Histology Flashcards by Karin Golob

What are the 3 types of cells present in the adenohypophysis?

Chromophobe

Basophil

Acidophil

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What do the pituitary basophils secrete?

BFLAT

Basophils secrete:

Follicle Stimulating Hormone (from gonadotrophs)

Luteinizing Hormone (from gonadotrophs)

Adrenocorticotrophic Hormone

Thyroid Stimulating Hormone

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What do pituitary acidophils secrete?

APG

Acidophils Secrete:

Prolactin (from lactotrophs)

Growth Hormone (somatotrophin from somatotrophs)

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What does Growth Hormone do?

Somatotrophin:

Stimulates production of somatomedins
Necessary for normal growth; most obvious effect is on cartilage
Has other complex metabolic effects

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What does prolactin do?

Initiates and maintains milk production

In males, has effects on secondary sexual glands such as prostate

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What hormones do corticotrophs produce?

ACTH

Beta-endorphin

Beta-Lipotropin

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What hormones do gonadotrphs produce?

FSH

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What hormones do thyrotrophs produce?

Thyrotropin

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What type of capillaries are present in the pituitary gland?

Fenestrated with diaphragms

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What is “brainsand”?

Calcium and mineral deposits present in the pineal body

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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

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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:
Circadian rhythm
Reproduction
Aging
Diseases:
- SAD
- MS
- Immune deficiencies

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What is the endocrine control of the male reproductive system; where does it come from?

Hypothalamus and Pituitary:

FSH
LH
Prolactin

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What are the accessory glands of the male reproductive system? What do they do?

Seminal Vesicles

Prostate

Bulbourethral glands

–> All release lubricands and nutrients that support sperm

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What are the excretory ducts of the male reproductive system? Why are they necessary?

Tubuli recti

Rete testis

Ductuli efferentes

Ductus epididymis

Vas deferens

Ejaculatory duct

Urethra

–> required for sperm maturation and delivery

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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

Functions:

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?

Straight tubules 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?

**Structure:** Pseudostratified epithelium with stereocilia (basal cells are undifferentiated progenitors) ``` **Function:** 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?

**Structure:** Three thick layers of smooth muscle, epithelial surface covered by stereocilia Pseudostratified columnar epithelium with long microvilli **Function:** To propel sperm by providing strong, peristaltic motions during ejaculation

What is the structure and function of seminal vesicles?

**Structure:** Paired, highly folded tubular gland covered by pseudostratified columnar epithelium **Function:** - Secrete fluid containing: fructose prostaglandins etc - 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?

**Structure:** Tubulo-alveolar glands that empty into the prostatic urethra **Function:** Synthesizes and secretes: Acid Phosphatase (PSA) Fibrolysin Citric acid --\> all a part of semen

What is the structure and function of the Bulbourethal Glands (Cowper's)?

**Structure****:** Pea-sized, paired tubuloalveolar gland Simple columnar epithelium, resembling mucus secretory gland **Function:** 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)