EXAM 4 Lecture

Urinary System functions

1. Kidneys regulate blood volume and composition, blood pressure, pH, glucose and produces hormones, filter wastes

2. Ureters transport urine from kidneys to urinary bladder

3. Urinary bladder stores urine and expels it into urethra

4. Urethra discharges urine from bod

What do the kidneys regulate?

blood volume and composition, blood pressure, pH, glucose

What do the Ureters do?

transport urine from kidneys to urinary bladder

What does the Urinary bladder do?

stores urine and expels it into urethra

What does the Urethra do?

discharges urine from body

What are the functions of the kidney? (8)

- Regulation of blood ionic composition
- Regulation of blood pH

- Regulation of blood volume

- Regulation of blood pressure
- Maintenance of blood osmolarity
- Production of hormones
- Regulation of blood glucose
- Waste removal

What makes up the blood’s ionic composition

Na+, K+, Ca²⁺, Cl-, HPO₄²

How does kidneys regulate blood volume?

Can choose whenever or not to conserve or eliminate water

How does the kidneys regulate blood pressure?

They can secret renin that then actives the renin-angiotensin-aldosterone pathway.

what is blood osmolarity

measures the concentration of all chemical particles found in the plasma. ( Water vs electrolytes: ions K+, Na+, Ca2+, Cl-, HPO42-)

How does the kidneys maintain blood osmolarity?

Primarily by adjusting the excretion or conservation of both water and electrolytes

Draw the The Renin-Angiotensin-Aldosterone System (RAAS)

What hormones do the kidney produce?

calcitriol hormone and erythropoietin hormone

What does the calcitriol hormone do?

It’s the active form of vitamin D. It increases Ca2+ absorption in large intestines, maintain calcium levels

What does the •erythropoietin hormone do?

Increases erythrocyte formation

How do the kidneys reglue blood glucose levels?

It uses glutamine (amino acid) to preform gluconeogenesis (synthesizes new glucose from non-carbohydrate precursors,)

What is waste in blood defined as?

Substances that have no useful function in the body. Some result from metabolic reactions in the body.

Where do Ammonia and Urea come from?

Deamination of amino acids

Where does Urobilin come from?

Catabolism of hemoglobin

Where does creatinine come from?

From the breakdown of creatine phosphate in muscle fibers

Where does Uric acid come from?

Catabolism of nucleic acids

What other wastes might be excreted in urine besides Ammonia, Urea, Urobilin, Creatinine, and Uric acid

Foreign substances from the diet, such as drugs or environmental toxins.

What are the primary waste products of metabolic reactions that the kidneys excrete in urine, and which metabolic processes produce them?

• Ammonia and urea from deamination of amino acids

• Urobilin from catabolism of hemoglobin

• Creatinine from the breakdown of creatine phosphate in muscle fibers

• Uric acid from catabolism of nucleic acids

What kidney is slightly lower?

Right is lower because the liver is there

Label this picture

1- Right kidney

2- rental artery

3- Right ureter

4- urinary bladder

5- urethra

6- left renal vein

7- left kidney

8- left ureter

What are the three layers of tissue around kidney?

renal capsule, adipose capsule, and the renal fascia

What is the renal capsule?

The outer surface of the kidney

What is the tissue of the renal capsule like?

Smooth, transparent sheet of dense irregular connective tissue, continuous with the outer coat of the ureter.

What is the adipose capsule?

Mass of fatty tissue surrounding the renal capsule

What does the adipose capsule do?

holds the kidney in place and protects from trauma

What is Nephroptosis?

floating kidney that is more common is women

What is the renal fascia?

The outer most layer of the kidney

What kind of tissue is the renal fascia?

Thin layer of dense irregular connective tissue

What does the renal fascia do?

Anchors kidney to abdominal wall and other surrounding structures

label this picture of the external anatomy of kidneys

1- renal fascia
2- adipose capsule
3- renal capsule

What is the External Anatomy of Kidneys

Three layers of tissue around kidney

Renal capsule is the outer surface of kidney.

Adipose capsule is a mass of fatty tissue surrounding the renal capsule; holds the kidney in place and protects from trauma

Renal fascia is a more superficial layer that anchors kidney to abdominal wall

Where is the renal cortex located and look like?

Inside of kidneys, superficial, light in color, and between / above renal pyramids

Where is the renal medulla and what does it look like?

deep part of the kidney, dark reddish-brown

What are renal pyramids?

cone-shaped structures in the renal medulla

What are renal papilla?

Concave portion, where ureter, vessels and nerves converge

What is a Renal lobe?

renal pyramid, renal cortex, ½ of renal columns to either side

What is the Minor Calyx?

Chamber in the kidney that collects urine from the renal pyramid

What is the Major Calyx?

A large, funnel-shaped structure in the kidney that collects urine from several smaller minor calyces

What is the Renal Pelvis?

Central collecting chamber within the kidney

What is the Parenchyma?

It’s the only functional portion of the kidney. It’s made up of the renal cortex, renal pyramids, and nephrons (all the brownish parts of the kidney)

What is a Nephron?

The the basic structural and functional unit of the kidney.

What makes up a nephron?

It’s made up of renal corpuscle and a renal tubule.

What is the renal corpuscle?

The initial filtering unit of the kidney nephron, located in the renal cortex.

What does the renal corpuscle do?

Blood plasma filtered. The initial site of blood filtration in the nephron, responsible for separating water, ions, and waste from blood plasma to form filtrate

What is the renal tubule?

a tiny, long tube within the kidney's nephron that filtered fluid passes into this

What is the glomerulus?

A tiny, specialized cluster of capillaries located within the nephron.

What is the glomerular (Bowman’s) capsule?

epithelial layers that surround capillaries

What are the Steps of Filtration?

1. Blood plasma filtered in glomerular capsule
2. Fluid passes into renal tubule
3. Fluid leaves distal convoluted tubule and empties into collecting duct.

What are the 3 sections of the renal tubule?

-Proximal convoluted tubule

-Loops of Henle

-Distal convoluted tubule

Whats the order of blood supply to the kidneys?

Rental artery – Segmental arteries – Interlobar arteries – Arcuate Arteries – Interlobular Arteries – Afferent Arterioles – Glomerular Capillaries – Efferent Arterioles – Peritubular capillaries – Interlobular veins – arcuate veins – interlobar veins – renal veins

Renal artery

Enters the kidney and Supplies kidney with blood

Afferent arteriole

Arteries that enters the glomerulus

Glomerular capillaries

Network of capillaries where filtration occurs

Efferent arterioles

Arteries that exits glomerulus

Peritubular capillaries

Exchange with tubules

What is filtrate?

. It’s the the fluid filtered from blood plasma into the Bowman's capsule of nephrons. It is formed from water and solutes

What is not filtered out in the Renal corpuscle?

cells and protein are not filtered out

Where does kidney filtration take place?

In the glomerulus

What main functions occur in the Renal tubules?

Reabsorption and secretion

What is fluid called in the Renal tubules?

tubular fluid

What reabsorption happens in renal tubules ?

99% of water and many solutes are returned from the tubular fluid to the blood (Peritubular capillaries)

What secretion happens in the renal tubules?

Wastes, drugs, excess ions secreted from the blood into the tubular fluid.

Label this picture

1- Afferent Arteriole
2- Glomerular Capsule
3- Efferent Arteriole
4- Filtrate
5- Pertiublar Capiilaries
6- Tubular reabsortion from tubular fluid into blood
7- tubular secretion from blood into tubular fluid
8- Tubular fluid
9- Renal corpuscle
10- Renal tubule
11- Urine
12- Blood
13- Filtration from blood plasma into nephron 

What happens in the Collecting ducts ?

Excretion

What is Excretion?

filtration + secretion - reabsorption

What is the fluid in the Collecting duct called?

Urine

What is fluid called in the Glomerular capsule, Proximal Convoluted Tubule, Loop of Henle, Distal Convoluted Tubule, Collecting Duct, Peritubular Capillaries called?

Glomerular capsule- Filtrate
PCT,LOH,DCT - Tubular Fluid
Collecting Duct - urine
Peritubular Capillaries - Blood Plasma

What happens during glomerular filtration?

Water and most solutes move across glomerular capillaries into the glomerular capsule, then into the renal tubule.

What is glomerular filtrate?

The fluid that enters the capsular space during glomerular filtration.

How much urine is typically excreted per day?

About 1–2 liters.

What is tubular reabsorption?

The process where tubule cells reabsorb 99% of filtered water and many useful solutes as fluid flows through renal tubules and collecting ducts.

Where do reabsorbed substances go after tubular reabsorption?

They return to the blood through the peritubular capillaries.

What is tubular secretion?

The process where renal tubule and duct cells secrete wastes, drugs (and their metabolites), and excess ions into the tubular fluid.

What percentage of filtrate is reabsorbed?

About 99% is reabsorbed.

What is the Body Fluid Composition of Blood Plasma?

( No Blood Cells)

Protein
Glucose
Amino Acids
Na⁺
H+
Urea

What is the Body Fluid Composition of Blood

Blood Cells
Protein
Glucose
Amino Acids
Na⁺
H+
Urea

What is the Body Fluid Composition of Filtrate?

( No Blood Cells or Proteins)

Glucose
Amino Acids
Na⁺
H+
Urea

What is the Body Fluid Composition of Tubular Fluid?

( No Blood Cells or Proteins)

Glucose
Amino Acids
Na⁺
H+
Urea

What is the Body Fluid Composition of Urine?

(No Blood Cells Proteins, Glucose, or Amino Acids)

Na⁺
H+
Urea

What is the fluid composition difference between Filtrate &Tubular fluid vs Urine

Filtrate and tubular fluid have Glucose and Amino Acids while urine does not.

What is the fluid composition difference between Blood Plasma and Filtrate &Tubular fluid

Blood plasma has proteins while Filtrate &Tubular fluid does not

What precent of filtrate returns after reabsorption?

99%

Is Glomerular Filtration selective or nonselective?

nonselective

What are the layers to Glomerular (Bowman’s) capsule?

Visceral layer, Parietal layer, and Capsular space

What is the Visceral layer of the Glomerular (Bowman’s) capsule?

The Inner most layer that is made of Podocytes. The Podocytes wrap around glomerular capillaries.

What tissue type is the Visceral layer of the Glomerular (Bowman’s) capsule?

Simple squamous epithelium ( made of podocytes)

What is the Parietal layer of the Glomerular (Bowman’s) capsule?

Outer layer Simple squamous epithelium.

What is the Capsular (Bowman’s) space?

The Space between the visceral and parietal layers where filtrate collects

What causes the large volume of filtrate?

Large surface area
Thin, porous filtration membrane.
High glomerular capillary blood pressure

What contributes to the Large surface area for filtrate to be produced

Highly branched network of glomerular capillaries

what are the layers and features of the glomerular capillaries?

Endothelium - Fenestrations
Basal lamina – negative charge and repels proteins
Filtration slits - Spaces between the podocytes

What are the Fenestrations of glomerular endothelium?

Inner most layer with large pores.

What is the Basal lamina layer of the glomerular capillaries

Connective tissue (Acellular material) that is negative charge and repels proteins

What are Filtration slits?

Spaces between the podocytes of the visceral layer of the glomerular capsule

What is NOT filtered in Glomerular Filtration?

plasma proteins and blood cells