Renal System and Long-Term Blood Pressure Regulation ~ Anatomy 2 Chapter 24

Renal system

Organ system that filters blood, removes wastes, regulates fluid/electrolytes, and maintains blood pressure

filters blood, removes wastes, regulates water content (fluid/electrolytes), and maintains blood pressure

What are the functions of the renal system?

~20%, cardiac output

Kidneys receive ____% of _________

Filters blood and removes metabolic wastes (e.g., remove toxins)

The Primary kidney function is -

Selective reabsorption

Kidneys retain necessary substances and eliminate toxins

blood pressure and RBC production

Kidneys release hormones (endocrine) that regulate -

renin, erythropoietin, calcitriol

What are 3 hormones (ligands?) produced by the kidneys?

Renin

Hormone that increases blood pressure and volume via RAAS

- functions in increasing antidiuretic (ADH/vasopressin and aldosterone)

Erythropoietin (EPO)

Hormone that stimulates red blood cell production in bone marrow

hypoxia (low oxygen)

EPO is released in response to-

Calcitriol

Active vitamin D that regulates calcium levels and gluconeogenesis

gluconeogenesis

formation of glucose from noncarbohydrate sources.

- Kidney metabolic role is to perform ___________ during fasting.

water content

Kidneys adjust total body-

Retroperitoneal (behind peritoneum)

Kidney location is-

(separated from other abd. organs 😢)

T12-L3

Vertebral level of kidneys

Posterior ribs (floating ribs)

Kidney are protected by-

(mostly lmao)

Renal fascia

Outer dense connective tissue anchoring kidneys and adrenal glands

- covers fat capsule

Perinephric/perirenal fat capsule

Middle adipose layer cushioning kidneys and adrenal gland

- covers renal capsule

Renal capsule

Inner fibrous layer directly covering kidney

Renal fascia -> perirenal fat capsule -> renal capsule

What are the kidney connective tissue layers from superficial to deep?

renal capsule -> perirenal fat capsule -> Renal fascia

What are the kidney connective tissue layers from deep to superficial?

Renal cortex

Outer region; granular appearance; contains most nephrons

Renal medulla

Inner region composed of renal pyramids

Renal pyramids

Cone-shaped structures containing tubules that make up the renal medulla

renal papilla

narrow, innermost apex end of a pyramid

Renal columns

Tissue separating pyramids

Renal lobe

Pyramid plus surrounding cortex

Minor calyx

Collects urine from a single renal lobe

Major calyx

Receives urine from multiple minor calyces

Renal pelvis

funnel-shaped reservoir that collects the urine and passes it to the ureter

renal papilla, minor calyx, major calyx, renal pelvis, ureter, urinary bladder

What is the flow of urine from a renal papilla to the urinary bladder?

urinary bladder, ureters, renal pelvis, major calyx, minor calyx, renal papilla

What is the flow of urine BACKWARDS from a renal papilla to the urinary bladder?

cortex, medulla, pelvis

Arrange the regions of the kidney in the order from superficial to deep.

- renal medulla

- renal pelvis

- renal cortex

Ureter

structures that transport urine from kidneys to bladder

Peristalsis

Smooth muscle contractions that move urine

Anti-reflux design

Ureters enter bladder at an oblique/posterior angle to prevent backflow

compresses distal ureters

Increased bladder volume _______ ________ to prevent reflux

Ureter mucosa

Transitional epithelium that stretches

transitional epithelium

type of tissue that stretches readily and permits distension (expansion) of urinary organ by contained urine

- lines the ureters, urinary bladder, and part of the urethra

Ureter muscularis

Smooth muscle that generates peristalsis

- senses distention with urine filling and triggers reflexive peristalsis

Ureter adventitia

Outer fibrous connective tissue anchoring ureter in place

Mucosa, muscularis, adventitia

What are the 3 ureter layers from deep to superficial?

Adventitia, muscularis, mucosa

What are the 3 ureter layers from superficial to deep?

muscularis layer

The _______ layer of the ureter mucosa contracts to move urine by peristalsis.

Trigone

Triangular region between ureter openings and urethra

Bladder mucosa

Transitional epithelium forming rugae

Rugae

series of folds of transitional epithelium in the mucosa lining the bladder

Detrusor muscle

Smooth muscle that contracts to drive urination

- is usually relaxed, but contracts to squeeze urine out of bladder

inner mucosa and detrusor

bladder layers to remember...

(just whats on slides lol)

Internal urethral sphincter

thick involuntary smooth muscle at bladder-urethra junction that contracts to open

External urethral sphincter

Voluntary skeletal muscle ring surrounding the urethra as it passes through the pelvic floor, on its way out.

Stratified squamous for protection

Epithelium (transitions to this type of tissue) near urethra opening is made of-

3-5 cm, only urine

The Female urethra is ____ cm long and transports ______.

~20 cm, urine and semen

The Male urethra is ____ cm long and transports ______.

spongy urethra, membranous urethra, prostatic urethra

What are the regions of the male urethra in the order that they would be encountered by a catheter?

(external to bladder)

The urinary bladder in females is anterior to the uterus, vagina, and rectum. This arrangement limits its capacity during pregnancy, as it is crowded by the growing uterus.

Why do pregnant women urinate with greater frequency?

relaxed (filling), passively contracted, contracted

During sympathetic stimulation (higher CNS input), the bladder is ________.

Internal sphincter is __________, external sphincter is ________.

contracted (emptying), passively pulled open, relaxed

During parasympathetic stimulation (lower CNS input), the bladder is ______________.

Internal sphincter is __________, external sphincter is ________.

micturition (voiding)

another term for urination

parasympathetic, inhibited, stimulated

detrusor muscle is under _________ control, is _______ during filling and _______ during micturition (emptying)

contract

parasympathetic control causes the detrusor muscle to-

sympathetic, stimulated, inhibited

internal urethral sphincter muscle is under _________ control (to open), is _______ during filling and _______ during micturition (emptying)

close

sympathetic control causes internal urethral sphincter muscle contraction to-

somatic motor, stimulated, inhibited

external urethral sphincter muscle is under _________ control (to open), is _______ during filling and _______ during micturition (emptying)

close

somatic motor control causes external urethral sphincter muscle contraction to-

stretch receptors

receptors that sense bladder muscle stretch and contraction

1. Stretch Receptors fire

2. Parasympathetic neurons fire. Motor Neurons stop firing.

3. Bladder smooth muscle contracts. Internal sphincter is passively pulled apart. External sphincter relaxes.

Steps of micturition via parasympathetic stimulation 💤

Higher CNS input

________ may facilitate or inhibit the micturition reflex in spinal arc

Renal artery

Supplies blood to kidney

Segmental arteries

First branches of renal artery

Interlobar arteries

oxygenated blood vessels that travel through renal columns

interlobar veins

deoxygenated blood vessels that travel through renal columns, ultimately carrying filtered blood back to the inferior vena cava

Arcuate arteries

Located at cortex-medulla boundary

- eyelash spine lol

Cortical radiate arteries (Interlobular Arteries)

Extend into cortex

- eyelashes

Afferent arteriole

Brings blood to glomerulus from Cortical radiate arteries

Really Smart Interns Always Carry Apples

Pneumonic for arery flow into kidneys....

Efferent arteriole

carries blood away from the glomerulus

Renal artery, segmental artery, interlobar artery, arcuate artery, cortical radiate, afferent arteriole

What is the order of artery flow from the hilum to the cortex (into the kidney)?

Nephron

Functional unit of kidney that forms urine

80%, 20%

___% of nephron is in cortex, while ___% in medulla

Glomerulus

Capillary network where filtration occurs

- ball-like bunch of capillaries

Bowman's capsule

cup-shaped structure of the nephron of a kidney which encloses the glomerulus and which filtration takes place.

- Collects filtrate from glomerulus (B in picture)

renal corpuscle

glomerulus + bowman's capsule =

Filtration

Movement of plasma and solutes into nephron

space surrounding the Bowman's capsule

Filtration occurs when fluid and solutes are forced from the blood in the glomerulus into the-

Peritubular capillaries

Blood supply that directly receives substances from the tubular cells. Site of reabsorption and secretion

Vasa recta

Capillaries around loop of Henle maintaining gradient

Proximal convoluted tubule (PCT)

Major site of reabsorption located entirely within the cortex

- simple cuboidal epithelium with microvilli

surface area, reabsorption, 99%

Microvilli in PCT are finger-like projections significantly increase the _________ to enhance ________ efficiency, returning, for example, ____% of filtered substances back into the bloodstream

Loop of Henle

establishes osmotic gradient for water reabsorption

- connects descending and ascending tubes, dipping into medulla

Descending tube (limb)

descends into the medulla, THIN, alternates between thick and thin segments

🌟 Permeable to water

- simple squamous epithelium

Ascending tube (limb)

ascends from medulla, THICK, alternates between thick and thin segments

🌟 Permeable to solutes, impermeable to water (water does not come out, only Na and Cl)

- simple squamous epithelium

Distal convoluted tubule (DCT)

Regulates ion balance

- simple cuboidal epithelium WITHOUT microvilli

Proximal

Which tubule has microvilli?

Collecting duct

Several nephrons empty into each collecting duct; Final regulation of urine composition

- urine must pass through on its way to the ureter.

- where water reabsorption is regulated via antidiuretic hormone (ADH)???

proximal convoluted tubule

Which region of the renal tubule is the most active in terms of filtrate processing?

Principal cells

conducting duct cells that adjust urine to regulate body's water, Na⁺, and K⁺ balance

Intercalated cells

conducting duct cells that regulate acid-base (pH) balance through HCO3- and H+

principal cells and intercalated cells

collecting duct cells include

water, Na⁺, and K⁺ balance

what do principle cells regulate?