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Biology 3.3 - Organisms Exchange Substances With Their Environment > Circulatory system > Flashcards

Circulatory system Flashcards

1
Q

Why do large organisms have a transport system?

A
  • to absorb nutrients and respiratory gasses
  • as large organisms have many layers of cells and a large volume, specialised transport systems ensure an efficient transport of materials
  • ensures a constant supply of metabolic reactants such as glucose and oxygen
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2
Q

What is mass transport?

A
  • the bulk movement of gasses or liquids in one direction
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3
Q

What are features of mass transport systems?

A
  • a suitable medium for transport such as blood or water
  • a form of mass transport
  • a closed system of tubular vessels
  • a mechanism for moving transport mediums
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4
Q

What is a closed system?

A
  • blood is pumped around the body but is contained within a network of blood vessels
  • this is used for all vertebrates and many invertebrates
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5
Q

What is an open system?

A
  • blood is not contained to blood vessels and is pumped directly into body cavities
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6
Q

What type of system do humans have?

A
  • a closed double circulatory system which is confined to vessels and passes twice through the heart
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7
Q

Why does blood pass twice through the heart?

A
  • in order to increase the pressure of blood so it can be efficiently transported around the body
  • This is because after blood passes the lungs, it has a lower pressure
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8
Q

What is the flow of blood through the heart?

A
  • Deoxygenated blood flows from the vena cava into the right atrium, which then passes through the tricuspid valve into the right ventricle
  • from the right ventricle it then passes through the pulmonary valve into the pulmonary artery, by which it travels to the lungs to be reoxygenated.
  • Once oxygenated, the blood travels from the lungs through the pulmonary veins into the left atrium, then the mitral valve, then the left ventricle
  • then the blood passes through the aortic valve, and then finally the aorta
  • the aorta then sends oxygenated blood out to the rest of the body.
  • oxygenated blood is transported to the kidneys from the aorta by the renal artery
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9
Q

Describe the structure of two chambers in the heart

A
  • Each side has two chambers, the atrium and the ventricle
  • the atrium = thin walled, elastic and stretches as it collects blood
  • ventricle = thick muscular wall, contracts strongly to pump blood over a great distance
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10
Q

What are the main valves in the heart and their purpose?

A
  • the left atrioventricular valve (bicuspid)
  • the right atrioventricular valve (tricuspid)
  • Semi - lunar valves = link the ventricles to the pulmonary artery or aorta
    -these prevent the backflow of blood in the heart
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11
Q

describe the function of the major blood vessels

A

Aorta = connected to the left ventricle and carries oxygenated blood to the body
Pulmonary artery = carries blood to the lungs from the right ventricle
Vena Cava= carries deoxygenated blood from all body parts to the right atrium
Pulmonary vein = Carries oxygenated blood from the lungs to the left atrium
renal artery = transports oxygenated blood from the aorta to the kidneys
renal vein = transports deoxygenated blood from the kidneys to the vena cava

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12
Q

What is step one in the cardiac cycle?

A
  • Diastole, relaxation of the heart
  • blood enters the right atria through the vena cava on the right side whereas blood enters the left atria through the pulmonary vein
  • this increases the pressure in the atria compared to the ventricles
  • This forces open the atrioventricular valves and pushes blood into the ventricles
  • the walls of the atria and the walls of the ventricles are relaxed
  • due to the relaxed and their recoil ventricular walls, this reduces the ventricles pressure compared to the pulmonary artery and aorta
  • this closes the semi - lunar valves preventing the flow of blood from the ventricles out of the vessels
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13
Q

What is step two of the cardiac cycle?

A
  • the contraction of the atrial (arial styole)
  • the contraction of the atrial walls and the recoil of the ventricles force any remaining blood put of the atria and into the ventricles as pressure in the atria is greater
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14
Q

What is step three

A
  • contraction of the ventricles
  • the walls of both ventricles contract simultaneously
  • this increases their pressure, forcing the atrioventricular valves to shut
  • the closing of these valves causes pressure to increase further
  • this exceeds the pressure in the aorta and pulmonary artery
  • this forces blood out of the ventricles and into these vessels
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15
Q

Why do ventricles have thick muscular walls?

A
  • ventricles have thick muscular walls to forcefully pump blood at a high pressure to the body or to the lungs
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16
Q

What is step four?

A
  • the ventricles and atrium both relax and the process restarts
17
Q

When do valves open?

A
  • when pressure below is higher than above
18
Q

When do valves close?

A
  • when pressure above is higher than below
19
Q

How do you calculate cardiac output?

A

Cardiac output = stroke volume x heart rate

20
Q

what is cardiac output?

A
  • the volume of blood pumped by one ventricle of the heart in one minute
21
Q

What is the function of the blood vessels?

A
  • arteries = carry blood away from the heart and into the arterioles
  • arterioles = smaller arteries that control blood flow from arteries to capillaries
  • capillaries = tiny blood vessels that link arterioles to veins
  • veins = carry blood from capillaries to the heart
22
Q

What are the general layers and function in the structure of arteries, arteioles and veins

A

tough fibrous outer layer = resist pressure changes from the outside and inside
muscle layer = can contract and control the flow of blood
elastic layer = help maintain blood pressure by stretching and recoiling
thin inner layer (endothelium) = smooth layer which reduces friction and allows diffusion
lumen = the central cavity of blood vessels which blood flows through

23
Q

What is the structure of arteries related to their function?

A
  • thick muscular wall compared to veins = allows arteries to contract and dilate to control the volume of blood
  • thick elastic layer compared to veins = pressures in the arteries and elastic walls enable them to stretch and recoil in styole and diastole. This allows them to maintain high pressures
  • greater thickness of wall = resists vessels bursting under pressure
  • no valves = as blood in arteries is at a high pressure, backflow is unlikely
24
Q

What is the structure of arterioles related to their function?

A
  • muscle layers are thicker than arteries = allows the construction of muscle layers so they can restrict the flow of blood and control its movement when moving into capillaries
  • elastic layers are thinner than arteries = pressure in the arterioles is lower so they do not require stretching and recoil
25
Q

What is the structure of veins related to their function?

A
  • muscular layers are relatively thinner than arteries as they carry blood away from tissues
  • elastic layers are thinner as they do not require stretching and recoil
  • thickness of the wall is thinner as pressure is too low to burst
  • wider lumen to transport more blood
  • valves to prevent backflow of blood as blood is at a low pressure
26
Q

What is the structure of capillaries related to their function?

A
  • their walls are very thin and one cell thick to reduce diffusion distance to cells
  • lined with a basement layer which has spaces, allowing tissue fluid to leak through capillaries
  • narrow diameter to once again reduce diffusion distance
  • numerous and highly branched = large surface area for diffusion
27
Q

What is the composition of tissue fluid and its function?

A
  • it is made of molecules that leave blood plasma such as oxygen, water and glucose
  • tissue fluid baths cells, supplying them with oxygen, glucose and nutrients and in return, recieves carbon dioxide and waste products from cells
28
Q

Describe the formation of tissue fluid

A
  • at the start of capillaries, hydrostatic pressure inside capillaries is higher than that of the tissue
  • the difference in hydrostatic pressure forces blood out of the capillaries and into tissues, bathing the cells
  • this is known as ultrafiltration
  • as the fluid links, hydrostatic pressure decreases in the venule end of capillaries
29
Q

Describe the return of tissue fluid

A
  • at the venule end, hydrostatic pressure and osmotic pressure is lower due to the loss of fluid
  • this causes water and some tissue fluid to osmose back into the capillaries from tissues
  • excess tissue fluid is drained in the lymphatic system which transports excess fluid back into the circulatory system
30
Q

Describe issues with the heart

A
  • atheroma formation = damage to the endothelium which causes lipids and wbcs to build up and from plauques, blocking conoary arteries
  • aneurysm = swelling of the arteries caused by atheromas. Due to these blockages, the inner walls of arteries are pushed inward, causing swelling
  • thrombrosis = atheroma plaque damages artery walls and causes blood clots
  • heart attacks (myocordinal infraction) = when a conoary artery is blocked causing areas of the heart to recieve no oxygen
31
Q

What supplies the heart with blood

A
  • coronary arteries
32
Q

What are risk factors for cardiovascular disease?

A
  • high blood pressure = causes atheromas which then leads to blood clots
  • high blood cholesterol and poor diet = can cause lipid build ups, increasing the risk of atheromas
  • smoking = carbon monoxide binds to haemoglobin and reduces the amount of oxygen transported in the blood

Biology 3.3 - Organisms Exchange Substances With Their Environment (8 decks)

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