The The mantle (MAN tuhl)mantle (MAN tuhl) is a membrane that is a membrane that surrounds the internal organs of the mollusk. surrounds the internal organs of the mollusk. In shelled mollusks, the mantle secretes the In shelled mollusks, the mantle secretes the shell.shell.
What is a mollusk?What is a mollusk?
Visceral mass
Mantle
Shell
Foot
Head
Mantle
GutShell
Foot
Snail
Mollusks are the oldest known animals to have Mollusks are the oldest known animals to have evolved excretory structures called nephridia.evolved excretory structures called nephridia.
Excretion in mollusksExcretion in mollusks
Nephridia (nih FRIH dee uh)Nephridia (nih FRIH dee uh) are organs that are organs that remove metabolic wastes from an animal’s remove metabolic wastes from an animal’s body.body.
Mollusks have one or two nephridia that collect Mollusks have one or two nephridia that collect wastes from the coelom, which is located wastes from the coelom, which is located around the heart only.around the heart only.
Wastes are discharged into the mantle cavity, Wastes are discharged into the mantle cavity, and expelled from the body by the pumping of and expelled from the body by the pumping of the gills.the gills.
Excretion in mollusksExcretion in mollusks
Food is taken in by Food is taken in by the mouth, an the mouth, an opening in the opening in the anterior end of the anterior end of the worm, and wastes worm, and wastes are released are released through the anus, through the anus, an opening at the an opening at the posterior end.posterior end.
What is a segmented worm?What is a segmented worm?
Food is taken in by Food is taken in by the mouth, an the mouth, an opening in the opening in the anterior end of the anterior end of the worm, and wastes worm, and wastes are released are released through the anus, through the anus, an opening at the an opening at the posterior end.posterior end.
What is a segmented worm?What is a segmented worm?
Segmented worms have a complete internal Segmented worms have a complete internal digestive tract that runs the length of the body.digestive tract that runs the length of the body.
Digestion and excretionDigestion and excretion
Food and soil taken in by the mouth eventually Food and soil taken in by the mouth eventually pass to the pass to the gizzardgizzard..
In the gizzard, In the gizzard, a muscular a muscular sac and hard sac and hard particles help particles help grind soil and grind soil and food before food before they pass into they pass into the intestine.the intestine.
Digestion and excretionDigestion and excretion
Mouth
Crop Gizzard
Undigested material and solid Undigested material and solid wastes pass out the worm’s wastes pass out the worm’s body through the anus.body through the anus.
Digestion and excretionDigestion and excretion
Segmented worms have two Segmented worms have two nephridia in almost every segment nephridia in almost every segment that collect waste products and that collect waste products and transport them through the coelom transport them through the coelom and out of the body.and out of the body.
Nephridia
Most terrestrial arthropods excrete wastes Most terrestrial arthropods excrete wastes through through Malpighian tubulesMalpighian tubules..
In insects, the tubules are all located in the In insects, the tubules are all located in the abdomen rather than in each segment.abdomen rather than in each segment.
Malpighian tubules are attached to and empty Malpighian tubules are attached to and empty into the intestine.into the intestine.
Arthropods have other complex body systemsArthropods have other complex body systems
The main function of the digestive system is to The main function of the digestive system is to disassemble the food you eat into its disassemble the food you eat into its component molecules so that it can be used component molecules so that it can be used as energy for your body.as energy for your body.
Digestion is accomplished through a number Digestion is accomplished through a number of steps. of steps.
Functions of the Digestive SystemFunctions of the Digestive System
First, the system takes ingested food and First, the system takes ingested food and begins moving it through the digestive tract.begins moving it through the digestive tract.
As it does so, it digests or breaks down As it does so, it digests or breaks down mechanically and chemically, the complex mechanically and chemically, the complex food molecules.food molecules.
Then, the system absorbs the digested food Then, the system absorbs the digested food and distributes it to your cells.and distributes it to your cells.
Functions of the Digestive SystemFunctions of the Digestive System
Finally, it eliminates undigested materials from Finally, it eliminates undigested materials from your body.your body.
Functions of the Digestive SystemFunctions of the Digestive System
MouthTongue
Teeth Salivary glands
Pharynx
EsophagusDiaphragm
Liver
Gallbladder
Stomach
Pancreas
Large intestine
AppendixAnus Rectum
Small intestine
Each kidney is made up of about one million tiny Each kidney is made up of about one million tiny filters.filters.
Nephron: The unit of the Nephron: The unit of the kidneykidney
A filter is a device that removes impurities from A filter is a device that removes impurities from a solution.a solution.
Each filtering unit of the kidney is called a Each filtering unit of the kidney is called a nephronnephron..
Blood entering a nephron carries wastes Blood entering a nephron carries wastes produced by body cells.produced by body cells.
Nephron: The unit of the Nephron: The unit of the kidneykidney
NephronBowman’s capsule
GlomerulusFrom renal artery
Renal artery
To renal vein
Renal vein
Ureter
Tubule
Capillaries
To ureter
As blood enters the nephron, it is under high As blood enters the nephron, it is under high pressure and immediately flows into a bed of pressure and immediately flows into a bed of capillaries called the glomerulus.capillaries called the glomerulus.
Nephron: The unit of the Nephron: The unit of the kidneykidney
Because of the pressure, water, glucose, Because of the pressure, water, glucose, vitamins, amino acids, protein waste products vitamins, amino acids, protein waste products (called urea), salts, and ions from the blood (called urea), salts, and ions from the blood pass out of the capillaries into a part of the pass out of the capillaries into a part of the nephron called the Bowman’s capsule.nephron called the Bowman’s capsule.
Nephron: The unit of the Nephron: The unit of the kidneykidney
NephronBowman’s capsule
GlomerulusFrom renal artery
Renal artery
To renal vein
Renal vein
Ureter
Tubule
Capillaries
To ureter
The liquid forced into the Bowman’s capsule The liquid forced into the Bowman’s capsule passes through a narrow, U-shaped tubule.passes through a narrow, U-shaped tubule.
Nephron: The unit of the Nephron: The unit of the kidneykidney
As the liquid moves along the tubule, most of the As the liquid moves along the tubule, most of the ions and water, and all of the glucose and amino ions and water, and all of the glucose and amino acids, are reabsorbed into the bloodstream.acids, are reabsorbed into the bloodstream.
Small molecules, including water, move back into Small molecules, including water, move back into the capillaries by diffusion. Other molecules and the capillaries by diffusion. Other molecules and ions move back into the capillaries by active ions move back into the capillaries by active transport.transport.
