図引用元:Singh, Vishram. Textbook of Clinical Embryology, 3rd Edition
The nephrogenic cord and the urogenital ridge are closely related embryological structures, but they are not exactly the same. Here’s a clear distinction:
🔹 Urogenital Ridge
A longitudinal elevation of intermediate mesoderm on each side of the dorsal aorta.
Forms during early embryonic development.
It gives rise to two major components:
Nephrogenic cord (or nephrogenic ridge) – related to the urinary system.
Gonadal ridge – related to the genital (reproductive) system.
🔹 Nephrogenic Cord (Nephrogenic Ridge)
A part of the urogenital ridge, specifically the lateral portion.
Gives rise to the three successive kidney structures:
Pronephros
Mesonephros
Metanephros (becomes the permanent kidney)
✅ In summary:
Nephrogenic cord = urinary portion of the urogenital ridge
Yes, the urogenital ridge runs from head (cranial) to tail (caudal) along the posterior wall of the embryonic abdominal cavity.
To elaborate:
The urogenital ridge is a longitudinal elevation of intermediate mesoderm.
It forms on either side of the dorsal aorta.
It gives rise to two key structures:
The nephrogenic cord (lateral part), which develops into the urinary system (kidneys, ureters).
The gonadal ridge (medial part), which develops into the reproductive organs (testes or ovaries).
So yes — it is an elongated structure that extends craniocaudally, reflecting the segmental development of the embryo.
(ChatGPT 4o)
AI による概要
Yes, the urogenital ridge, a structure in embryonic development, does run from the head to the tail (cranially to caudally) of the developing embryo.This ridge gives rise to both the urinary and genital systems.Specifically, the intermediate mesoderm, which forms the urogenital ridge, develops into three sets of nephric structures (from head to tail): the pronephros, mesonephros, and metanephros.
Here’s a more detailed breakdown:
Urogenital Ridge Formation:
The urogenital ridge arises from the intermediate mesoderm, located on either side of the aorta.
Cranio-caudal Development:
The three sets of nephric structures (pronephros, mesonephros, and metanephros) develop sequentially from the urogenital ridge, starting from the head (cranial) and progressing towards the tail (caudal) of the embryo.
Pronephros:
The first to appear, located in the neck region.
Mesonephros:
Located in the mid-section of the embryo, developing into mesonephric tubules and ducts.
Metanephros:
The final kidney structure, developing from the caudal end of the mesonephric duct and a condensation of nearby mesoderm.
泌尿器系の発生の講義動画 Development of the Urogenital System – Urinary System and Kidney Development by John McLachlan, PhD Urogenital ridgeについての解説 1:39~
https://app.lecturio.com/#/article/3809
自分:Does the intermediate mesoderm change its name to the urogenital ridge, and further change the name when it turns to three sets of nephric structures (from head to tail): the pronephros, mesonephros, and metanephros?
ChatGPT 4o:
Great question — you’re touching on the dynamic naming and regional specialization of the intermediate mesoderm during development. Here’s a precise explanation:
🌱 1. Intermediate Mesoderm:
Initially, a longitudinal column of mesoderm located between the paraxial and lateral plate mesoderm.
It appears bilaterally along the dorsal body wall.
This structure is simply called intermediate mesoderm in early stages (around week 3–4 of human development).
🪴 2. Urogenital Ridge:
As development progresses, the intermediate mesoderm bulges into the coelomic cavity, forming the urogenital ridge (starting ~week 4).
The urogenital ridge is a broader term that includes:
Nephrogenic cord (lateral part) → forms the urinary system.
Gonadal ridge (medial part) → forms the genital system.
Yes, you can think of the urogenital ridge as a regionally specified derivative of the intermediate mesoderm.
🌊 3. Pronephros → Mesonephros → Metanephros:
These are successive nephric structures derived from the nephrogenic cord (i.e., the urinary part of the urogenital ridge), and they appear in a cranial-to-caudal sequence:
Region
Structure
Fate
Cranial
Pronephros
Rudimentary; regresses quickly
Intermediate
Mesonephros
Temporary kidney; forms mesonephric duct (Wolffian duct)
Caudal
Metanephros
Becomes the definitive kidney
So, in essence:
✅ Intermediate mesoderm →
➡️ Urogenital ridge (as it bulges into body cavity) →
➡️ Nephrogenic cord (for urinary structures) →
➡️ Pronephros → Mesonephros → Metanephros (in sequence, cranial to caudal)
Summary Answer:
Yes, the intermediate mesoderm functionally and regionally transforms — first becoming the urogenital ridge, then differentiating further into specific nephric structures (pronephros, mesonephros, metanephros) along the cranio-caudal axis, as well as the gonadal ridge for the reproductive system.
Let me know if you’d like a diagram to go with this!
Embryological Differences Between the Upper and Lower Urinary Tracts
The upper and lower urinary tracts have different embryological origins. The upper urinary tract (kidneys and ureters) is primarily derived from the mesoderm, while the lower urinary tract (bladder and urethra) is primarily derived from the endoderm.
The kidneys develop from a part of the mesoderm called the intermediate mesoderm. Specifically, they form through three successive stages: the pronephros, mesonephros, and finally the metanephros, which becomes the permanent kidney.
The ureters develop from the ureteric bud, which branches off from the mesonephric duct.
The majority of the bladder and the upper part of the urethra develop from the urogenital sinus, which is formed when the cloaca (the terminal end of the primitive gut, derived from the endoderm) is divided.
However, a part of the bladder, known as the bladder trigone, is formed by the incorporation of the mesoderm-derived ureters into its wall. Therefore, it is not composed entirely of endoderm.
Thus, the upper and lower urinary tracts originate from completely different germ layers, which contributes to differences in their structure, function, and the types of diseases that affect them.
ECG Simplified #1 Cardiac dipole and Instantaneous vector The Physiology Channel チャンネル登録者数 1.23万
ECG and Electric Dipoles UCL Medical Physics and Biomedical Engineering チャンネル登録者数 3440人
https://www.bem.fi/ 12-Lead ECG System https://www.bem.fi/book/15/15.htm Bioelectromagnetism(本のPDF)https://www.bem.fi/book/book.pdf
Physiological basis of electrocardiography By Alex Yartsev – 20/01/2018 Last updated 25/11/2024 – 14:43 https://derangedphysiology.com/main/cicm-primary-exam/cardiovascular-system/Chapter-735/physiological-basis-electrocardiography
The ECG Curve: What Is It and How Does It Originate? https://thoracickey.com/2-the-ecg-curve-what-is-it-and-how-does-it-originate/
AP End − AP Epi = ECG
Fig 1. A. Asymmetry of ventricular wall and AP propagating from endocardial side to epicardial side and repolarization from epi to end generating R and T waves of ECG (lead II Positive Waves). B. Relationship between the cardiac dipole model and ECG: Depolarization starts from the endocardial side of ventricle muscle (Epi) and spreads to the epicardial side (End). Since the duration of the action potential is shorter on the Epi than the End., repolarization begins on the Epi and terminates on the End. The difference between the total potential on the Epi and that on the End of the myocardium is approximately equal to the ECG waveform. D. End and Epi AP elicit positive and negative potential, respectively. Their difference is closely related to ECG.
Tensor cardiography: A novel ECG analysis of deviations in collective myocardial action potential transitions based on point processes and cumulative distribution functions Shingo Tsukada ,Yu-ki Iwasaki,Yayoi Tetsuo Tsukada Published: August 8, 2024 https://doi.org/10.1371/journal.pdig.0000273 https://journals.plos.org/digitalhealth/article?id=10.1371/journal.pdig.0000273
# 左室は内膜(endocardium)から外膜(epicardium)へ脱分極が進み、再分極は逆向きに起こるため、内層は正極性、外層は負極性の電位を ECG に与えます。結果として ECG 波形は「内層 AP − 外層 AP」の差分でほぼ説明できる.したがって「AP End − AP Epi = ECG」