The kidneys Kidneys The kidneys are a pair of bean-shaped organs located retroperitoneally against the posterior wall of the abdomen on either side of the spine. As part of the urinary tract, the kidneys are responsible for blood filtration and excretion of water-soluble waste in the urine. Kidneys: Anatomy are primarily in charge of the maintenance of water and solute homeostasis Homeostasis The processes whereby the internal environment of an organism tends to remain balanced and stable. Cell Injury and Death through the processes of filtration, reabsorption, secretion Secretion Coagulation Studies, and excretion. Glomerular filtration is the process of converting the systemic blood supply into a filtrate, which will ultimately become the urine Urine Liquid by-product of excretion produced in the kidneys, temporarily stored in the bladder until discharge through the urethra. Bowen Disease and Erythroplasia of Queyrat. Complex regulatory processes ensure that only the appropriate substances in the systemic blood are lost in the urine Urine Liquid by-product of excretion produced in the kidneys, temporarily stored in the bladder until discharge through the urethra. Bowen Disease and Erythroplasia of Queyrat and that the urine Urine Liquid by-product of excretion produced in the kidneys, temporarily stored in the bladder until discharge through the urethra. Bowen Disease and Erythroplasia of Queyrat flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure is satisfactorily balanced to maintain adequate systemic volume status Volume Status ACES and RUSH: Resuscitation Ultrasound Protocols. Abnormalities of the glomerulus can cause several clinically important conditions.
Last updated: 12 Apr, 2022
The GFR GFR The volume of water filtered out of plasma through glomerular capillary walls into Bowman’s capsules per unit of time. It is considered to be equivalent to inulin clearance. Kidney Function Tests is the rate of filtration of plasma Plasma The residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation. Transfusion Products through the glomerular membrane. Filtration is 1 of 4 primary mechanisms involved in the regulation of water, electrolytes Electrolytes Electrolytes are mineral salts that dissolve in water and dissociate into charged particles called ions, which can be either be positively (cations) or negatively (anions) charged. Electrolytes are distributed in the extracellular and intracellular compartments in different concentrations. Electrolytes are essential for various basic life-sustaining functions. Electrolytes, and waste excretion:
Other renal functions:
Overview of the glomerulus:
Blood and filtrate
flow
Flow
Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls.
Vascular Resistance, Flow, and Mean Arterial Pressure through the glomerulus. Blood enters through the
afferent
Afferent
Neurons which conduct nerve impulses to the central nervous system.
Nervous System: Histology arteriole, and as it moves through the glomerular
capillaries
Capillaries
Capillaries are the primary structures in the circulatory system that allow the exchange of gas, nutrients, and other materials between the blood and the extracellular fluid (ECF). Capillaries are the smallest of the blood vessels. Because a capillary diameter is so small, only 1 RBC may pass through at a time.
Capillaries: Histology (which are closely associated with filtering podocytes), a portion of the
plasma
Plasma
The residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation.
Transfusion Products is filtered across the glomerular barrier into Bowman’s space. The filtrate (which becomes the
urine
Urine
Liquid by-product of excretion produced in the kidneys, temporarily stored in the bladder until discharge through the urethra.
Bowen Disease and Erythroplasia of Queyrat) then moves out through the
proximal tubule
Proximal tubule
The renal tubule portion that extends from the bowman capsule in the kidney cortex into the kidney medulla. The proximal tubule consists of a convoluted proximal segment in the cortex, and a distal straight segment descending into the medulla where it forms the u-shaped loop of henle.
Tubular System, while the blood that was not filtered (and remains in the vessels) leaves through the
efferent
Efferent
Neurons which send impulses peripherally to activate muscles or secretory cells.
Nervous System: Histology arteriole.
Primary renal functions
Image by Lecturio.Renal circulation Renal Circulation The circulation of the blood through the vessels of the kidney. Systemic and Special Circulations
Image by Lecturio.The renal blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure is as follows (in order):
Renal circulation Renal Circulation The circulation of the blood through the vessels of the kidney. Systemic and Special Circulations
Image by Lecturio.Nephrons are the functional units of the kidney
Nephron Nephron The functional units of the kidney, consisting of the glomerulus and the attached tubule. Kidneys: Anatomy anatomy
Image by Lecturio.Blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure within the nephron Nephron The functional units of the kidney, consisting of the glomerulus and the attached tubule. Kidneys: Anatomy
Image: “The two capillary beds Capillary beds Groups of 10–100 individual capillary vessels supplied by a single metarteriole. Capillaries: Histology” by Phil Schatz. License: CC BY 4.0The GFR GFR The volume of water filtered out of plasma through glomerular capillary walls into Bowman’s capsules per unit of time. It is considered to be equivalent to inulin clearance. Kidney Function Tests is the volume of plasma Plasma The residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation. Transfusion Products filtered by the glomerulus per unit of time. It is the most important laboratory indicator Indicator Methods for assessing flow through a system by injection of a known quantity of an indicator, such as a dye, radionuclide, or chilled liquid, into the system and monitoring its concentration over time at a specific point in the system. Body Fluid Compartments of kidney function.
Equation 2: GFR GFR The volume of water filtered out of plasma through glomerular capillary walls into Bowman’s capsules per unit of time. It is considered to be equivalent to inulin clearance. Kidney Function Tests = Kf [ (PGC – PBS) – (Ď€GC – Ď€BS) ]:
The glomerular barrier is the filtration structure of the nephron Nephron The functional units of the kidney, consisting of the glomerulus and the attached tubule. Kidneys: Anatomy that surrounds the glomerular capillaries Capillaries Capillaries are the primary structures in the circulatory system that allow the exchange of gas, nutrients, and other materials between the blood and the extracellular fluid (ECF). Capillaries are the smallest of the blood vessels. Because a capillary diameter is so small, only 1 RBC may pass through at a time. Capillaries: Histology and includes the following 3 layers:
Diagram of the glomerular barrier:
A: Fenestrated
endothelium
Endothelium
A layer of epithelium that lines the heart, blood vessels (vascular endothelium), lymph vessels (lymphatic endothelium), and the serous cavities of the body.
Arteries: Histology of the glomerular
capillaries
Capillaries
Capillaries are the primary structures in the circulatory system that allow the exchange of gas, nutrients, and other materials between the blood and the extracellular fluid (ECF). Capillaries are the smallest of the blood vessels. Because a capillary diameter is so small, only 1 RBC may pass through at a time.
Capillaries: Histology
B: Basal membrane
C: Epithelial layer demonstrating
podocyte
Podocyte
Highly differentiated epithelial cells of the visceral layer of bowman capsule of the kidney. They are composed of a cell body with major cell surface extensions and secondary fingerlike extensions called pedicels. They enwrap the kidney glomerulus capillaries with their cell surface extensions forming a filtration structure. The pedicels of neighboring podocytes interdigitate with each other leaving between them filtration slits that are bridged by an extracellular structure impermeable to large macromolecules called the slit diaphragm, and provide the last barrier to protein loss in the kidney.
Nephritic Syndrome
foot
Foot
The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons.
Foot: Anatomy processes and structural
proteins
Proteins
Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein.
Energy Homeostasis creating the slit
diaphragm
Diaphragm
The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force.
Diaphragm: Anatomy
The kidney has multiple levels of regulatory mechanisms on the GFR GFR The volume of water filtered out of plasma through glomerular capillary walls into Bowman’s capsules per unit of time. It is considered to be equivalent to inulin clearance. Kidney Function Tests:
Renal blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure is autoregulated through a localized reflexive process called the myogenic response.
Impact of
mean
Mean
Mean is the sum of all measurements in a data set divided by the number of measurements in that data set.
Measures of Central Tendency and Dispersion arterial blood pressure on the
flow
Flow
Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls.
Vascular Resistance, Flow, and Mean Arterial Pressure rate of renal
blood flow
Blood flow
Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute).
Vascular Resistance, Flow, and Mean Arterial Pressure (RBF) and
glomerular filtration rate
Glomerular filtration rate
The volume of water filtered out of plasma through glomerular capillary walls into Bowman’s capsules per unit of time. It is considered to be equivalent to inulin clearance.
Kidney Function Tests (
GFR
GFR
The volume of water filtered out of plasma through glomerular capillary walls into Bowman’s capsules per unit of time. It is considered to be equivalent to inulin clearance.
Kidney Function Tests):
Notice that within the autoregulatory range,
GFR
GFR
The volume of water filtered out of plasma through glomerular capillary walls into Bowman’s capsules per unit of time. It is considered to be equivalent to inulin clearance.
Kidney Function Tests and RBF remain relatively constant.
The primary regulation of glomerular filtration occurs within the glomerulus itself by constricting and dilating the afferent Afferent Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology and efferent Efferent Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology arterioles Arterioles The smallest divisions of the arteries located between the muscular arteries and the capillaries. Arteries: Histology. This affects the hydrostatic pressure Hydrostatic pressure The pressure due to the weight of fluid. Edema within the glomerular capillaries Capillaries Capillaries are the primary structures in the circulatory system that allow the exchange of gas, nutrients, and other materials between the blood and the extracellular fluid (ECF). Capillaries are the smallest of the blood vessels. Because a capillary diameter is so small, only 1 RBC may pass through at a time. Capillaries: Histology.
Effects of constriction (left) and dilation (right) of the efferent Efferent Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology arteriole
Image by Lecturio.Effects of constriction (left) and dilation (right) of the efferent Efferent Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology arteriole
Image by Lecturio.Macula Macula An oval area in the retina, 3 to 5 mm in diameter, usually located temporal to the posterior pole of the eye and slightly below the level of the optic disk. It is characterized by the presence of a yellow pigment diffusely permeating the inner layers, contains the fovea centralis in its center, and provides the best phototropic visual acuity. It is devoid of retinal blood vessels, except in its periphery, and receives nourishment from the choriocapillaris of the choroid. Eye: Anatomy densa cells within the tubules can sense tubular flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure and adjust secretion Secretion Coagulation Studies of substances that affect Affect The feeling-tone accompaniment of an idea or mental representation. It is the most direct psychic derivative of instinct and the psychic representative of the various bodily changes by means of which instincts manifest themselves. Psychiatric Assessment GFR GFR The volume of water filtered out of plasma through glomerular capillary walls into Bowman’s capsules per unit of time. It is considered to be equivalent to inulin clearance. Kidney Function Tests. This process is called tubuloglomerular feedback.
Metabolic responses of the kidney to high and low tubule
flow
Flow
Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls.
Vascular Resistance, Flow, and Mean Arterial Pressure
AA
AA
Amyloidosis:
afferent
Afferent
Neurons which conduct nerve impulses to the central nervous system.
Nervous System: Histology arteriole
EA:
efferent
Efferent
Neurons which send impulses peripherally to activate muscles or secretory cells.
Nervous System: Histology arteriole
JG: juxtaglomerular
Clearance describes the amount of plasma Plasma The residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation. Transfusion Products volume that is completely cleared of a particular substance per unit of time. Clearance equals GFR GFR The volume of water filtered out of plasma through glomerular capillary walls into Bowman’s capsules per unit of time. It is considered to be equivalent to inulin clearance. Kidney Function Tests with substances that are freely filtered (not blocked by the glomerular barrier), not reabsorbed, and not secreted.
Cx = Ux â‹… V/Px
Serum creatinine is typically what is used for GFR GFR The volume of water filtered out of plasma through glomerular capillary walls into Bowman’s capsules per unit of time. It is considered to be equivalent to inulin clearance. Kidney Function Tests determination, owing to its ease of collection and rapid turnaround time.
Relationship
Relationship
A connection, association, or involvement between 2 or more parties.
Clinician–Patient Relationship between creatinine and
GFR
GFR
The volume of water filtered out of plasma through glomerular capillary walls into Bowman’s capsules per unit of time. It is considered to be equivalent to inulin clearance.
Kidney Function Tests
eGFR: estimated
GFR
GFR
The volume of water filtered out of plasma through glomerular capillary walls into Bowman’s capsules per unit of time. It is considered to be equivalent to inulin clearance.
Kidney Function Tests
Glomerular filtration is most commonly used to assess overall kidney function and to stratify CKD CKD Chronic kidney disease (CKD) is kidney impairment that lasts for ≥ 3 months, implying that it is irreversible. Hypertension and diabetes are the most common causes; however, there are a multitude of other etiologies. In the early to moderate stages, CKD is usually asymptomatic and is primarily diagnosed by laboratory abnormalities. Chronic Kidney Disease into stages. Additionally, there are specific disease processes of the glomerulus that impair filtration. Diseases are typically categorized as nephrotic (primarily proteinuria Proteinuria The presence of proteins in the urine, an indicator of kidney diseases. Nephrotic Syndrome in Children) or nephritic (primarily hematuria Hematuria Presence of blood in the urine. Renal Cell Carcinoma).