Transcript Chapter 44 - Excretory

Chapter 25: Control of
the Internal Environment
NEW AIM: How do organisms deal with metabolic waste?
I. Excretion
A. removal of metabolic waste
i. Carbon dioxide
ii. Nitrogenous waste
a. produced from breakdown of proteins and nucleic acids
iii. Water
Chapter 25: Control of
the Internal Environment
NEW AIM: How do organisms deal with metabolic waste?
b. Forms of nitrogenous waste
1. Ammonia (NH3)
- highly toxic
- highly water soluble
- formed by deamination of AAs
- secreted by most aquatic animals
- Must be secreted immediately or will
denature proteins and cause death
Land animals do not have the luxury of being
able to secrete waste continuously due to water
loss…how do we get around this?
Adide: NH3 (ammonia) can get protonated to NH4+ (ammonium)
in aqueous solution and vice versa. NH3 < - - > NH4+ ; pKa = 9.23
Fig. 25.8
Chapter 25: Control of
the Internal Environment
NEW AIM: How do organisms deal with metabolic waste?
b. Forms of nitrogenous waste
2. Urea
- 100,000X less toxic than NH3
- Highly water soluble
- mammals, adult amphibians,
sharks, some fish
- convert NH3 to urea (occurs in
liver – site of deamination)
- urea travels in blood and is
removed by kidneys
- why don’t all organisms just make
urea?? It is not free, costs ATP
- certain toads switch back and forth
depending if they are in water where they
can get rid of NH3 quickly or on land.
Fig. 25.8
Chapter 25: Control of
the Internal Environment
NEW AIM: How do organisms deal with metabolic waste?
b. Forms of nitrogenous waste
2. Urea
- 100,000X less toxic than NH3
- Highly water soluble
- mammals, adult amphibians,
sharks, some fish
- convert NH3 to urea (liver –
site of deamination)
- urea travels in blood and is
removed by kidneys
- why don’t all organisms just make
urea?? It is not free, costs ATP
You thought Krebs and Calvin were awesome, but
what about THE UREA (ornithine) CYCLE…
Formation of urea requires many enzymes (which take lots of ATP
to make) and additional ATP to power endergonic reactions!!
Aside: This was the first metabolic cycle
discovered by…wait for it…Hans Krebs!!
Chapter 25: Control of
the Internal Environment
NEW AIM: How do organisms deal with metabolic waste?
b. Forms of nitrogenous waste
2. Urea
Compare hypothetical storage of NH3 to
storing urea in bladder.
Ammonia (NH3), cannot be stored at high
concentration as it is too toxic and would destroy the
bladder. Therefore, it must be gotten rid of
immediately
1. If you live on land you would need to constantly
be urinating to get rid of it and you would thus be
constantly losing water…dehydration (on top of
constantly urinating…).
2. If you live in water, you just let the ammonia
diffuse across the epithelium into the water…
Fig. 25.8
Chapter 25: Control of
the Internal Environment
NEW AIM: How do organisms deal with metabolic waste?
b. Forms of nitrogenous waste
2. Urea
What about birds (no bladder) or many
insects / reptiles that are highly susceptible
to drying out – desiccation)?
Fig. 25.8
Chapter 25: Control of
the Internal Environment
NEW AIM: How do organisms deal with metabolic waste?
b. Forms of nitrogenous waste
3. Uric acid
- relatively non-toxic
- Largely INSOLUBLE in water
- birds, insects, many reptiles, land
snails, amphibians in deserts
- secreted as a paste or dry powder
- costs a lot of ATP to make
- savings is in water
- great for external development
(egg) – why?
Birds don’t urinate!
Fig. 25.8
Chapter 25: Control of
the Internal Environment
NEW AIM: How do organisms deal with metabolic waste?
b. Forms of nitrogenous waste
Summary
Form of
nitrogenous
waste
toxicity
Solubility in
water
Energy cost
to make
NH3
(ammonia)
high
high
none
urea
low
high
high
Uric acid
Very low
low
Very high
Fig. 25.8
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
II. Excretion in other organisms
A. Protists
- diffusion through membrane
- ammonia and CO2
- Some use contractile vacuoles to remove water waste
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
II. Excretion in other organisms
B. Cnidaria (hydra)
- entire body in contact with water
- diffusion of ammonia and CO2
directly into surrounding water
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
II. Excretion in other organisms
C. Annelida (Earthworm)
- Nephridia = excretory organs of Earthworm
- one pair (2) in each segment
- excrete urine (urea, ammonia, salts dissolved in water)
out the nephridopores
- CO2 excreted through skin (skin-breathers)
Body fluid from one segment containing waste
enters the funnel of the nephridia in the next
segment. Capillaries surround the nephridia. Some
of the solutes like salts, and water (the solvent of
course) diffuse back into the blood (reabsorbed).
The fluid, now mostly waste products like urea and
ammonia dissolved in water, continues to the
bladderlike storage organ and will then be excreted
through the nephridopores.
(nephridopores)
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
II. Excretion in other organisms
F. Arthropod (Grasshopper)
- CO2 diffuses into tracheal tubes and expelled through
spiracles
- Malpighian tubules = excretory organs closely associated
with the intestines that removes uric acid and excess salts
from hemolymph and put it into the intestines…
- excretes URIC ACID with fecal matter
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
II. Excretion in other organisms
Summary
Organism
Form of
nitrogenous
waste
Method of
excretion
Protist
NH3 (ammonia)
diffusion
cnidaria
NH3
diffusion
annelida
Urea, NH3
nephridia
arthropoda
Uric Acid
Malpighian
tubules
Humans
Urea
kidneys
Chapter 25: Control of
the Internal Environment
NEW AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
Fig. 25.9
In addition:
*LIVER - makes urea from ammonia from deamination of amino acids
**Skin (urea with sweat) and lungs (CO2) also involved in excretion
Chapter 25: Control of
the Internal Environment
NEW AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
A. Kidneys
i. Site of urine formation
ii. maintains the homeostatic balance of blood
1. Regulates metabolic waste
-filters out metabolites (urea)
2. Regulates osmolarity
- filters out minerals (salts) /water
3. Regulates blood pressure
4. Regulates pH
iii. 1100-2000L of blood filtered
per day
Fig. 25.9
Chapter 25: Control of
the Internal Environment
NEW AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
B. Flow of the excretory system
i. Blood enter via renal artery
ii. Urea, water and salts extracted
by nephrons of kidneys (filtrate)
iii. Filtrate drains into renal pelvis
(urine now) -> ureter -> bladder ->
urethra -> toilet
iv. Blood leaves via renal vein
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
C. How does the kidney extract filtrate?
1. The Nephron
i. Functional unit of the kidney
ii. ~1,000,000 per kidney
Fig. 25.9
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
C. How does the kidney extract filtrate?
1. The Nephron
i. Functional unit of the kidney (tiny filtering unit)
ii. ~1,000,000 per kidney
iii. Each extracts tiny amount of filtrate
Fig. 25.9
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
C. How does the kidney extract filtrate?
1. The Nephron
** Fig. 25.9
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
C. How does the kidney
extract filtrate?
1. The Nephron
- Flow chart through nephron
Fig. 25.9
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Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
C. nephron
Practice Labeling
http://www.biologymad.com/resources/kidney.swf
Fig. 25.9
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
C. nephron
Urine is produced in 4 major processes
Fig. 25.10
IMPORTANT: Water, urea, salts, monomers, toxins, etc… are forced out of the glomerulus
capillaries by high blood pressure into Bowman’s capsule and enter the nephron tubule nonselectively. The only selective filter is the size of the molecule. Glucose and smaller enters
automatically. The kidney can only control what is taken back (reabsorbed) into the blood, NOT
what goes into Bowman’s and the nephron tubule!!
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
C. nephron
A closer look at urine formation
Fig. 25.11
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
A diuretic is any drug that elevates the rate of urination.
III. Human Excretory System
D. Regulating the nephron (water reabsorption)
i. Under hormonal control
ii. The kidneys regulates blood osmolarity (solute concentration of blood)
a. If blood is hypertonic, cells will lose water and crenate.
b. If blood is hypotonic, cells will gain water and lyse.
- The kidney must controls how much water is in the blood
by removing it or not removing it from the nephron tubule…
****By default, monomers and smaller will enter Bowmans. The only selecive
criteria is size!! The kidney cannot stop these molecules from entering!!
Therefore it can only control what it takes back. If you are dehydrated,
hypertonic, it will take back water. If your blood is hypotonic, they will NOT
take back water. It is all about reabsorption.
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
A diuretic is any drug that elevates the rate of urination.
III. Human Excretory System
D. Regulating the nephron (water reabsorption)
i. Under hormonal control
ii. The kidneys regulates blood osmolarity (solute concentration of blood)
a. If blood is hypertonic, cells will lose water and crenate.
b. If blood is hypotonic, cells will gain water and lyse.
- The kidney must controls how much water is in the blood
by removing it or not removing it from the nephron tubule…
iii. Kidneys also regulate blood pressure (BP)
- BP is controlled by controlling blood volume
- Low blood volume = low BP, add water to blood
- high blood volume = high BP, take water out of blood
- Renin – angiotensin – aldosterone system
Water reabsorption by the kidneys is contolled by AntiDiuretic Hormone (ADH), also called vasopressin
Diuresis = urination
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
D. Regulating the nephron (water reabsorption)
iv. How does ADH accomplish this?
-Solute sensor cells are located in the hypothalamus of the brain
(ex. too little solute = too much water; BP to high = too much water)
-What if you eat a lot of salty food (food
high in sodium) and your blood volume
increases because ADH is secreted and
your kidneys are reabsorbing water from
the nephron tubules to maintain the
osmotic balance so your cells do not
crenate?
-Your blood pressure will be high and your kidneys
really can’t do anything about it because if they
remove water, the blood will become hypertonic
relative to your cells…
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
D. Regulating the nephron (water reabsorption)
iv. How does ADH accomplish this?
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
D. Regulating the nephron (water reabsorption)
Alcohol inhibits release of ADH
1. Drink alcohol,
2. Inhibit ADH release
3. Water not reabsorbed from nephron
tubule
4. Urinate a lot.
5. Dehydration occurs…
Caffeine has the same affect
Therefore alcohol and caffeine are
called diuretics (make you pee)
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
D. Regulating the nephron (water reabsorption)
i. Under hormonal control
ii. Solute sensors in brain (too little solute = too much water)
iii. Regulates blood pressure
High [water] = high BP
Negative feedback
Alcohol inhibits release
of ADH
ADH = vasopressin
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
D. dialysis
i. Kidneys are damaged
a. toxic waste builds up, unregulated BP, unregulated pH,
unregulated salt/water concentration
b. causes
- hypertension and diabetes (60%)
-prolonged use of pain relievers, alcohol, other drugs and
medicines
ii. Dialysis machine “Artificial kidney”
a. Dialysis = separation
b. 3 times a week, 4 to 6 hours a session
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
D. dialysis
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
E. gout
i. Hyperuricemia
- elevated levels or uric acid in blood (we do
make some uric acid when we break down
purines)
- causes
1. Accelerated generation of uric acid
2. Impaired excretion in kidney
3. Consumption of purine-rich diet as uric
acid is breakdown product of purines
- crystals of uric acid can form in joints (pain) = GOUT
Humans make a small amount of uric acid when we break down adenine and
guanine (purines), which is put into the urine by the kidneys.
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
E. gout
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
III. Human Excretory System
F. Kidney Stones (for Joel)
i. AKA renal calculi
ii. Form inside kidneys or bladder
iii. Most made of Calcium oxalate crystals
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
IV. The liver
A. More functions than any other organ
i. Bile production
ii. Deamination and synthesis of urea from ammonia
iii. Detox of alcohol and other drugs
iv. Synthesize blood clotting factors
v. Involved in blood glucose regulation (stores glucose as glycogen)
vi. Forms lipoproteins
- transport fat and cholesterol to body tissues
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
IV. The liver
A. More functions than any other organ
i. Bile production
ii. synthesis of urea from ammonia
iii. Detox of alcohol and other drugs
iv. Synthesize blood clotting factors
vi. Forms lipoproteins
Lipoprotein (ex. LDL)
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
IV. The liver
A. More functions than any other organ
i. Bile production
ii. Deamination and synthesis of urea from ammonia
iii. Detox of alcohol and other drugs
iv. Synthesize blood clotting factors
v. Involved in blood glucose regulation (stores glucose as glycogen)
vi. Forms lipoproteins
- transport fat and cholesterol to body tissues
So where do you think your blood goes straight after absorbing
molecules at the small intestines?
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
IV. The liver
A. More functions than any other organ
First “stop”…the liver.
The hepatic portal express
- nutrients and harmful chemicals go
straight to liver from duodenum
- detox before entering body, and
modify nutrients (deamination,
lipoprotein synthesis, etc…)
Fig. 25.13
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
IV. The Skin (not in book)
Fig. 25.13
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
IV. The Skin
a. epidermis
i. Top layer of skin
ii. Protects body, keeps in moisture
iii. Couple layers of living cells topped
with many layers of dead cells
iv. Holds skin pigment
Chapter 25: Control of
the Internal Environment
AIM: How do organisms deal with metabolic waste?
IV. The Skin
b. dermis
i. Layer underneath epidermis
ii. Connective tissue
iii. Nerve endings for heat/pressure/pain
iv. Exocrine Glands (pores)
- sebaceous (oil) gland - associated with hair
- eccrine (sweat) gland
-sweat = 99% water, bit of NaCl, waste products (urea)
- thermoregulation, excretion, protection (slightly acidic to
prevent bacterial and fungal growth)
v. Blood vessels