Circulation and gas exchange Flashcards
How can oxygen and CO2 move between cells?
small nonpolar molecules like oxygen and Co2 can move between cells and surroundings by diffusion
this takes a long time though
How do sponges do gas exchange?
sponges are just a collection of cells which communicate directly with water so diffusion is sufficient for gas exchange and nutrients
How do small animals perform gas exchange?
small animals (flatworms and jellies) can meet demands by exchanging gases directly with the environment through diffusion but they also have the gastrovascular cavity which facilitates diffusion of gases and nutrients to cells deep in the body
Discuss the advantages of the open system
lower hydrostatic pressure= less energy consumed
ex- spiders use the hydrostatic pressure to extend legs
more “advanced” animals have a closed circulatory system Why?
More reliable
higher blood pressure because everything is contained (push liquid through) this allows for efficient delivery of oxygen and nutrients to cells of large animals
very through can direct the blood where it needs to go, control the blood flow to different parts of the body as you need (direct blood to certain part)
open circulatory system
don’t have blood vessels heart pumps blood to top of animal and it trickles down
fluid is called hemolymph which directly bathes organs
ex- arthropods and most molluscs
closed circulatory system
blood cells remain within vessels and is kept separate from the interstitial fluid
fluid is blood
one or more hearts pump blood into large vessels that branch into smaller ones and infiltrate organs
chemical exchanges occur between blood and interstitial fluid then to body cells
ex- annelids (earthworms) cephlapods (octupuses and squids)
What are the 3 types of blood vessels
- Artery
- Veins
- capillaries
Artery
vessel taking blood away from the heart to the capillary beds/ other organs
Much higher blood pressure than in veins because they are delivering blood from the pump to the capillary bed walls are thicker and stronger
Vein
vessel taking blood from other tissues to the heart
Low pressure because blood has already gone through a capillary bed
Capillaries
microscopic vessels that permeate all tissues
So small that blood cells go single file
Really low pressure because they are tiny
Portal veins
conveys blood from one capillary bed to another capillary bed
Big fat
Low pressure
What distinguishes arteries and veins?
direction in which they carry blood not whether if they take oxygenated or deoxygenated blood
What color are oxygenated and deoxygenated blood?
Whether oxygen rich or poor depends on which circuit
Oxygenated blood is red
Deoxygenated is also red
Which direction can blood flow in..
within each blood vessel blood can flow in only one direction
How do large animals perform gas exchange?
they need a circulatory system because diffusion cannot happen because their body is too large
atria
receive blood entering heart and transfer to ventricle
Diffusion
is the net movement of anything from a region of higher concentration to a region of lower concentration
is driven by a gradient in concentration.
Bulkflow
Animals rely on bulk flow (or other active mechanism) to obtain oxygen and release carbon dioxide (hence breathing, fish sweep water across gills, frog swallowing)
the movement of a fluid due to a difference in pressure b/t two locations
Sinuses
spaces surrounding the organs
contraction of 1 or more hearts pumps the hemolymph through the circulatory vessels into interconnected sinuses,
within the sinuses, chemical exchange occurs b/t the hemolymph & body cells
relaxation of the heart draws hemolymph back in through pores, which are equipped with valves that close when the heart contracts
body movements help circulate the hemolymph by periodically squeezing the sinuses
Hemolymph
the fluid within the hemocoel of invertebrates that exchange nutrients and waste within internal tissue
Blood Lymph/Interstitial fluid
is a solution that bathes and surrounds the cells of multicellular animal
Double Circulation
circulatory system consisting of separate pulmonary and systematic circuits in which blood passes through the heart after completing each circuit
(blood moving between the heart and the rest of the body- systematic- is separated from the blood that travels between the heart and the respiratory surface
Pulmocutaneous Circuit
a branch of the circulatory system in amphibians that supplies the lungs and the skin
Pulmonary Circuit
supplies the lungs
Systemic Circuit
supplies oxygenated blood to and carries deoxygenated blood away from the organs and tissues throughout the body
Respiration
also called gas exchange
the uptake of molecular oxygen from the environment and the discharge of carbon dioxide to the environment
Gill
outfoldings of the body surface that are suspended in the water
Ventilation
the flow of air or water over a respiratory surface
describe the fish circulatory system
have a single circuit (blood just goes round and round)
Blood collects in the atrium then enters the ventricle
contraction of ventricles pumps blood to arteries that leads to gills to collect oxygen and get rid of CO2 and then to body releasing oxygen before returning to heart
have a 2 chambered heart
heart receives only deoxygenated blood