Exam 4: Urinary System Flashcards
Urinary System Components, Functions
- kidneys, ureters, urinary bladder, and urethra
- urinary tract: ureters, bladder and urethra
- function: filter blood, and transport the liquid waste (urine) outside the body
- urinary tract transports the urine
- process of releasing urine: urination, or micturition
Why does blood need to be filtered?
-contiains waste products from (lymph, CSF, cells) and if you dont filter it you will die
What is urine?
-water, some ions (Na+, C+) ammonia, urea, uric acid, must dissolve these substances in water
Urinary System Innervation
- primarily autonomic nervous system
- only one musle is under voluntary control: external urethral sphincter in urogenital diaphragm
Kidneys External Gross Anatomy and Function
- posterior abdominal wall
- right lower than left because liver is directly above it
- kidneys reponsible for filtering blood and turning the filtrate into urine
Kidneys Internal Gross Anatomy
- outer cortex and inner medulla
- renal columns
- renal pyramids
Renal Columns
-extension of cortex that divide medulla into renal pyramids
Renal Pyramids
- portions of medulla (each kidney had 8-15)
- each drains into minor calyx, several of these form major calyx, major calyces drain int renal pelvis connected to ureter.
Blood Flow of Kidneys
- blood must supply nutrients to the kidney and be filtered by the kidney
- renal arteries–>segmental arteries–>interlobar arteries–>arcuate arteries–>interlobular arteries–>afferent arterioles–>glomerulus–>efferent arteriole–>peritubular apillaries/vasa recta–>interlobular veins–>arcuate veins–>interlobar veins–>renal veins
Renal artery
-receives arterial blood from aorta, high in oxygen here, blood is “dirty”
Interlobar Arteries
- travel in renal columns
- between lobes
Arcuate Arteries
-found at CORTEX-MEDULLA JUNCTION
Glomerulus
- each afferent arteriole brings blood here
- capillary ball
- blood is filtrated here so goes from dirty to clean (everything after is “clean” blood and everything before in blood flow is “dirty”
- still high in oxygen
Vasa Recta/Peritubular Capillaries
- peritubular capillaries are in cortex
- vasa recta is in medulla
- gas exchange happens here (everything before in blood flow is high in oxygen and everything after is low in oxygen)
Interlobular Veins
-in cortex
Arcuate Veins
-in cortex-medulla junction
Nephrons
- functional filtration unit of the kidney
- function: filters blood and then modifies this “filtrate” that is squeezed out from glomerulus
- each kidney contains over 1 million nephrons
Nephron Composition
- Renal Corpuscle (Glomerulus + Glomerular Capsule)
- Proximal Convoluted Tubule
- Nephron Loop (Loop of Henle)
- Distal Convoluted Tubule
- most of nephron is in cortex (nephron loop goes into medulla)
Renal Corpuscle
- glomerulus plus glomerular capsule
- glomerular capsule surrounds the glomerulus
- apsular space: between capsule an dglomerulus, filtrate is squeezed into here, not yet urine, lots of water, sodium, potassium, and glucose
Proximal Convoluted Tubule
- function: to resorb some materials and water in the filtrate
- resorbed material is sent to the peritubular capillaries
Nephron Loop (Loop of Henle)
- function: to resorb more materials and water in the filtrate
- resorbed material is sent to the vasa recta
Distal Convoluted Tubule
- last segment of nephron
- function: to resorb more materials and water in the filtrate
- resorbed material is sent to the peritubular capillaries
Flow of Filtrate/Urine
filtrate is squeezed out of glomerulus, enters capsular space (space in glomerular capsule)–>proximal convoluted tubule–>nephron loop–> distal convoluted tubule–>the filtrate travels through the collecting duct–>minor calyx (now urine)–>major calyx–>renal pelvis–>ureter–> urinary bladder–>urine exits the body via the urethra
ADH Note
- ADH acts on DCTs and collecting ducts
- if dehydrated, ADH signals these structures to resorb more water
- alcohol inhibits/interferes with ADH secretion
Ureters General Description and Function
- long, thin, paired muscular tubes
- function: transport urine (via peristalsis) from kidney to urinary bladder
Why do ureters use peristalis instead of just gravity?
-not always in anatomical position and urine would pool in kidneys if lying down or upsidedown
Layers of Ureters
- Mucosa: transitional epithelium
- Muscularis: 2 layers of smooth muscle
- Adventitia: areolar connective tissue
Renal Calculi (Kidney Stones)
- formed from crystaline materials (e.g. salts, Calcium, uric acids) in urine
- pain is sharp and stabbing (called ureteric colic)
- Risk factors: dehydration/inadequate fluid intake, dome diet/medical issues
Urinary Bladder General Description and Function
- function: urine reservoir (muscular storage sac for urine)
- its shape changes as it fills: empty: pyramidal in shape in pelvic cavity, full: oval, extends into abdominal cavity (to belly button)
- neck of the bladder = narrow base of bladder
Layers of Bladder
- Mucosa: transitional epithelium
- Submucosa: dense irreg CT
- Muscularis: 3 layers of smooth muscle: together, these layers are known as the detrusor muscle
- internal urethral sphincter, involuntary sphincter
- Adventitia: areolar CT
Urethra General Morphology and Function
- single muscular tube running from bladder to exterior of body
- function: expels urine from body
- urethra pierces a group of skeletal muscles called the urogenital diaphragm
- some of the skeletal muscle fibers thicken and form an external urethral sphincter (around urethra), voluntary sphincter able to control when you become toilet trained
Female Urethra
-1.5 inches long
Male Urethra
- 8 inches long
- transports urine and semen but can’t do both at the same time
