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:
