Genitourinary / reproductive system Flashcards
Urinary System: Components
● Kidneys, ureters, urinary bladder, urethra.
Urinary System: Function
● Produce, Store, eliminate urine
● Eliminate wastes and regulates volume and composition of blood; aids in the maintenance of acid/base balance of body fluids
● Maintains body’s mineral balance
● Aids in the regulations of red blood cell production
Reproductive system: Components
● Female: Uterus, Ovaries, Vagina, Uterine tubes, Vulva. Breast (accessory).
● Male: Scrotum, Testes, Ducts, Penis. Prostate, Epididymis, Seminal vesicle (accessory).
Reproductive system: Function (male + female)
Female:
● Formation of ova.
● Reception of spermatozoa. Provision of suitable environment for fertilisation and fetal development.
● Parturition (childbirth)
● Lactation, production of breast milk.
Male:
● Production, maturation and storage of spermatozoa.
● Delivery of spermatozoa in semen to the reproductive tract.
Kidneys – Functions
- Regulation of blood composition and concentration (osmolarity), including electrolytes/ions
- Regulation of blood volume and interstitial fluid
- Regulation of blood pressure
- Regulation of blood pH
- Regulation of calcium homeostasis
- Red blood cell production
- Regulation of blood glucose
- Excretion of metabolic waste products and toxins
Kidneys - Basic Structure
- Paired structures on posterior abdominal wall, lateral to spine
- Retroperitoneal structures; fixed
- Level of T12 to L3, right lower than left
- Partially protected by lower ribs
- Bean-shaped - Convex laterally, Concave medially
- 10-12cm long, 5-7cm wide, 3cm thick, 150 grams
- Outer - renal fascia – Fibrous connective tissue surrounding kidneys and adrenal glands
- Middle - Perirenal / perinephric fat
- Deep - peripheral fibrous capsule of kidney
- Smooth transparent membrane, Maintains shape, Attachment and protection
Kidneys - Internal Structure
Cortex (outer)
- Surrounds and extends into medulla. Extend internally between pyramids- renal columns
Medulla (inner)
- Darker in colour. Contains cone-shaped renal pyramids. Striped appearance – tubules and capillaries. (8-18 per kidney)
Calyces (singular – calyx)
- Collect urine from papillae. Transitional epithelium lined – impermeable/ waterproof. Smooth muscle walls – peristalsis of urine
Renal pelvis
- Direct continuation from calyces (similar structure). Funnel-shaped. Continuous with ureter
Renal hilum
- Renal artery enters, renal vein exits. Lymphatic vessels and nerves. Ureter exits
Renal sinus
- Cavity inside medulla. Contains calyces, renal pelvis, and blood vessel
Ureters
- Carry urine from kidneys to urinary bladder
- Continuous with renal pelvis
- 25-30cm long, 3mm in diameter
- Retroperitoneal, anterior to Psoas muscles, over brim of pelvis
- Passes obliquely into posterior aspect of bladder
- Pressure in bladder compresses distal ureter to prevent reflux
- Peristalsis to help gravity propel urine – 1-5 waves per minute
- Comprised of 3 layers:
Peripheral protective fibrous tissue (adventitia), continuous with renal capsule
Middle muscular layer to propel urine
Inner protective mucosa
Urinary bladder
- Temporary storage/reservoir for urine
- Smooth muscular sac, collapsed when empty, walls fold into rugae. Pyramidal shape when empty.
- Retroperitoneal on pelvic floor, posterior to symphysis pubis
- Relational anatomy dependent on sex
- Lies in pelvic cavity but changes position and size when distended, moves into abdominal cavity
- Three layers (similar to distal ureter):
External fibrous tissue (peritoneum superiorly), Middle thick smooth muscular layer; Internal mucosal layer - Three orifices on base for bilateral ureters and urethra
- Allows micturition to be infrequent and controlled
- Normally holds 300-500mls. Can hold up to 800mls
Urethra
- Tube extending from neck of bladder to external urethral orifice
- Approximately 4cm in females
- Approximately 20cm in males
- Differences in structure due to different roles
- Thickening of detrusor muscle at junction; internal urethral sphincter
- Involuntary – autonomic nervous system
- External urethral sphincter – skeletal muscle as passes urogenital diaphragm
- Voluntary - assisted by levator ani muscle
Male reproductive system: Scrotum
- Pouch / sack supporting testes
- Externally: Loose skin/fascia/dartos muscle. Attached to root of penis
- Internally: Septum divides into two sacs with a testis
- Temperature of testes regulated by location and contraction of muscle fibres
- Required to be 2-3 degrees below core temperature for normal sperm production
- Dartos (skin) muscle is smooth muscle - Contraction causes wrinkling of scrotum in cold/arousal; reduces surface area/heat loss
- Cremastor muscle in spermatic cord; skeletal muscle, - also Elevates testes in cold/arousal
- Relaxation of both causes opposite.
Male reproductive system: Testis (singular) Testes / testicles (plural)
- Paired glands; 5 x 2.5cm in size, approx. 15g
- Covered by two layers:
- Outer serous membrane;
- Inner dense fibrous capsule
- Each lobule (250-300 per testis) contains 1-3 tightly coiled seminiferous tubules
- Location of sperm production –spermatogenesis
- Walls are smooth muscle
- Lined with spermatogonic stem cells
- Dormant until puberty
Ducts
- Travel through convoluted seminiferous tubules to straight tubules distally and into a network of ducts called the rete testis. Move then through efferent ducts into epididymis
Epididymis
- Comma-shaped organ on posterior border of each testis.
- Efferent ducts join epididymis superiorly at head. Continue as tightly coiled ductus
- epididymis to form main body. Smaller distal tail continues as ductus (vas) deferens
- 6m long if laid out (<4cm in length when coiled), 1mm diameter
- Site of sperm storage and maturation (up to a month)
- Encircled by smooth muscle to propel sperm via peristalsis
Vans Deferens
- Larger diameter, straighter. 45cm, joins ejaculatory ducts
- Site of storage of sperm, up to few months
- Reabsorption of sperm not ejaculated
- Layers of muscles, peristalsis moves sperm:
Ejaculatory Ducts
- Formed at junction between ampulla of vas deferens and duct from seminal vesicles
- Approximately 2cm long
- Pass from superior to prostate, inferiorly and anteriorly through prostate. Terminate into prostatic portion of urethra
- Release sperm and secretions from seminal vesicles into the urethra prior to ejaculation
Penis
- Contains urethra as passageway for urine and semen
- Method to deliver semen
- Consists of:
Body
Root
Glans - Supported by two ligaments continuous with fascia of penis:
- Fundiform ligament; inferior part of linea alba
- Suspensory ligament of penis; from pubic symphysis
Male reproductive - accessory organs: Seminal vesicles
- Paired pouch-like structures, convoluted in shape. Secrete viscous/sticky fluid 60% semen volume. Fluid passed into ejaculatory duct
Male reproductive - accessory organs: Prostate
- Lies inferior to bladder, surrounds prostatic urethra
- Grows slowly until puberty, then rapidly until around 30
- Produces milky slightly acidic fluid (around 25% semen volume) which aids sperm motility and viability. Enters urethra through numerous prostatic ducts
- 3 zones: Central, Peripheral and Transitional
Male reproductive - accessory organs: Bulbourethral glands
- Paired pea-sized organs
- Inferior to prostate, within urogenital diaphragm
- Ducts open onto spongy urethra in root of penis
- Produces fluids to protect sperm: alkaline substance to neutralise acids in urethra, mucous to lubricate tip of penis and urethra
Female reproductive – Uterus
- Hollow muscular organ within the pelvis
- Inverted pear, 7.5cm long, 5cm wide, 2.5cm thick
- Posterior to bladder, anterior to rectum
- 3 sections: Fundus, Body, Cervix,
Structure
- Outer layer, perimetrium - lines the outside of the uterus
- Middle layer, myometrium - 3 layers of smooth muscle
- Inner layer, endometrium - subject to changes in preparation for pregnancy (uterine cycle)
- Held in place by ligaments: two of each of uterosacral, cardinal and pubocervical ligaments
- Uterus function: pathway for sperm to reach fallopian/uterine tubes. Receive , retain, protect and nourish the fertilised ovum and developing embryo-fetus. To expel mature fetus at end of pregnancy
Female reproductive - Vagina
- Thin walled distensible tube 8-10cm in length
- Runs in superior posterior direction from cervical canal to exterior surface. Lies posterior to urethra, anterior to rectum
- Muscular canal lined with mucous membrane
- Acidic environment to limit microbial growth and harmful to sperm. Alkaline component of semen raises pH to increase sperm viability.
Female reproductive - Cervix
- Connects the interior of the vagina and cavity of the body of the uterus
- 2-3cm in length. Width depends on age - premenopausal is widest
- Dips into vagina forming the fornices, anterior, posterior and lateral. Posterior fornix the deepest
- Acts as mechanical barrier to infectious microorganisms present in the vagina
- External os very small opening with thick sticky mucus plug. During ovulation plug becomes watery to facilitate sperm travel under the influence of oestrogen
Fallopian (uterine) tubes:
- Function- Provide passage to the uterine cavity for released ovum
- Approx 10cm in length 1cm diameter
- Radiate laterally from uterus running through peritoneum - between folds of broad ligament.
- Distal end curves around ovary - ampulla
- Infundibulum - distal part of the tube, funnel shaped terminating in fimbriae
- Tube narrows as runs medially from the ampulla. Narrowest at entry to uterus - isthmus
Ovaries
- Paired organs on each side of uterus.
- Within peritoneal cavity
- Oval shaped
- Size dependant on age and hormonal status. 3.5cm long, 2.5cm wide, 2cm, thick
- Double in size during pregnancy. Smaller then atrophic during/ after menopause.
- Structure: Outer fibrous coat. Cortex - Contains the oocytes/ follicles. Medulla..
- Held in place by ligaments: ovarian, suspensory, mesovarian and broad ligament
- Functions: Endocrine: secretion of hormones - oestrogen and progesterone. Oogenesis: production and release of mature ova.
Breast
- Paired structures on anterior thoracic wall in pectoral region
- Developmentally breasts are part of the skin and are modified sweat glands. Mammary gland – contained within skin covered breast
- Overlie 2nd – 6th rib. Anterior to pectoral muscle
- Medial border – sternum. Lateral border – anterior or mid-axillary line. Superior border – infraclavicular fossa. Inferior border – mid sternum
- Nipple – surrounded by areola – pigmented. Dense fibrous tissue with smooth muscle fibres – erectile function. Areola contains modified sweat glands. Secretions lubricate during breastfeeding.
- Internal anatomy:
Internally 15 – 20 lobes
Separated by connective tissue and adipose tissue
Within each lobe – 20 – 40 lobules containing clusters of alveolar glands
Alveolar glands produce milk - Milk passes from alveolar gland to lactiferous ducts. Lactiferous ducts open to the outside at the nipple
