Chapter 8 - Transport in animals Flashcards
What are the reasons for needing a specialised transport system
- high metabolic demands
- small SA:V ratio
- large diffusion distance
- molecules often made in one place and needed in another
- food digested in one organ system but needs to be transported for respiration
- wasted products need to be removed
What are common features of most circulatory systems
- liquid transport medium
- vessels to carry the transport medium
- have a pumping mechanism to move the fluid around the system
What are the two main types of circulatory systems
Open and closed systems
What are the features of an open circulatory system
Very few vessels to contain the transport medium
Pumped straight from heart to the haemocoel
Transport fluid comes into direct contact with tissues and the cells
In what type of animals are open circulatory systems most commonly found
Invertebrates
What is a common example of an animal with an open circulatory system
Insects
What is insects version of blood called
Haemolymph
Where does gaseous exchange take place in insects
In the trachea
What does the haemolymph in insects transport
Food and nitrogenous waste products
What are the features of a closed circulatory system
The blood is enclosed in blood vessels
The blood does not come into direct contact with the cells of the body
The heat pumps blood around the body under pressure
Blood returns to the heart
How do substances leave the blood vessels
Diffusion
How can the amount of blood flowing to a particular tissue be adjusted
The widening or narrowing of blood vessels (vasodilation or vasoconstriction)
In what type of animals would you find a closed circulatory system
Vertebrates
What is a single closed circulatory system
When blood travels through the heart once per full circulation
How many sets of capillaries does blood pass through in a single circulatory system
Two
What happens in the first set of capillaries in a single circulatory system
Exchanges oxygen and carbon dioxide
What happens at the second set of capillaries in a single circulatory system
Substances exchanged between blood and the cells
Why is a single circulatory system generally inefficient
Blood returns to the heart slowly as blood pressure drops when passing through the narrow capillaries
Will the metabolic rate of single circulatory system animals tend to be high or low
Low
What is the exception to inefficient single circulatory systems
Fish
How do fish have a more efficient single circulatory system
Countercurrent exchange at the gills
Don’t support their own weight
Don’t have to maintain their own body temperature
What is a double circulatory system
When blood passes through the heart twice per circulation
What are the two parts to the circulations of a double circulatory system
Blood is pumped from the heart to the lungs where it is oxygenated and unloads CO2
Blood is pumped from the heart to the body where oxygen is used and CO2 is gained before it returns to the heart
What are the 3 main components of blood vessels
Elastin fibres
Smooth muscle
Collagen
What is the role of elastin fibres
Stretch and recoil providing vessel walls with flexibility
What is the role of smooth muscle
To contract or relax changing the size of the lumen
What is the role of collagen
To provide structural support to the vessel to maintain its shape and volume
What is the role of arteries
Carry oxygenated blood away from the heart to the body
What is the exceptional artery that carries deoxygenated blood
Pulmonary artery
What are the layers of an artery from inside to outside
Lumen - endothelium - elastic layer - muscle layer - tough outer collagen layer
Why do arteries need elastic fibres
To withstand the large force of the blood pumping out of the heart
What is the role of the endothelium
To act as a smooth lining so blood can easily flow over it
What is the role of arterioles
To link the arteries to the capillaries
