DAT Lymphatic and Digestive Systems Flashcards
Osmoregulation
maintenance of
osmotic pressure of fluids by control of
water and salt concentrations
Marine fish osmoregulation
body is hypotonic
to the environment → water is
constantly lost by osmosis, so these
fish are constantly drinking water,
rarely urinating, and secreting
accumulated salts through gills
freshwater fish osmoregulation
body is
hypertonic to the environment →
water moves in, so the fish are rarely
drinking water, constantly urinating,
and absorbing salt though gills
Annelids excretory system
excrete CO2 directly through
moist skin
Nephridia (metanephridia)
functional unit of excretion that occur
in pairs within each segment of
annelids (earthworms).
Platyhelminthes excretory system
possess flame cells/
flame bulbs, which are bundles of flame
cells that combine to form
protonephridia; they are distributed
along a branched tube system that
permeates the flatworm
Arthropods excretory system
CO2 is released from
tissue via trachea, which lead to the
external air via spiracles
Malpighian tubules
found in most
terrestrial arthropods and are
tubules that attach at the junction
between the midgut and the
hindgut. They collect body fluids
from the hemolymph that bathes
the cells. The fluids are deposited at
the junction of the midgut and
hindgut
what is nitrogenous waste usually converted to?
converted
to ammonia, which is also toxic.
4 places excretion occurs in humans
lungs, liver,
skin, and kidney:
Lungs
CO2 and H2O (gas) diffuse from
the blood and are continually exhaled
Liver
largest internal organ that
processes nitrogenous wastes, blood
pigment wastes, other chemicals,
produces urea via the urea cycle
Skin
sweat glands in the skin excrete
water and dissolved salts to regulate
body temperature
what is the largest overall organ
skin
Kidney
i. Excrete waste via the path - kidneys
→ ureter → bladder → urethra
ii. Maintain homeostasis of body fluid
volume and solute composition
iii. Regulate blood pressure
regions of the kidney
i. The outer cortex
ii. Inner medulla
iii. Renal pelvis which drains to the
ureter
nephrons
composed of a renal
corpuscle and renal tubule, and function to
reabsorb nutrients, salts, and water.
Renal corpuscle
contains
the glomerulus, which acts as a sieve, and
Bowman’s capsule, which encloses the
glomerulus.
2 arterioles of Bowmans capsule
an afferent
arteriole that leads into the glomerulus,
and an efferent arteriole that leads out of
the glomerulus
what happens in the renal corpuscle
Hydrostatic pressure forces plasma
through the fenestrations (small
pores) of the glomerular endothelium
and into Bowman’s capsule. These
fenestrations screen out blood cells
and large proteins from entering
Bowman’s capsule, After the efferent arteriole passes out
of the glomerulus, it just webs around
the entire nephron structure as the
peritubular capillaries (which surround
the proximal convoluted tubule and
distal convoluted tubule and reabsorb
materials) and vasa recta (which
surrounds the Loop of Henle in the
kidney’s medulla and maintains the
concentration gradient) before
dumping back into the renal branch
of the renal vein
When substances are reabsorbed from
the tubules (or secreted into them), it takes place in…
the interstitium. It is this network of capillaries that lets
us reabsorb into/secrete from the blood.
the renal corpuscle leads to…
Renal tubule
components of the renal tubule
Proximal convoluted tubule (PCT), Loop of Henle, Distal convoluted tubule, Collecting duct
Proximal convoluted tubule (PCT)
where active reabsorption of almost
all glucose, amino acids, and some
NaCl, as well as passive reabsorption
of K+ and HCO3
-, begins. Water
follows these ions out so the cortex is
not salty. Most reabsorption takes
place here.
Loop of Henle compnenets
ascending loop and descending loop
largest component of the nephron?
loop of henle
Descending loop
only
permeable to water (but this
water is picked up by the vasa
recta so the medulla stays salty)
via lots of aquaporins. The
solute concentration in the tube
increases as a result
Ascending loop
makes the
renal medulla salty: first
passively and then actively by
pumping out NaCl. The
ascending loop is also
impermeable to water! Solute
concentration in the tube
decreases as a result.
Distal convoluted tubule
(DCT)
more reabsorption of
glucose, ions and water occurs here
so the cortex isn’t salty.
Collecting duct
collects the
remaining filtrate. What happens here
(concentrated or dilute urine) is highly
dependent on what hormones are
acting on it.
Path of urea through collecting duct:
- Urea first descends to the medulla
(salty part) where antidiuretic
hormones (ADH/vasopressin) can
make more water leave from urine
by increasing permeability of the collecting duct (via increased
aquaporins) → urine is even more
concentrated. Note that one
collecting duct is shared by many
nephrons.
entire process of urine formation can be
summarized in four overarching steps:2. Aldosterone can also act on the
collecting duct by increasing Na+
reabsorption, resulting in water
passively following Na+ - By the time urine emerges, it usually
has varying amounts of: H2O, urea,
NaCl, K+, and creatinine
entire process of urine formation can be
summarized in four overarching steps:
filtration,
reabsorption, secretion, and concentration
filtration (urine formation)
the fluid that goes through
the glomerulus (afferent arteriole →
glomerulus → efferent arteriole) to the
rest of the nephron is called filtrate,
which is pushed into Bowman’s capsule.
Particles that are too large to filter
through the glomerulus (such as blood
cells or albumin) remain in the circulatory
system.
i. This is a passive process that is driven
by the hydrostatic pressure of blood.
Reabsorption
glucose, salts, and amino
acids are reabsorbed from filtrate and
return to the blood. This process takes
place primarily in the PCT via active
transport.
Secretion
substances such as acids,
bases, ammonia, drugs, and ions are
secreted by both passive and active
transport from the peritubular capillaries
and into the nephron
Concentration
when we’re dehydrated,
the volume of fluid in the bloodstream is
low, so we need to make small amounts
of concentrated urine (and increase our
blood fluids). ADH prevents water loss; it
increases water retention by making the
collecting duct more permeable to water.
When blood pressure is low, aldosterone
increases reabsorption of Na+ by the
DCT and collecting duct, which increases
water retention
where does filtration occur?
renal corpuscle
where does reabsorption/secretion occur?
PCT
filter becomes more conc as it moves thru what part of loop of henle
down loop
where does DCT dump into
collecting duct
macula densa,
monitor the
filtrate pressure in the DCT.
Osmolarity Gradient
created by the entering and exiting of
solutes, and increases from the cortex to the
medulla
Aquatic animals nitrogenous waste
excrete NH3 and
NH4 directly into the water
