introduction to circulatory system Flashcards
(28 cards)
Why do multicellular organisms need transport systems?
Multicellular organisms are larger, so the diffusion distance across their surface would be too large.
Multicellular organisms have a higher metabolic rate.
Multicellular organisms need to supply nutrients and oxygen rapidly to a larger number of active cells.
use a diagram to show single circulatory system
check cognito
Explain how the single circulatory system in fish works
The heart pumps blood to the gills to pick up oxygen
blood flows from the gills to the rest of the body to deliver oxygen
explain how the double circulatory system in mammals work
The right side of the heart pumps deoxygenated blood to the heart to pick up oxygen
the left side of the heart pumps oxygenated blood to the rest of the body
explain what you understand by closed circulatory system
A closed circulatory system has their blood enclosed in a blood vessel
arteries=oxygenated
veins=deoxygenated
explain what is meant by open circulatory system
An open circulatory system has the blood moving freely in the body cavity
which blood do they carry
arteries, veins, pulmonary artery, pulmonary vein
Arteries=oxygenated blood
veins=deoxygenated blood
Pulmonary artery=deoxygenated blood
Pulmonary veins=oxygenated blood
Mention the main type of blood vessel and their function
Arteries: carries oxygenated blood away from the heart to the body tissue
Arterioles: carries blood from the artery to the capillary
Capillaries: site of diffusion between blood and blood tissue
venules: carry blood from capillary to vein
veins: returns blood to the heart
Explain 3 adaptations for arteries and arterioles relate your explanation to vasoconstriction and vasodilation
Arteries and arterioles:
Collagen- provides strength to prevent vessel from bursting, maintains vessel shape
Thick smooth muscle layer: maintains blood flow through vasoconstriction and vasodilation
Elastic fibre: contains elastin that let them stretch and coil
VASOCONSTRICTION: smooth muscles contract, making artery narrower which increases blood pressure
VASODILATION: smooth muscles relaxes, widening the artery decreasing blood pressure
Explain 3 adaptations of capillary
CAPILLARY
Narrow lumen: it slows down blood in capillary allowing for gas exchange
Walls are thin: substances can exchange across a short distance by diffusion
Highly branched: large surface area for diffusion
Explain three adaptation for veins and venules
VEIN AND VENULES
Collagen: provides strength to prevent vessel from bursting, maintains vessel shape
Little smooth muscle and elastic fibre: not much is needed due to low blood pressure
Valves: pocket valve shut to prevent the backflow of blood when veins are squeezed by surrounding skeletal muscle
The blood consists of…..
Plasma: mostly water, transport substances in solution
Red blood cells: carry oxygen
White blood cells: immune cells
Platelets: involved in clotting
Name 4 functions of blood
Transport oxygen and carbon dioxide
Transport hormones
Transport food from storage
Transport waste for excretion
Transport nutrients from digestion
what is hydrostatic pressure
This is the pressure in the blood caused by hearth contraction
what is oncotic pressure and the value for it
the tendency of water to move into the blood by osmosis
formula for filtration pressure
Hydrostatic pressure - Oncotic pressure
Name one plasma protein
ALBUMIN
Explain what happens in hydrostatic pressure with key words
Found in the capillary:
arterial ends: where blood enters (+4.6kpa)
venules end: where the blood is leaving(+2.3kpa)
As blood flows from arterioles to to the capillaries it is under hydrostatic pressure
At the arterial end of the capillary the, the hydrostatic pressure forcing the fluid out of the capillary is around 4.6kpa which is higher than the oncotic pressure causing fluid to be squeezed out of the capillary this creates TISSUE FLUID
as blood moves through capillaries towards the venous system the hydrostatic pressure falls to 2.3kpa (oncotic pressure is still -3.3kpa) oncotic pressure is now stronger than hydrostatic pressure causing water to move back into the capillaries by osmosis
WHEN BLOOD RETURNS TO THE VEIN 90 PERCENT OF THE TISSUE FLUID IS BACK IN THE BLOOD VESSEL
The lymph
10 percent of tissue fluid does not return to the capillary
it leaves blood vessels to drain into the LYMPH CAPILLARIES
lymph has less oxygen and nutrient than plasma and tissue fluid
lymph contains FATTY ACIDS that have been absorbed into the lymph from the villi of small intestine
what are platelets and what is the role of platelets in the body?
platelets are fragments of large cells called MEGAKARYOCYTES found in the red blood marrow and they are involved in the clotting mechanism of the blood.
Describe the events that occur during ventricular contraction in the cardiac cycle.
..First, ventricular volume decreases
..while ventricular pressure increases
..AV valve closes as the pressure in the ventricles is greater than in the atria
..SL Valves open as the pressure in the ventricles is greater than in the arteries
..Blood enters the arteries
..SL valves close to prevent backflow of blood
Describe and explain the shape of the oxyhaemoglobin dissociation curve for haemoglobin in a human adult
..In human adults, the oxyhaemoglobin dissociation curve has a sigmoid shape
..This is because as the partial pressure of oxygen increases saturation of haemoglobin also increases
Describe how oxygen association, transport, and dissociation take place in our body
..Oxygen association takes place when there is high partial pressure
..Oxygen is transported via binding with haemoglobin haem group
..Oxygen dissociation takes place in respiring tissues where there is low partial pressure
Give three molecules that contains the phosphate ions
Phospholipids
ATP
DNA
