PNB Spring Quiz Prep - Renal System

What is the function of the renal system?

filters blood, removes waste, maintains homeostasis

What is the kidney?

high vascular; has many blood vessels

What is the main function of the kidney?

filter blood continuously to make urine

Why does the kidney require blood flow?

remove waste products (ex. urea)

What does the kidney help maintain?

water, salts, and pH

What is the result of having more blood vessels?

faster and more efficient filtering

What happens as blood moves through the kidney?

waste is removed, filtration occurs

What does the kidney remove?

metabolic and nitrogenous waste

What is the end product of amino acid metabolism?

urea

How is urea made?

body breaks down proteins for energy, and needs to be removed from the blood because it’s toxic in high amounts

What is a type of nitrogenous waste?

urea

What are the 5 renal functions?

excretion, ion regulation, osmolarity & pH, endocrine, BP regulation

What is excretion?

kidneys remove waste and extra substances from the blood and send them out in urine

What is excreted from the kidneys?

drugs, organic molecules, and xenobiotics

What are organic molecules the kidneys excrete?

natural compounds like urea, creatinine, and small metabolites

What are xenobiotics?

foreign chemicals the body doesn’t normally produce (like pollutants or toxins)

Why is the process of excretion important?

helps keep the blood clean and the body safe

What is Na+ ion regulation?

controls blood volume and pressure

What is K+ ion regulation?

keeps heart and muscles working properly

What is H+ ion regulation?

maintains blood pH

What is Ca²⁺ ion regulation?

important for bones, muscles, and nerve signaling

What is Cl- ion regulation?

helps maintain fluid balance and pH

What is HCO₃- ion regulation?

buffers blood pH

What is PO₄^3- ion regulation?

needed for energy and bone health

What is H₂O ion regulation?

regulates hydration and blood pressure

What is renal homeostasis regulation?

kidneys keep the body’s internal environment stable

What does the renal homeostasis regulation control?

fluid balance; regulates water to maintain blood volume and pressure

How do the kidneys control the concentration of solutes in the blood (osmolarity)?

adjust how much water and salts are reabsorbed or excreted

What is the result of high blood osmolarity?

kidneys reabsorb more water to dilute blood

What is the result of low blood osmolarity?

kidneys excrete excess water to concentrate blood

What is the first step of long-term blood pressure regulation?

adjusts fluid volume

What is the result of the body keeping more water?

blood volume increase, blood pressure goes up

What is the result of the kidneys removing more water (urine)?

blood volume decreases, blood pressure goes down

What does more fluid in the bloodstream result in?

more pressure in the pipes

What is the second step of long-term blood pressure regulation?

control sodium (salt) balance

What does sodium pull?

water with it

What is the result of the kidneys keeping more sodium?

water stays too, BP increases

What is the result of the kidneys getting rid of sodium?

water follows, BP decreases

What is the third step of long-term blood pressure regulation?

uses hormones (RAAS system)

What is the result of BP being too low?

kidneys release a hormone called renin

What does renin convert into?

angiotensin II

What does angiotensin II convert into?

aldosterone

What does the narrowing of blood vessels result in?

raises BP

What is the result of the kidneys keeping sodium and water?

increases blood volume, raises BP

What are the structures of the renal system?

kidney, ureter, bladder, urethra

What are the 3 functions of the kidney?

filtration, reabsorption, secretion

What is removed out of the blood during kidney filtration?

water, glucose, ions (Na+, K+, Cl-), urea (waste

What is kept in the blood during kidney filtration?

blood cells and large proteins

What is kidney reabsorption?

body takes back useful substances from the filtered fluid

What is reabsorbed into the kidney?

glucose, amino acids, water, sodium and other ions

What is kidney secretion?

additional wastes are actively moved from blood into nephron

What is secreted from the kidney?

H+ ions (help control pH), K+, drugs and toxins

What is filtration?

everything small gets pushed out of blood

What is reabsorption?

body takes back what is needs

What is secretion?

adds extra waste into urine

What are ureters?

two thin tubes that carry urine from each kidney to the bladder

What do ureters use to carry out their function?

peristalsis; push urine downward

What do walls of the ureter contain?

smooth muscle

What is the bladder?

hollow, muscular organ that stores urine until you’re ready to urinate

What does the bladder wall contain?

smooth muscle (aka detrusor muscle)

What happens as the urine fills the bladder?

bladder stretches and expands like a balloon

What is the urethra?

tube that carries urine from the bladder to the outside of the body

What is the main function of the urethra?

eliminate urine during urination

What hapens when the bladder contracts?

urine is pushed into the urethra; urine flows out of the body

What is the urine flow pathway?

kidney → ureter → bladder → urethra

What are the parts of the kidney?

cortex, medulla, calyces, nephron

What is the first part of the cortex?

outer cortex

What does the outer cortex contain?

glomeruli

What are glomeruli?

tiny blood-filtering units in nephrons

Where does blood filtration begin?

glomerulus

Where is plasma pushed?

into Bowman’s capsule

What is the outer cortex?

rich in blood vessels to supply the nephrons for filtration

What is the second part of the cortex?

juxtamedullary area (inner cortex near the medulla)

What is the juxtamedullary area?

located close to the medulla (inner part of the kidney)

What does the juxtamedullary contain?

juxtamedullary nephrons

What do juxtamedullary nephrons contain?

long loops of henle that extend deep into the medulla

What are juxtamedullary nephrons?

crucial for concentrating urine (reabsorbing water and salts efficiently)

What is the juxtamedullary area?

helps the kidney adjust water balance and control blood pressure

What is the medulla?

inner region of the kidney, located beneath the cortex

What does the medulla contain?

renal pyramids (cone-shaped structure)

What are renal pyramids?

made up of collecting ducts and loops of henle from the nephrons

What is the renal papilla?

tip of each pyramid; drains urine into a minor calyx

What is the function of the medulla?

helps concentrate urine by reabsorbing water and salts as urine moves through the pyramid