DAT bio chapter 11.9 excretory system

Question 1

What is excretion

Answer 1

filtering out of metabolic wastes
from the body’s fluids and eliminating them as
urine.

Question 2

How many kidneys do humans havw

Answer 2

2

Question 3

Structure of kidney

Answer 3

a cortex (outer portion where blood enters
the kidney), a medulla (middle portion), and a
pelvis (inner portion where filtrate exits the
kidney).

Question 4

What is a nephron

Answer 4

a single, functional unit of a kidney.

Kidney is made up of thousands of these nephrons

Question 5

what are four main processes that occur in the

nephron:

Answer 5

1. Filtration
2. Reabsorption
3. Secretion
4. Excretion

Question 6

Why is the excretory system so important?

Answer 6

it helps expels urine and make sure the body retains the water and solutes it needs to survive

Question 7

Where does filtration occur?

Answer 7

in the cortex at the renal

corpuscle,.

Question 8

Renal corpuscle contains what

Answer 8

consists of the glomerulus and

the Bowman’s capsule.

Question 9

Filtration path way (look at the pictures

Answer 9

Blood enters from the
afferent arteriole into the glomerulus, which acts
as a sieve. Podocytes from the Bowman’s
capsule surround the glomerulus to form
fenestrations that allow small substances (water
and solutes) to be filtered into the Bowman’s
capsule while larger substances (proteins and
blood cells) remain in the blood. The glomerulus
exits the Bowman’s capsule via the efferent
arteriole, which goes on to form the peritubular
capillaries.

Question 10

How does Reabsorption happen in nephron?

Answer 10

The loop of Henle descends into the medulla
and has selective permeability. It is surrounded
by the vasa recta (capillaries running parallel to
the loop of Henle). Water is reabsorbed into the
blood as the filtrate travels down the
descending limb (filtrate becomes more
concentrated), and solutes are reabsorbed as the
filtrate travels up the ascending limb (filtrate
becomes less concentrated).

Question 11

What is secretion

Answer 11

transfer of solutions from the
blood vasculature directly into the nephron tubule
filtrate.

Question 12

where does secretion happen?

Answer 12

distal convoluted

tubule and the proximal convoluted tubule.

Question 13

How does excretion happen?

Answer 13

filtrate (now urine) travels from the
nephrons to the collecting duct, which leads to
the renal pelvis and then to the ureter.
The ureter connects the kidney to the bladder,
where urine is stored. When the signal is received,
urine is excreted from the bladder and the body
via the urethra.

Question 14

Parathyroid Hormone (PTH)

Answer 14

more
blood calcium. Stimulates calcium
reabsorption in the tubules, and indirect
stimulation of osteoclasts (more bone
breakdown)

Question 15

Calcitonin (hormone)

Answer 15

less blood calcium (calcitonin
tones down calcium). Inhibits calcium
reabsorption in the tubules, inhibits
osteoclasts (less bone breakdown)

Question 16

Renin Angiotensin Aldosterone
System:
Juxtaglomerular cells
renin

Answer 16

Juxtaglomerular cells can detect
changes in blood pressure and sodium
levels. When blood pressure or blood
sodium is low, these cells release renin.

Renin is an enzyme which acts on
angiotensinogen to activate it to the
form angiotensin I. Another enzyme
called Angiotensin Converting Enzyme
(ACE) acts on angiotensin I to convert it to
angiotensin II. Angiotensin II is the active
hormone.

Question 17

Angiotensin II effects on the body

Answer 17

It stimulates additional aldosterone
release from the adrenal gland cortex
(so aldosterone levels increase).
● It increases Na+ reabsorption from
the proximal tubule (and water will
follow the salt).
● It is a potent systemic
vasoconstrictor, causing vessels to
constrict and thereby increasing total
peripheral resistance (TPR).
● It makes the individual more thirsty:
so they drink more and increase their
blood liquid volume (increasing TPR).

Question 18

Aldosterone (hormone)
Is what
produced by what
function

Answer 18

is a mineralocorticoid
produced by the adrenal cortex. It
increases salt and water reabsorption and
potassium secretion in the distal tubules
and collecting ducts

Question 19

Antidiuretic hormone
Is what
produced by what
function

Answer 19

vasopressin
Hormone (aka ADH or
vasopressin). Released from the posterior
pituitary upon stimulation from the
hypothalamus. Causes aquaporins to
insert into the collecting duct of the
nephron and increases water reabsorption

Question 20

Atrial natriuretic peptide
Is what
produced by what
function

Answer 20

produced by atrial cells in response to atria
distension by increased blood volume and
pressure. ANP will reduce the blood
volume and blood pressure. It
accomplishes this by: Increasing the
glomerular filtration rate (GFR); decreasing
sodium reabsorption and increasing
sodium excretion; inhibiting renin and the
renin-angiotensin-aldosterone system
(RAAS).

Question 21

Together, the glomerulus and the bowmans capsule is known as

Answer 21

Renal corpuscle