Single Opening Digestive SystemsSponge Hydra Planarian
Two Opening Digestive System More specialized in digesting food Digestion is both mechanical and enzymatical.
Digestion starts in the mouth Mechanical Digestion through the teeth Chemical Digestion through the saliva, which contains an enzyme called salivary amylase that starts the digestion of starch into sugar.
Pharynx and Esophagus Bolus – used to refer to the food that has already been chewed and swallowed. Epiglottis – a small flap of tissue at the opening to the airway that is closed when swallowing. Peristalsis – muscular contraction that pushes the food down the epiglottis.
Stomach Parietal cells produce hydrochloric acid Chief cells produce pepsinogen The hydrochloric acid activates the pepsinogen in the stomach Pepsinogen converts to pepsin, the main digestive enzyme of the stomach
Small Intestine-Responsible for most of thechemical digestion-Responsible for absorption ofnutrients-Tiny finger-like projectionslocated at the lining of theintestines called villi increases thesurface area for absorption.Additionally, there are microvilliprotruding from the villi.
Parts of the small intestine Duodenum – first part of the small intestine, responsible for absorbing iron and most of the digestion Jejunum – middle part of the small intestine, responsible for absorbing carbohydrates and protein Ileum – final part of the small intestine, responsible for absorbing vitamin B12 and Bile salts
Large Intestine Responsible for waste removal Where water and sodium are absorbed After the large intestine, defecation takes place.
Accessory Organs in Digestion Liver – secretes bile that is released to the small intestine. Bile digests fats. Liver is also helping maintain homeostasis by adding or removing nutrients from the or to the blood. It converts glucose into glucogen, amino acids to fatty acids and urea, stores iron, and detoxifies alcohol, drugs and poisons that enters the body.
Accessory Organs in Digestion Pancreas – secretes enzymes and hormones that assist in digestion. Its enzymes are responsible for digesting polypeptides into dipeptides, carbohydrates (except cellulose) into disaccharides, degrading neutral fats, and RNA and DNA to free nucleotides.
Different Nitrogenous Wastes Ammonia Uric acid Urea
Ammonia Produced when the amino group of amino acids are removed and then converted to ammonia. Highly toxic. Excreted by aquatic animals and some terrestrial animals. Soluble in water
Uric acid Produced from ammonia and by the breakdown of nucleotides from nucleic acids. Conserves water. Water insoluble. Expelled usually with the feces. Non-toxic.
Urea Produced in the liver. Less toxic, meaning it can be stored in higher concentrations without tissue damage. Dissolves in water. Requires more water to be excreted than uric acid.
Two Processes that maintainhomeostasis of fluids in animals: Osmoregulation The active regulation of osmotic pressure of body fluids to keep them from becoming too dilute or too concentrated. Excretion The ridding of metabolic wastes from the body.
Excretory System Its function is to maintain homeostasis by adjusting the concentrations of salts and other substances in blood. 1st step 2nd step 3rd step • Excretory • Excretory • Excretory system collects system adjusts system fluids from the the eliminates blood. composition of wastes and the fluid. excretes metabolic wastes.
What is the difference betweenexcretion and elimination? Excretion = disposal of metabolic wastes as urine Metabolic wastes = substances from the excretory process that can no longer be used by the body Elimination = ejection of undigested and unabsorbed food as feces
Osmoconformers vs. Osmoregulators Osmoconformers Animals whose body fluids are in osmotic equilibrium with the surrounding environment. Osmoregulators Animals who maintain an optimal salt concentration in their tissues regardless of changes in the salt concentration of their surroundings.
Human Excretory System • Urine is produced flowing from collecting ducts into the renal pelvis. Kidneys • Urine flows to the urinary bladder via the ureter. • Holds up to 800 mL of urine. Urinary Bladder • During urination, the urine is released from the bladder and flows through the urethra. Urethra
The Kidney Contains at least a million nephrons. A nephron consists of a Bowman’s Capsule, which is connected to a renal tubule. The Bowman’s Capsule has a cluster of capillaries within called a glomerulus. The renal tubule has three regions : Proximal Convoluted tubule Conducts the filtrate from the Bowman’s Capsule. Loop of Henle Distal Convulated tubule Conducts the filtrate to a collecting duct.
Nephrons Two types: Cortical nephrons Have small glomeruli Juxtamedullary nephrons Have large glomeruli Have very long loops of Henle Contributes to the concentration of urine.
Loop of Henle Descending – receives filtrate from the proximal convoluted tubule Ascending – filters the filtrate to the distal convoluted tubule Countercurrent Exchange
The Kidney : Overview Bowman’s Capsule proximal convoluted tubule Descending Loop of Henle Ascending Loop of Henle Distal Convoluted Tubule Collecting Duct
Production of Urine Filtration Reabsorption Secretion
Filtration Non-selective to ions and small molecules Glomerular capillaries are permeable to most fluids and small solutes found in the blood This allows the solutes to pass through the glomerular capillaries to joined the filtrate, at the same time holding back the blood from joining the filtrate.
Reabsorption Permits regulation of blood chemistry by the kidneys. Without Regulation, the body would excrete 180 Liters of urine per 24 hours. With reabsorption, this is lessened to 1.5 L. Happens in the renal tubule.Tubular Transport Maximum (Tm) = maximum rate at which a substance can be absorbed
Secretion Happens in the distal convoluted tubule. Important to regulate blood pH level as it secretes Potassium, hydrogen and ammonium ions. Secreted substances go straight to thee filtrate.
Questions? Assignment for tomorrow : Learn the names of the bones in your body. More bones named, higher grade. Most bones named, +10 house points.