Renal: The Kidney Structure and Function

Question 1

What are the 7 Renal Functions?

Answer 1

1. Regulation of Water and Electrolyte Balance
2. Excretion of Metabolic Waste
3. Excretion of Bioactive Substances
4. Regulation of Arterial Blood Pressure
5. Regulation of Red Blood Cell Production
6. Regulation of Vitamin D Production
7. Metabolism

Question 2

Our input of water and electrolytes is enormously variable. How do the Kidneys respond?

Answer 2

The kidneys respond by varying the output of water of minerals in the urine to maintain homeostasis

Question 3

Our bodies continuously form end products of metabolic process. What are most excreted by the Kidneys?

Answer 3

1. Urea (from proteins)
2. Uric Acid (from nucleic acids)
3. Creatinine (from Muscle creatine)
4. Hemoglobin breakdown products
5. Metabolites of various hormones (from endocrine system)

Question 4

Drugs are actively or passively excreted by the kidney?

Answer 4

Both.

Question 5

Hormones in the blood are mostly removed where in the body but are removed in parallel to renal? processes.

Answer 5

Liver

Question 6

Balance of what molecules achieve regulation of blood volume?

Answer 6

Na and H2O balance

Question 7

Angiotensin is an example of what substance released by the Kidneys?

Answer 7

Vasoactive substance that actively regulate smooth muscle in peripheral vasculature

Question 8

What is released by the kidney and controls erythrocyte production by the bone marrow?

Answer 8

Erythropoietin

Question 9

True/False: Vitamin D increases absorption of Calcium by the gut

Answer 9

True

Question 10

True/False: CNS is an obligate user of fat, protein, ketone bodies?

Answer 10

False. Blood Glucose

Question 11

Whenever carbohydrate intake is stopped, our body synthesizes new glucose from non-carbohydrate precursors of glucose (amino acids and glycerol). What is this called?

Answer 11

Gluconeogenesis

Question 12

What is crucial to maintaining acid-base homeostatsis?

Answer 12

Renal ammonioagenesis

Question 13

True/False: Nephron is a functional unit of the Kidney

Answer 13

True

Question 14

True/False: Only Plasma is moved into the Nephron

Answer 14

True

Question 15

What part of the Nephron is mainly Filtration?

Answer 15

Glomerulus

Question 16

What are the parts of the Nephron? (in order of processes)

Answer 16

1. Renal Corpusle (Glomerulus and Bowman’s Capsule)
2. Proximal Tubule
3. Loop of Henle
4. Distal Tubule
5. Collecting Duct

Question 17

What part of the Nephron is segmented and mainly Reabsorption?

Answer 17

Proximal Tubule

Question 18

What complex part of the Nephron creates a concentration gradient by low and high osmolarity levels?

Answer 18

Loop of Henle

Question 19

What part of the Nephron has Regulation (Acid-Base Balance) and some Re-absorption?

Answer 19

Distal Tubule

Question 20

What part of the Nephron has mainly H2O reabsorption (regulated by ADH)?

Answer 20

Collecting Duct

Question 21

Blood enters capillaries of the Glomerulus by afferent arteriole and leaves Bowman’s capsule through efferent arteriole. What enters the remaining Nephron?

Answer 21

Only Plasma

Question 22

What drains from Bowman’s capsule?

Answer 22

Proximal Tubule

Question 23

What are the 2 segments of the Proximal Tubule?

Answer 23

1. Proximal convoluted tubule

2. Proximal straight tubule

Question 24

What are the parts of the Loop of Henle?

Answer 24

1. Descending thin limb
2. Ascending thin limb
3. Ascending thick limb

Question 25

Loop of Henle

Answer 25

Create and maintains a medulla osmotic gradient

Question 26

What demarks the area between the Loop of Henle and the Distal Tubule?

Answer 26

Macula Densa

Question 27

Is there a Distal Convoluted Tubule and Distal Straight Tubule?

Answer 27

No. Only the Distal Convoluted Tubule

Question 28

Last portion of the independent Nephron and functions as the concentrating mechanism of the nephron

Answer 28

Collecting Duct

Question 29

Before the Distal Convoluted Tubule, the cells in any given segment are homogeneous. What are the 2 different cell types in the Distal Tubule?

Answer 29

1. Principal cells (primary cell type) | 2. Intercalated cells (alpha and beta)

Question 30

What are the 2 types of Nephrons and their populations?

Answer 30

Cortical (80%) | Juxtamedullary (20%)

Question 31

True/False: Nephrons do not differ in location and structures.

Answer 31

False. Have similar structures, but differ in their location and length of segments which leads to important consequences (length of Loop of Henle).

Question 32

Kidneys receive how much cardiac output and how many Liters per minute?

Answer 32

Kidney receives 20% of cardiac output. 1 Liter/Min

Question 33

What are the 2 capillary systems of the Kidney coming off the efferent arteriole?

Answer 33

1. Peritubular capillaries (cortical nephron) | 2. Vasa Recta (juxtamedullary nephron)

Question 34

True/False: Afferent arteriole and Efferent arteriole are sites of regulation

Answer 34

True

Question 35

True/False: 1 Renal Artery branches 1 million times to form 1 million nephrons

Answer 35

True

Question 36

Peritubular capillaries extend from....

Answer 36

Cortical efferent artierioles and are profusely distributed throughout the cortex

Question 37

juxtamedullary glomeruli long efferent arterioles extend

Answer 37

Downward into the outer medulla, where they divide many times to form bundles of parallel vessels called the VASA RECTA

Question 38

Whole blood enters the glomerulus, but only plasma is filtered by the glomerular capillaries. What is this called?

Answer 38

Renal Plasma Flow

Question 39

Blood is filtered by the glomerulus...approached by the afferent and exits through the efferent arteriole

Answer 39

Renal Blood Flow

Question 40

What is the Renal Plasma Flow equation?

Answer 40

RPF = RBF*(1-HCT) ex: RPF = 1L/min*(1-.4)=600 ml/min

Question 41

A substance is filtered into Bowman’s space and excreted in the urine. How many cell membranes must it cross in order to exit the body?

Answer 41

0. No cellular membranes are crossed in the glomerulus. Substances must pass through TIGHT DEFINED SPACES, but not across any cellular membranes.

Question 42

What is Macula Densa cell's role?

Answer 42

Sensory cells of Flow Rate. Low Flow--> Macula Densa cells tell Juxtaglomerular cells need more filtrate for more flow. Juxtaglomerular cells release Renin in response High Flow--> Turn off Renin secretion

Question 43

What is Juxtaglomerular cell's role?

Answer 43

Release Renin into blood supply.

Question 44

Where are Macula Densa cells located?

Answer 44

Macula Densa cells are only found connected to the glomerulus. All glomeruli are found in the cortex.

Question 45

Process by which water and solutes leave the vascular system through the filtration barrier and enter Bowman’s space

Answer 45

Filtration

Question 46

Process of moving substances into the tubular lumen from the cytosol of epithelial cells that form the walls of the nephron

Answer 46

Secretion

Question 47

Process of moving substances from the lumen across the epithelial layer into the surrounding interstitium

Answer 47

Reabsorption

Question 48

Reabsorption has a 2-step process:

Answer 48

Resabsorbed substances move from the interstitium into surrounding blood vessels

Question 49

Exit of the substance from the body

Answer 49

Excretion

Question 50

Substance is broken down into smaller component molecules

Answer 50

Catabolism

Question 51

Substance T is present in the urine. Does this prove that it entered the renal tubule by filtration at the glomerulus?

Answer 51

No. Substance T could have been filtered to enter the urine OR Substance T could have been secreted into the urine.

Question 52

Substance J is not normally present in the urine. Does this prove that it is neither filtered nor secreted?

Answer 52

No. Substance J may have been filtered, but 100% of it could have been reabsorbed back into the blood stream. Thus it could have been filtered, but not appear in the urine.