What are the 3 types of cells present in the adenohypophysis?
What do the pituitary basophils secrete?
Follicle Stimulating Hormone (from gonadotrophs)
Luteinizing Hormone (from gonadotrophs)
Thyroid Stimulating Hormone
What do pituitary acidophils secrete?
Prolactin (from lactotrophs)
Growth Hormone (somatotrophin from somatotrophs)
What does Growth Hormone do?
- Stimulates production of somatomedins
- Necessary for normal growth; most obvious effect is on cartilage
- Has other complex metabolic effects
What does prolactin do?
Initiates and maintains milk production
- In males, has effects on secondary sexual glands such as prostate
What hormones do corticotrophs produce?
What hormones do gonadotrphs produce?
What hormones do thyrotrophs produce?
What type of capillaries are present in the pituitary gland?
Fenestrated with diaphragms
What is "brainsand"?
Calcium and mineral deposits present in the pineal body
What is the process of sympathetic innervation of the pineal gland when the eyes are exposed to light?
Light is detected by the eye --> suprachiasmatic nucleus --> sympathetic central pathways --> superior cervical ganglioin --> pineal gland --> inhibit release of melatonin
What are the effects of melatonin?
Increased secretion at night leads to:
metabolic changes in the CNS and liver
Targets the retina, CNS, pituitary, and others affecting:
- Immune deficiencies
What is the endocrine control of the male reproductive system; where does it come from?
Hypothalamus and Pituitary:
What are the accessory glands of the male reproductive system? What do they do?
--> All release lubricands and nutrients that support sperm
What are the excretory ducts of the male reproductive system? Why are they necessary?
--> required for sperm maturation and delivery
What do the peritubular contractile (myoid) cells of the seminiferous tubule do?
Provide peristaltic waves, easy to mistaken for fibroblasts
What are Type A dark (Ad) spermatogonia?
Cells with ovid nuclei with intesnsely basophilic, finely granular chromatin.
- Stem cells of the seminiferous epithelium
- Divide to give rise to either type Ad spermatogonia or type Ap spermatogonia
What are Type A Pale (Ap) spermatogonia?
Cells with ovid nuclei with lightly staining, finely granular chromatin
- Committed to differentiation process that produces sperm
- Undergo several successive mitotic divisions, thereby increasing their number
What are type B spermatogonia?
cells with spherical nuclei with chromatin that is condensed into large clumps along the nuclear envelope and around a central nucleolus
What are sertoli cells? What are their functions?
non-replicating support cells for the developing sperm
- Sertoli-Sertoli cell junctional complex creates the blood-testis barrier (because haploid spermatogenic cells are "foreign" to the body)
- Support and nutrition of spermatozoa: metabolites, collect "waste"
- Phagocytosis: residual bodies, failing cells, etc
- Secretion of fluid and testis-specific proteins: androgen binding protein
- Synthesis of inhibin: feedback on FSH in the pituitary
Where does meiosis occur in sperm?
Primary spermatocytes = 1st meiotic cell division
Secondary spermatocytes = 2nd meiotic cell division
What is the succession of cell types that ends in motile sperm?
Type Ad spermatogonia --> Type Ap spermatogonia (which replicate a lot) --> Type B spermatogonia --> Primary spermatocytes --> secondary spermatocytes --> early spermatids --> late spermatids --> spermatozoa + residual bodies --> motile sperm after epididymis, but not activated --> activation of sperm ocurs in female genital tract
What is the golgi phase of spermatogenesis?
Proacrosomal granules in the golgi complex fuse --> acrosomal vesicles
(golgi phase --> acrosomal phase --> maturation phase)
What is the acrosomal phase of spermatogenesis?
Acrosomal vesicle expands (hyaluronidase, phosphatase, protease, etc are produced), flagellum forms, mitochondria condenses
(Golgi phase --> acrosomal phase --> maturation phase)
What is the maturation phase of spermatogenesis?
Cytoplasm is shed (residual bodies are released and get phagocytosed by sertoli cells), spermatozoa are released
(Golgi phase --> acrosomal phase --> maturation phase)
What are Leydig cells?
Cells of the interstitium testis that synthesize and secrete testosterone (appear as crystals of Reinke)
What are the tubuli recti?
Short, straightened terminal end of the seminiferous tubules
- contain sertoli-like cells (initial portions)
- no germ cell component
- connect seminiferous tubules to rete testis
What are the rete testis?
Complex, interconnected channels in the mediastinum testis
- simple cuboidal or low columnar epithelium
- with apical cilia and microvilli
What are the ductuli Efferentes?
Connect rete testis to ductus epididymis, moe sperm, absorb fluid
--> pseudostratified, ciliated columnar epithelium
What is the structure and function of the epididymis?
Pseudostratified epithelium with stereocilia
(basal cells are undifferentiated progenitors)
Sperm maturation (sperm gain motility), phagocytosis (debris from broken sperm and maturation process), secretion, absorption of fluid
What is the structure and function of ductus deferens?
Three thick layers of smooth muscle, epithelial surface covered by stereocilia
Pseudostratified columnar epithelium with long microvilli
To propel sperm by providing strong, peristaltic motions during ejaculation
What is the structure and function of seminal vesicles?
Paired, highly folded tubular gland covered by pseudostratified columnar epithelium
- Secrete fluid containing:
- The fluid is the "propellant" for the sperm, it is discharged during ejaculation due to the contractions
What is the structure and function of the prostate gland?
Tubulo-alveolar glands that empty into the prostatic urethra
Synthesizes and secretes:
Acid Phosphatase (PSA)
--> all a part of semen
What is the structure and function of the Bulbourethal Glands (Cowper's)?
Pea-sized, paired tubuloalveolar gland
Simple columnar epithelium, resembling mucus secretory gland
Secretes preseminal, mucus-like fluid, lubricant
What is the hormonal process of menarche?
Pulses of GnRH stimulate the release of FSH and LH
- Increase in FSH and LH --> increased estrogen
- Increased estrogen --> breast enlargement, altered fat distribution, and growth spurt
--> after a year, sufficient estrogen is produced to induce endometrial changes resulitng in periodic bleeding
What is the hormonal process of the menstrual cycle?
At the beginning of the cycle, one follicle develops under influence of FSH
--> FSH and LH cause granulosa cells to secrete E
- E stimulates proliferation of the endometrium (proliferative phase)
- E peaks and begins to drop just before ovulation
Now FSH and LH surge causing ovulation
- Follicle becomes corpus luteum (CL) and cells of the CL produce E and Progesterone (P)
- P stimulates glandular endometrium (secretory phase)
- If no pregnancy, CL degenerates and menses occurs
What is the biosynthesis of estradiol-17ß?
Estriol -->--> Estrone -- Estradiol-17ß
(occurs in the ovary)