Chapter 5: Communication, Homeostasis, Excretion - Kidney (complete)

Question 1

Define excretion

Answer 1

Removal of metabolic waste from the body - products of chemical reactions

Question 2

What are excreted substances and what are the organs responsible?

Answer 2

Urea and Carbon dioxide - Lungs and kidneys

Question 3

What is carbonic acid and how is it made?

Answer 3

Alters PH of blood and interferes with cellular processes - made by dissociation of carbon dioxide

Question 4

What’s the Ornithine cycle?

Answer 4

Liver deaminates excess amino acids, forming ammonia - ammonia converted to urea (less toxic and less soluble) to be excreted

Question 5

What’s the formula equation for the conversion of ammonia to urea?

Answer 5

2NH3 + CO2 -> CO(NH2)2 + H2O

Question 6

Where is the glomerulus located in the kidney?

Answer 6

In the Nephron (the functional unit of the kidney)

Question 7

What does the fibrous capsule do?

Answer 7

Protects the kidney

Question 8

What is the medulla in the kidney made up of?

Answer 8

Segments called pyramids

Question 9

How are podocytes adapted for their function?

Answer 9

foot like projections - allow filtration

Question 10

How have the cells of the PCT adapted for their function?

Answer 10

Microvilli and mitochondria - increase surface area

Question 11

What does it mean if glucose appears in the urine?

Answer 11

Diabetes type 1 - the glomerulus filters more than the PCT can reabsorb
OR
damage to the kidney

Question 12

What is the process of Ultrafiltration into the Bowman’s capsule?

Answer 12

1) Blood enters glomerulus via afferent arteriole - build up of pressure in capillaries that make up glomerulus
2) Increase in hydrostatic pressure is enough to force into lumen of Bowman’s capsule

Question 13

What does PCT stand for and what process occurs within it?

Answer 13

Proximal convoluted tubule: selective reabsorption

Question 14

What’s the concentration of RBC and WBC in the glomerular filtrate and why?

Answer 14

0 because the membrane has tiny pores for smaller substances

Question 15

What is found in glomerular filtrate?

Answer 15

Water, urea, glucose, ions, amino acids

Question 16

How is glucose reabsorbed in the PCT?

Answer 16

Initially by passive diffusion, then active transport ensures all glucose is reabsorbed - needs cotransporter molecules and sodium

Question 17

What does the loop of henle do?

Answer 17

Creates a high concentration of salts in the medulla so water can be reabsorbed from the collecting duct and produce hypertonic or concentrated urine

Question 18

In the Nephron, what is the order that the filtrate goes through?

Answer 18

afferent arteriole, Bowman’s capsule, glomerulus, PCT, Loop of henle, distal tubule, collecting duct

Question 19

Compare the structure of the descending and ascending limbs

Answer 19

Descending: Narrow thin walls, highly permeable to water
Ascending: Wider thick walls, impermeable to water

Question 20

Describe the loop of henle process

Answer 20

Na+ and Cl- ions pumped out, lowers water potential of medulla - draws water out of descending limb as ascending limb reaches minimum water potential (at the bottom), filtrate flows up ascending limb - filtrates water potential increases as ions pumped out

Question 21

What happens in the distal convoluted tubule?

Answer 21

Na+ actively pumped out and k+ actively pumped in, this fine tunes the PH of blood by selective reabsorption of some minerals and is connected to the collecting duct

Question 22

What are two causes of kidney failure?

Answer 22

1. High blood pressure - damage epithelial cells and basement membrane
2. Polycystic kidney disease - healthy tissue replaced by fluid filled cysts - put pressure on the kidney

Question 23

What are two symptoms of kidney failure?

Answer 23

1. Protein in urine - damage to the basement membrane allowed large protein molecules to pass through
2. Blood in the urine - shows that the filter is damaged

Question 24

What are 4 effects of kidney failure?

Answer 24

loss of electrolyte balance - no excess ions, osmotic balances, weakened bones due to loss of calcium, build up of urea

Question 25

How do you measure kidney function?

Answer 25

Glomerular filtration rate- rate at which blood is filtered: Creatinine level will increase if there is a problem

Question 26

5 things to consider when measuring kidney function

Answer 26

Age, sex, ethnicity, diet, exercise

Question 27

What is osmoregulation?

Answer 27

The maintenance of constant osmotic pressure in the fluids of an organism by the control of water and salt concentrations.

Question 28

NEGATIVE FEEDBACK: how do the osmoreceptors and effectors work in osmoregulation?

Answer 28

Osmoreceptors in hypothalamus monitor the water content of blood
Effectors = alter production of ADH

Question 29

What does ADH do?

Answer 29

stops diuresis when the blood-water concentration is low - effects permeability of collecting duct

Question 30

What type of hormone is ADH and where does it travel to be stored?

Answer 30

Peptide hormone, from hypothalamus to be stored in the posterior pituitary gland

Question 31

When is ADH released?

Answer 31

If water-blood content too low

Question 32

What is the name of the hormone released by pregnant women in their urine?

Answer 32

Human chorionic gonadotrophin (HCG)