Module 3: Transport in Animals Flashcards
Blood vessels , lymphatic system , types of circulatory system
What are the 3 main types of blood vessels?
arteries
veins
capillaries
What do arteries do?
What structures do they contain?
thy carry oxygenated blood away from the heart to the rest of the body/respiring tissues
smooth muscle
elastic tissue
collagen
smooth endothelium
lumen
Do arteries have a narrow/wide lumen?
Why?
they have a narrow lumen so they are able to pump blood at a higher pressure
Why do arteries need to pump blood at higher pressure?
because they have to transport blood to the rest of the body very quickly
Why do arteries contain thick elastic walls and smooth muscle walls?
What is the role of collagen?
elastic-enables them to stretch to withstand high pressure
smooth muscle-ensures the vessels don’t burst under high pressure and helps to regulate the pressure when blood reaches arterioles
helps them withstand high pressure
What is the role of the smooth endothelium in arteries and veins?
to reduce friction and ease blood flow
What are the names of the three layers of smooth muscle?
Tunica intima
Tunica media
Tunica externa
What do veins do ?
What structures do they contain?
they carry deoxygenated blood towards the heart
the same as arteries but have a wider lumen and thinner layers of tissue
What do veins contain that arteries don’t and why?
valves , because blood is pumped at a lower pressure they ensure there is no backflow of blood
Why do veins have a wider lumen than arteries?
2
to maximise the volume of blood being carried to the heart
they don’t need to carry blood at high pressure
Why do veins contain thinner layers of smooth muscle and elastic tissue?
because they arent carrying blood at high pressure so dont need to stretch and recoil
What do capillaries do ?
What structures do they contain?
they are the site of metabolic exchange between cells and the bloodstream
they are only 1 cell thick
narrow lumen
smooth endothelium
Why do capillaries have a narrow lumen and a small diameter?
lumen-enables them to fit into small spaces throughout body tissues
diameter-creates a short diffusion pathway which increases efficiency as an exchange surface
What is the order of blood flow around the body?
(excluding the lungs)
heart
arteries
arterioles
capillaries
venules
veins
heart
What is the composition of blood and what does each component do ?
55% plasma -carries dissolved solutes
45% erthrocytes (RBC) -carry oxygen
less than 1% leukocytes(WBC) and platelets-attack pathogens and clot blood
What is tissue fluid?
What is its role?
a liquid containing dissolved solutes such as amino acids , hormones , glucose etc
to supply bodily tissues with the essential solutes in exchange for waste products such as carbon dioxide and urea
-therefore it enables exchange of substances between blood and cells
What is hydrostatic pressure and what does it do?
What is oncotic pressure?
What are fenestrations?
pressure created when blood is pumped along arteries , arterioles and capillaries
it forces blood fluid in the plasma out of the capillaries through fenestrations
A type of osmotic pressure that leads to a tendency for water to flow into the capillaries due to the presence of large proteins in blood that lower water potential
tiny gaps within capillary walls
What is the name given to the process of these substances leaving the fenestrations?
ultrafiltration
What happens at the arterial end of capillaries?
Which type of pressure is greater?
What happens at the venous end of capillaries and what type of pressure is greater?
tissue fluid moves out of capillaries into extracellular space as hydrostatic pressure is greater ( more neg ) than osmotic pressure
tissue fluid moves into capillaries as osmotic pressure is greater ( more neg ) than hydrostatic pressure
How many different types of circulatory system are there? What are they?
4
Open , closed , single , double
Why do multicellular organisms need transport systems?
4
-they are much larger
-they have a much higher metabolic rate so require more substances and faster
-they have a small SA:V ratio so cant rely on diffusion
-we need to transport molecules made in one place to where they are needed in the body
What is the difference between and open/closed system ?
In a closed system , does the transport medium come directly into contact with bodily cells , and does this happen in an open system either?
open-fluid isnt always contained in vessels
closed-fluid is always contained in vessels
closed-no
open-yes , this is where exchange takes place
What do all transport systems contain?
3
-a transport medium
-vessels that carry this medium
-a pumping mechanism to move the fluid around the system
How do single and double circulatory systems differ?
2 for each type
single systems-the heart has 2 chambers so blood passes through the heart once for a complete circuit
double system-the heart has 4 chambers so blood passes through the heart twice for a complete circuit of the body
In terms of pressure and speed of blood flow , what is the difference between open and closed circulatory systems?
open-blood travels at a low speed and is pumped at low pressure
closed-blood travels relatively quickly and is pumped under greater pressure
Is tissue fluid or blood more negative in terms of water potential?
What does this result in?
blood is more negative as it contains more solutes
tissue fluid is positive compared to blood which causes water to move down the water potential gradient from tissue fluid to blood by osmosis
What happens to remaining tissue fluid that isn’t pushed back into capillaries?
it is carried back by the lymphatic system
What does the lymphatic system contain?
What is the composition of this substance?
Explain why it has this composition
lymph fluid
its similar in content to tissue fluid but contains less oxygen and nutrients as its main purpose is to carry waste products
it also contains fatty acids that’ve been absorbed from the villi of the small intestine
Name two other structures present in the lymphatic system and explain their purpose…
lymph nodes-to filter out bacteria and foreign material from the lymph fluid
lymphocytes-produce antibodies that destroy these invaders
