L1 Endocrinal function of Kidney (P1 Mid)

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of the macula densa in the juxta-glomerular apparatus?

Monitor sodium chloride concentration (correct)

Facilitate filtration at Bowman’s capsule

Secrete renin into the bloodstream

Regulate blood flow in the efferent arteriole

Which structure is involved in the secretion of renin?

Podocyte

Smooth muscle cells

Granular cells (correct)

Macula densa

Which component of the juxta-glomerular apparatus monitors the flow within the afferent arteriole?

Podocyte

Granular cell (correct)

Distal convoluted tubule

Macula densa

What effect does increased sodium chloride transport in the distal convoluted tubule lead to?

Increased adenosine levels affecting the afferent arteriole Signup and view all the answers

Which vessel branches directly from the renal artery and carries blood towards the glomerulus?

Afferent arteriole Signup and view all the answers

What is the primary metabolic waste excreted by the kidneys?

Urea Signup and view all the answers

What hormone secreted by the kidneys is essential for red blood cell production?

Erythropoietin Signup and view all the answers

Which of the following factors inhibits renin secretion?

Increased blood pressure Signup and view all the answers

Which enzyme is responsible for converting 25 hydroxycholecalciferol to its active form?

1α-hydroxylase Signup and view all the answers

Which substance do prostaglandins secreted by the kidneys act as?

Vasodilators Signup and view all the answers

In which condition might the kidneys synthesize glucose from amino acids?

Prolonged fasting Signup and view all the answers

What is the main action of renin in the body?

Trigger the production of angiotensin II Signup and view all the answers

Which of the following does NOT play a role in the regulation of blood pressure through the kidneys?

Erythropoietin Signup and view all the answers

What is the primary functional unit of the kidney?

Nephron Signup and view all the answers

What are the two main types of nephrons?

Cortical and juxtamedullary nephrons Signup and view all the answers

What is the role of the Juxtaglomerular apparatus?

Regulation of blood pressure Signup and view all the answers

Which segment of the nephron is primarily responsible for reabsorption?

Proximal convoluted tubule Signup and view all the answers

Where in the nephron does filtration occur?

Glomerulus Signup and view all the answers

Which function is associated with juxtamedullary nephrons?

Concentration of urine Signup and view all the answers

What type of capillaries surround the nephron tubules and participate in reabsorption?

Peritubular capillaries Signup and view all the answers

Which component of the kidney is involved in maintaining the acid-base balance?

Collecting ducts Signup and view all the answers

What is produced as a result of the functional loss of more than ¼ of kidney nephrons?

Renal diseases Signup and view all the answers

Which part of the nephron contains a brush border for increased reabsorption surface area?

Proximal convoluted tubule Signup and view all the answers

How do juxtamedullary nephrons differ from cortical nephrons?

They have longer loops that extend deep into the medulla. Signup and view all the answers

Which part of the nephron is primarily involved with secretion rather than reabsorption?

Distal convoluted tubule Signup and view all the answers

What is the main function of the renal pelvis?

Containment of urine before it enters the ureter Signup and view all the answers

Study Notes

Renal Module Information

Course code: IMP-07- 20318
Phase: I
Year/semester: 2nd year / Semester 3
Academic year: 2022-2023

Lecture 1: Endocrine Function of the Kidney

Intended Learning Outcomes (ILOs):
- Describe functions of the renal system.
- Identify types of nephrons and their functions.
- Describe the juxtaglomerular apparatus and its significance.

Structure of the Urinary System

The urinary system comprises the kidneys, renal arteries, renal veins, aorta, ureters, urinary bladder, and urethra.

Kidney Composition

Composed of 6-18 lobes.
Each lobe consists of a pyramid of medulla covered by cortex.

Nephron

Functional unit of the kidney.
Each kidney has one million nephrons.
1/4 of kidney nephrons can carry the function; more loss causes renal disorders.
Divided into renal corpuscles (filtering) and renal tubules (reabsorption & secretion).
- Renal corpuscles:
  - Glomerulus (ball of capillaries)
  - Bowman's capsule (expanded, double-walled cup)
- Renal tubules:
  - Proximal convoluted tubules (PCT)
  - Loop of Henle
  - Distal convoluted tubules (DCT)
  - Collecting tubules (CT)

Types of Nephrons

Cortical nephrons (80%): Glomeruli close to the surface, short loops of Henle.
Juxtamedullary nephrons (20%): Glomeruli near the medulla, long loops of Henle.

Kidney Functions

Homeostasis of ECF: Maintains water, electrolyte balance, and pH & osmolarity.
Excretion of metabolic wastes: Removes urea, uric acid, creatinine, and foreign compounds (e.g., drugs).
Gluconeogenesis: Synthesizes glucose from amino acids during prolonged fasting.
Regulation of arterial blood pressure: Secretes renin.

Endocrine Functions

Secretion of erythropoietin.
Secretion of renin.
Conversion of vitamin D into active form.
Secretion of prostaglandins (PGE2 & PGI2).
- Vasodilator (PGE2)
- Vasoconstrictor (PGA2)
Regulation of acid-base balance.
Regulation of body buffer stores.

Renin

Hormone secreted by the juxtaglomerular apparatus.
Important for salt conservation, regulating blood volume and blood pressure.
- Stimuli for Renin secretion:
  - Renal ischemia
  - Hypotension
  - Hemorrhage
  - Sympathetic stimulation
  - Increased blood catecholamines
- Inhibitors for Renin secretion:
  - Increased blood pressure
  - Increased NaCl or Na reabsorption across the macula densa
  - Angiotensin II
  - Vasopressin (ADH)
  - Aldosterone
Renin-angiotensin-aldosterone system (RAAS): The most crucial hormonal system for sodium level regulation.

Erythropoietin

Hormone secreted by peritubular capillaries in response to hypoxia (low oxygen).
Stimulates red bone marrow to produce red blood cells (RBCs).
Kidney plays a vital role in erythropoiesis.
About 85% of the body's erythropoietin is produced by the kidneys.

Prostaglandins

Secreted by the kidney as PGE2 & PGI2.
Regulates glomerular filtration rate (GFR) and renal blood flow.
Locally acting in the kidney.

Regulation of 1,25-dihydroxy vitamin D3

1α-hydroxylase enzyme converts 25-hydroxycholecalciferol into 1,25 dihydroxycholecalciferol (calcitriol).
Essential for calcium homeostasis and bone formation.
Regulation in renal diseases is critical as it prevents bone decalcification.

Juxtaglomerular Apparatus (JGA)

Structure that lies between the afferent arteriole and the distal convoluted tubule (DCT).
Two main cell types:
- Macula densa: Cells in the DCT wall that monitor sodium chloride (NaCl) concentration in the tubular fluid.
- Granular cells: Cells in the afferent arteriole wall that secrete renin.
Monitors blood flow and plays a crucial role in regulating blood pressure.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers the endocrine functions of the kidney, focusing on the renal system's roles, types of nephrons, and the juxtaglomerular apparatus. Test your knowledge on the composition and structure of the urinary system and the nephron's functions and importance in renal health.