Digestion 1
What is the main purpose of digestion?
To break down food and absorb nutrients for metabolic processes
What are the 2 main digestive structures called?
Gastrovascular cavity and alimentry canal
What is the purpose of the circulatory system?
The transport of materials within the internal environment for exchange with all cells.
What are the three main parts of the circulatory system?
fluid, vessels, heart / muscular pump
What is the purpose of a gas exchange system?
steady supply of oxygen to cells and release of carbon dioxide.
What is an alimentry canal and what are the main organs?
Series of organs that food travels through includes: mouth, pharynx, esophagus, stomach, small intestine, Large intestine
Describe the two main types of digestion
Chemical - break down opf complex molecules by enzymes
mechanical - breaking up food to increase surface area
What is the fluid called in an open circulatory system and how is different from blood?
Heamolymph - doesn't carry oxygen
What is an example of an animal with an open circulatory system?
Molluscs, cricket
What structures are used by small insects for gas exchange?
Spiracles
Why do cows chew cud?
To break up the cellulose plant wall
Describe a gastrovascular cavity
Cavity in an oragnisms body with a sigular opening and no specialised structures
List the systems from most efficient to least
open, single, double
What is the difference in a double loop system between a 3 chamber heart and a 4 chamber heart?
3 chamber - mixing of blood, 4 chamber no mixing
What are the five requirments for a gas exchange surface?
Thin, moist, highly vascular, concentration gradient and large surface area
What are the two types of herbivores and how are they different?
Ruminants - 4 chanmbered stomach
non-ruminants (hind gut fermenters) - large caecum
What are the key differences in a carnivores digestion?
Shorter intestine, no digestive enzymes in saliva
Name an animal for each of the closed circulatory systems.
single - fish, double (3 chamber) - frog, double (4 chamber) - mammals
Explain the interdependence between the 3 systems using the heart as an examples.
Heart cells need glucose and oxygen to function, must be supplied by the digestion and respiratory systems and transported by the circulatory system.
What is the most efficient gas exchange structure?
Gills
What are the 4 stages of digestion?
Ingestion, digestion, absorption and elimination
Carnivores - have pointed incisors and canines, and jagged premolars and molars
Herbivores - molars with broad, ridged surfaces.
Describe an open circulatory system
Fluid is pumped through vessels and then leaves the vessels to wash over cells before being collected and pumped around again.
How are sinlge and double loop circulatory systems different?
Double has two circuts - one to lungs, one to body, remains at high pressure
single has one loop - lower pressure
Explain counter current flow in gills
Water flows through gill filaments in the opposite direction from blood flowing inside the blood vesselsto maximise the concentration gradient.