Week 10 Flashcards
List the major structures in the anatomy of the testes.
Ductus deferens: Carries sperm from the epididymis to the ejaculatory duct.
Epididymis: Stores and matures sperm.
Rete testis: Network of tubules connecting seminiferous tubules to efferent ducts.
Mediastinum: Central region of the testis, contains rete testis.
Seminiferous tubules: Sites of spermatogenesis.
Tunica albuginea: Dense connective tissue capsule surrounding the testis.
Tunica vaginalis: Outer serous membrane derived from the peritoneum.
Describe the layers surrounding the testes.
Tunica albuginea: Dense regular connective tissue containing fibroblasts and blood vessels.
Tunica vaginalis: Simple squamous mesothelium layer, derived from the peritoneum.
histology of septa of testes
The testes are divided into approximately 250 lobules by connective tissue septa.
Each lobule contains 1-4 seminiferous tubules.
Septa are composed of incomplete loose connective tissue.
What are the main cell types in the seminiferous tubules and their functions?
Spermatogonia: Diploid stem cells that divide by mitosis.
Spermatocytes: Undergo meiosis to produce spermatids.
Spermatids: Undergo spermiogenesis to form mature sperm.
Sertoli cells: Support, nourish, and regulate spermatogenesis; form the blood-testis barrier.
Myoid cells: Contractile cells aiding in peristalsis of spermatozoa.
What are the roles of Sertoli cells in the seminiferous tubules?and histology
Create the blood-testis barrier via tight junctions.
Provide nutrients and structural support to developing germ cells.
Phagocytose excess cytoplasm during spermiogenesis.
Secrete Androgen Binding Protein (ABP) to maintain high testosterone levels.
Large columnar epithelial cell
* Attached to basement membrane
* Ovoid, euchromatic nuclei
* Prominent single nucleoli
Where are Leydig cells located and what is their function?
Location: In the connective tissue stroma between seminiferous tubules.
Large, polygonal,
eosinophilic cells,
lipid droplets
Function: Produce testosterone, a steroid hormone.
Histology: Large, polygonal cells with eosinophilic cytoplasm and lipid droplets.
What is the blood-testis barrier and its function?
Formed by tight junctions between Sertoli cells.
Separates germ cells into basal (diploid) and adluminal (haploid) compartments.
Protects germ cells from harmful substances and autoimmune reactions.
Outline the stages of spermatogenesis.
Spermatogonia (Diploid, mitosis) →
Primary Spermatocytes (Diploid, meiosis I) →
Secondary Spermatocytes (Haploid, meiosis II) →
Spermatids (Haploid) →
Spermatozoa (Haploid, mature sperm).
What are the key events during spermiogenesis?
Nuclear volume decreases.
Formation of the acrosome.
Development of the flagellum (tail).
Mitochondria arrange around the midpiece.
Sertoli cells remove excess cytoplasm.
Release of sperm into the lumen of the seminiferous tubules.
Describe the function of myoid cells in the testes
Myoid cells are modified smooth muscle cells.
Modified smooth muscle
* Simple squamous nuclei
* 3-5 layers
* Periphery of tubule in lamina propria
* Produce collagen
They contract to assist in the movement of sperm and fluid through the seminiferous tubules.
Produce collagen, contributing to the structural framework of the tubules
How is testosterone produced and what are its roles?
Produced by: Leydig cells.
Roles:
Embryo: Development of male gonads.
Puberty: Initiates spermatogenesis, secondary sex characteristics.
Adult: Maintains spermatogenesis and regulates sex drive.
Front: Describe the main structural components of mature sperm.
Back:
Acrosome: A cap-like vesicle covering the anterior half of the sperm’s nucleus, contains enzymes (e.g., hyaluronidase) to penetrate the oocyte.
Nucleus: Houses tightly packed chromatin (haploid, 23 chromosomes).
Mitochondria: Arranged helically around the midpiece; provide ATP for motility.
Axoneme: Core of the flagellum with a 9 + 2 microtubule arrangement, essential for sperm motility.
Tail: Responsible for sperm propulsion, divided into midpiece, principal piece, and end piece.
Front: What are the key histological features of the epididymis?
Back:
Epithelium: Pseudostratified columnar epithelium with stereocilia, which facilitate sperm absorption and secretion.
Stereocilia: Non-motile, long microvilli that increase surface area for absorption of fluid.
Smooth Muscle: Multiple layers surrounding the tubule; promote peristalsis for sperm movement.
Connective Tissue: Provides structural support.
Functions: Final maturation of sperm (spermiogenesis), sperm storage, and reabsorption of excess fluid.
Front: Outline the pathway of sperm from the testis to ejaculation, and its contribution to semen.
Back:
Pathway: Testis → Epididymis → Vas deferens → Ejaculatory duct → Urethra → Penis.
Contribution to Semen:
Epididymis: Adds nutrients.
Vas deferens: Contributes more nutrients.
Seminal Vesicles: Secrete fructose (energy), prostaglandins (motility), and clotting factors.
Prostate Gland: Adds enzymes like PSA (Prostate-Specific Antigen) and fibrinolysin for semen liquefaction.
Bulbourethral Glands: Secrete mucous for lubrication and to neutralize the urethra’s acidity.
Front: What is the histological structure of the prostate gland and its secretory function?
Back:
Histology:
Tubuloalveolar Gland: Embedded in a fibromuscular stroma.
Epithelium: Columnar, of varying heights, indicating different secretory states.
Fibromuscular Septa: Separate glandular lobules, composed of connective tissue and smooth muscle.
Secretions:
Clear alkaline fluid containing PSA, PAP (Prostate-Specific Phosphatase), fibrinolysin.
Function: Liquefies sperm, neutralizes the acidic environment of the vagina, and facilitates sperm motility.
