histology exam iv review part 2

8/12/2019 Histology Exam IV Review Part 2

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Male Reproductive System The testisis involved in the production of sperms (seminiferous tubules) and

the male hormones (cells of Leydig: release testosteronein response to LH)

The developing germ cells undergo meiosis and maturation processes leadingto the formation of a spermatozoa (spermatogenesis and spermiogenesis)

A number of channels conduct the sperms out of the testis and into theexcurrent ducts

Sperms are stored in the epididymisand undergo maturation process

Ductus (vas) deferens forms part of the spermatic cord

A number of accessory sex glands secrete substance which help to protect and

nourish the sperms (seminal vesicles, prostateand bulbourethral glands) The penisis made up of three cylinders of erectile tissues

The semen is composite fluid with contributions from various sources

Sperms must under capacitation before they can fertilize an ovum


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Effects of androgens on target tissues

Testosterone

Testis

Pituitary

Dihydrotestosterone (5 -r eductase does this conversion of

testosterone)

Accessory sex glands

Estrogen (aromatization)

Hypothalamus

Cryptorchism

Undescended testis in the abdominal cavity or inguinal canal

Testis subjected to higher temperature than in scrotum

Sperms do not develop properly

Unilateral = fertile; bilateral = sterile

Androgen production not affected

Increased risk of testicular cancer

Testis


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Tunica albuguinea: thick CT capsule; septa divide the

testis into many lobules. Each lobule contains one to four

seminiferous tubules

Leydig cells: make testosterone; adjacent to blood vessels

LH (from AP) stimulates Leydig cells to produce

androgens, which diffuse across the basil laminainto seminiferous tubules (where high [androgen] is

required for sperm development)

FSH stimulates synthesis of androgen binding

protein

Seminiferous tubules: sperm production and maturation

takes place in the seminiferous tubules

Myloid cells: contractile filaments that move fluid alongseminiferous tubules

Leydig cell

with smooth

ER and lipiddroplets

Release

testosterone in

response to LH


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Sertoli cell: in seminiferous tubules; large, sit on the basallamina, apex reaches to the lumen; poor-staining nucleuslooks like a baked potato and has a prominent nucleolus

Physical support & nourishment for developing sperm;forms blood-testis barrier, isolating primaryspermatocytes from any immune cells

Secrete important factors including: Androgen bindingprotein [which localizes testosterone in seminiferoustubules], K+, HCO3

-, Mullerian inhibitory factor(embryonic) [which inhibit formation of female genitalia]

The Sertoli Cells

Sertoli cells

Poor-staining nucleus

looks like abaked

potatoand has a

prominent nucleolus

Seminiferous Tubule,Semi-thin

Sertoli cells

Basal lamina

Seminiferous Tubule,HP

Sertoli cells

Basil

lamina


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The Spermatogenic Cells in the Seminiferous Tubule

Spermatogonium spermatocytes spermatids sperm

Spermatogonia

Spermatogonia(2N chromosomes; 2N DNA)

Sitting on the basil lamina

Located right on the basal

lamina; dont have a

prominent nucleolus (as in

Sertoli cells)

Spermatogenesis


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Primary Spermatocyte

Located away from the basal lamina;

earthworm like condensed

chromosomes First meiotic division; long prophase

Cross over takes place (daughter cells

are genetically different than the

somatic cells)

Yields 2 secondary spermatocytes

Primary Spermatocytes

Primary Spermatocyte (4N DNA; 2N chromosomes)

Myoid cell (contractile CT cell)

Round (Early)

spermatids (N)

Sertoli Cell Nucleus

Residual Bodies

Secondary Spermatocyte

At middle of the epithelium

N chromosomes, 2N DNA

Genetically unique

Second meiotic division

Short prophase

Yields 2 spermatids


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Early Spermatids Two morphological forms

small cells up at the lumen with round

nuclei [jelly-filled doughnut]

Close to the lumen Small round to elongated

N chromosomes, N DNA

Does not divide further

Undergoes spermiogenesis resulting

in one sperm (spermatozoa)

SpermatidsEarly spermatids(jelly-filled

doughnut)

Spermiogenesis**Mitochondria

are located on

the mid-piece

Seminiferous Tubule, Semi-thin

Late spermatids

Spermiogenesis,PAS-1

Acrosomes contain hydrolytic enzymes

Clonal nature of developing

sperm: Spermatocytes that are

developing are all attached

until they are released into

the lumen


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Rete TestisRete testis

Network of interconnecting channel

surrounded by a chunk of CT

Within the Mediastinum Testis

Lobule with Seminiferous tubule

Ductuli Efferentes 1

Ductuli efferentes

Draining of Rete Testis

Inside lumen looks likea rollercoaster

(scalloped appearance due to different cell types)

Ductuli Efferentes

Ductuli efferentes

Two types of cells:

Cuboidal type cells:

absorb residual bodies

Ciliated cells becausesperm are unable to

swim yet

Ductuli Efferentes

Cilliated &

absorptive

cells

Only placewhere

ciliated cells

appear in the

male


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Epididymis

Ductus Epididymis

Sperm

storage

Swells of smooth muscle

becomes thicker down the

tube; assists in peristalsis

for sperm movement

Epididymis,HP

Stereocilia

Golgi

Epididymis

(long microvilli) at apex of

tube; help with absorption

and secretion of fluid

Smooth muscleIncreases in thickness

proximal-to-distal


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Ductus (Vas) Deferens

Has the thickest

muscular wall in the

male genital tract;

contracts strongly

during orgasm

Spermatic cord

Suspends the testis;

houses the Ductus

Deferens

Ductus (Vas) Deferens

Small lumen; muscular, strong tube

that contracts during ejaculation

Spermatic Cord

Cremaster muscle

Ductus deferens

Small lumen;

muscular tube

Venous plexus

Runs between testis and

inguinal canal; contains

testicular artery,

pampiniform plexus of

veins, vas deferens and its

vessels, and cremaster

muscle (causes testicular

sac inward movement)

Pampiniform Plexus ofVeins

Testicular artery

Pampiniform plexus of veins

Testicular artery

Pampiniform plexus of veins

Testicular artery

Pampiniform plexus of veinsSurround the testicular artery

Heat exchange: Warm blood from aorta; Cooler venous

blood lowers blood that comes into the testis


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Accessory sex organs:

Seminal vesicle

Prostate

Bulbourethral gland

All help secrete fluid and require 5-a-DHT

for proper function

Epithelium of Seminal Vesicle

Yellow lipid droplets show up

after puberty and increase in

numbers with age; auto

fluorescent; contributes to semen


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Prostatic AciniProstate: between the

bladder and penile

urethra; chestnut shape

and size; fibromuscular

stroma (fibroblasts and

smooth muscle)

Acini: secretory units of the

prostate; secretion

neutralizes acidic

environment of vagina

Pseudostratified columnar epithelium with basal cells

Basal Cells in Prostate

Normal prostate acini

have a complete ring

of basal reserve cells

Broken ring canindicate prostate

cancer

Corpora Amylacea

in lumen of

Prostate Acinicondensation of protein

fluid


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Bulbourethral gland of Cowper

Secrete a thick, sticky mucous high in sialoprotein due to sexual

excitement for lubrication of urethra

Pale, basophilic cytoplasm

Bulbourethral Gland


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Penis Section, GrossTunica albuginea

Tunica

albuginea

Important

for

maintaining

an erection;

Thicker for

Corpora

cavernosa

versus

Corpus

spongiosum

Urethra

Penis Ross 21-30

Penis

Corpora cavernosum:

thicker tunic; paired (2);on dorsal side

Corpus spongiosum:

contains the urethra

Parasympathetic

innervation causes

erectionSympathetic

innervation causes

ejaculation

Nitrous Oxide isreleased by the nerves

in erectile tissues,

dilates the arterioles

for erection

Tunica Albuginea of Penis

t.a. of corpora

cavernosum

t.a. of corpus spongiosum

Penile urethra

Tunica Albuginea of Penis

Cavernous Blood Spaces in thePenis

Erectile Tissue

Trabeculae with smooth muscle walls lined by endothelial cells

Blood flood into the spaces results in erection

Penile Urethra

Glands of

Littre

Penile urethra

Littre glands: secrete a lipid to keep

urethra lubricated for urine flow


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OvaryCortex with

follicles

Medulla with

blood vessels

follicles

Ovarian arteries

& veins

OvaryCortex: germ cellsMedulla: blood vessels


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Ovary: Cycle,

Summary

Primordial

Arrested at MI prophase

Primary

Unilaminar

Multilaminar

Secondary (vesicular; fluid

accumulation in antral)

Early (still has primary

oocyte)

Mature (Graafian;

secondary oocyte):

matures M and arrests at

MII metaphase Ovulation of secondary

oocyte

Corpus luteum

Corpus albicans

Mature

Stigma

P i di l F lli l i t ith i l l


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Primordial Follicles: primary oocyte with single layer

of flattened follicular cells

Primary Follicle (unilaminar): oocytes enlarge during

follicular growth under influence of FSH (from pituitary

Primary Follicle (multilaminar): Follicular cells

proliferate and form a stratified follicular epithelium,

granulosa layer. Zona pellucida begins to form

S d (A t l/ V i l ) F lli


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Secondary (Antral/ Vesicular) Follice

Follicular fluid contains glycosaminoglycans,

steroid binding proteins, high concentration of

steroids (progesterone, androgens, estrogens)

The theca interna is highly vascularized Theca interna cells secrete androstenedione

Granulosa cells synthesize aromatasewhich

transforms androstenedioneinto estrogen.

Estrogen back diffuses into the stroma and

enters the blood supply.

Theca interna cellsbecome active

during formation of

secondary oocyte;

produce androgens

that diffuse into the

granulosa cells to be

converted intoestrogens by

aromatase

M t (G fi ) F lli


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Mature (Graafian) Follice

Can be as large as 2.5 cm; easily observed in

ultrasounds image (for IVF)

Primordial to mature follicle takes about 90 days

Follicle Sizes

Graafian

Follicle

Antrum

follicle

Ovulation

Mid-cycle surge of LH. Ovulation 16-24hr

after that. Surge is essential for ovulation.

Without the LH surge, ovulation is

imminent

Graafian Follicle

Theca

P i O t (2N)


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Primary Oocytes (2N)

Enter first meiotic division and arrest at

prophase I

Secondary oocyte(haploid, N)

Product of first meiotic division (in ovary) Arrested at metaphase II until fertilization

Released from ovary at the time of

ovulation

MIcompletes right before ovulation

MIIcompletes right after sperm penetration Follicular Atresia

Collapsed

follicle

Remains of ZP

Glassy Membrane

Glassy Membrane

Corpus luteum will undergo degeneration and apoptosis if


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Corpus luteum will undergo degeneration and apoptosis if

no fertilization due to negative feedback of progesterone and

estrogen on LH production

Corpus Albicans

remains (scar tissue) of a degenerated corpus luteum

Degenerating Corpus Luteum

Near ovary:

Mucosa well developed

and muscularis less well

developed

Endometri m

Menstrual Phase


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Endometrium

Changes during menstrual cycle

Uterine artery is blood supply; can be divided into

straight and spiral arteries

Cavities become the endometrial glands; bottom portion

supplied by straight arteries

Top portion: Stratum functionalis, is the part that comes

off during menstration Bottom portion: Stratum Basilas

Myometrium

muscular portion of uterine wall

Cells from cervical canal do not get shed with the

endometrium during menstration

Proliferative Phase

Lots of cell

division in

stroma and

glands

(endometrium

proliferation)

Increasing

thickness

Glands are very

straight

Lot of stroma

inbetween the

glands

Secretory Phase

(Luteal/ Progesterone phase)

Convoluted

glands

Little stroma

left

Secretions

fluid found

in gland

lumen

Ready for

zygote

implantation

Myometrium

Menstrual Phase

Dead cells and spiral

arteries on surface to be

shed with endometrium &

stratum functionalis

ESTROGEN PROGESTERONE


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Vagina


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Vagina

SS Epithelium

Fermentation

produces slightly

acidic

environment

Dilated blood vessels

There are no glands

Surface epithelium with

presence of glycogen

Vagina

Poor stainingdue to large

amount ofglycogen

accumulation inepithelium

Lactating Mammary GlandResting Mammary Gland


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Inactive Mammary Gland

Lactating Mammary Gland

Secretory

materialDuct

g y



Resting Mammary Gland

Joining of ducts

Milk j ti fl t i

histology exam iv review part 2

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