BIOL 2510 Wonil Choi - Exam 3

(Lecture 1 Fun fact) The bladder can stretch to hold up to

2 cups of urine

The urinary system is composed of

kidneys

ureters

urinary bladder

urethra

The kidneys

filter blood and convert filtrate into urine

Ureters

the liquid waste is transported by the ureters (Kidneys → Urinary bladder)

Urinary bladder

Stores urine until it is eliminated from the body

Urethra

Urine is eliminated through the urethra

Kidneys (Diagram)

What is A on the diagram?

Ureters (Diagram)

What is B on the diagram?

Urinary Bladder (Diagram)

What is C on the diagram?

Urethra (Diagram)

What is D on the diagram?

When filtrate is converted to urine, 3 different physiological processes occur:

1 - elimination of metabolic wastes

2 - Regulation of ion wastes

3 - regulation of acid-base balance

(Kidneys) Elimination of metabolic wastes

the kidneys remove waste within the filtrate (e.g. urea, uric acid) so these substances do not reach toxic levels within the blood

(Kidneys) Regulation of ion levels

the kidneys help control the blood's ion balance, such as sodium, potassium, calcium, and phosphate ions by eliminating them in the urine

(Kidneys) Regulation of acid-base balance

the kidneys maintain acid-base balance by altering blood levels of both hydrogen and bicarbonate ions

(Kidneys) Regulation of blood pressure

the kidneys help regulate blood pressure by excreting fluid in the urine

regulating fluid lost in the urine helps regulate blood volume

the kidneys can also release enzyme "renin", which is required for production of angiotensin II (a hormone that increases blood pressure)

Renin

hormone secreted by the kidney that leads to the production of angiotensin II which increases blood pressure (influences vasoconstriction)

(Kidneys) Elimination of biologically active molecules

small molecules (e.g. hormones, drugs) are filtered, but are not reclaimed, and then become part of urine

In addition to filtering blood and processing filtrate to form urine, your _______ perform/participate in other functions

kidneys

(Kidneys) Formation of Calcitrol

this hormone increases the absorption of calcium from the small intestine (increased blood calcium concentration)

(Kidneys) Production and release of erythropoietin

Kidney's response to low blood oxygen levels by secreting this hormone (EPO)

erythropoietin

hormone that leads to increased erythrocyte formation

(Kidneys) Potential to engage in gluconeogenesis

during fasting or starvation

to product glucose from noncarbohydrate sources to maintain normal blood glucose levels

Your kidneys take care of your blood by: removing ________ materials from the blood

Unwanted

Your kidneys take care of your blood by: maintaining blood plasma ____

Ions

Your kidneys take care of your blood by: regulating blood __

pH

Your kidneys take care of your blood by: altering blood ______

volume

Your kidneys take care of your blood by: regulating the number of ____________

Erythrocytes

Your kidneys take care of your blood by: Maintaining _____ _______ ______ during fasting or starvation

blood glucose levels

Healthy kidney means

Healthy blood

Shape of Kidneys

symmetrical bean shaped

Each kidney has a concave medial border called

Hilum

The Hilum is where

the vessels, nerves, and ureter connect to the kidney

An _______ gland sits on the superior aspect of each kidney

Adrenal

Kidneys are located along the

posterior abdominal wall, lateral to the vertebral column (Retroperitoneal)

The left kidney is found between the level of the

T12 and L3

The right kidney is located ________ to the left kidney; why?

Inferior

due to the position of the liver

Each kidney is surrounded and supported by several tissue layers

fibrous capsule (renal capsule)

perinephric fat (adipose capsule)

renal fascia

paranephric fat

(INNERMOST TO OUTERMOST!)

Fibrous Capsule (Renal capsule) (Diagram)

What is A on the diagram?

Perinephric Fat (Adipose capsule) (Diagram)

What is B on the diagram?

Renal Fascia (Diagram)

What is C on the diagram?

Paranephric fat (Diagram)

What is D on the diagram?

Fibrous capsule (renal capsule)

directly adhere to the external surface of the kidney

mainly composed of dense irregular connective tissue

maintains kidney's shape, protects it from trauma, and prevents pathogens from penetrating the kidney

Perinephric fat (adipose capsule)

composed of Adipose connective tissue

provides cushion and stabilization for the kidney

Renal Fascia

composed of dense irregular connective tissue

anchors the kidney to surrounding structures

Paranephric fat

the outermost layer surrounding the kidney

composed of adipose connective tissue (cushioning and stabilization)

Renal ptosis and hydronephrosis

the loss of adipose connective tissue in very thin elderly or individuals with anorexia may result in renal ptosis

the dropping of the kidney

Dropping of the kidney from renal ptosis can ultimately cause

a "kink" in the Ureter, which leads to

decreased urine flow,

urine backs up into the proximal part of the ureter,

and enlargement of the renal pelvis

When the kidney is sectioned coronally, the

parenchyma ("functioning tissue") is visible

2 distinct regions of the parenchyma

outer renal cortex

inner renal medulla

Renal Columns

extensions of the cortex

project into the medulla and subdivide it into renal pyramids (medullary pyramids)

Renal cortex (Diagram)

What is A on the diagram?

Renal Medulla (Diagram)

What is B on the diagram?

Renal Column (Diagram)

What is C on the diagram?

Renal Pyramid (Medullary Pyramid) (Diagram)

What is D on the diagram?

Corticomedullary Junction (Diagram)

What is E on the Diagram?

Renal Papilla (Diagram)

What is F on the diagram?

Renal Sinus (Diagram)

What is G on the diagram?

Corticomedullary Junction

the wide base of the renal pyramids

external edge of the medulla, where it meets the cortex

Renal papilla

medially directed tip of the renal pyramid

Each kidney also contains a medially located space called

renal sinus

the Renal sinus of the kidney

urine drainage area

minor and major calyces and renal pelvis

The Functional anatomy of the kidney includes

nephrons

collecting tubules

collecting ducts

and other associated structures

Nephron

microscopic, functional filtration unit of the kidney

Each nephron consists of 2 major structures

a renal corpuscle and a renal tubule

Almost all renal corpuscles and renal tubules

reside in the cortex (outer region)

Renal corpuscle

an enlarged, round portion of a nephron housed within the renal cortex

composed of 2 structures: glomerulus and glomerular capsule

2 structures that make up the renal corpuscle

glomerulus

glomerular (Bowman's) capsule

the glomerulus and bowman's capsule are only found in the

cortex

Nephron diagram

Nephron diagram 2 (Note the Bowman's capsule and Glomerulus!)

Glomerulus

a thick tangle of capillary loops (glomerular capillaries)

blood enters the glomerulus by an ________ arteriole and exits by an ________ arteriole

afferent; efferent

Glomerular (Bowman's) Capsule is formed by 2 layers:

visceral and parietal

Between the visceral layer and parietal layer of the glomerular capsule is a

capsular space that receives filtrate, which is then modified to form urine

Your renal corpuscle has 2 opposing poles, what are they?

the vascular and tubular poles

the vascular pole of the renal corpuscle is where the

afferent and efferent arterioles are attached to the glomerulus

the tubular pole of the renal corpuscle is where the

renal tubule originates

The renal tubule makes up the remaining part of the nephron and consists of 3 continuous sections

the proximal convoluted tubule (PCT)

the nephron loop (loop of Henle)

the distal convoluted tubule (DCT)

the convoluted tubules usually reside in the

cortex

the loop of Henle typically extends

from the cortex to the medulla

(Lecture 2 Fun fact) UTIs are more common in

women than in men

One of the reasons for this is because they have shorter urethra (easier for bacteria to reach your bladder)

The proximal convoluted tubule (PCT)

the first region of the renal tube

originates from the tubular pole (simple cuboidal epithelium with apical microvilli)

brush border

The microvilli of the proximal convoluted tubule are for

Reabsorption

Loop of Henle (Nephron loop) consists of two regions

ascending and descending limbs that are continuous at a hairpin turn within the medulla

The loop of henle consists of

thick and thin regions as well

Distal Convoluted Tubule (DCT)

originates in the renal cortex at the end of the loop of Henle's ascending limb and extends into a collecting tubule

also composed of simple cuboidal epithelium (like the PCT), but have sparse, short, apical microvilli

for this reason, they do not have the "fuzzy edge" when looked under the microscope

Why does the DCT not have the "fuzzy edge" seen under a microscope?

Because reabsorption primarily happens in the PCT

Cortical nephron: where is its renal corpuscle located?

renal corpuscle located near the edge of the cortex

Cortical nephron: Loop of Henle

short loop of Henle that barely penetrates the medulla

Cortical nephrons make up __% of nephrons

85

Juxtamedullary nephrons make up __% of nephrons

15

Juxtamedullary nephrons: where is its renal corpuscle?

renal corpuscle is adjacent to the corticomedullary junction

Juxtamedullary nephrons: loop of Henle

long Loop of Henle deep into the medulla

Cortical nephron vs Juxtamedullary nephron (Diagram)

Several nephrons drain into each

collecting tubule

Each kidney has thousands of collecting _______, and they eventually empty into larger collecting _____

tubules; ducts

the collecting ducts and tubules both project through the renal medulla toward the

renal papilla

The collecting ducts then drain into a

papillary duct

Where are papillary ducts found?

within the Renal Papilla

Then, from the papillary ducts, it is drained to the

minor calyx