Module 3: Section 2 - Transport in Animals Flashcards
(74 cards)
why cant multicellular organisms rely on solely diffusion
-low SA:V
-higher metabolic rate
-relatively big
-Many multicellular organisms are also very active so a large number of cells are respiring very quickly
what are the types of circulatory systems
-single
-double
-closed
-open
what type of circulatory system do fish and mammals have
fish=single closed
mammals=double closed
what happens in a single circulatory system
blood only passes through the heart once for each complete circuit of the body
what happens in a double circulatory system
the blood passes through the heart twice for each complete circuit of the body
what does the systemic system do
sends blood to the rest of the body
what does the pulmonary system do
sends blood to the lungs
what is a closed circulatory system
its when the blood is enclosed within the blood vessels
What is an advantage of a double circulatory system
heart can give the blood an extra push between the lungs and the rest of the body so blood travels faster and oxygen is delivered to the tissues more quickly
what is an open circulatory system
it is when blood is not enclosed in the blood vessels all the time and it instead flows freely through the body cavity
what are the blood vessels we need to know about
-arteries
-capillaries
-Veins
-venules
-arterioles
what is the function of the arteries
carry blood away from the heart to the body
what is the arteries structure why is it beneficial
-thick elastic tissues(elastin) to help arteries to stretch when blood is pumped out of the heart and recoil between heartbeats to maintain high pressure
-inner lining(endothelium) is folded, allowing the artery to expand and maintain high blood pressure
-thick muscular walls of smooth muscle and elastin
-narrow lumen
-no valves as blood flows at high pressure so wont backflow
-collogen to maintain its structure
what is the function of the veins
take blood from the body back to the heart under low pressure
what is the veins structure why is it beneficial
-collogen to maintain its structure
-thinner walls as blood is flowing through them at lower pressures and so higher volumes of blood can flow through them
-The large lumen reduces the resistance to blood flow, which helps blood return to the heart even though it’s under lower pressure.
-valves to prevent backflow
-smooth endothelium: smooth lining ensures that blood flows efficiently without forming clots.
what is the function of the capillaries
to enable the exchange of oxygen, nutrients, and waste products between the blood and surrounding tissues through their thin walls.
what is the structure of the capillaries
- single layer of endothelium cells (one cell thick) for short diffusion distance
-narrow lumen to allow close contact with tissues
-many capillaries (capillary network) increase the surface area
small pores to allow molecules to be pushed out
what do arteries branch off into
arterioles
what do arterioles branch off into
capillaries
what do capillaries branch off into
venules
what do venules branch off into
veins
what is the function of the venules
to collect deoxygenated blood from the capillaries and transport in to the veins
what is the function of the arterioles
to regulate blood flow from arteries into capillaries by constricting or dilating in response to the body’s needs.
what is the venules structure
small amounts of smooth muscle and elastic tissue