10.2 Blood Flashcards
What is the blood’s transport function?
transports nutrients, wastes, and hormones
What is the blood’s regulatory functions?
- helps regulate body temperature by dispersing body heat
- helps regulate blood pressure because the plasma proteins contribute to the osmotic pressure of blood
What is the blood’s protective functions?
- helps protect the body against invasion by disease causing pathogens
- clotting mechanisms
What do buffers in blood do?
help maintain blood pH at about 7.4
What do clotting mechanisms in the blood do?
protect against potentially life-threatening loss of blood
When does blood separate into 3 layers?
if blood is collected from a person’s vein into a test tube and prevented from clotting and then centrifuged
What is the upper layer of blood?
plasma: the liquid portion of the blood
What is the middle layer of blood?
white blood cells and platelets
What is the bottom layer of blood?
red blood cells
What is the middle and bottom layer of blood together?
the “formed elements”
leukocytes and platelets, <1% of whole blood
(erythrocytes, about 45% of whole blood)
What are the components of plasma?
- water: 90-92%
- plasma proteins: 7-8%
- salts: less than 1%
- gases
- nutrients
- nitrogenous wastes
- other (ie. hormones, vitamins)
What is the function and source of water in the plasma?
function:
- maintains blood volume
- transports molecules
source: absorbed from intestine
What is the function of plasma proteins in the plasma?
- maintain blood osmotic pressure and pH
- assist in transporting large organic molecules in blood
What are the 3 main plasma proteins in plasma?
albumin, antibodies, fibrinogen
What is the function and source of albumin in the plasma?
function:
- maintains blood volume and pressure
- transports bilirubin
source: liver
What is the function and source of antibodies in the plasma?
function: fight infection
source: B lymphocytes
ie. immunoglobulins
What is the function and source of fibrinogen in the plasma?
function: blood clotting
source: liver
What is bilirubin?
a breakdown product of hemoglobin
What do lipoproteins do in the plasma?
plasma proteins that transport cholesterol
Why do plasma proteins maintain blood volume?
they are too large to leave the capillaries
therefore, blood in capillaries normally has a higher solute concentration than does tissue fluid, and water automatically diffuses into them
Where are red blood cells continuously manufactured?
in the red bone marrow of the skull, ribs, vertebrae, and ends of long bones
How many red blood cells are there in the body?
4-6 million per mm^3 of whole blood
Describe mature red blood cells (2).
- no nucleus
- biconcave disk
What does the shape of the red blood cell do?
- increases their flexibility for moving through capillary beds
- increases their surface area for diffusion of gases
Why do red blood cells carry oxygen?
because they contain hemoglobin, the respiratory pigment responsible for the red colour of cells
Describe the structure of hemoglobin.
- 4 polypeptide chains
- each chain is associated with heme, a complex iron-containing group
What does the iron portion of hemoglobin do?
iron portion of hemoglobin acquires oxygen in the lungs and gives it up in the tissues
What is the function and source of salts in the plasma?
function:
- maintain blood osmotic pressure and pH
- aid metabolism
source: absorbed from intestine
What are the 2 gases in plasma?
oxygen and carbon dioxide
What is the function and source of oxygen in the plasma?
function: cellular respiration
source: lungs
What is the function and source of carbon dioxide in the plasma?
function: end product of metabolism
source: tissues
What are the 3 nutrients in the plasma?
lipids, glucose, amino acids
What is the function and source of nutrients in the plasma?
function: food for cells
source: absorbed from intestine
What are 2 nitrogenous wastes in the plasma?
urea and uric acid
What is the function and source of nitrogenous wastes in the plasma?
function: excretion by kidneys
source: liver
Name 2 “other” contents in the plasma.
hormones and vitamins
What is the function and source of hormones and vitamins in the plasma?
function: aid metabolism
source: varied
Why do red blood cells only live around 120 days?
possibly because they lack nuclei
Where are red blood cells destroyed?
mainly in the liver and the spleen, where they are engulfed by large phagocytic cells
What happens to the iron when red blood cells are destroyed?
- mostly salvaged or reused
- heme portion undergoes chemical degradation, and the liver excretes it into the bile as bile pigments
What is anemia?
when the body has an inefficient number of red blood cells or the red blood cells do not contain enough hemoglobin
What are the 3 basic causes of anemia?
- decreased production of red blood cells
- loss of red blood cells from the body
- destruction of red blood cells within the body
What happens in iron-defficiency anemia (most common type)?
red blood cell production is decreased, most often due to a diet that does not contain enough iron
What happens in chronic anemia?
when arterial blood carries a reduced amount of oxygen