SUGER Flashcards
What is the glomerulus like?
Tuft of convoluted fenestrated capillaries
Glomerular basement membrane
Lined by podocytes
Supported by mesangial cells
Encased in Bowman’s capsule
What are the components of the juxtaglomerular apparatus?
2 Components:
Afferent arteriole
Distal convoluted tubule
Afferent arteriole contributes Granular cells
Secrete renin in response to low blood pressure
What is the function of the juxtaglomerular apparatus?
Distal convoluted tubule contributes the Macula Densa
Patch of closely packed endothelial cells along tubule
Senses NaCl concentration and regulates tubuloglomerular feedback
What is the function of the juxtaglomerular apparatus?
Distal convoluted tubule contributes the Macula Densa
Patch of closely packed endothelial cells along tubule
Senses NaCl concentration and regulates tubuloglomerular feedback
What is the structure of the PCT?
Cuboidal epithelium
Round central/basal nuclei
Brush border of microvilli at apical end
Many mitochondria
so appears eosinophilic
Reabsorption of NaCl, proteins, polypeptides, amino acids, glucose
What is the loop of henle like?
Descending and ascending limbs
Both with thick and thin segments
Thin - simple squamous
Thick - low cuboidal
Supplied by a rich vasa recta
What is the DCT?
Low cuboidal epithelium
Scanty microvilli
Numerous mitochondria
Regulates acid base by secreting H+ and absorbing HCO3-
(Via cellular carbonic anhydrase)
Regulates Na level by exchanging Na for K
What is the CD like?
Cuboidal epithelium
Principal cells
Respond to aldosterone and ADH
Intercalated cells
Exchange H+ for HCO3-
What is the blood supply of the kidneys?
Abdominal aorta
Renal artery at L1
Anterior & posterior division
Interlobar artery
Arcuate artery (corticomedullary)
Interlobular artery
Afferent arteriole
What is the loop of henle and vasa recta path of blood?
After glomerulus blood drains:
Efferent arteriole (from renal corpuscle)
Peritubular capillaries
Descends into medulla
Vasa recta
Renal veins
Inferior vena cava
What is the renal pelvis like?
Lined by urothelium
Transmits filtrate from nephron to ureter
What is urothelium?
Specialised epithelium found in the collection/drainage parts of the urinary tract
Complex stratified epithelium
Layer of umbrella cells overlies a pseudostratified layer of polygonal cells
What are ureters like?
Transitional epithelium
Spiral muscular tube
Inner longitudinal
Outer circular
No serosa
Loose adventitia
What is the bladder composed of?
Urothelium
Lamina propria
Muscularis Mucosa
Submucosa
Muscularis Propria
Subserosa and Serosa
Functional valve prevents reflux into ureter
What is the female urethra like?
4-5cm long
Proximally transitional epithelium
Distally squamous epithelium
Paraurethral and periurethral glands open into the urethra
What is the male urethra like?
20cm long
1.Prostatic urethra
- Membranous urethra lined by urothelium
- Penile urethra
Pseudostratified epithelium proximally
Stratified squamous epithelium distally
What lining does the renal pelvis, ureter, bladder and urethra?
The renal pelvis, ureter, bladder and urethra all have the same urothelial lining
What is the urothelium like?
Urothelium is a complex stratified epithelium unique to the urinary tract.
What is the testis?
The testis
Paired organ in the scrotum
Average weight 15-19g
Capsule
Tunica vaginalis
What are the testis structure?
Three layers forming a capsule
Tunica vaginalis
Flattened layer of mesothelial cells
Tunica albuginea
Collagen fibres with some fibroblasts, myocytes, nerve fibres.
Tunica vasculosa
Loose connective tissue containing blood vessels and lymphatics.
What are the testicular parenchyma like?
The testis
Testicular parenchyma is divided into lobules by septa originating from the capsule.
~ 250 lobules
Each lobule contains 1-4 seminiferous tubules.
What do seminiferous tubules contain?
The testis
Seminiferous tubules contain germ cells in varying stages of maturation and Sertoli cells.
What is the structure of a spermatazoon?
Spermatagonia -> primary spermatocyte -> secondary spermatocyte -> spermatid -> spermatazoon
Type A darkly stained stem cells (Ad) and pale stained (Ap) cells
Type B differentiating progenitor cells have spherical nuclei with densely stained masses of chromatin.
What are Sertoli cells like?
Columnar cells on the basement membrane of the tubule.
Send cytoplasmic projections around the germ cells.
Nuclei are irregularly shaped, folded and have a prominent nucleolus (helps to distinguish from germ cells)
Supportive , phagocytic and secretory functions
What is teh structure of spermatozoa?
Spermatozoa
Head
Acrosomal cap
Nucleus
Midpiece
Spiral mitochondria
Tail
Neck – centrioles
Axoneme
Plasma membrane
What are leydig cells?
Leydig cells
Present singly and in clusters in the interstitium between tubules
Abundant cytoplasm containing lipid
Reinke’s Crystalloids
Produce testosterone.
What are Rete testis?
Anastomosing network of tubules at the hilum of the testis
Receive luminal contents from seminiferous tubules
Lined by simple squamous or low columnar epithelium on a relatively thick basement membrane.
Have cilia at the luminal surface
Rete testis
Mixing chamber for contents of seminiferous tubules
Possible secretions
Reabsorption of protein from the luminal contents
What are efferent ducts like?
ducts
12-15 convoluted tubules which empty into epididymis
Lined by ciliated and non ciliated simple columnar epithelium with interspersed cuboidal cells (basal cells) giving a pseudostratified appearance.
What is the epididymis structure?
Epididymis
A tubular structure 4-5cm long containing a highly convoluted epididymal duct (5m!)
Lined by tall columnar cells with long atypical cilia
Epithelium supported by a thick basement membrane surrounding which is a well defined muscular coat.
What is the vas deferens?
Vas deferens
30-40cm tubular structure arising from the caudal portion of epididymis.
Distal part enlarged to form the ampulla which joins the excretory duct of the seminal vesicle to form the ejaculatory duct.
Lined by pseudostratified columnar epithelium
comprising columnar and basal cells.
Has thick muscular wall of 3 layers.
What is the prostate like?
Pear shaped glandular organ
Weighs up to 20g in young adult
Surrounds the bladder neck and prostatic urethra
Lobes-anterior, middle, posterior and two lateral lobes
Peripheral, central, transitional and peri-urethral gland regions
What is the composition of the prostate?
Prostate
Covered by a an ill-defined fibro-connective tissue capsule.
Glandular and non glandular components
Ducts
Large primary and small secondary
Acini
30-50 tubuloalveolar glands with convoluted edges
What cells are present in the prostrate?
Prostate
Acini are lined by secretory cells, basal cells and neuroendocrine cells
Secretory cells located in the luminal side of the glands secrete PSA and PAP into the seminal fluid
Basal cells form a continuous layer
Cells rest on a basement membrane
What comprises the stroma of the Prostate?
Prostate
Stroma
Smooth muscle
Fibroelastic fibres
Blood vessels
Nerves
Both the stroma and the glands undergo hyperplasia with increasing age.
What are the seminal vesicles?
Seminal vesicles
Paired highly coiled tubular structures posterolateral to the bladder
The duct empties into the ejaculatory duct
Lined by tall non-ciliated columnar epithelium
Vacuoles and lipofuscin
Mucosa is folded
Smooth muscles (2 layers) and adventitia
What is the penis like?
Penis - Erectile tissue arranged into 3 components
- Left and right corpora cavernosa on the dorsal side
- Corpus spongiosum on the inferior side (surrounds urethra)
- Erectile tissue comprises irregular vascular spaces separated by fibroelastic tissue and smooth muscle.
- Rich nerve supply.
What does the testis contains?
The testis contains seminiferous tubules that produce spermatazoa
What does the testis contains?
The testis contains seminiferous tubules that produce spermatazoa
What do leydig and Sertoli cells do?
Leydig cells produce testosterone
Sertoli cells are polyfunctional
What do leydig and Sertoli cells do?
Leydig cells produce testosterone
Sertoli cells are polyfunctional
Where is seminal fluid made?
The prostate, seminal vesicles and Cowper’s glands produce the bulk of the seminal fluid
Where is seminal fluid made?
The prostate, seminal vesicles and Cowper’s glands produce the bulk of the seminal fluid
What is the ovary?
- Covered by a single layer of modified mesothelium
- Under this is a poorly defined connective tissue layer called tunica albuginea
- Stroma divided into cortex and medulla
What is the ovarian cortex like?
Ovarian cortex
Spindle stromal cells arranged in whorls /storiform pattern.
Ovarian follicles.
Some leutinised cells.
What is the ovarian medulla like?
Ovarian medulla
Loose fibroelastic tissue with blood vessels,lymphatics and nerves.
Rete ovarii - analogue of rete testis-present at the hilum
What are the primordial follicles?
Primary follicles
Cyclic FSH secretion from the ant. pituitary stimulates follicular development.
Follicular epithelial cells proliferate (granulosa cells)
Oocyte enlarges
Stromal cells become organised into connective tissue sheath.
Zona pellucida forms directly around the oocyte.
What are secondary follicles?
Secondary follicles
Formation of antrum (space filled with follicular fluid)
CT differentiates into inner Theca interna and outer Theca externa
Oocyte is supported in the antrum by a stalk of granulosa cells (Cumulus oophorus)
What are mature (Graafian follicles?)
Mature (Graafian) follicles
Ovum is surrounded by a thick zona pellucida
A layer of granulosa cells surround the oocyte - corona radiata
Basal lamina
Theca interna and Theca externa
What happens to primordial follicles?
Approximately 400,000 primordial follicles are present at birth. Out of these only approx 400 mature to ovulate. 99% of the remaining undergo atresia
What is the corpus luteum?
Corpus luteum
Follicle converts into a corpus luteum
Leutinisation of the granulosa and theca cells occurs (become polygonal, larger in size, have abundant cytoplasm containing lipid.)
Secrete progesterone and oestrogen
If pregnancy does not occur, they regress.
What occurs in the corpus luteum?
Corpus luteum
Regression starts 8-9 days after ovulation of pregnancy does not occur.
Granulosa cells decrease in size, develop pyknotic nuclei, and accumulate abnormal lipid.
Cells undergo dissolution and are phagocytosed.
There is progressive fibrosis by ingrowth of connective tissue
What is the corpus albicans?
Corpus albicans
Well circumscribed structure with convoluted borders, almost entirely composed of densely packed collagen with occasional follicles.
Eventually they may be resorbed/ replaced by ovarian stroma
What is the fallopian tube like?
Run throughout the length of the broad ligament
Transports ovum to the uterus
Fertilization occurs here.
4 segments
Intramural - inside uterine wall
Isthmus - 2-3 cm, thick walled
Ampulla - expanded area
Infundibulum - Trumpet - shaped opening to peritoneum, has fimbriae.
What do fallopian tubes contain?
Mucosa
Thrown into branching folds (plicae)
2 cell types
- Secretory
- ciliated
(peg cell – effette secretory)
(basal – lymphocytes)
Muscularis (myosalpinx)
- Inner circular layer
- Outer longitudinal layer.
Serosa
Connective tissue covered by mesothelium
What is the uterus like?
Composed of three layers:
- endometrium
- myometrium
- serosa
Endometrium
Deep basal layer - stratum basalis
Superficial functional layer - stratum compactum (towards the surface) and stratum spongiosum
What is the uterus like?
Composed of three layers:
- endometrium
- myometrium
- serosa
Endometrium
Deep basal layer - stratum basalis
Superficial functional layer - stratum compactum (towards the surface) and stratum spongiosum
What is the proliferation phase of the endometrium?
Endometrium
Proliferative phase
Oestrogen stimulation
Straight proliferating glands with mitotic activity
No luminal secretions
Stromal cells are spindled and compact, and show mitotic activity
What is involved in the secretory phase?
Secretory phase
Progesterone stimulation
Early - Sub-nuclear glycogen vacuoles
Mid - vacuoles above and below the nucleus and later intraluminal secretions, glands more rounded
Stroma-oedema
Late - Elongated and saw-toothed glands with more intraluminal secretions
Stroma - spiral arterioles, decidual change
(Image shows late-secretory endometrium)
What is the menstrual phase of the endometrium?
Menstrual phase
Progesterone stimulation withdrawn
Stromal haemorrhage and granulocytes
Stromal and glandular fragmentation
What is the myometrium like?
Thick muscular wall with 3 ill-defined layers of smooth muscle
Inner longitudinal
Middle circular
Outer longitudinal
What is the endocervix like?
Loose fibromuscular stroma lined by simple columnar ciliated epithelium
Thrown into crypts
What is the ectocervix like?
Ectocervix
Dense smooth muscle stroma lined by non-keratinised stratified squamous epithelium
Site of squamocolumnar junction varies
Atrophic in postmenopausal women
What is the vagina like?
Vagina
Tubular structure
Mucosa
Lined by non keratinising stratified squamous epithelium.
Stroma contains elastic fibres and a rich vascular network.
Muscular wall
Smooth muscle cells
Inner circular
Outer longitudinal.
Adventitia
Loose connective tissue
What is the vulva like?
Vulva
Mons pubis Clitoris
Labia minora Labia majora
Vulvar vestibula Hymen
Urethral meatus Skein’s gland
Bartholins gland Introitus.
Labia majora
Lined by keratinising stratified squamous epithelium and has skin adnexae.
Labia minora
Mostly non keratinising stratified squamous epithelium.
What is bartholins gland?
Bartholin’s gland
Tubuloalveolar glands. Acini lined by mucus-secreting epithelium
What are the minor vestibular glands?
Minor vestibular glands
Simple tubular glands lined by mucus-secreting epithelium
What is the skeins glands?
Skein’s glands (periurethral glands)
•Analogous to prostate
•Lined by peudostratified columnar epithelium
What is the hymen and clitoris like?
Hymen
•Lined by non-keratinising sqaumous epithelium
Clitoris
•Erectile tissue rich in blood vessels and nerves.
How does the appearance of ovary and endometrium vary?
Histological appearance of the ovary and endometrium varies according to the phase of the menstrual cycle in reproductive life
How is the female reproductive tract like in postmenopausal women?
In postmenopausal women the ovary, endometrium, cervix and vagina atrophy
What is the function of the skin?
Barrier to infection
Waterproofing
Thermoregulation
Protect against trauma
Protect against UV-light
Vitamin D synthesis
Sensation
What is the epidermis like?
Basement membrane - not typically visible in HandE
Made of type 4 (IV) collagen
Stratum basale
Melanocytes
Stratum spinosum
Stratum granulosum
Stratum corneum
What is the stratum basale like?
Sits on BM
Basal epithelial cells (stem cells)
Melanocytes
