Renal System

Question 1

To identify the components of the renal system

Answer 1

There are 4 main component parts:

1. kidneys
2. Ureters
3. Bladder
4. Urethra

• also known as the urinary system or urinary tract
• Filter blood and remove waste (make urine)
• control red blood cell production
• control blood pressure

Question 2

1. KIDNEYS:

To understand the functions of the components of the renal system

Answer 2

• behind the peritoneum
• right kidney is lower than the left
• respond to hormones (ADH, PTH, aldosterone)
• makes hormones (Renin, vitamin D and erythropoietin

GROSS ANATOMY

• Capsule -covers the whole kidney
• Cortex - outer layer
• Medulla - inner layer (ball like)
• Renal pelvis - drains to the ureter
• Function unit is a nephron

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Question 3

To understand the physiology of the renal system
Kidney in detail including:

• nephron structure and function

Answer 3

Capsule: protection, fibrous, fat layer on top, lowers the risk of trauma to the kidney (also ribs)

Nephron: the functional unit of the kidneys (crosses between layers) Glomeruli and proximal tubule are in the cortex, loop of henle and collecting duct in the medulla, each kidney has around 500,000 nephron which main function is to form using

Glomerulus

• Supplied by capillaries (high pressure) forced out blood into
• contains Bowmansb capsule (hollow)
• made of tubular epithelium (epithelial cells lining)
• forces water, ions and small molecules (out of blood) into Bowman capsule
• 1st stage of urine production
• located in the cortex- contains all the glomeruli

Proximal convoluted tubule

• cortex
• convoluted
• Columnar epithelium lining - microvilli
• high surface area
• source of most re-absorption
• absorbs many substances- active absorption, Na, K, Ca, phosphate, nutrients: glucose, amino acids and water

Loop of Henle
- medulla
- creates osmotic gradient
- split into two sections:
descending limb (water permeable), - secretes water =reabsorption, absorbs urea =excreted from blood
ascending limb (water impermeable) - secretes Cl and Na=reabsorption

Distal convoluted tubule (DCT)

• cortex
• hormone controlled
• responds to parathyroid hormones (PTH) - re-absorbs calcium
• responds to aldosterone- red absorbs Na+ Secretes K+

Collecting duct
- medulla
- concretrates urine when required
    Absorbs water
    Anti-diuretic hormones (ADH) can affect function-promotes water reabsorption (active) 
    ADH is inhibited by alcohol
- medulla is salty (gradient) 
   Water leaves by osmosis(passive)

Question 4

To understand how all the components of the renal system work together

Answer 4

A

Question 5

To understand the physiology of the renal system
Kidney in detail including:

Hormonal control and hormone production:

• Renin
• Vitamin D-products
• Erythropoietin
• (Prostaglandins)

Answer 5

RENIN

• Produced by the juxtaglomerular apparatus
• released in response to low sodium
• Leads to formation of angiotensin II
  
  • Acts of nephrons
    
    • promotes sodium retention (in blood)
  • Potent vasoconstrictor
    
    • Regulation of blood pressure
    • multiple organ involvement

ERTHROPOIETIN

• Made by fibroblasts (internal space(in the kidneys))
• In response to low oxygen concentrations (hypoxia) in blood
• Promotes red blood cell formation in bone marrow

 VITAMIN D (STEROID HORMONE)-PRODUCT
- Metabolised in the kidney
- 1,25- dihydroxycholecalciferol
   - Promotes Ca and K absorption from the gut
(Renal system 3 )

Question 6

Ureters

Answer 6

URETERS

• Tubes
  
  • one from each kidney
• Transport urine from renal pelvis (kidney) to bladder
• Muscular tubes
  
  • Peristalsis (urines bolts), smooth muscle, lined with epithelium (transitional=stretch)

URINARY BLADDER
- AKA bladder
- revives urine via two ureters 
- hollow 
- smooth muscle
- size depends on urine content
• transitional epithelium: •stretch 1ml-1000ml
• After few 100 millilitres- reflex is activated 
- contraction in smooth muscle
- release to urethra
- controlled by urinary sphincters 
   - internal: involuntary
   - external: voluntary