Lecture 9: Blood Flashcards
what does your body prioritize when it comes to maintaining warmth
brain and core
the hands and feet get cold because you body is sending blood to core organs; your body will sacrifice your extremities to save brain and core
what are the cellular elements known as, what are they?
formed elements
they include:
- RBC
- WBC
- Platelets (cell fragments; megakyrocyte)
what is the extra cellular matrix within a blood vessel, what is it mostly made up of? what does it do
plasma, water
perpetually suspends the formed elements and ebanables them to circulate throughout the body within the CV system
- evenly distributes and carries cells
what is the composition of blood
55% plasma
45% formed elements
what’s the primary function of blood?
to transport and deliver O2 + CO2 and nutrients to and remove waste from the body cells
- also provides defence/protection;
- regulation/maintenance of homeostasis
where are nutrients from absorbed? how are they transported/delivered
in digestive tract
most travel in bloodstream directly into liver, where they are processed back into the bloodstream for delivery to body cells
how is O2 transported (basically)
diffuses into the blood, which moves from lungs to heart, which then pumps it out to the result of the body
how are waste products removed
CO2 is brought to the lungs for exhalation
various waste products are transported to the kidneys for excretion in the form of urine, or bile from the liver
what is the function of WBC
to protect the body from external threats (like bacteria)
and to seek out and destroy internal threats (mutated DNA/infected cells)
role of platelets
when damage to vessels results in bleeding, blood platelets and certain proteins dissolved in the plasma, interact to block the ruptured areas of the blood vessel involved
how do platelets block ruptured areas? when do they cease?
they create clots which keep building until there is no further blood loss
which fb loop regulates body temp? how is homeostasis of blood maintained?
negative
- blood helps to maintain the chemical balance of the body
- proteins and other compounds in blood act as buffers, which thereby help to regulate the pH of body tissues
- blood also helps to regulate the water content of the body cells (albumins hold water in body by osmotic pressure)
explain the properties of blood
blood rich in O2 in lungs is bright red, and blood that has released O2 in the tissues is a more dusky red
- hb id a pigment that changes colour and varies with O2 saturation levels
sticker and thicker than water - viscosity
how does hb vary with O2 saturation levels
when more O2 is bonded, shape of molecule causing light to refract (results in a bright red colour)
what is viscosity
the measure of a fluid’s thickness or resistance to flow, and is influenced by the presence of the plasma proteins and formed elements within the blood
what is the normal blood hematocrit levels? what is the viscosity of water? what about normal blood? how about plasma?
40-45% is normal
20-65% is still acceptable
>75% blood is too thick to move around (need lots of energy)
- hard to reach this level cuz even if you’re dehydrated, you never get above 55%
water=1
normal blood=5x
plasma=2 (twice as viscose as water)
during exercise, what happens to hematocrit levels?
slight raise in hematocrit cuz of higher pressure, plasma is pushed out into the interstitial space (not that u made more RBC’s)
- decrease in plasma = increase in hematocrit levels
what is the normal blood temp
slightly higher than body - 38°c
how do blood vessels experience friction/resistance? what is this known as?
as blood flows through them, it produces some heat and other effects
shear stress
what is the normal pH range of blood? is it slightly basic/acidic? how does it regulate pH
average about 7.4, but ranges from 7.35-7.45
slightly basic (alkaline)
contains numerous buffers to aid in regulation of pH
blood constitutes about _% of adult body weight. what is the amount of blood in males and females? what happens when we don’t hav enough blood
8%
in males: 5-6 litres
in females: 4-5 litres
start to notice symptoms at around 400-500 ml
(requires blood donation)
1L-can’t even stand up
2-2.5L is fatal
what is the amount of hematocrit for differnt conditions of the body? what about after blood donation
normal - 45%
anemia - 35%
polycythemia - 70%
dehydration - 70%
hematocrit goes down after 24-48hrs
- plasma is replenished quickly (within 24-48hrs), but RBC’s take up to 90 days
what are the components of plasma
91% water, 7% proteins;
- albumin (largest part of plasma)
- globulins (soluble in blood)
- fibrinogen
what is serum?
plasma without the clotting factors