Renal Flashcards
How much blood do your kidneys hold at any time?
22%
How often does blood pass through your kidneys?
Every 5 mins
What aspects of homeostasis does the kidney maintain?
To maintain homeostasis: pH - H+ ions Blood pressure - Na+ and Cl- ions Osmolarity Waste - urea
What are main functions of the renal system?
1. Filtrate Blood Absorb ions and water into renal veins 2. Collection 3. Activates Vitamin D 4. Keeps blood in neutral non-acid state
Label diagram of kidney
Renal hilum (whole entrance part - artery and vein) Renal pelvis (of collecting system) Renal calyx (renal collecting parts - touch medulla) Renal medulla (inner portion) Renal cortex - outer portion
What is smallest functional unit of kidney?
Nephron
Where do nephrons sit?
Between cortex and medulla
What is purpose of renal calyx?
First point that collects urine
Describe the pathway of urine
Renal calyx Calyces Renal pelvis Ureter Bladder
What is bladder lined with?
Transitional epithelium.
Inbetween columnar and squamous - allows bladder to expand
How much can the bladder hold?
300-500ml
What is at the neck of the bladder?
Internal urethral sphincter
Smooth muscle (involuntary) controlling bladder. Not under our control
Describe urethra in females
Internal urethral sphincter
Membranous urethra:
Has external urethral sphincter/passes through membrane
Outside world
What is difference between internal and external urethral sphincter
Internal = smooth muscle = involuntary
External = skeletal muscle = voluntary
Describe urethra in males
internal urethral sphincter Prostatic urethra Membranous urethra (has external urethral sphincter) Spongy urethra (in penis)
Why are men less likely to have UTIs?
Because women have less urethra to outside space
How many nephrons in kidney
1 million
What is different between afferent and efferent arterioles?
afferent = towArds
efferent = lEft kidney
What is glomerulus?
Tight circling of blood vessel
Has afferent arteriole leading into it and efferent arteriole coming away
What is Bowmans capsule?
Sits underneath glomerulus and collects the filtrate. Bowmans space is top part of the capsule
What is cellular structure of glomerulus?
Fenestrated endothelial cells ‘holy’
Also basement membrane which ions, amino acids and glucose can leak through but larger molecules like proteins can’t.
Then have tubule cells underneath (epithelial cels) with podocytes - some have legs that hug around the arteriole
Describe a nephron
Starts with glomerulus and bowman capsule
Proximal tubule - convoluted (cortex)
Descending loop of henle - drops into medulla
Ascending loop of henle
Distal tubule - convoluted
Goes to collecting ducts
Describe action of loop of Henle
ascending - pumps out Na, Cl and K to make the medulla hypertonic. No water leaves this part
Descending - permeable to water, which leaves because the medulla is hypertonic.
How does glomerular filtration rate change with age?
Low at birth
Rapidly increases in first 6 months
Then gradually increases to reach adult levels by 1-2 years old
What is adult body surface area?
1.73m2