Circulation & Gas Exchange Flashcards
Definition of gas Exchange
The uptake of oxygen from the environment, and the discharge of carbon dioxide to the environment
Why does the body need gas exchange & the circulatory system
To provide the oxygen necessary for aerobic cellular respiration and removes the waste product, carbon dioxide.
Do hydra and other cnidarians need a circulatory systme
No, the body wall is only a few cells thick that serves for both digestion and diffusion of substances throughout the body.
What do open and closed circulatory systems have in common
Both have circulatory fluid (blood) a set of tubes (blood vessels) and a muscular pump (the heart)
Function of the heart
Power circulation by elevating the hydrostatic pressure of the blood (blood pressure)
How does the open circulatory system in insects and mollusks work
There is no distinction between blood and interstitial fluid (collectively called hemolymph). One or more hearts pump the hemolymph into interconnected sinuses surrounding the organs, allowing exchange between hemolymph and body cells.
Tracheal system in Insects and Mollusks
Larger insects ventilate their tracheal systems. They have many little holes across their body which connect to trachea and proliferate throughout the organism.
Why do insects need widespread tracheal system
An insect in flight has a very high metabolic rate, consuming to to 200 times more O2 than it does at rest
Closed Circulatory System
Blood is confined to vessels and is distinct from interstitial fluid. One or more hearts pump blood into large vessels that branch into smaller ones cursing through organs. Materials are exchanged by diffusion between the blood and the interstitial fluid bathing the cells.
Worms respiratory system
The entire outer skin is a respiratory organ - just below the moist skin is a dense net of capillaries. The respiratory surface must be moist.
Arteries
Carry blood away from the heart to organs
Arterioles
Small vessels that carry blood to capillaries
Capillary beds
Networks of very thin capillaries with porous walls.
Veins
Return blood to the heart
What type of circulatory system do 2 chambered fish have
Closed circulatory system
What does 2 chambered mean
One atrium one ventricle
How do 2 chambered system in fish works
Blood is pumped from the ventricle to the gills where it picks up oxygen and disposes of carbon dioxide. The gill capillaries converge into a vessel that carries oxygenated blood to capillary beds at the vein and back to the heart.
Metabollic rate of two chambered fish
Is SLOW - blood is depressurized and not repressurized causing blood pressure to substantially drop which therefore LOWERS metabolic rate.
Frogs circulatory system
3 chambered
3 chambered circulatory system
2 atria and one ventricle
How do 3 chambered systems work
The ventricle pumps blood into a forked artey that splits the ventricles output into the pulmocutneous and systematic circulations.
3.x chambered reptiles
Ventricle is not quite completely divided into seperate right and left chambers
Incomplete septum
ALMOST separated the two ventricles
Foramen of panizza
Make sure the blood doesnt go to the lungs when they are suspended in water for a long time as they are not useful.
4 chambered mammal and bird
Ventricle is completely divided into separate right and left chambers
How does a 4 chambered system work
The left side of the heart receives and pumps only oxygen-rich blood, while the right side handles only oxygen-poor blood.
Most effect method of circulation
Double circulation
Left Ventricle
Receive and pump oxygen-rich blood around the body
Right Ventricle
Receive and pump oxygen poor blood to the lungs
Left Atrium
Collect oxygen rich blood
Right Atrium
Collect oxygen poor blood
Systole
Contraction
Diastole
Relaxation
How to determine cardiac output
Beats per second x stroke volume
Avg stroke volume for humans
75 mls
How long does the average cardiac cycle take
0.8 seconds
3 stages of cardiac cycle
Ventricular and atrial diastole (0.4 seconds)
Atrial systole and ventricular diastole (0.1 seconds)
DELAY IN SIGNAL TO CONTRACT
Atrial diastole and ventricular systole (0.3 seconds)
How does structure of ventricle differ to aorta
Much thicker and contract much more strongly than atria as they have to pump blood right around the body
Why is the left ventricle more muscular
Has to push oxygenated blood all around the body (limbs) rather the just the lung
Sinoatrial node
Creates a signal that first tells atria to contract, then goes down to the ventricles (with some delay) and they contract.
Why does the sinoatrial node have a delay
If the atrium and the ventricle contracted simultaneously it wouldn’t work - the ventricles must be filled with blood before it can be pumped around
Energy use in ecto vs endotherms
Endotherms use ten times as much energy as ectotherms of the same size
What animal uses positive pressure for gas exchange
Frogs
How doe positive pressure in frogs work
Muscles lower floor of oral cavity, enlarging it and drawing in air through the nostrils.
Nostrils and mouth close. Floor of oral cavity rises and air is forced down the trachea.
Flow through system what animal?
Birds
How does the flow through system work
Take air in,
What breathing system to humans have
Negative pressure
How does negative pressure in humans work
Pushes diaphragm downwards, expanding your body cavity and lungs. Creates a gap and air rushes into our lungs, through bronchi, bronchiolles, and alveoli (dead ends)
How do birds exchange gasses
Birds have eight or nine air sacs that do not function directly in gas exchange, but act as bellows that keep air flowing through the lungs.
Instead of alveoli, which are dead ends, the sites of gas exchange in bird lungs are tiny channels called parabronchi, through which air flows in one direction.
