Digestive System
Breaking down of complex molecules mechanically and chemically into simpler organic molecules that can be used by the animal
Mechanical Digestion
Physical digestion of food - chewing, churning - increases surface area
Chemical Digestion
Enzymes break down food
4 Functions of Digestion System
Ingestion - Eating
Digestion - Breakdown
Absorption - Absorbed into body
Egestion - Poo
Microscopic Animals Digestive System
High surface area to volume ratio - Don’t possess digestive system - Nutrients absorbed directly into cells.
Gastrovascular Cavity
Nutrients does into cavity
Enzymes break down nutrients - absorbed
Waste is excreted from cavity
Breakdown of Proteins into x
Proteins —Protease—> Amino Acids
Breakdown of Carbohydrates into x
Carbohydrates —Amylase—> Glucose
Breakdown of Fats into x
Fats —Lipase—> Fatty Acids + Glycerol
Breakdown of Nucleic Acids into x
Nucleic Acids —Nuclease—> Nucleotides
What is broken down in the mouth
Carbohydrates
What is broken down in the stomach
Proteins
What is broken down in the Small Intestine
Carbohydrates, Proteins, Fat
Herbivores break down x into x
Herbivores break down Cellulose into Glucose through an enzyme called Cellulase, produced by microorganisms in the Herbivore’s digestive system.
Carnivore/Omnivore Digestive System
Small stomach, short small intestine, tiny caecum with no function.
Ruminant Digestive System
Four large stomachs with cellulase producing microbes, longest small intestine, tiny caecum with no function.
Hind-Gut Fermenter Digestive System
Small stomach, medium small intestine, large caecum with cellulase producing microbes.
Large Intestine
Absorbs water.
Mammals have a x circulatory system
Closed
Insects have a x circulatory system
Open
Amoebas have a x circulatory system
Non-Existant
Open Circulatory System
A heart
Haemocoel - space through which haemolymph flows
Not as effective due to mixing of oxygenated and deoxygenated blood (lowers conc. gradient)
Red Blood Cells
Biconcave disk
no nucleus - maximises haemoglobin content
carries oxygen
Haemoglobin
Compound which enables O2 to attach to R.B.C
Makes oxygenated blood red
White Blood Cells
Have a nucleus
Macrophages
Lymphocytes
Macrophages
Eat foreign material (bacteria)
Lymphocytes
Produce antibodies
Plasma
The liquid portion - contains dissolved nutrients, hormones, gases, and the majority of the CO2.
Order blood travels around the body
Heart > Arteries > Arterioles > Capillaries (exchange blood) > Venuoles > Veins > Heart
Double Circulation - Pulmonary Circulation
Deoxygenated blood goes from the right ventricle to the lungs and oxygenated blood then goes to the left atrium.
Double Circulation - Systemic Circulation
Oxygenated blood goes from the left ventricle to the body cells and deoxygenated blood then goes to the right atrium.
Countercurrent Flow in fish
Blood flows from the body of the fish, to the gills, forming a concentration gradient of oxygen. When the low oxygen blood is in the gills, water travels the opposite direction and flows through the gills, and oxygen attaches to the blood due to the difference in concentration.
Gas exchange in amphibians
Frogs have capillaries just under the skin, to allow CO2 to exit and O2 to enter through the moist permeable skin.
Spiracles
Tracheal System relies on spiracles, openings on the body surface that lead to tracheae.
insect v animal
open v closed