Transport to and from exchange surfaces Flashcards
What are the two circulatory systems
Open circulatory and closed circulatory system
What are the two circulatory systems
Open circulatory and closed circulatory system
What is the open circulatory system
It is where heart pumps blood via vessels into the fluid-filled cavity
where tissues bathe in the blood directly and exchange of materials take place
What is the closed circulatory system
the blood is transported in tubes called blood vessels. Blood is pumped by muscular heart at high pressure resulting in rapid flow.
The tissues are not in direct contact with the blood but bathe in tissue fluid which can exit out of the walls of capillaries.
There are two types of closed circulatory system, what are they?
The single circulatory system
- blood goes through the heart once for each circuit around the body (e.g fish)
The double circulatory system
- blood passes twice through the heart because of two circuits (pulmonary - lungs (low pressure) and systemic - rest of body (high pressure))
for each complete circuit of the body. (e.g humans)
What is an advantage of having double circulatory systems
Blood leaving lungs will be fully oxygenated and blood entering lungs can enter at a lower pressure (high pressure will damage lungs).
What is the general structure of a blood vessel (from outside to inside)
1 - TUNICA EXTERNA - strong fibrous protein, helps vessel withstand high pressure
2 - TUNICA MEDIA - smooth muscle - for contractions and constrictions of vessel. Elastic tissue - allows stretch and recoil of vessel. This layer helps sustain blood pressure.
3 - TUNICA INTIMA - single layer of endothelial cells. smooth and flat to reduce friction of the flowing blood
4 - LUMEN - cavity where the blood flows through.
What does the artery do
Takes high pressure blood away from the heart to other regions of the body
What does the vein do
returns low pressure blood to the heart from the lung to the body
What does the capillary do
connects small arteries with small veins and allows exchange of materials with the tissues.
Description of the artery
Thick walls made of collagen (Tunica Externa) which provides resistance against high pressured blood, traveling away from heart.
Lots of elastic tissue (tunica media) allowing blood vessels to stretch and accommodate surge of blood from ventricles and recoil to maintain the pressure
Smooth muscle - allows vasoconstriction to reduce diameters of lumen = reducing blood supply to organs.
Description of vein
elastic tissue is less (tunica media) - blood travels at low pressure = less need for these structures.
Large diameter of lumen - helps in returning low-pressure blood to heart.
Valves - prevent backflow of blood.
What is the open circulatory system
It is where heart pumps blood via vessels into the fluid-filled cavity
where tissues bathe in the blood directly and exchange of materials take place
What is the closed circulatory system
the blood is transported in tubes called blood vessels. Blood is pumped by muscular heart at high pressure resulting in rapid flow.
The tissues are not in direct contact with the blood but bathe in tissue fluid which can exit out of the walls of capillaries.
There are two types of closed circulatory system, what are they?
The single circulatory system
- blood goes through the heart once for each circuit around the body (e.g fish)
The double circulatory system
- blood passes twice through the heart because of two circuits (pulmonary - lungs (low pressure) and systemic - rest of body (high pressure))
for each complete circuit of the body. (e.g humans)
What is an advantage of having double circulatory systems
Blood leaving lungs will be fully oxygenated and blood entering lungs can enter at a lower pressure (high pressure will damage lungs).
