seminiferous tubules
Secrete Testosterone
Leydig Cells
Hormone that promotes the development of masculine characteristics
Androgen
Promotes a man’s libido
Testosterone
Scrotum consists of:
Loose skin
Superficial fascia
Smooth muscle
Survival of sperm is optimal at a temperature of:
2-3 degrees C below normal body temp
The process by which the seminiferous tubules of the testes produce sperm
Spermatogenesis
Three stages of spermatogenesis
Meiosis I
Meiosis II
Spermiogenesis
Meiosis
Two chromosomes that make up each pair
Homologous chromosomes
Somatic cells contain two sets of chromosomes
Diploid cells
Differ from somatic cells because they contain a single set of 23 chromosomes
Gametes (haploid)
In sexual reproduction, an organism results from the fusion of:
Two gametes, one from each parent
The time from on-set of cell division in a spermatogonium until sperm are released into the lumen of a seminiferous tubule
65-75 days
Spermatogonia and primary spermatocytes are:
Diploid
Spermatogenesis Cycle
The net effect of _______ is that each resulting cell contains a haploid set of chromosomes
Meiosis I
The cells formed by meiosis I are:
Haploid secondary spermatocytes
Each chromosome within a secondary spermatocyte is made up of:
Two chromatids (2 copies of DNA) still attached by a centromere
Cells formed in this process are termed spermatids, contain 23 chromosomes each of which is composed of a single chromatid
Meiosis II
Final stage of spermatogenesis
Spermiogenesis
Sperm are produced at a rate of:
300 million per day
Once ejaculated, most sperm only survive:
48 hours
Part of the sperm that contains DNA
Head
A vesicle containing enzymes that aid penetration by the sperm cell into a secondary oocyte
Acrosome
Four parts of the sperm cell tail
Neck, middle, principal, end piece (terminal)
Part of the sperm that contains mitochondria that provide ATP for locomotion
Middle piece
Longest portion of the tail
Principal
What propels sperm and fluid through the seminiferous tubules and into the epididymis?
Fluid secreted from Sustentacular cells
Comma-shaped organ that lies posterior to the testes
Epididymis
Each epididymis consists mostly of the:
Tightly coiled ductus epididymis
Site of sperm maturation
Sperm acquire the motility and the ability to fertilize a secondary oocyte
Ductus Epididymis
How many days does it take in the ductus epididymis for sperm to become mobile?
10-14
Stores sperm and helps propel them during sexual arousal by peristaltic contraction of its smooth muscle into the vas deferens
Ductus epididymis
Sperm may remain in storage in the ductus epididymis for:
Several months
Ascends along the posterior border of the epididymis and penetrates the inguinal canal
Ductus deferens
Has a heavy coat of 3 muscles
Stores sperm for several months
Ductus deferens
Conveys sperm from the epididymis toward the urethra during sexual arousal by peristaltic contractions of the muscular coat
Ductus deferens
Supporting structure of the male reproductive system
Spermatic cord
The ejaculatory ducts are formed by the union of:
Ductus deferens and seminal vesicles
Carry sperm into the urethra
Short ejaculatory ducts
Terminal duct of the male reproductive system
Urethra
Males
The urethra passes through the:
Prostate
Deep perineal muscles
Penis
Pouch-like structures, lying posterior to the base of the urinary bladder and anterior to the rectum
Seminal vesicles
Seminal vesicles secrete an alkaline viscous fluid containing:
Fructose
Prostaglandins
Clotting proteins
Used for ATP production by sperm
Fructose
Contribute to sperm motility and viability and may also stimulate muscular contraction within the female reproductive tract
Prostaglandins
Fluid secreted by the seminal vesicles normally constitute about __% of the volume of semen
60%
Single, doughnut-shaped gland about the size of a golf ball
Prostate
Prostate size is attained at age 30 and remains stable until:
45
Secretes a milky, slightly acidic fluid (6.5) that contains citric acid, phosphatase, and several protein-digesting enzymes
Prostate secretions
Can be used by sperm for ATP production via the Krebs cycle
Citric Acid
Prostatic secretions make of __% of the volume of semen
25%
Size of peas
Located inferior to the prostate on either side of the urethra
Bulbourethral glands
Secrete an alkaline substance into the urethra glands that protects the passing sperm by neutralizing acids from urine in the urethra
Bulbourethral glands
Secrete mucus that lubricates the end of the penis and the lining of the urethra thereby decreasing the number of sperm damaged during ejaculation
Bulbourethral glands
Volume of semen in a typical ejaculation
2.5-5 mL
___ million sperm per mL
50-150 million
Male is likely to be infertile when sperm numbers fall below
20 million per mL
pH of semen
7.2-7.7
Gives a milky appearance, and fluids from the seminal vesicles and bulbourethral glands give it a sticky consistency
Prostatic secretion
Penis consists of:
Root
Body
Glans penis
Penis
Two dorsolateral masses are called the:
Corpora cavernosa penis
Penis
Smaller midventral mass, contains the urethra
Corpus spongiosum penis
Covering of glans in an uncircumcised penis
Prepuce (foreskin)
What type of impulses cause release of neurotransmitters and local hormones, including the gas nitric oxide, which relaxes vascular smooth muscle in the penile arteries?
Parasympathetic
What type of reflex is ejaculation?
Sympathetic, from the lumbar
Onset of puberty, neurosecretory cells in the hypothalamus increase their secretion of:
Gonadotropin-releasing hormone (GnRH)
GnRH stimulates the anterior pituitary to increase its secretion of:
Luteinizing hormone (LH)
Follicle-stimulating hormone (FSH)
LH stimulates Leydig cells, which are located between seminiferous tubules, to secrete:
Testosterone
Testosterone is synthesized from:
Cholesterol
Principal Androgen
Testosterone
In some target cells, such as those in the external genitals and prostate, an enzyme converts testosterone to another androgen called:
Dihydrotestosterone (DHT)
Act together to stimulate spermatogenesis
FSH
Testosterone
What cells release inhibin, which inhibit FSH secretion by the anterior pituitary?
Sertoli cells
Before birth, what stimulates the male pattern of development of reproductive system ducts and the descent of the testes
Testosterone
Stimulates development of the external genitals
DHT
Testosterone is converted in the brain to ______. Which may play a role in the development of certain regions of the brain in males
Estrogens
At puberty, what hormones bring about development and enlargement of the male sex organs and the development of masculine secondary sexual characteristics
Testosterone
DHT
Anabolic hormones
Stimulate protein synthesis
Androgens