Urinary System (in progress)

SBI4U - Howes

The ________ is the major organ involved in ________ ___________

Kidney, waste removal

Deamination occurs where?

The liver

in the liver, the amino group is converted into ________, then quickly converted into _____, where it enters the ____ and is removed by the kidney

ammonia, urea, blood

function of the excretory system

to filter the body’s blood!

what else is the excretory system critical in?

• removing nitrogenous waste

• balancing blood pH

• maintaining water balance

• nutrient recovery

the goal of urine formation is to:

get rid of toxic and excess substances while keeping as much water, ions, and nutrients as possible

Filtration

• blood moves to glomerulus and dissolved solutes (small molecules) pass through into Bowman’s capsule

• plasma, platelets, and blood cells are too big to move into Bowman’s capsule (stay in the blood)

• Driven by high blood pressure across a selectively permeable membrane

Secretion

the movement of wastes from blood ➠ the nephron

Secretion involves _____ transport

active

Secretion occurs mainly in the _____ __________ ____

distal convoluted tubule

Reabsorption

ions and molecuiles move OUT of nephron (into interstitial fluid)

purpose of reabsorption

to get rid of urea, excess molecules, toxins, and keep water, important salts, and nutrients

reabsorption involves both ______ & ______ transport

passive, active

label the kidney

A: Renal Artery

B: Renal Vein

C: Ureter

D: Towards bladder

E: Calyces

F: Renal Pelvis

G: Renal Medulla

H: Renal Cortex

Renal Artery vs Renal Vein

Artery is smaller: thicker walls = high pressure

Vein is wider: thinner walls

Identify

nephron!

Each kidney contains about ____________ nephrons — the _________ ___ of the kidney

1 million, functional unit

Glomerulus

a network of capillaries inside the bowman’s capsule

⇨ performs first steps of filtration

The glomerulus has very _____ ________, which forces the liquid portion of ______ into the _________

high pressure, blood, nephron

Bowman’s Capsule

a small folded structure that encircles the glomerulus

⇨ during the first steps of filtration, small molecules enter bowman’s capsule from the glomerulus

Blood is supplied to the glomerulus via the ______ ________ and exits via the ________ _________

Afferent Arteriole, Efferent Artiole

the efferent arteriole carries blood to the ______________ ______________

peritubular capillaries

Peritubular Capillaries

a net of capillaries that allow for reabsorbtion of ions and minerals back kinto bloodstream

After the Bowman’s capsule, the _______ (product of filtration) enters the ________ __________ ______, which is within the ______ ______

filtrate, proximal convoluted tubule, renal cortex

After the PCT, the tubule descends into the _______, forming the _________ __ _______

medulla, loop of henle

After ascending the loop of henle, the urine enters the _____ __________ _______, which drains it into a system of __________ ______

distal convoluted tubule, collecting ducts

The collecting ducts lead to the ______ ____, which then leads to the _______

renal pelvis, ureter

What molecules enter the nephron during filtration? Which ones remain in the blood?

• water

• NaCl

• glucose

• urea

🩸 large molecules like blood cells, platelets, plasma, and proteins remain in the blood

What molecules get reabsorbed in the PCT? Which are active and which are passive?

• bicarbonate

• glucose (active)

• Na⁺ and Cl^- (active)

• water (passive)

Besides reabsorption, ________ also occurs in the PCT: the _______ transport of ___ ions

secretion, active, H⁺

The descending loop of Henle is permeable to _____, meaning it is reabsorbed via ______ transport

water, passive

The start of the ascending loop of Henle is permeable to ______, meaning it is reabsorbed via ________ transport

NaCl, passive

At the top of the _________ loop of Henle, it is no longer permeable — therefore NaCl must be reabsorbed via ________ transport

ascending, active