Download Chapters 41 42 44 (digestion, circulatory, respiratory, excretory)

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Invertebrate Phyla
Porifera = sponges
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Most are marine (=salt water)
Filled with pores: circulates water for nutrients, oxygen, getting rid of wastes
Cnideria = codenterates
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Jellyfish, hydra, sea anemone, coral
Mouth; no heart, blood, organs, anus
Platyhelminthes = flat worms
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Tape worm, liver flukes, planaria
Are endoparasites that live in the small intestine
Nematods = round worms
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Trichina, hook work, pin work, ascaris, heart worm
1st to have a mouth + an anus
2 separate sexes
Annelids = segmented worms
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Ectoparasites: earthworm, leeches, clam worm
Mouth + anus
1st to have a circulatory system: carry nutrients and water and get rid of waste
- Gives them an advantage: have a specific way of delivering nutrients and removing waste
Mollusks or Mollusca
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Gastropods: snail, slug
Bivalves: clams, scallops, mussels, oysters
Cephalopods: octopus, squid, nautil – have a closed circulation system, nervous system
Arthropods
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Have an exoskeleton of chitin, joint appendages (mouth, antennae, legs, bodies)
Insets: bee, butterflies, beetles, housefly
Arachnids: spider, tick, mite, scorpions
Crustaceans: crabs, lobster, shrimp, crayfish, silverfish
Echinoderms
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Starfish, sea urchin, sea cucumber, brittle star, sand dollars
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Chapter 41: Animal Nutrition
Comparative Anatomy
Earthworm: 2 ended digestive system (mouth, crop/gizzard, anus)
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The alimentary canal of an earthworm includes a muscular pharynx that sucks food in through
the mouth. Food passes through the esophagus.
Crop: where food is stored and moistened
Gizzard: where mechanical digestion occurs; pulverizes food
Further digestion and absorption occur in the intestine, which has a dorsal fold, the typhlosole,
that increases the surface area for absorption
Grasshopper
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A grasshopper has several digestive chambers grouped into 3 main regions: a foregut (with an
esophagus and crop), a midgut, and a hindgut
Food is moistened and stored in the crop, but most digestion occurs in the midgut.
Gastric cecae pouches extending from the beginning of the midgut, fuction in digestion and
absoption
Bird
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Many birds have 3 separate chambers – the crop, stomach, and gizzard – where food is
pulverized and churned before passing into the intestine
A bird’s crop and gizzard function very much like those of an earthworm.
In birds, most chemical digestion and absorption of nutrients occur in the intestine
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Digestion in Mammals
Digestion starts in the oral cavity, or mouth
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pH is 7 (neutral because it’s mostly water)
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Physical digestion:
1. Teeth: chewing action which increases the surface area  able to be broken down faster
2. Tongue: allows food to come in contact with the saliva; moves food around
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Chemical digestion:
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salivary glands: contain digestive enzymes that begins chemical digestion
salivary amylase: an enzyme that digests amylose to shorter polysaccharides and maltose
When you swallow food, it passes over the epiglottis
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Epiglottis: a trapdoor-like tissue that normally prevents food and liquids from entering the
larynx or trachea (or airway)
Food then enters the esophagus
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Esophagus: a muscular tube connecting the mouth to the stomach
No digestion
Made of smooth muscle
Carries food to the stomach through peristalsis: wavelike contractions that move food from the
mouth to the stomach
Food then passes through the cardiac sphincter
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Cardiac sphincter: the structure that regulates the movement of food from the esophagus into
the stomach
Is a ring-like muscle that acts like a valve relaxes, releasing small amounts of partially digested
food into the stomach
The food then reaches the stomach
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Come
from
gastric
glands
Made of smooth muscle
Infolding or ridges in the stomach called rugi
- increases surface tension  more gastric glands
- leaves room for expansion
Digestion of proteins takes place in the stomach
pH is 2-3
- denatures the salivary amylase
- the enzymes that break down proteins require a strongly acidic environment
this acidic condition is provided by the stomach glands that secrete HCl
 the cells of the stomach lining aren’t harmed because some of them secrete a thick,
protective coat of mucus
The presence of food secretes gastrin which secretes HCl which secretes pepsin
gastrin: secretes HCl
HCl: makes the stomach really acidic which means carbs can’t be digested here; secretes pepsin
pepsin: breaks peptide bonds – takes polypeptide chains and breaks then into amino acids
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-pepsinogen is pepsin’s inactive form
Food then passes through the pyloric sphincter
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pyloric sphincter: the structure that allows food out of the stomach and into the small intestine
Accessory organs provide digestive material to break down substances even though
they aren’t part of the digestive tract
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Accessory organs are organs that aren’t a part of the digestive tract but are important in
secreting chemicals that help to digest food and contribute digestive juices to the small intestine
through ducts:
 Liver (secretions enter gallbladder)
- Breaks down toxins, detoxifies blood
- Produces bile: emulsifies fats – large fat droplets broken down into smaller fat droplets
- Bile duct: little tubes that transport bile from the liver to the gallbladder
- The presence of food is the signal to release chemicals from the gallbladder: it’s a
feedback loop
 Gallbladder (secretions enter small intestine)
- Stores bile
 Pancreas (secretions enter small intestine)
- pH of 7-8
- Secretes pancreatic bicarbonate: raises pH to active enzymes
- Secretes pancreatic amylase – breaks down amylose into glucose
- Secretes lipase – breaks lipids into 1 glycerol and 3 fatty acids
- Secretes trypsin – breaks down small polypeptides into amino acids
Food then enters the small intestine
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pH of 7-8
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1st third involved in chemical digestion of carbs, lipids, and proteins
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2nd third is involved in absorption of nutrients
- Nutrients diffuse through the brush border to villi
- The brush border secretes chemicals
- They move through epithelial cells to capillaries
- Villi: dramatically increase the surface area to absorb nutrients
- Villi contain capillaries: tiny, thin blood vessels that serve as entry points to the bloodstream
and absorb glucose and amino acids
Exchange of nutrients occurs through interstitial fluid to the plasma (liquid part) of the blood
- Interstitial fluid: the medium through which exchange occurs through blood supply and
cells
- The blood carries the molecules to all the cells where they are used in metabolism
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Any undigested material eventually passes to the large intestine, where bacteria help
produce several vitamins, gases, and other compounds
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Reabsorbs water
Collects undigested wastes
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The vitamins and much of the water that was mixed with the food are absorbed through the
walls of the large intestine
3 types of muscle:
1. Smooth: involuntary
2. Skeletal (striated): voluntary
3. Cardiac: involuntary
Enzymes and Such
Mouth
Carbohydrates: salivary amylase
(amylose  smaller polysaccharides, maltose)
Esophagus
Stomach
Proteins: pepsin (proteins  small polypeptides)
Liver
Lipids: bile (produced)
Gallbladder
Pancreas
Small
intestine
Lipids: bile (stored)
Carbohydrates: pancreatic amylase
Lipids: lipase
Carbs: pancreatic amylase (polysaccharides  maltose and disaccharides)
Carbs: disaccharidases (disaccharides  glucose)
Lipids: bile salts (fat globules  fat droplets)
Lipids: lipase (fat droplets  fatty acids + glycerol)
Proteins: trypsin and chymotrypsin (polypeptides  smaller polypeptides)
Proteins: dipeptidases (small polysaccharides  amino acids)
Nucleotides: nuclease (DNA + RNA  nucleotides)
Large
intestine
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Chapter 42: Circulation and Gas Exchange
The Circulatory System
Circulatory systems link exchange surface with cells throughout the body
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A cell’s aqueous environment must provide oxygen and nutrients and permit disposal of carbon
dioxide and metabolic wastes.
Diffusion allows transport of nutrients in all organisms.
However, because diffusion is too slow a process across distances more than a few millimeters,
most animals have organs that exchange materials with the environment and an internal
transport system to service body cells.
Gastrovascular Cavities
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Organisms without circulatory systems use diffusion to exchange nutrients
The central gastrovascular cavity inside the 2-cell thick body wall of cnidarians serves for both
digestion and transport of materials
The internal fluid exchanges directly with the aqueous environment through the single opening.
Flatworms also have gastrovascular cavities that branch throughout their thin flat body
Have cells and tissues but no organs
Open and Closed Circulatory Systems
 Open circulatory system (e.g. grasshopper)
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Most arthropods, molluscs, and invertebrates have an open system
Hemolymph: the body fluid that circulates spaces between organs, bathes the internal
tissues, providing for chemical exchange
 Closed circulatory system (e.g. earthworm)
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Annelids, cephalopods, and vertebrates; earthworm is one of the few invertebrates with a
closed system
Blood remains in vessels and materials are exchanged with interstitial fluid bathing cells
The circulatory systems of more complex animals consist of a pumping heart, circulatory
fluid, and blood vessels
In earthworms, they have aortic arches (instead of hearts) and muscle contractions move
fluids throughout the body: this is not very efficient so it doesn’t require as much ATP
Organization of Vertebrate Circulatory Systems
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Have closed circulatory systems which is more efficient
The heart is the central structure that pumps and moves the blood. Most of the blood is carried
to the lungs and then back to the heart.
In the cardiovascular system of vertebrates, arteries (which carry blood away from the heart)
branch into tiny arterioles within organs, which then divide into capillaries which infiltrate
tissues in networks called capillary beds.
Capillaries converge to form venules, which meet to form the veins that return blood to the
heart.
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The vertebrate heart has 1 or 2 atria which receive blood, and 1 or 2 ventricles which mump
blood out of the heart
 Fish
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2 chambered heart
The ventricle pumps blood to the gills, from which the oxygen-rich blood flows through
a vessel to capillary beds in the other organs
Veins return the oxygen-poor blood to the atrium.
Passage through 2 capillary beds slows the flow of blood, but body movements help to
maintain circulation.
 Amphibians
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Respiration through skin: lots of capillaries
3 chambered heart: 2 atriums, 1 ventricle  less efficient because the oxygenated and
deoxygenated blood may mix
Undergo metamorphosis
 Reptiles
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3 chambered heart
Has a partially divided ventricle that helps to separate blood flow through a pulmonary
circuit to the gas exchange tissues in the lungs and through a systematic circuit to the
body tissues
 Mammals and Birds
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Blood travels into the upper chamber  lower chamber  lungs (where it’s highly
oxygenated)  back to the heart
Have a septum to divide oxygen and deoxygenated blood
 Allows the maximum delivery of oxygen to all cells (the delivery of oxygen for
cellular respiration is the most efficient in birds and mammals)
Birds fly so they need a high metabolism powered by food and oxygen
The left side of the heart handles only oxygen rich blood, and the right receives and
pumps oxygen-poor blood.
The Heart
Mammalian Circulation
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The human heart is composed mostly of cardiac muscle
- Atria = upper chambers – thin walls
- Ventricles = lower chambers– thicker walls
The cardiac cycle consists of systole, the contraction, or pumping, phase of the heart and
diastole, the relaxation, or filling, phase
The cardiac output is the amount of blood pumped by ventricles per minute.
- It depends on heart rate and stroke volume, the amount of blood pumped every time heart
beats
Atrioventricular (AV) valves between each atrium and ventricle are snapped shut when blood is
forced against them as the ventricles contract
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Blood flow: artery  arterioles  capillaries  venuoles  veins
Nicotine and caffeine: increases heart beat
Maintaining the Heart’s Rhythmic Beat
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SA (sinoatrial) node, referred to as the “pacemaker,” generates wave of signals to contract.
- The heart is myogenic: innervates 1 patch of nervous tissue and then self stimulates
 The nerve impulse spreads from the SA node to the AV (atrioventricular) node
 SA node  atria contract  AV node  ventricles contract
 Purkinje network/bundle of his
Blood Vessel Structure and Function
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Arteries: bigger, deeper, more smooth muscle tissue
*Highest pressure
Veins: lower pressure, carries deoxygenated blood, superficial (closer to the surface), have oneway valves
Vasoconstriction: contraction of smooth muscles in arteriole walls  it increases resistance and
thus increases blood pressure
Vasodilation: relaxation of smooth muscles of arterioles  it increases blood flow into
arterioles and lowers blood pressure
(controlled by the medulla of the brain)
Precapillary sphincters: regulate blood flow in capillaries
Blood Composition
 Plasma (55% of the blood): water + electrolytes + plasmatic proteins
 Erythrocytes (red blood cells): transport oxygen and help transport carbon dioxide
 Leukocytes (white blood cells): defense and immunity
 Platelets: blood clotting
- Fibrin-network of clotting proteins
Respiratory System
 Gas exchange, or respiration, is the uptake of O2 from the environment and the discharge of CO2
to the environment
Respiratory Surfaces
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The respiratory surface, where gas exchange with the respiratory medium occurs, must be
moist, thin, and large enough to supply the whole body
In sponges, cnidarians, and flatworms, gas exchange takes place across the entire surface of the
body
In animals with denser bodies, a localized region of the body surface is usually specialized as a
respiratory surface with a thin, moist epithelium associated with a rich blood supply.
Most animals have an extensively branched or folded respiratory organ
Gills in Aquatic Animals
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Gills are out-foldings of the body surface, ranging from simple mumps on the echinoderms to
the more complex gills of molluscs, crustaceans, and fishes
Infolds to maximize surface area
Due to the low oxygen concentration in water environment, gills usually require ventilation, or
movement of the respiratory medium across the respiratory surface
Annelids, arthropod, echinoderms all use gills for respiration
Fish gills use a counter current exchange system, where the blood flows in the opposite
direction to water passing over the gills
- Blood is always less saturated with oxygen than water
- Maximizes amount of oxygen
Operculum covers gills
Gill filaments = increased surface area and are feathery
There is diffusion of oxygen from water to blood
Tracheal Systems in Insects
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Tracheal systems are tiny air tubes, which branch throughout the body and come into contact
with nearly every cell.
Enlarged portions of tracheae form air sacs near organs that require a large supply of oxygen
Thus, an insect’s open circulatory system doesn’t function in O2 and CO2
Air enters the tracheae through openings in the insect’s body surface
Lungs
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Lungs are respiratory surfaces restricted to one location from which oxygen is transported by
the circulatory system
The lungs of the mammals are located in the thoracic cavity
Air, entering through the nostrils, is filtered, warmed, humidified, and smelled in the nasal
cavity.
Air passes through the pharynx and enters the respiratory tract through the glottis.
The larynx moves up and tips the epiglottis over the glottis when food is swallowed.
The larynx functions as a voice-box in most mammals; exhaled air vibrates a pair of vocal chords
The trachea, or windpipe, branches into 2 bronchi which then branch repeatedly into
bronchioles within each lung.
Ciliated, mucus coated epithelium lines the major branches of the respiratory tree
Alveoli are air sacs encased in a web of capillaries at the tips of the tiniest bronchioles
Gas exchange takes place across their thin, moist epithelium. These tiny sacs are coated with
surfactants, which decrease surface tension and help keep them from sticking shut
How Birds Breathe
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4 chambered heart
Complex delivery system of oxygen because of high energy demands
Birds have air sacs on either side of their lungs that act as bellows to maintain air flow through
the lungs
Posterior air sacs  lungs  anterior air sacs
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Cross current exchange
Mammals
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Nasal cavity (filters, warms, and moistens air)
Pharynx
Larynx
Tracheae
Diaphragm
Contraction of the rib muscles and the diaphragm expands the chest cavity and the volume of
the lungs. Air pressure is reduced within this increased volume, and air is drawn into the lungs
Relaxation of the rib muscles and diaphragm compresses the lungs, increasing the pressure and
forcing air out.
C shaped rings of smooth muscle: keeps front open
Regulating Respiration
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Exercise is initiated
Increase in heart rate which increases blood flow
Increase in rate of cellular respiration which consumes oxygen and produces carbon dioxide
Increased carbon dioxide dissolves in the plasma of the blood to produce carbonic acid (H2CO3)
The blood pH goes down due to slightly acidic H2CO3
The breathing centers within the medulla send messages to the intercostals (muscles between
ribs) and diaphragm to increase the rate of contraction
- Chemoreceptors- regulate pH
- Baroreceptors- measure pressure
- Thermoreceptors-temperature
7. Increased respiratory rate allows more oxygen to be brought in and carbon dioxide to be
exhaled
8. Blood pH rises slightly due to less carbon dioxide
9. Chemoreceptors within the heart and brain send signals to the diaphragm to lower respiratory
rate
**This involves the autonomic nervous system**
Bohr effect: “loading/unloading” oxygen – gets picked up by hemoglobin and dropped off in the lungs
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Increase in carbon dioxide  decrease in oxygen concentration
Decrease in carbon dioxide  increase in oxygen concentration
Tracheophytes
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Have xylem (water) and phloem (sugar) tubes for transport of nutrients
 Similar to arteries, veins, and capillaries
3 types:
1. Gymnosperms (cones with naked seeds)
2. Ferns
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3. Angiosperms (flowers with seeds within fruit)
- Monocots: parallel veins; vascular tissue in rings (e.g. lilies, grasses like wheat and barley)
- (Eu)Dicots: network of veins; vascular tissue scattered
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Chapter 44: Osmoregulation and Excretion
Osmoregulation balances the uptake and loss of water and solutes
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Most marine invertebrates are osmoconformers
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Are isotonic in their surroundings
Most marine vertebrates are osmoregulators
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Regulate their internal osmolarity
Must get rid of excess water or take in water to offset osmotic loss
They lose water by osmosis and gain salt by diffusion (through gills) and by food
They balance water loss by drinking sea water and excreting salts
The Excretory System
Excretory organs:
Annelids (e.g. earthworm) – protonephridia
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Branched systems of closed tubules
Water and solutes from the interstitial fluid pass into the flame bulbs at the ends of the tubules
Insects and arthropods (e.g. grasshoppers) – malpighian tubes
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Excretory organs that secrete solutes from Hemolymph into the tubule which passes into the
rectum where most of the solutes are pumped back into the Hemolymph
Fish – kidneys/gills
Frog, reptile, bird, mammal – kidneys, ureters
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Mammals: ureters – bladder – urethra
Amphibians, reptiles, birds: ureters – cloaca
3 types of nitrogenous waste:
1. Ammonia
- Most toxic
- Aquatic animals excrete this – water washes it away
2. Uric acid
- Insects, land snails, and reptiles
3. Urea
- Least toxic
- Mammals, amphibians, sharks, and some marine fishes and turtles
 Nitrogenous waste comes from proteins and nucleic acids
 Nitrogenous waste is another way to get rid of carbon dioxide in the form of carbon and oxygen
Excretory Processes
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During filtration, water and small solutes are forced out of the blood or body fluids across a
transport epithelium into an excretory tubule
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2 mechanisms transform this filtrate into urine: valuable solutes are returned from the filtrate in
selective reabsorption. In selective secretion, excess salts, toxins, and other solutes are added
to the filtrate.
The osmotic movement of water into or out of the filtrate follows the pumping of solutes
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