ANA110 Exam 4: The Renal System

Excretory function of the kidneys

Creation and concentration of water-soluble waste

Endocrine function of the kidneys

Secretion of and response to hormones

Cardiovascular function of the kidneys

Regulation of blood pressure through RAS system

What is the ideal BP?

120/80

Respiratory function of the kidneys

removal of dissolved gases

Retroperitoneal organs

Found posterior to the peritoneum of the abdomen, situated on posterior abdominal wall

The peritoneum holds kidneys against:

Paired posterior abdominal muscles quadratus lumborum

Referred pain from kidney infections

Is felt in the back

Kidneys do not have ____ peritoneum

Visceral

Path of the ureters through the body

Exit the hilum of the kidney and remain retroperitoneal and enter the bladder posteriorly

Where is bladder found?

In the pelvis, subperitoneal organ

Micturition is another name for

Urination

How does urine exit the body?

The bladder contracts, allowing urine to exit the body through the urethra

Lumen of ureter

Star-fish appearance, prevents incontinence episodes

Transitional epithelium of ureter

Important for expansion

Areolar c.t. of ureter

Shape, rigidity, bounce back and why catheterization works

Smooth muscle of ureter

ANS control, involuntary

Basal Lamina of ureter

Connects serosa to deep structures

Serosa of ureter

Outermost layer

Urinary bladder is a

Hollow, distensible muscular organ housed in the pelvic cavity

Where is the urinary bladder situated?

Just posterior to the pubic symphysis, inferior to the peritoneum

Trigone of bladder

A smoothed section of mucosa which has 3 openings to mark its borders

Bladder wall has how many layers

3

Innermost layer of the urinary bladder

Inner mucosa with rugae

What do the rugae of the bladder do?

Allows bladder to distend/expand without injury

What type of epithelium makes up the inner mucosa?

Transitional epithelium

What is the middle layer of the bladder wall?

Detrusor muscle

What is the detrusor muscle?

3 layers of smooth muscle

Describe aspects of the detrusor muscle

No specific directional layer, irregular/crisscrossed, allows it to decrease volume which increases pressure leading to urine exiting

What is the outermost layer of the bladder wall?

Superficial adventitia or peritoneum

How many urethral sphincters are there?

2

Internal urethral sphincter

Composed of smooth muscle, involuntary, contracts and relaxes entirely based on ANS

External urethral sphincter

Made of skeletal muscle, under voluntary control

Define micrution

Discharge of urine from the urinary bladder into the urethra

How does micturition occur?

Stretch receptors within the mucosa stimulate the spinal reflex arc

How does internal urethral sphincter relax?

Stimulation of parasympathetic impulses, detrusor muscle contracts

How does external urethral sphincter relax?

Inhibition of somatic motor neuron impulses

Potty training involves

Initiation or delay voluntarily through learned control by the cerebral cortex

Describe the length and shape of urethra

It varies drastically in length and slightly in shape

Anatomic female urethra

Typically about 4 cm long and contributes only to the urinary system.

Anatomic male urethra

Typically about 20 cm long and contributes to both urinary and reproductive system

Unique components of the male urethra

Prostatic urethra, membranous urethra, penile urethra

Male internal urethral sphincter

Closes during ejaculation, prevents cross-contamination of urine and semen

Male external urethral sphincter location

At the base of penis, embedded in pelvic floor

Hilum of kidney

Indentation in centro-medial region of the kidneys where ureter, nerves, blood vessels, and lymphatic vessels enter/exit.

Layers of connective tissue surrounding the kidney

3: Renal fascia, adipose capsule, renal capsule

Most superficial layer of connective tissue that surrounds the kidneys

Renal fascia

Renal fascia

Encapsulates perirenal space, holds everything together

Middle layer of connective tissue that surrounds the kidneys

Adipose capsule

Adipose capsule purpose

holds everything in place

Deepest layer of connective tissue that surrounds the kidneys

Renal capsule

Why is it important for the kidneys to be encapsulated by so many protective layers?

Protects them from possible traumas

Renal cortex

blood enters then filtered to pyramids

Renal medulla

Made of renal pyramids

Minor calyx

Sends urine to major calyx

Renal pyramids

Filter blood into urine then sent to minor calyx

Main artery in the kidney

Renal artery

What percent of our resting cardiac output goes to kidney?

20%

Renal artery splits into

segmental arteries

Segmental arteries split into

interlobar arteries

Interlobar arteries split into

arcuate arteries

Arcuate arteries split into

cortical arteries

Cortical arteries give off

afferent arterioles

Afferent arterioles go to

Each individual nephron

Afferent arterioles branch into

a network of capillaries called the glomerulus

Efferent arteriole leaves the

glomerulus

Blood drains from the efferent arteriole into the

peritubular capillaries

Peritubular capillaries

participate in gas exchange and eventually empty into efferent veins and into the renal vein

Renal vein drains into

inferior vena cava

In the process of filtration, the kidney also…

Regulates certain chemical properties of blood, produces hormones, and excretes wastes and other foreign substances.

The nephron is composed of

The renal corpuscle and the renal tubule

The renal corpuscle is composed of

Glomerulus and glomerular capsule

The renal tubule is composed of

Proximal convoluted tubule, nephron loop, and distal convoluted tubule

Nephron loop (of Henle)

Extends into the renal medulla, has an ascending limb and a descending limb

The functional unit of the kidney is called

the nephron

The nephron allows for

Careful control of urine composition

The three principal actions of the nephron are

Glomerular filtration, tubular reabsorption, and tubular secretion

Proteins should

never get filtered from the blood into the nephron itself

Glucose should

get filtered by should ALWAYS be 100% reabsorbed

Glomerular filtration

Blood is filtered at the glomerulus

Tubular reabsorption

Fluid and solutes are reabsorbed from the filtrate and returned to the blood

Tubular secretion

Substances are secreted from the blood into the filtrate

Glomerular capsule cell types

Simple squamous epithelium, podocytes, mesangial cells

Glomerular capsule simple squamous epithelium function

diffusion

Glomerular capsule podocytes function

Narrows filtration opening

Glomerular capsule mesangial cells function

cleans up excess/clogged matter

Proximal convoluted tubule cell type

Cuboidal cells with brush border

Proximal convoluted tubule function

Reabsorbing glucose and other critical material

Descending nephron cell loop cell type

Simple squamous

Descending nephron loop function

reabsorbing H20

Ascending nephron loop cell type

Cuboidal —→ columnar

Ascending nephron loop function

Reabsorbing salt

Juxtaglomerular apparatus cell types

Macula densa cells, juxtaglomerular cells

Juxtaglomerular apparatus macula densa cells function

sensing salt concentration

Juxtaglomerular apparatus juxtaglomerular cells functions

Change afferent arteriole, secreting renin

Distal convoluted tubule cell type

Principal cells w/ intercalated discs

Distal convoluted tubule function

Adjusting pH/H2O

Collecting duct cell type

Principal cells with intercalated discs

Collecting duct function

Adjusting pH/H2O

First step in filtering blood

creation of filtrate