renal objectives 1-5 (kidney function and hormone stuff)

Question 1

What is the glomerulus?

Answer 1

A group of capillaries that loop into a circle, serving as a filtration membrane.

Question 2

How does blood enter and exit the glomerulus?

Answer 2

Blood enters via the afferent arteriole and exits via the efferent arteriole.

Question 3

What is the function of the glomerular capillary walls?

Answer 3

They serve as a filtration membrane, pulling water and small solutes out of the blood.

Question 4

What happens to water and small solutes filtered by the glomerulus?

Answer 4

They enter Bowman’s capsule.

Question 5

Name some of the small solutes that pass through Bowman’s capsule.

Answer 5

Glucose, sodium, chloride, amino acids, and urea (similar to blood plasma).

Question 6

What large solutes do not pass through Bowman’s capsule?

Answer 6

Red blood cells (RBCs), platelets, and proteins.

Question 7

After leaving Bowman’s capsule, where does the fluid go?

Answer 7

It moves to the proximal convoluted tubule (PCT).

Question 8

What does the proximal convoluted tubule reabsorb?

Answer 8

Sodium, water, glucose, amino acids, phosphate, and 80% of filtered bicarbonate (HCO3-).

Question 9

What is secreted from the bloodstream into the tubules for excretion?

Answer 9

Potassium (K+), hydrogen ions (H+ or acid), and medications.

Question 10

How do the kidneys regulate blood pH?

Answer 10

By adjusting the reabsorption of bicarbonate (HCO3-) and the excretion of hydrogen ions (H+).

Question 11

Which part of the nephron is important for acid-base balance?

Answer 11

Both the proximal convoluted tubule (PCT) and the distal convoluted tubule (DCT) are involved.

Question 12

What is the proximal convoluted tubule (PCT) responsible for?

Answer 12

It reabsorbs sodium, water, glucose, amino acids, phosphate, and 80% of filtered bicarbonate (HCO3-), helping to maintain acid-base balance.

Question 13

After the Loop of Henle, where does the fluid go?

Answer 13

It moves to the distal convoluted tubule (DCT).

Question 14

What substances are reabsorbed in the distal convoluted tubule (DCT)?

Answer 14

Some sodium (Na+) and calcium (Ca2+).

Question 15

How is calcium reabsorbed in the DCT?

Answer 15

By the effects of parathyroid hormone (PTH), which enhances the synthesis of calcium transport proteins.

Question 16

How does the DCT adjust pH depending on blood acidity?

Answer 16

The DCT may either: - Excrete H+ (acid) and reabsorb bicarbonate to raise blood pH. - Excrete bicarbonate and reabsorb H+ to lower blood pH.

Question 17

How much of the cardiac output do the kidneys receive?

Answer 17

20-25% of the cardiac output.

Question 18

What is the glomerular filtration rate (GFR)?

Answer 18

The amount of plasma filtered by the glomerulus per minute. Normal GFR is 125 mL/min.

Question 19

What percentage of plasma is filtered by the glomerulus each minute?

Answer 19

20% of the plasma that flows through is filtered per minute.

Question 20

What is the relationship between GFR and capillary perfusion pressure?

Answer 20

GFR is directly related to the perfusion pressure in the glomerular capillaries.

Question 21

What happens to GFR if mean arterial pressure decreases or vascular resistance increases?

Answer 21

There is a drop in glomerular filtration.

Question 22

What role does renal blood flow play in GFR?

Answer 22

Renal blood flow supplies the capillaries with plasma for filtration, which is essential for maintaining GFR.

Question 23

What are the three mechanisms that regulate renal blood flow?

Answer 23

1. Autoregulation 2. Neural regulation 3. Hormonal regulation (Renin-Angiotensin-Aldosterone System - RAAS)

Question 24

What is the goal of autoregulation in the kidneys?

Answer 24

To maintain a consistent GFR by preventing large fluctuations in BP from affecting the glomerular capillaries.

Question 25

What happens to afferent arterioles when systemic BP increases?

Answer 25

Afferent arterioles constrict to prevent an increase in GFR and filtration pressure.

Question 26

What happens to afferent arterioles when systemic BP decreases?

Answer 26

Afferent arterioles dilate, allowing GFR and filtration pressure to increase.

Question 27

What system innervates the blood vessels of the kidneys in neural regulation?

Answer 27

The sympathetic nervous system.

Question 28

What happens when systemic arterial pressure drops (e.g., in shock)?

Answer 28

Baroreceptors send messages to the brain, triggering increased sympathetic activity, which constricts the arterioles, decreasing renal blood flow and GFR.

Question 29

Why does GFR decrease during neural regulation?

Answer 29

To retain salt and water in the bloodstream, helping to maintain systolic blood pressure.

Question 30

What is an example of neural regulation during exercise or dehydration?

Answer 30

Mild arteriole constriction decreases GFR to retain salt and water, preventing dehydration.

Question 31

How does the body respond to hypoxia?

Answer 31

Chemoreceptors in the carotid and aorta trigger sympathetic stimulation in the kidneys, decreasing renal blood flow and GFR to conserve water and improve perfusion.

Question 32

What does the renin-angiotensin-aldosterone system (RAAS) regulate?

Answer 32

Blood volume, electrolyte balance, and systemic vascular resistance.

Question 33

How does angiotensin II affect blood vessels?

Answer 33

It constricts blood vessels, increasing systemic vascular resistance.

Question 34

What is the role of aldosterone in the kidneys?

Answer 34

Aldosterone triggers the retention of salt and water, increasing systemic vascular resistance and capillary hydrostatic pressure.

Question 35

Which hormones act on the kidneys?

Answer 35

1. Antidiuretic hormone (ADH) 2. Aldosterone 3. Natriuretic peptides

Question 36

Which hormones are activated or synthesized in the kidneys?

Answer 36

1. Vitamin D (activated) 2. Erythropoietin (synthesized)

Question 37

What hormone increases water reabsorption in the distal tubule and collecting ducts?

Answer 37

Antidiuretic hormone (ADH), secreted by the posterior pituitary gland.

Question 38

What is the function of ADH?

Answer 38

Increases blood pressure by promoting water reabsorption in the distal tubule and collecting ducts.

Question 39

Where does aldosterone act on the kidneys?

Answer 39

Distal tubule and collecting ducts.

Question 40

What is the main function of aldosterone?

Answer 40

Increases blood pressure by promoting sodium and water reabsorption, prevents hyperkalemia, and regulates pH by excreting potassium (K+) and hydrogen (H+).

Question 41

Which hormone prevents hyperkalemia and promotes pH regulation in the kidneys?

Answer 41

Aldosterone, secreted by the adrenal gland.

Question 42

What is the role of natriuretic peptides?

Answer 42

Inhibit sodium and water reabsorption, inhibit renin and aldosterone secretion, and promote vasodilation of afferent arterioles.

Question 43

Where are natriuretic peptides secreted from?

Answer 43

Atria and ventricles of the heart in response to wall dilation.

Question 44

How do natriuretic peptides affect urination?

Answer 44

They promote increased urination by dilating efferent arterioles,

Question 45

How is vitamin D activated in the kidneys?

Answer 45

After being initially processed in the liver, it is activated in the kidneys by the action of parathyroid hormone (PTH).

Question 46

What is the role of vitamin D in the body?

Answer 46

Promotes absorption of calcium and phosphorus in the small intestine.

Question 47

What hormone stimulates the bone marrow to produce red blood cells (RBCs)?

Answer 47

Erythropoietin, which is synthesized in the kidneys.

Question 48

What triggers the release of erythropoietin?

Answer 48

Decreased oxygen delivery to the kidneys, leading to secretion by peritubular cells to stimulate RBC production.

Question 49

What is the main function of erythropoietin?

Answer 49

To prevent or correct hypoxia by stimulating the bone marrow to produce more red blood cells for oxygen transport.

Question 50

Where does fluid go after the distal convoluted tubule?

Answer 50

It goes to the collecting duct.

Question 51

What do several nephrons merge into after the collecting ducts?

Answer 51

They form cortical collecting ducts.

Question 52

Which hormones influence the cortical collecting ducts?

Answer 52

Antidiuretic hormone (ADH) and aldosterone.

Question 53

What is the effect of ADH and aldosterone on the cortical collecting ducts?

Answer 53

They stimulate water and salt reabsorption and promote potassium excretion.

Question 54

What substances can be excreted or reabsorbed in the collecting ducts?

Answer 54

Sodium (Na+), potassium (K+), hydrogen (H+), and bicarbonate (HCO3-).

Question 55

What happens to sodium, potassium, hydrogen, and bicarbonate in the collecting ducts?

Answer 55

They may either be excreted from the bloodstream into the duct or reabsorbed into the bloodstream.