Blood pressure, blood, tissue fluid, and lymph (8) Flashcards
what is the def of blood pressure
the force exerted by the bblood on the walls of the blood vessels as it passes through them
what is chronically long term low blood pressure called
hypotension
what is chronically high blood pressure called
hypertension
what is the unit of pressure
pascals and kilopascals or mm of mercury (mm Hg)
what is blood pressure affected by
ventricle contraction, narrowing arteries (with age),
what is used to measure blood pressure
a sphygmomanometer or a cuff connected to a mercury manometer
Where does blood that is pumped out of the left ventricle go
The aorta
what happens when the ventrcile wall contracts
a surge of blood at high pressure moves into the aorta
what happens when the ventricle wall muscle relaxes
the pressure drops before the ventricle contracts again
What does and up and down (oscillation) represent on a blood pressure graph
it represents 1 heart beat
What does the elastic artery walls stretching and recoiling allow
The recoil helps to increase the blood pressure in between heart contractions and it smooths out the flow of blood
When do the artery walls stretch and when do they recoil
Stretch - When the blood pressure is highest
Recoil - When the blood pressure is the lowest
What are arterioles
They are smaller arteriarteries, they are smaller to allow more SA, more contact with the blood
When blood flows through the arterioles, what happens to the pace of the blood and why
The blood is slowed beacuse of friction this occurs becasue there is now more contact betwwen the bllood and teh walls of the vessells
why does the blood flow rate decrease as it passes through the arterioles
many capillaries arise from each arteriole, and their total cross sectional area is greater than that of the arterioles, so the blood has more room to spread out in the capillaries so its rate of flow decreases
why is the slow blood flow rate needed
its needed to give time for substances such as o2 and co2 to diffuse between the blood and the tissues
by the time the blood has passed thru the capillaries its pressure is very low, the pressure remains fairly constant as it flows thru the veins and back to the atrium of the heart .with the pressure of the blood being so low what is needed
valves r necessary to prevent backflow
what is blood composed of
plasma and formed elements
what is plasma made of
nutrients - glucose and amino acids
waste poducts - co2 and urea
proteins - albumin, fibrinogen, globulins
electrolytes
hormones
where do the amino acids come from and what are they used for
obtained mostly from dietary protein and used for protein synthesis
how is glucose transported into the blood
It is transported from the small intestine where digested dietary carbohydate is abosrbed iinto the blood
And from the liver and muscles if glucagon is is causing the breakdown from glycogen, it is then used by respiring cells as respiratory substrate
in what from does co2 dissolve into the plasma
hydrogencarbonate
what is urea
a nitrogenous waste made in the metabolism of excess amino acids
what is albumin, and what is a feature of albumin
its a plama protein.important for maintaining oncotIc (osmotic) pressure of the blood. albumin is polar, so water within the plasma makes a ashell around these protein molecules, this reduces the water potential of the blood.
what is fibrionogen
plasma protein.important in blood clotting. it converts into fibrin which helps form a blood clot after trauma to a blood vessel
what is globulins
moat common one is immunoglobulins, known as anyibodies
what is a electrolyte
these are mineral ions. includes calcium, chloride, magnesium, phosphate, potassium, sodium
what are hormones, where are they made, and what do they do
they are protein/lipid in nature. these chemical messengers are made by endocrine glands and travel in the blood to their target cells where they bind to a complementary shaped receptor
what is in the formed elements of the blood
erythrocytes, leucocytes, monocytes, lymphocytes, platelets
what are erythrocytes
RBCs. they are nucleate cells shaped like biconcave discs full of haemoglobin.
what are leucocytes
WBCs. many diff types, but all involved in the immune response
what are monocytesand how do they become macrophages
these are phagocytic. become macrophages when they leave the blood stream, by squeezing thru the fenestrations of the capillary wall
what are lymphocytes and what are 2 types
they produce antibodies. eosinophils - responsible for combating multicellular parasites and certain infections.
basophils - important in the inflammatory response
what are platelets
they are cell fragments, which are produced in the red bone marrow from megakaryocyte cells. they clot the blood when the blood vessel walls are damaged, reducing blood loss when injury occurs
how do platelets form
they break off of megakaryocytes
how can plasma and the formed elements of the blood can be separated. and how does it work
by spinning whole blood in a centrifuge. the denser blood cells sink to the bottom and the less dense plasma floats to the top
where do the components of the blood end up when spun thru a centrufuge
erythrocytes at the bottom, leucocytes + platelets in the middle, plasma at the top
what percentage does plasma make up of the blood. and same for formed elements
55% plasma
45% formed elements
capillaries have 2 ends what are they called
the end near an arteriole (higher blood pressure side) and the end near a venule (lower blood pressure side)
how is tissue fluid formed
blood enters capillary at a high pressure, this helps substances to move out of the capillary forming tissue fluid.
at the arterial end the hydrostatic pressure is greater than the oncotic pressure so water from the plasma + dissolved substances (o2,glucose) are forced out the permeable capillary wall due to high blood pressure. the forced out substances form tissue fluid. (larger blood components remain in the capillary like red blood cells)
why does the water potential within the capillary decrease after tissue fluid has formed (reabsorption of tissue fluid)
its due to the loss of water molecules and large plasma proteins (these are what form the tissue fluid) from tissue flid formation. some but not all water diffuses back into the capillary by osmosis.
what is tissue fluid for/ what is it good for
allows more efficient exchange of substances between the blood supply and the cells
what is hydrostatic pressure
the pressure from the heart beat forcing liquid out through the pores/fenestrations of the capillary.
hydrostatic pressure at venous end
and arteriole end
venous - low
arteriole - high
what is oncotic pressure
its the result of the water potential in the capillary due to the plasma proteins. the proteins attract free water molecules within the plasma toward themselves and therefore reducing water potential of plasma
what does it mean if something has a a higher water potential
its a solution with high concentration of water molecules
talk about the hydrostatic pressure and oncotic pressure of the arterial end of a capillary
at the arterial end its hydrostatic pressure is greater than its oncotic pressure, so water from the plasma and its solutes are forced out of the capillary and forms tissue fluid.
how does tissue fluid reabsorption happen
as blood moves along capillary the force caused by ventricular contraction becomes less, and as more liquid leaves the capillary the hydrostatic pressure decreases. when the blood reaches the venule end of the capillary the hydrostatic pressure is lower at the arteriole end. now at the venule end the oncotic pressure is higher than the hydrostatic pressure so this causes 90% of the tissue fluid to return by osmosis to the capillary.
the tissue fluid that does return will have already given up most of its oxygen and nutrients when it was outside the capillary)
how is oxygen, glucose and other nutrients delivered to the cells surrounding the capillary
the tissue fluid moves out over the cells that’s surround the capillary delivering all nutrients to the surrounding cells
how do u calculate filtration pressure
filtration pressure = hydrostatic pressure - oncotic pressure
while 90% of tissue fluid returns to the capillary what happens to the 10% of tissue fluid that doesn’t return to the blood capillary
this 10% enters the lymphatic system and becomes lymph.
what are lymph capillaries
these are blind ended capillaries with bigger fenestrations (pores) than blood capillaries. excess tissue fluid drains here and becomes lymph.
what does the lymphatic system do
it absorbs the products of fat digestion - fatty acids - from the villi in the small intestine
what is the composition of lymph
its similar to tissue fluid except there’s a lower concentration of o2 +nutrients, and higher concentrations of co2+ waste products + fatty acids which were absorbed in the small intestine.
what is lymph
drained tissue fluid + fatty acids
what is a lymph vessel
many lymph capillaries joined tg
how is the lymph able to move through the lymph vessels
the lymph can move through the lymph vessels because of the pressure on the walls caused by contracting muscles.
when does the lymphatic system drain into the blood
lymph drains into the blood when the left + right lymphatic duct drains into the left and right subclavian veins
at points along the lymphatic system there are lymph nodes, what accumulates at these lymph nides.
lymphocytes (WBCs) and leucocytes (produce antibodies) and phagocytic cells (these engulf and digest bacteria in the lymph this is why enlarged lymph nodes are a a sign of infection)
what are subclavian veins
they are major blood vessels under the clavicles/collar bone
what happens if excess tissue fluid remains in the tissues
a person can get oedema
what would be the cause of excess tissue fluid in the tissues (oedema)
immobility
lack of plasma proteins in plasma (low dietary protein)
a blockage in the lymphatic system (from parasites etc)
what is extreme oedema called
elephantitis
