Renal

Question 1

Renal system functions

Answer 1

• Removal of excess water
• Removal of wastes
• Regulation of electrolytes
• Regulation of pH
• Regulate blood pressure via the renin – angiotensin – aldosterone pathway
• Release the hormone erythropoietin
• Synthesise calcitrol (active form of vitamin D)
• Perform gluconeogenesis

Question 2

Renal system consists of

Answer 2

• 2 kidneys – on posterior wall of abdomen
• 2 ureters - transport urine to bladder
• 1 bladder - stores urine
• 1 urethra - carries urine to outside

Question 3

Processes within nephron

Answer 3

1) Filtration
2) Reabsorption
3) Secretion

Question 4

Filtration

Answer 4

Pressure through net filtration in in glomerular capsule

Question 5

Reabsorption

Answer 5

In proximal tubule, moving needed substances from nephron tubule in blood stream

Question 6

Secretion

Answer 6

Everywhere but glomerular capsule, moving substances from blood in nephron tubule

Question 7

Hormones affecting reabsorption

Answer 7

• ADH increases water reabsorption

* Renin-Angiotensin-Aldosterone increases water reabsorption

Question 8

Atrial natriuretic

Answer 8

• Lower blood pressure

* Control electrolyte homeostasis

Question 9

Micturition reflex

Answer 9

• Contraction of bladder and involuntary contraction of internal sphincter
• Controlled relaxed of the external sphincter allows urination to occur

Question 10

Filtrate contains

Answer 10

Wastes, water, glucose, amino acids, electrolytes

Question 11

Blood supply through kidneys

Answer 11

1) Aorta
2) Renal artery
3) Afferent arteriole
4) Glomerulus (capillaries)
5) Efferent arteriole
6) Peritubular
7) Renal vein
8) Inferior vena cava

Question 12

Nephrons empty their products into

Answer 12

Collecting ducts, which drain into calyces, then the renal pelvis, then the ureter

Question 13

Kidney structure

Answer 13

• An outer cortex
• A medulla made up of pyramids
• Calyces leading to a pelvis

Question 14

Role of adipose tissue

Answer 14

• Protects the kidney
• Holds the kidney in place
• Acts as an energy (food) reserve

Question 15

Nephron

Answer 15

Functional unit of the kidney

Question 16

Each nephron consists of

Answer 16

• Renal corpuscle
- glomerulus
- glomerular (Bowman’s) capsule
• Tubule
- proximal tubule
- loop of Henle (nephron loop) 
- distal tubule

Question 17

Podocytes

Answer 17

Maximise the surface area for filtration

Question 18

Net filtration pressure is

Answer 18

Blood hydrostatic pressure = 55 mmHg
Capsular pressure - 15 mmHg
Blood colloid osmotic pressure - 30 mmHg
Net filtration pressure =10mmHg

Question 19

Proximal tube reabsorption

Answer 19

100% glucose and amino acids, 65% of the water, sodium and potassium, 80% of the bicarbonate

Question 20

Loop of Henle reabsorption

Answer 20

50% of the water is reabsorbed

Question 21

Distal tubule reabsorption

Answer 21

‘Fine tuned’ depending on the body’s requirements

Question 22

Reabsorption takes place by

Answer 22

• Passive transport: no energy required
- Diffusion
- Osmosis
• Active transport: energy required
• Mediated: uses a protein carrier
• Non mediated: no carrier molecule

Question 23

Obligative water reabsorption

Answer 23

Water reabsorbed by osmosis (85%)

Question 24

Facultative water reabsorption

Answer 24

Water selectively reabsorbed, regulated by ADH in the collecting duct

Question 25

Reabsorption – Renin-angiotensin-aldosterone system

Answer 25

1) Stimulus - Low blood pressure 2) Receptors - Baroreceptors 3) Kidneys release renin 4) Activates angiotensinogen to convert to angiotensin 5) Angiotensin causes vasoconstriction and aldosterone release from adrenal cortex 6) Increases sodium reabsorption 7) Increases water reabsorption 8) Increased blood volume and narrower blood vessler increase blood pressure

Question 26

Ureters transport urine to the bladder by

Answer 26

Peristalsis

Question 27

Micturition

Answer 27

The expulsion of urine from the bladder

Question 28

Micturition steps

Answer 28

* Bladder fills * Stretch receptors fire * Involuntary internal sphincter relaxes * Voluntary external sphincter relaxes

Question 29

Osmolarity

Answer 29

The number of solute particles dissolved

Question 30

A high osmolarity

Answer 30

A high Na+ concentration and low water concentration.

Question 31

A low osmolarity

Answer 31

A low Na+ concentration and high water concentration.

Question 32

Antidiuretic hormone - Reabsorption

Answer 32

1) High sodium/high osmolarity 2) Osmoreceptors in hypothalamus detect dehydration 3) Stimulates posterior pituitary to release ADH hormone 4) Targets collecting ducts of kidneys to reabsorb water 5) Water reabsorption increases 6) Lower osmolarity Negative feedback