Module 2 Lecture 1: The Blood Flashcards
What can the blood be split up into? What are the percentages of each thing the blood may be split into?
Blood is split into plasma, buffy coat and formed elements
* Plasma is 55%
* Buffy Coat is <1%
* Formed Elements is 45%
Formed elements means cell fragments like RBCs & WBCs suspended in plasma; make up a part of the entirety of blood
What is hematocrit?
Percentage of RBCs in the blood
45% Hematocrit in males while females is 42% on average - remaining percentage is plasma
What are the three suspended cellular elements in the plasma?
- Erythrocytes (RBC)
- Leukocytes (WBC)
- Platelets
What physiological roles do the suspended cellular elements play within the plasma?
- Carrying (o2, wastes, nutrients) - transport via blood
- Regulation (body temp., pH) - sweat dissipates in plasma cooling the blood
- Protection (clotting, immunoglobulins) - Protection from pathogens (gammaglobulins) & involved in hemostasis
haemoglobin and plasma maintain pH
What constituents make up the plasma?
- Water
- Electrolytes
- Nutrients, wastes, gases, hormones (others)
- Plasma Water acts as a medium to carry substances and is able to withstand heat changes
- Electrolytes (Na and Cl) excite the membrane, osmotic distribute of fluid between ECF and cells
- Transports nutrients and wastes through the plasma via endocrine glands
How do plasma proteins stay in the plasma and not leave the cell?
Large size does not allow diffusion through capillary wall which causes Colloid osmotic pressure to build up. Absence of plasma proteins causes osmotic gradient to be established with blood and interstitial fluid so that plasma does not leak into IF.
Colloid osmotic pressure is created by large molecules to hold water in the vascular space that it is in
What are the three plasma proteins and their roles?
- Albumin - Transport non-specific substances (poorly soluble) in the plasma; most abundant in the blood
- Globulins - Alpha and Beta transport specific substances, involved in blood clotting, inactive precursor molecules
- Gamma globulins are used as antibodies - Fibrinogen - Key factor for helping form clots
Albumins contribute the most to colloid osmotic pressure; proteins made in the liver (***except for gammaglobulins)
Explain the structure of RBCs and how it is beneficial for it’s job
- RBCs look like bioconcave discs that allows for more O2 to attach and increases SA for O2 to diffuse across the membrane
- Thinness allows for easy diffusibility from outside to inside the cell
Flexibility of RBC membrane allows it to go from squeezing through 8 μm to 3 μm (size of capillary wall)
**Sickle cell anemia does not allow squeezing of RBC through gaps.
What does the structure of haemoglobin consist of and how does it bind oxygen?
- Globin proteins - four highly folded polypeptide chains
- Heme group - iron containing non protein group
- 4 oxygen reversibly bind to the iron (only the iron) and can carry it through the plasma and vessels
- oxygen is poorly soluble so about 98.5% of Oxygen binds to haemoglobin
It can bind to CO2 as well but does not usually prefer to do that
Other than binding O2, does haemoglobin bind to anything else?
- Acidic hydrogen ion portion (H+) of ionized carbonic acid: buffers this to minimize changes to pH
- Carbon monoxide: binds to haemoglobin irreversibly causing CO poisoning
- Nitric oxide: In the lungs binds to haemoglobin; stabilizes pressure and dilates the vessels
Nitric oxide makes sure to get oxygen to the tissues
RBCs do not have organelles due to being so small. How do they create energy?
Via glycolytic enzymes and anaerobic respiration
No nucleus or organelles because space is required for haemoglobin
Although RBCs have nothing other than Hb molecules in them they have carry glycolytic enzymes and carbonic annhydrase. What is the purpose of the latter?
Carbonic anhydrase: CO2 transport, catalyzes reaction allowing CO2 to convert into H2CO3 (bicarbonate) reversible reaction which is how CO2 is primarily transported
Second method of transport for CO2 is binding to Hb molecule
