Bootcamp.com - Excretory System

what is the primary role of the excretory system?

to filter out metabolic wastes from the body and eliminate them as urine

the excretory system also aids the body in retaining water and solutes

how many kidneys do humans have?

2

the outer portion portion of the kidney is called the ______ , and this is where blood enters

cortex

the middle portion of the kidney is called the ______

medulla

the very inner portion of the kidney is called the ______, and this is where filtrate exits the kidney

pelvis

a ______ is the single, functional unit of the kidney

nephron

kidneys are made of thousands of individual nephrons!

what are the 4 main processes that occur in the kidneys?

filtration; reabsorption; secretion; excretion

the excretory process begins when blood flows from the body and into the ______ artery, which branches off into the ______. From there it is led into the ______

renal artery (interlobular artery is an accepted answer too) --> afferent arteriole --> glomerulus

the ______ is a ball/collection of blood vessels located in the renal cortex of the kidney

glomerulus

the glomerulus is strategically located adjacent to the ______

Bowman's capsule

together, the glomerulus and Bowman's capsule are known as the ______

renal corpuscle

the substances that filter from the blood and into the Bowman's capsule are known as ______

filtrate

smaller substances can pass into the Bowman's capsule while the larger substances that cannot pass into the Bowman's capsule remain in the glomerulus. This process is called ______

filtration

the glomerulus acts like a sieve - it allows small substances (like _______ and ______) to pass into the Bowman's capsule while it keeps larger substances (like ______ and ______) in the blood

water; solutes; proteins; blood cells

the Bowman's capsule has ______ (hint: long, foot-like processes) that wrap around the glomerulus

podocytes (podo = foot or foot-like part)

the podocytes form ______ (hint: 'window' or 'opening'). Some of these slits are large enough for certain small substances to pass through but small enough to prevent other large ones from passing through the Bowman's capsule

fenestrations (fenestra = window; opening)

blood within the glomerulus leaves the renal corpuscle via the ______ _______

efferent arteriole

the efferent arteriole goes on to form a set of capillaries called the ______ capillaries

peritubular

the ______ capillaries surround the different tubules of the nephron and exchange water, salts, and other important molecules with them. This modifies the content of the filtrate through processes of ______ and ______

peritubular;

reabsorption; secretion

what is the mnemonic to remember the order of the afferent arteriole vs. the efferent arteriole in the kidney?

A comes before E in the alphabet, so the Afferent arteriole comes before the Efferent arteriole in the kidney (afferent enters and efferent leaves)

the process of the removal of water and solutes from filtrate back into the blood vasculature is called ______

reabsorption

reabsorption occurs from the ______ up to and including the ______

proximal convoluted tubule (predominantly); collecting duct

filtrate flows from the Bowman's capsule to the ______, then into the ______

proximal convoluted tubule; loop of Henle (descending limb is also an acceptable answer)

the _____ is the part of the nephron that descends from the cortex of the kidney to the medulla

loop of Henle

the descending limb of the loop of Henle has a _____ permeability to water and _____ permeability to solutes

high; low

the ______ limb of the loop of Henle has a high permeability to water and low permeability to solutes

descending

as filtrate travels down the descending limb it becomes ______ concentrated

more

(because water leaves the filtrate)

the water that leaves the descending limb is absorbed back into the blood supply by the ______, which are blood capillaries that run adjacent and parallel to the loop of Henle

vasa recta

this is our body's way of reabsorbing and retaining water!

the ascending limb of the loop of Henle has a very ______ permeability to water and ______ permeability to solutes

low; high

the ______ limb of the loop of Henle has a very low permeability to water and high permeability to solutes

ascending

as filtrate travels up the ascending limb it becomes ______ concentrated

less (because solutes leave the filtrate)

the solutes that leave the ascending limb are absorbed back into the blood supply by the ______, which are blood capillaries that run adjacent and parallel to the loop of Henle

vasa recta

this is our body's way of reabsorbing and retaining important salts

the process of the transfer of solutions from the blood vasculature directly into the nephron tubule filtrate secretion is called ______

secretion

via the process of ______ certain (usually harmful) substances are extracted from the blood, specially from the ______ capillaries, and taken up by the nephrons directly

secretion; peritubular

the proximal convoluted tubule is located between the ______ and the _____ of the loop of Henle

renal corpuscle (Bowman's capsule is an acceptable answer too); descending limb

the distal convoluted tubule is located between the ______ of the loop of Henle and the ______

ascending limb; collecting duct

the process by which the filtrate (after filtration, reabsorption and secretion have occurred) is removed from the body as urine is called ______

excretion

After filtration, reabsorption, and secretion, the filtrate is called ______ and is excreted

urine

the ______ collects filtrate from several different nephrons. The ______ leads to the renal pelvis, and from there goes to the ______

collecting duct; collecting duct; ureter

the ______ is the connecting passageway between the kidneys and the urinary bladder

ureter

the _____ is where the urine is temporarily stored until the body signals for it to be excreted, and when this signal comes, the fluid flows to the ______

urinary bladder; urethra

the _____ is where the urine is excreted and exits the body

urethra

parathyroid hormone (PTH) ______ calcium levels in the blood

increases

parathyroid hormone (PTH) increases calcium levels in the blood by stimulating reabsorption of calcium in the ______ (hint: part of the kidney), and causing the ______ to release calcium

nephron tubules; bones

calcitonin _____ calcium levels in the blood

decreases

calcitonin lowers calcium levels in the blood by ______ reabsorption of calcium in the nephron tubules, and causing the ______ to retain calcium

inhibiting; bones

(calcitonin is released by the thyroid gland)

parathyroid hormone and calcitonin have the ______ effects on calcium levels in the blood

opposite

aldosterone is considered a _____ hormone, and is produced by the adrenal _____

mineralocorticoid; cortex

aldosterone functions to increase ______ and ______ reabsorption and to increase ______ secretion

increase sodium (Na+) and water (H2O) reabsorption; increase potassium (K+) secretion

aldosterone functions in the ______ of the nephron and in the ______

distal convoluted tubule; collecting duct

antidiuretic hormone (ADH/vasopressin) prevents ______ (production of urine)

diuresis = production of urine

antidiuretic hormone (ADH/vasopressin) is produced by the ______; however, it is stored in the ______

hypothalamus; posterior pituitary

the hypothalamus stimulates the ______ to release antidiuretic hormone (ADH/vasopressin) when the extracellular fluid volume is _____

posterior pituitary; low

antidiuretic hormone (ADH/vasopressin) causes ______to insert into the ______, which allows more water reabsorption

aquaporins; collecting duct

(less water goes into the urine, leading to very concentrated urine)

the special cells in the afferent arteriole near the glomerulus are called ______, and they can detect changes in blood pressure and sodium levels

juxtaglomerular cells (juxta = nearby)

when blood pressure or blood sodium is low, these cells release ______

renin

renin is an ______ which acts on ______ to activate it to the form angiotensin I

enzyme; angiotensinogen

a different enzyme called ______ acts on angiotensin I to convert it to ______, which is the active form of the hormone

angiotensin converting enzyme (ACE); angiotensin II

atrial natriuretic peptide (ANP), which is made by atrial cells in the heart, has what three main effects in order to reduce blood volume and pressure?

1. Increases the glomerular filtration rate (GFR)

2. Decreases sodium reabsorption and increase sodium excretion

3. Inhibits renin and the renin-angiotensin-aldosterone system (RAAS)

What is the excretion pathway?

• body

• renal artery

• afferent arteriole

• glomerulus

• bowlman’s capsule

• proximal convulted tube

• descending limb (absorb water)

• ascending limb (absorb solutes)

• distal convoluted dtube

• collecting duct

• renal pelvis

• ureter

• bladder

• urethra

What filter the blood and prepares urine for excretion?

kidney

What are the key kidney functions?

• regulates blood pressure

• regulates pH

• stimulates generation of RBC

What is the functional unit of the kidney?

nephorn

What are the main structures of the nephron?

• glomerulus

• proximal convoluted tubule

• loop of henle

• distal convoluted tubule

• collecting duct

What is the renal corpsucle?

• first structure of nephron and first site of blood entry

• contains glomerulus and bowman’s capsule

• site of filtration within renal cortex

• blood brought there by afferent arteriole

Where are the glomerulus and bowman’s capsule?

Renal corpuscle

what is the glomerulus?

• network of capillaries inside the nephron where blood filtration begins

• surronded by Bowma'n’s capsule

• inside renal corpuscle

What is Bowman’s capsule?

• encapsulates renal corpuscle of nephron

• surrounds glomerulus and collects filtrate produced when blood is filtered

What brings blood to the renal corpuscle?

afferent arteriole

What are podocytes?

• Cells in glomerulus that help form kidney’s filtration barrier

• foot-like

What is the efferent arteriole?

• blood vessel that exits renal corpuscle and forms capilarry networks

• can form peritubular capillaries or the vasa recta

What are peritubular tubes?

blood vessels surronding convoluted tubes; stem from efferent arteriole

What is the vasa recta?

blood vessels surronding the loop of henle; stem from efferent arteriole

What blood vessels surround the loop of henle?

vasa recta

What blood vessels surround the convoluted tubes?

peritubular capillaries

What makes the efferent arteriole more likely to form the peritubular capillaries around the convoluted tube?

deeper within cortex, away from medulla

What is the proximal convoluted tubule?

• site of majority of reabsorption into the blood in nephron

• reabsorption occurs via active transport

• reabsorbs sodium, chloride, 100% of glucose and amino acids

• Secretes H+

What does the proximal convoluted tube absorb?

sodium, choloride, glucose, amino acids

How is glucose reabsorbed in the proximal convoluted tube?

• cotransport with Na

• Na/K ATPase creates low Na+ in nephron, so Na+ wants to leave

• Na+ moves back into blood down its gradient, and glucose moves with it

what is the loop of henle?

• nephron tube that descends into the kidney medulla

• has two limbs, descending and ascending

• urea enters the filtrate

Describe the descending limb of the loop of henle

• descends into the medulla from the proximal convoluted tube

• permeable to water, so water flows out of the urine into the blood

• increases urine conc, decreasing vollume

Describe the ascending limb of the loop of henle

• ascending out of the medulla, connecting to the distal convoluted tube

• imperable to water, so ions and salts flow out of the urine into the blood

• decrease urine concentration

What limb of the loop of henle is permeable to water?

descending limb

What limb of the loop of henle bumps out sodium, potassium, and chloride?

ascending limb

What limb of the loop of henle dilutes the filtrate?

ascending

What is the distal convoluted tubule?

• reabsorbs Na and Cl-, secretes K+ and H+

• water follows reabsorb salts back into bloo

What is the collecting duct?

• long tube at end of nephron

• passively reaborbs water through aquaporins and secretes K+

• increases conc of urine

What is the pathway of urine post nephron?

• collecting duct

• renal pelvis

• ureter

• bladder

• urethra

Where in the nephron does the bulk passive reabsorption of water occur?

collecting duct

How can excretory hormones affect blood/filtrate?

• manipulate blood volume and blood pressure

• change conc of molecules and substrates within blood and filtrate

What is the Renin-Angiotensin-Aldosterone (RAS) system?

system of hormones tissues and organs that increase blood pressure in response to low blood pressure

What system increases blood pressure?

Renin-Angiotensin-Aldosterone (RAS) system

What are juxtaglomerular cells?

• modified smooth muscle cells associated with the afferent arteriole

• detect changes in blood pressure and volume

• release renin in times of low blood pressure

What is the afferent arteriole?

• brings blood to the glomerulus of the nephron

• filtered by podocytes

• has juxtaglomerular cells that detect changes in blood pressure and blood volume, and release renin

What releases renin in times of low blood pressure?

juxtaglomerular cells in afferent arteriole

What is renin?

• enzyme that converts angiotensinogen into angiotensin 1

• released from the liver

• made in response to low blood pressure or sympathetic NS

• released at juxtaglomerular cells in afferent arteriole

What releases angiotensinogen?

the liver

What is angiotensin converting enzyme (ACE)?

• enzyme that converts angiotensin 1 to angiotensin 2

• released from walls of blood vessels in the lungs

What is angiotensin 2?

• enzyme that increases blood pressure and volume

• formed from angiotensin by ACE

What converts angiotensin 1 to angiotensin 2?

angiotensin converting enzyme (ACE)