Chapter 8- Transport in animals Flashcards
What is the need for specialised transport systems in animals?
metabolic demand is high
small SA:V ratio
hormones needed may be made in one place and needed in another
food is digested in one organ system and needed in another
waste products need to be removed from cells and taken to excretory systems
What is an open circulatory system:?
Blood is pumped from the heart straight into the body cavity
In haemocel, transport medium is under low pressure
Blood comes into direct contact with the cells
Transport medium returns directly to the heart through an open ended vessel
What is haemolymph?
Doesnt carry O2 or CO2
Transports food and nitrogenous waste products to cells involved in fighting against disease
What is a single closed circulatory system?
Continuous cycle of blood flow through the heart and body
Blood pumps through two sets of capillaries before returning to the heart
set 1- where O2 and CO2 are exchanged
set 2- substances from different organ systems are exchanged
blood returns to the heart slowly
What is a double closed circulatory system?
Happens in active land mammals that maintain their own temperature
1st circulation- Blood is pumped from the heart to the lungs to pick up oxygen and unload CO2
2nd circulation- through the heart all around the body and back to the heart
has high blood pressure and blood flow
What are the main components of blood vessels and their functions?
Elastic fibres- made of elastin, can stretch and recoil
Smooth muscle- contracts and relaxes, changes size of lumen
Collagen- provides structure, maintains shape and volume
What are arteries?
They carry oxygenated blood away from the heart
High blood pressure
What are the two arteries that do not carry blood away from the heart?
Pulmonary artery- carries deoxygenated blood away from the heart to the lungs
Pregnancy umbilical artery- carries blood from foetus to placenta
What are arterioles?
Link arteries and capillaries
More smooth muscle than elastin
Can contract or dilate to control blood flow
What is vasoconstriction?
When smooth muscle contracts, it constricts blood flow
What is vasodilation?
When smooth muscle relaxes, it increases the blood flow into the capillaries
What are capillaries?
Link arterioles with venules
RBCs flow through in single file
Blood has less O2 and more CO2 once it leaves them
What are capillary adaptions?
Walls are 1 endothelial cell thick
Large SA for diffusion of substances
Total cross section area is always greater than the arteriole supplying it
What are the 4 main functions of blood?
Transports oxygen to and carbon dioxide from respiring cells
Transports digested food from small intestine
Transports nitrogenous waste products to excretory organs
Transports hormones, food molecules, platelets, cells and antibodies
What are the steps for tissue fluid formation?
- Hydrostatic pressure is high and forces O2 , glucose and other substances through fenestrations
- This forms the tissue fluid which bathes the body cells
- Substances in the tissue are able to diffuse into the body cells
- Plasma proteins are too big to fit through the fenestrations, however, lymph capillaries have larger pores and closed ends
- Plasma proteins are taken into the lymphatic system which drains excess fluids, removes debris from the body cells and transports fats
- Liquid in the lymphatic system is moved by compressions from body movements.
- Lymph re-enters the blood system via veins located close to the heart.
What is the average mass of the mammalian heart?
300g
What is the pericardium?
Tough fibrous sac that protects the heart in the chest cavity
What are the top two chambers of the heart called?
Atria
What are the bottom two chambers of the heart called?
Ventricles
What is the part of the septum that separates the atria?
Interatrial septum
What part of the septum that separates the ventricles?
Interventricular septum
What is the importance valves?
Prevents backflow
Maintain correct pressure of blood in heart chambers
Why is the heart myogenic?
It can control its own contractions and relaxations without impulses from the central nervous system
What does the SAN do?
Like a pacemaker
In wall of right atrium
Sets hearts rhythm by sending out regular electrical waves
Causes left and right atria to contract simultaneously
