URINARY SYSTEM MIDTERM (PART 1)

It is the major organs of the urinary system

Kidneys

What is the typical shape of the Kidneys in mammals?

Bean shaped (shape varies in other animals)

Kidneys is bilaterally located in the __________?

retroperitoneal cavity

This organs is responsible for metabolic waste removal

kidneys

What hormones does kidney secrets?

Erythropoietin and renin

What are the five functions of the Urinary System

1. Balances water and electrolytes

2. Regulates plasma osmolality and arterial pressure

3. Maintains acid-base balance

4. Secretes important hormones (Renin, Erythropoietin)

5. Helps in glucose production

Functional units of the kidneys

Nephons

What are two primary parts of the nephrons?

Glomerulus and Renal Tubules

Part of the nephron that is responsible for Reabsorption and Secretion

Renal Tubules

Part of the nephron responsible for filtration process?

Glomerulus

Kidney capillary pores are described as __________, meaning “Oval windows”

FENESTRAE

These structures of the nephron are made up of glomerular capillaries (tuft)

Glomeruli (singular: Glomerulus)

Kidneys are composed of two groups of capillaries

1. Glomerular capillaries

2. Peritubular capillaries

Capillaries in the nephron known for being as high pressure capillary bed

Glomerular capillaries

Capillaries in the nephron known for being operate under low pressure

Peritubular capillaries

What are the four function of the Nephron?

1. Filtration

2. Reabsorption

3. Secretion

4. Excretion

They are consider first stage in urine formation?

Glomerular Filtration

Glomerular Filtration Occurs in ??

Glomerular capillary membrane

Glomerular capillary membrane contains three layers?

1. Endothelial cells

2. Basement membrane

3. Epithelial cells/podocytes (called outer layer).

They are similar to blood plasma but protein-free devoid of blood cells

Glomerular Filtrate

Glomerular Filtrate contains______ in proportion to ECF composition

Salt

A term in formation of urine which the is amount of filtrate formed in each nephron

GLOMERULAR FILTRATION RATE (GFR)

GFR is determined by the these pressure? What are these?

1. Glomerular Hydrostatic Pressure (GHP)

2. Plasma Colloid Osmotic Pressure (PCOP)

3. Bowman’s Capsule Pressure (BCP)

4. Bowman’s Capsule Osmotic Pressure (BCOP)

What is the standard Pressure of GHP?

60 mmHg

What is the standard Pressure of BCOP?

10 mmHg

What is the standard Pressure of PCOP

32mmHg

What is the standard Pressure of BCP?

18 mmHg

A term use to describe the distribution of blood to different tissues and/or organs of the body via the arterial tree

Systemic circulation

The ______ supplies blood to the kidneys

Renal artery

These is arterioles that collect blood from the glomerulus to the peritubules

Efferent arterioles

Arcuate arteries branch off to supply blood to ____________ and the _______________,

afferent arterioles and glomerulus (glomerular capillaries)

These is an extensions of peritubular capillaries which release blood to the arcuate veins

Vasa recta

Autoregulation of GFR is possible due to the _______ and/or ________?

regulation of blood flow and arterial pressure

Whenever there is a need to increase or decrease the GFR, there are physiological mechanisms that help in returning the situation to normal? Which is?

TUBULO-FEEDBACK mechanisms

Tubulo-feedback mechanisms has two types which are?

1. Afferent Arteriolar Mechanism

2. Efferent Arteriolar Mechanism

What effect does sympathetic nerve fiber (SNF) stimulation have on the arterioles?

constricts the arterioles, decreasing blood flow and the glomerular filtration rate (GFR).

What substance triggers sympathetic nerve fiber (SNF) activity?

Angiotensin II

What is the role of Angiotensin II in SNF stimulation?

It acts as a vasoconstrictor that triggers sympathetic nerve fiber activity

What are the three structure of Juxtaglomerular complex (JG COMPLEX)?

1. Macula Densa

2. Juxtaglomerular (JG) Cells

3. Mesangial Cells

Part of the JG complex located at distal Tubules, contacts afferent and efferent

arterioles

Macula Densa

Part of the JG COMPLEX located in the walls of afferent and efferent arterioles

Juxtaglomerular (JG) Cells

What stimulates the juxtaglomerular (JG) complex?

A decrease in sodium chloride (NaCl) in the macula densa

What happens to the afferent and efferent arterioles when the JG complex is stimulated?

Dilate afferent and efferent arterioles

How do angiotensin I and II differ?

Angiotensin I is a mild vasoconstrictor; angiotensin II is a potent vasoconstrictor.

What does renin do?

Converts angiotensinogen to angiotensin I

What triggers renin release?

Dilation of afferent and efferent arterioles

Where is angiotensinogen produced?

liver

What does angiotensin II stimulate in the adrenal glands?

Aldosterone secretion

What is the function of aldosterone in the kidneys?

increases sodium (NaCl) reabsorption from the renal tubules

What direct effect does angiotensin II have on the renal tubules?

It increases sodium retention

It is the part of the nephron responsible for urine Formation?

Renal Tubules

What are the parts of Mammalian Renal Tubules(In order)?

Proximal Tubules, loop of henle the descending, loop of henle the ascending, early distal tubule, late distal tubules and cortical collecting tubules

Part of the renal Tubules receives filtrate from Bowman’s capsule

Proximal Tubule

Part of the renal Tubules that is more on water reabsorption and consider thin anatomically?

Descending Loop of Henle

Part of the renal Tubules that is more on solutes (Na+, Cl-, K+, Ca++, Mg++) reabsorption Part of the renal Tubules that is more on water reabsorption and consider thick anatomically?

Ascending loop of Henle

It has many of the same characteristics as the thick ascending loop of Henle and reabsorbs sodium, chloride, calcium, and magnesium but is virtually impermeable to water and urea.

early distal tubule

These are the last segment of the nephron composed of two distinct cell types?

late distal tubules and cortical collecting tubules

What are the two distinct cell types late distal tubules and cortical collecting tubules?

Principal cells and the intercalated cells.

What is the function of principal cells in the renal tubules?

They reabsorb sodium and secrete potassium into the lumen.

What do intercalated cells reabsorb and secrete?

They reabsorb potassium and bicarbonate and secrete hydrogen ions into the lumen

What hormone controls water reabsorption in this tubular segment?

Antidiuretic hormone (ADH)

This is the terminal part of the nephron?

Renal Pelvis

Which animal that has no renal pelvis?

cattle

A term that is refer as a removal of unneeded substances into renal pelvis.

Secretion

A term that is refer as movement of needed substances back into ECF

Reabsorption

What are the two processes involved in reabsorption?

Diffusion and active transport.

What are the types of urine?

• Hypotonic urine - Low salt, high water

• Hypertonic urine - High salt, low water

• Diluted urine - High water (diluent/ solvent), low solutes (solid matters)

• Concentrated urine - High solutes, low water

• Acidic urine - High H+, low bicarbonate

What is the normal color of the urine?

pale yellow to yellow

What is the normal odor of the urine?

odorless (depending on what an individual takes/eats)

What is the normal transparency of the urine?

clear, except horse that thick and syrupy

Why horse has thick and syrupy urine?

because they excrete a high concentration of calcium carbonate crystals

What is the normal pH of the urine?

It depends on the diet, however carnivorous has acidic, herbivorous has alkaline/ basic, and omnivorous like man = sometimes acidic at times basic

What is the nitrogenous component of mammalian urine?

Urea

How is urea formed in the body?

Formed by the liver from ammonia produced during amino acid metabolism.

Why does the body produce urea instead of excreting ammonia?

To avoid the toxicity of ammonia.

Is urea toxic?

No, urea is relatively non-toxic.

Do horses urinate while lying down?

No, horses do not urinate while lying down

Why does an over-distended bladder in horses hang into the abdominal cavity?

Because the position of the fundus of the bladder is lower than the urethra.

Why do oxen's urine dribble away?

Due to the curved character of their urethral canals

Where are the urethral canals of oxen directed?

Toward the ground

What is commonly found at the extremity of oxen's sheaths?

A tuft of hair