BIOS1170 & BIOS2170: Urinary System Anatomy

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Questions and Answers

What are the three main functions of the urinary system?

Regulating blood pressure (correct)

Maintenance of body temperature

Endocrine production (correct)

Excretion and elimination (correct)

The kidneys help regulate blood volume by controlling urine volume. True or False?

True

What is the function of erythropoietin?

Stimulates the production of red blood cells

Daily urea production is approximately __.

21g Signup and view all the answers

What is the purpose of the fibrous (renal) capsule?

Anchoring the kidney to surrounding tissue Signup and view all the answers

The renal pelvis exits the kidney at the hilum.

True Signup and view all the answers

What are the two layers that make up the kidney?

Renal cortex and renal medulla Signup and view all the answers

Urine is produced in a renal lobe and drains into a ______.

minor calyx Signup and view all the answers

Match the external structure of the kidney with their descriptions:

Renal cortex = Outer layer of the kidney Renal column = Cortical tissue separating the renal pyramids Renal papilla = Tip of the renal pyramid projecting into the renal sinus Renal pelvis = Funnel-shaped chamber draining into the ureter Signup and view all the answers

What is the potential health risk associated with over-hydration?

Exercise-associated hyponatremia Signup and view all the answers

What is the function of the ureter?

Transports urine toward the urinary bladder Signup and view all the answers

What is the location of the kidneys in the abdominal cavity?

Behind the peritoneum Signup and view all the answers

What percentage of body weight does the typical adult kidney represent?

0.5% body weight Signup and view all the answers

What is the percentage of cardiac output that the kidneys receive at rest?

20-25% cardiac output Signup and view all the answers

What is the function of the urinary bladder?

Temporarily stores urine prior to elimination Signup and view all the answers

What is the level of the vertebral column where the kidneys are located?

T12-L3 Signup and view all the answers

What is the approximate length of the typical adult kidney?

10 cm Signup and view all the answers

What is the primary function of the urinary system?

Elimination of body wastes Signup and view all the answers

What is the by-product of protein breakdown in the liver?

Urea Signup and view all the answers

What is the daily production of uric acid in the body?

480mg Signup and view all the answers

What is the role of creatine phosphate in muscle tissue?

Energy storage Signup and view all the answers

What is the process of urination called?

Micturition reflex Signup and view all the answers

What is the importance of the urinary system in daily life?

Maintenance of water balance Signup and view all the answers

How much dehydration does not impair endurance performance?

4% body mass Signup and view all the answers

What is the recommended way to monitor hydration levels?

Drinking until you have clear urine Signup and view all the answers

What is the primary role of the urinary system in the study of exercise physiology?

Maintenance of water and electrolyte balance Signup and view all the answers

What is the effect of exercise-induced dehydration on athletic performance?

It has a minimal impact on endurance performance, up to a 2% body weight loss Signup and view all the answers

What is the recommended approach to hydration during exercise?

Drinking to thirst, with no additional hydration Signup and view all the answers

What is the impact of over-hydration on athletic performance?

It may actually impair performance, according to some research Signup and view all the answers

What is the criticism of the 2003 research by the US Army Research Institute of Environmental Medicine?

The study was poorly designed and didn't accurately reflect real-world exercise conditions Signup and view all the answers

According to Goulet's meta-analysis, what is the percentage of body weight loss that does not significantly affect endurance performance?

4% Signup and view all the answers

What is the current understanding of the impact of dehydration on athletic performance?

Dehydration only has a negative impact on athletic performance at high levels of body weight loss Signup and view all the answers

What is the concern related to over-hydration during exercise?

There is no data on its effects Signup and view all the answers

What is the function of the renal fascia?

To anchor the kidney to the surrounding tissue Signup and view all the answers

What is the location of the perinephric fat?

Between the fibrous capsule and the renal fascia Signup and view all the answers

What is the position of the kidney in the body?

Retroperitoneal Signup and view all the answers

What is the function of the fibrous capsule?

To surround the kidney with a tough layer Signup and view all the answers

What is the structure that exits the kidney at the hilum?

Renal pelvis Signup and view all the answers

What is the structure that surrounds the kidney and is composed of fat?

Perinephric fat Signup and view all the answers

What is the structure that urine drains into after passing through the minor calyx?

Major calyx Signup and view all the answers

What is the funnel-shaped chamber that drains the kidney?

Renal pelvis Signup and view all the answers

How many minor calyces merge to form a major calyx?

4-5 Signup and view all the answers

What is the location of the renal pelvis in relation to the kidney?

Inside the renal sinus Signup and view all the answers

What is the structure that surrounds the kidney?

Fibrous capsule Signup and view all the answers

What is the structure that the renal pelvis drains into?

Ureter Signup and view all the answers

How many major calyces form the renal pelvis?

2-3 Signup and view all the answers

What is the structure that produces urine?

Renal lobe Signup and view all the answers

What is the structure that the ureter drains into?

Bladder Signup and view all the answers

What is the term for the triangular-shaped structure in the kidney?

Renal pyramid Signup and view all the answers

Study Notes

The Urinary System

The urinary system has three main functions:
Homeostatic balance: regulating blood ionic composition, blood volume, blood pressure, blood osmolarity, and blood pH.
Endocrine production: producing hormones that regulate various physiological processes.
Excretion and elimination: removing metabolic wastes and foreign chemicals from the blood.

Homeostatic Balance

Blood ionic composition and volume are regulated by the kidneys.
For a 70 kg person, total body water is approximately 42 L, with 2/3 being intracellular fluid (ICF) and 1/3 being extracellular fluid (ECF).
Blood plasma makes up approximately 25% of ECF.
Dehydration leads to a decrease in blood volume, resulting in reduced cardiac output, increased blood pressure, and increased solute concentration.
The kidneys regulate blood volume by regulating urine volume.

Endocrine Production

The kidneys produce hormones, including vitamin D and erythropoietin.
Vitamin D helps control calcium absorption from the gut and is produced in the skin, liver, and kidney.
Erythropoietin stimulates the production of mature red blood cells from precursor cells in the bone marrow in response to hypoxia.
Severe kidney disease can lead to anemia due to inadequate erythropoietin production.

Excretion and Elimination

The urinary system eliminates organic wastes and foreign chemicals from the blood through filtration, processing, and additional secretion.
The most toxic endogenous wastes are nitrogenous compounds, including urea, uric acid, and creatinine.
Urea is produced in the liver and is a by-product of protein breakdown, with a daily production of approximately 21 g.
Uric acid is generated from the breakdown of purine nucleic acids, with a daily production of approximately 480 mg.
Creatinine is derived from creatine phosphate in muscle tissue, with a daily production of approximately 1.8 g.

Anatomy of the Urinary System

The urinary system consists of the kidneys, ureters, bladder, and urethra.
The kidneys are located in a retroperitoneal position, behind the peritoneum, and are protected by the 11th and 12th ribs.
The kidneys receive approximately 20-25% of cardiac output at rest and are responsible for producing urine.
The ureters transport urine from the kidneys to the urinary bladder.
The urinary bladder temporarily stores urine prior to elimination.
The urethra transports urine to the exterior, and in males, also transports semen.

The Kidney

The kidney is comprised of a fibrous capsule, renal fascia, and perinephric fat.
The fibrous capsule is a tough layer that surrounds the kidney.
The renal fascia is a tough, fibrous outer layer that anchors the kidney to surrounding tissue.
The perinephric fat is located between the fibrous capsule and renal fascia.
The kidney is divided into two layers: the renal cortex and the renal medulla.
The renal cortex is the outer layer, and the renal medulla is the inner layer.
The renal medulla is composed of 6-18 triangular structures called renal pyramids.
The renal papilla is the tip of the pyramid that projects into the renal sinus.
The renal columns are cortical tissue that separates the pyramids.

External Structures of the Kidney

The kidney is ensheathed by a shiny, tough fibrous capsule.
The renal vein exits the kidney via the hilum on the medial border.
The renal artery enters the kidney at the hilum, usually posterior to the vein.
The renal pelvis exits at the hilum, usually posterior to the artery and vein, and droops down to become the ureter.

Urinary System in Exercise and Sports Science

The urinary system plays a crucial role in water and electrolyte balance during exercise.
Dehydration can lead to decreased cardiac output, reducing oxygen delivery to tissues and impairing heat dissipation.
The widely accepted belief that a ≥2% decrease in body weight due to dehydration adversely affects athletic performance is being challenged by recent studies.
Drinking to thirst boosts performance, while drinking more offers no extra benefit.
Over-hydration can lead to severe health risks, including exercise-associated hyponatremia (water poisoning).### Renal Lobe Structure
Urine production occurs in a renal lobe, which drains into a minor calyx.
A renal lobe consists of renal cortex, renal medulla, and a renal pyramid.

Urine Drainage

4-5 minor calyces merge to form a major calyx.
2-3 major calyces form the renal pelvis, a large funnel-shaped chamber.
The renal pelvis is located in the renal sinus and fills most of the space.
The renal pelvis drains into the ureter, which then drains the kidney into the bladder.

Renal Anatomy

The renal columns are located between the renal pyramids.
The fibrous capsule surrounds the kidney and provides protection.

Diagram Reference

Figure 26-4 from Martini et al.'s Fundamentals of Anatomy and Physiology, 11th Ed.

Urinary System

The urinary system is responsible for eliminating organic wastes and foreign chemicals from the blood through filtration, processing, and secretion.
The system eliminates nitrogenous compounds, such as urea, uric acid, and creatinine, which are produced in the liver and muscle tissue.
Urea production is approximately 21g per day, while uric acid production averages around 480mg per day, and creatinine production is around 1.8g per day.
Exogenous wastes, such as pharmaceuticals like penicillin, can also be eliminated through the urinary system.

Importance of Urinary System

The urinary system plays a crucial role in homeostatic regulation, not just waste elimination.
It helps regulate water balance, with the importance of hydration being emphasized.

Hydration and Performance

Over-hydration can lead to severe health risks, including exercise-associated hyponatremia (water poisoning), which can cause deadly cerebral and pulmonary edema.
Drinking to thirst boosts performance, while drinking more offers no extra benefit.
Losing up to 4% of body weight from exercise-induced dehydration does not significantly affect endurance performance.
Aiming for 'euhydration' may actually impair performance.

Anatomy of the Kidney

The kidney is located in a retroperitoneal position, behind the peritoneum, and is protected by the 11th and 12th ribs.
The kidney is about 10 cm long, 5.5 cm wide, and 4 cm thick, and represents around 0.5% of body weight.
The kidney receives around 20-25% of cardiac output at rest.
The kidney's position and stability are maintained by two layers of connective tissue and fat.

Structure of the Kidney

The kidney has a fibrous capsule, renal fascia, and perinephric fat that surround and anchor it to the surrounding tissue.
The renal pelvis is a large funnel-shaped chamber that drains into the ureter.
The ureter transports urine from the kidney to the urinary bladder.
The kidney has a renal cortex, renal medulla, and renal pyramid, which produce urine that drains into a minor calyx.

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Description

This lecture introduces the urinary system, covering its functions and anatomy, including the kidney, ureters, bladder, and urethra.